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Title: Zoology: The Science of Animal Life - Popular Science Library, Volume XII (of 16), P. F. Collier & Son Company, 1922
Author: Ingersoll, Ernest
Language: English
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LIFE***
Transcriber's note:
Text enclosed by underscores is in italics (_italics_).
[Illustration:
Photo, American Museum of Natural History]
[Illustration: _Giraffes in their native African haunts_]
POPULAR SCIENCE LIBRARY
EDITOR-IN-CHIEF
GARRETT P. SERVISS
AUTHORS
WILLIAM J. MILLER HIPPOLYTE GRUENER A. RUSSELL BOND
D. W. HERING LOOMIS HAVEMEYER ERNEST G. MARTIN
ARTHUR SELWYN-BROWN ROBERT CHENAULT GIVLER
ERNEST INGERSOLL WILFRED MASON BARTON
WILLIAM B. SCOTT ERNEST J. STREUBEL
NORMAN TAYLOR DAVID TODD
CHARLES FITZHUGH TALMAN
ROBIN BEACH
ARRANGED IN SIXTEEN VOLUMES
WITH A HISTORY OF SCIENCE, GLOSSARIES
AND A GENERAL INDEX
_ILLUSTRATED_
[Illustration]
VOLUME TWELVE
P. F. COLLIER & SON COMPANY
NEW YORK
Copyright 1922
BY P. F. COLLIER & SON COMPANY
MANUFACTURED IN U. S. A.
ZOÖLOGY
THE SCIENCE OF ANIMAL LIFE
BY
ERNEST INGERSOLL
[Illustration]
P. F. COLLIER & SON COMPANY
NEW YORK
PREFACE
In this volume, occupying the place in the series assigned to the
subject "Zoölogy," the writer was called upon to survey the whole
range of animal life on the globe, and to keep in view the fact that
these books were to be a library of science. The casual reader, with
no particular interest in natural history, seeks in such a book little
more than stories of animal life thought of mainly as "big game," with
an appetite for the adventurous and wonderful. But beasts and birds
and snakes, although they number in the aggregate thousands of kinds,
are but few compared with the almost innumerable hosts of the lower
orders of animal life that dwell in the wildernesses of the world,
or throng in the seas, or hover about us in the air; yet they are a
part of the zoölogy of the globe, and a most important part. Although
they may rarely have the picturesque interest that attaches to the
vertebrate groups, they exhibit great beauty in many cases, and are
the foundation on which the others rest, for they furnish the food
on which the more highly organized creatures subsist. To the student
this lower half is often more attractive than the upper half; and the
history and philosophy of animal life could not be understood unless it
was fully considered. The author has therefore devoted a proportionate
space to the lower orders, at the expense of detailed descriptions of
birds and beasts, knowing that these are easily accessible elsewhere.
The arrangement of the matter in the volume is according to the latest
results of critics of classification, and it illustrates, as well as
any lineal arrangement can, the principle of the development of the
higher classes from the inferior by a gradual evolution toward more and
more complex forms. Space did not permit of much exposition of methods
of development, as revealed by fossils; and the volume on Paleontology
should be read in connection with this one.
ERNEST INGERSOLL.
CONTENTS
CHAPTER PAGE
I. HOW THE GLOBE WAS STOCKED WITH LIFE 9
II. THE SEA A VAST AQUARIUM 16
III. A CHAPTER OF FOUNDATIONS 25
IV. THE HUMBLEST OF ANIMALS--SPONGES 30
V. FLOWERS OF THE SEA 33
VI. UNINVITED GUESTS 44
VII. DWELLERS BETWEEN TIDE MARKS 46
VIII. BUILDERS OF THE PEARLY SHELLS 57
IX. BUILDERS OF THE PEARLY SHELLS--_Continued_ 64
X. ANIMALS WITH JOINTED FRAMES 81
XI. FROM BUTTERFLIES TO BEETLES AND BEES 99
XII. AT THE DOORWAY OF THE "UPPER CLASSES" 127
XIII. FISHES--THE ARISTOCRACY OF THE WATERS 132
XIV. SHARKS--THE TIGERS OF THE SEA 142
XV. THE FEARFUL DEVILFISH AND OTHER RAYS 148
XVI. BONY FISHES--TELEOSTOMI 151
XVII. MODERN FISHES--TELEOSTEI 154
XVIII. AMPHIBIANS--A CONNECTING LINK 167
XIX. AMPHIBIANS--_Continued_ 174
XX. REPTILES--MONARCHS OF THE MESOZOIC WORLD 182
XXI. SERPENTS, GOOD AND BAD 211
XXII. BIRDS--KINGS OF THE AIR 239
XXIII. SOME NOTABLE WATER BIRDS 250
XXIV. VULTURES, FALCONS, AND GAME BIRDS 260
XXV. FROM GULLS TO KINGFISHERS 264
XXVI. PASSERINE BIRDS 268
XXVII. THE BEASTS OF THE FIELD--SOME PRIMITIVE TYPES 270
XXVIII. THE GNAWERS 285
XXIX. MAMMALS OF THE SEA 297
XXX. THE WORLD'S HERDS AND FLOCKS 300
XXXI. THE WORLD'S HERDS AND FLOCKS--_Continued_ 313
XXXII. SOME SUPREMELY USEFUL ANIMALS 324
XXXIII. BEASTS OF PREY--THE CARNIVORA 332
XXXIV. BEASTS OF PREY--_Continued_ 354
XXXV. INSECTIVORA--HEDGEHOGS, MOLES, AND SHREWS 366
XXXVI. THE BATS--WING-HANDED MAMMALS 369
XXXVII. MAN'S HUMBLE COUSINS 373
LIST OF ILLUSTRATIONS
GIRAFFES, IN THEIR NATIVE AFRICAN HAUNTS _Frontispiece_
FACING PAGE
STARFISH AND OTHER TYPICAL LIFE IN A TIDE POOL 48
CORAL FORMATIONS OF THE GREAT BARRIER REEF, AUSTRALIA 49
CATERPILLAR BEGINNING TO WEAVE ITS COCOON 118
MOTH AND EGGS 119
CATERPILLAR PROTECTED BY FORM AND COLOR RESEMBLING THE TWIGS
OF A TREE 148
SEA HORSE PROTECTED BY FORM AND COLOR RESEMBLING THE MARINE
PLANTS AMONG WHICH IT LIVES 148
GILA MONSTER, FEARED, THOUGH ITS BITE IS NOT ALWAYS DEADLY
TO MAN 149
IGUANA, A REMARKABLE LIZARD OF THE NEW WORLD 149
PELICAN, NOTABLE FOR ITS THROAT POUCH 248
PEACOCK WITH BRILLIANT TAIL SPREAD 249
SACRED PHEASANT 249
OPOSSUM MOTHER AND YOUNG 272
ANTEATER, WHICH LIVES ON INSECTS CAUGHT IN THE STICKY SALIVA
OF ITS LONG TONGUE 273
SLOTH, AN ANIMAL WHICH KEEPS TO TREES AND IS ALMOST HELPLESS
ON THE GROUND 273
WART HOG, ONE OF THE UGLIEST ANIMALS TO SEE 304
MALAY TAPIR, RELATED TO THE PIG AND THE RHINOCEROS 304
MARKHOR, AN ASIATIC WILD GOAT 305
MOUNTAIN SHEEP OR BIGHORN OF THE ROCKY MOUNTAINS 305
THE KUDU, OR STRIPED ANTELOPE, OF AFRICA 312
HEAD OF THE GREATER SABLE ANTELOPE 312
HEAD OF ALASKAN MOOSE 312
AXIS, OR SPOTTED DEER OF THE EAST INDIES 313
AMERICAN DEER WITH HORNS IN VELVET 313
WOLVES IN WESTERN NORTH AMERICA 336
BEAR IN A ROCKY MOUNTAIN FOREST 337
BAT, WITH YOUNG BAT IN EACH POUCH 352
BLACK SPIDER MONKEY 353
RUFFED LEMUR, ATTRACTIVE BY ITS COLORING 353
MANDRILL, MOUTH OPEN TO SNARL 368
GORILLA, SOMEWHAT THOUGHTFUL 368
CHIMPANZEES, IMITATING SOME OF THE WAYS OF MAN 369
CHAPTER I
HOW THE GLOBE WAS STOCKED WITH LIFE
Ever since man began to think in the connected way that follows
self-consciousness, he has pondered, with a mixture of fear, reverence,
and curiosity, on the nature of life and its origin. The world in which
he found himself was a vast mystery which, very crudely at first, he
sought to penetrate. All his paths of thought led him circling back to
himself as the greatest mystery of all. He struggled with the problem
for thousands of years, framing fanciful guessworks, erecting elaborate
structures of logic on foundations of error, emotion, and presumption,
fashioning beautiful fables and theories (and waging wars to compel
other men to accept them), yet found no better solution than that life
must be a gift from some unknown, perhaps unknowable, source. Even
lately, learned philosophers, such as Helmholtz and Kelvin, supposed it
brought to the earth (in germs) by meteorites--fragments of exploded
planets that had borne life before they went to destruction; or, like
Arrhenius, postulated an impalpable dust, or "panspermia," scattered
through all space and borne from the atmosphere of one planet to
another. But all such hypotheses only threw the question of origin one
step further back.
Meanwhile, beginning a few hundred years ago, when greater privilege of
inquiry became possible in a jealous society, naturalists had tried
to attack the problem from a new angle. They asked themselves whether
they might not, by intensive study of living things, find the quality
of life itself, hoping that if that could be done the source of it
might be disclosed. In their earnest work they constantly improved
their methods and their instruments, and so penetrated deeper and
deeper into the constitution of plants and animals, until at last they
found the ultimate particle in the cell and discovered living things so
simple that they consisted of one cell alone; but why that microscopic
particle was _alive_, while the grain of crystal beside it, or the drop
of water in which it swam, was _not_ alive, remained unexplained.
Thereupon some of the naturalists fell back into the ranks of the
speculative and religious persons who were content to believe the
endowment of the world with life an act of a Divine Creator--something
above and outside of nature as otherwise manifested; others asserted
an equivalent but more materialistic doctrine that they styled
"spontaneous generation," which presently was shown to be untrue, at
least in the way they formulated it; and a third group confessed that
they did not know whence life came, nor were they much concerned to
know.
LIFE CONSTANTLY ORIGINATED BY NATURE'S PRODUCTIVE ENERGY
This quest having failed--although it had taught much by the way--the
chemists, who had been making marvelous discoveries in the inorganic
lifeless half of nature, undertook a far more serious exploration of
the organic living half. You have interpreted very fully, they told
the naturalists, the forms, and structure, and functions of organisms,
but can get no further; now let us chemists try whether we cannot find
the principle of life by analyzing the _substance_ of living things.
Profiting by their experience, they turned to the colloids in hope of a
clue. A colloid is a substance that shows no power of crystallization,
and is composed of molecules united by their own affinity, and not
by atomic affinity. They have a gelatinlike nature or composition,
although varying greatly in chemical composition and general character.
They differ widely in stability, for instance, some being easily upset
by a change in conditions; and this peculiarity is of great importance
in relation to the phenomena of life, for colloids enter largely into
the composition of all living bodies, but always in a delicately
balanced union with crystalloids. "The colloid is in fact," declared
Thomas Graham, who first investigated its properties, "a dynamical
state of matter; the crystalloid being the statical condition. The
colloid possesses Energia. It may be looked upon as the probable
primary source of the force appearing in the phenomena of vitality."
Now, many of the properties of inorganic colloids approximate those
found in living structures, which appear to be "alive" by reason of the
conversion of the energy of the sunlight into the chemical energy of
their constituent (organic) colloids. The agent in this conversion is
the green substance chlorophyll in the cell or cells of the plant; and,
directly or indirectly, all the energy in living things arises from
this one source, transmuted by this one transformer. Yet chlorophyll
is far too complex a substance to arise as a first step from inorganic
matter, even where conditions are suitable for life to appear; and the
spontaneous production of such a thing as a bacterium would not solve
the problem, for the new-born cell would have no organic food, and
must at once perish. In an utterly lifeless planet inorganic colloids
must first develop, and in time one of these must begin to evolve not
a living cell, or anything so complex as a bacillus, but something in
the way of a molecule holding a higher store of chemical energy than
anything before it. Later such colloids, perhaps uniting with others,
would begin to condense and form more complex organic molecules, and
finally effect unions with crystalloids. Thus would organic complexity
gradually be led up to, chlorophyll brought into being, and life
appear. One of the foremost of the biochemists, Prof. Benjamin Moore,
of the University of Liverpool, has summed this up picturesquely:
"It was no fortuitous combination of chances, and no cosmic dust, which
brought life to the womb of our ancient Mother Earth in the far-distant
Paleozoic ages, but a well-regulated orderly development, which comes
to every mother earth in the universe in the maturity of her creation
when the conditions arrive within the suitable limits. Given the
presence of matter and energy forms under the proper conditions, life
must come inevitably.... If this view be the true one, there must
exist a whole world of living creatures which the microscope has never
shown us, leading up to bacteria and the protozoa. The brink of life
lies ... away down among the colloids, and the beginning of life was
not a fortuitous event occurring millions of years ago and never again
repeated, but one which in its primordial stages keeps on repeating
itself all the time and in our generation. So that, if all intelligent
creatures were by some holocaust destroyed, up out of the depths in
process of millions of years intelligent beings would once more emerge."
That is to say, life arose through a recombination of forces
preexisting in the cosmos, and the fact was but a step in the
evolutionary process. "Such evolution," the American biologist, Henry
Fairfield Osborn, declares with emphasis, "is essentially constructive,
and ... is continually giving birth to an infinite variety of new forms
and functions which never appeared in the universe before. It is a
continuous creation or creative evolution. Although this creative power
is something new derived from the old, it presents the first of the
numerous contrasts between the living and the lifeless world."
LIFE'S BORDERLAND
Although in some respects a deceptive resemblance may appear between
the living and the nonliving, the distinction is definite. Living
bodies, plant or animal, are made up of protoplasm, which, although
mineral in substance, consists of a combination never found in the
mineral kingdom. It gives to the body containing it the power of
growth, and this growth is by additions from within. Minerals may
increase in size, but only by additions from without. The prime
characteristics of living organisms is that they reproduce their kind,
given favorable conditions. Minerals never do so. A correlative of
life and growth is death, but minerals never die. In the course of its
career every animal or plant, in proportion to its need or the degree
of complexity of its organs, develops within itself characteristic
compounds, such as albumin, gluten, starch, cellulose, fat and other
chemical results, not a trace of any of which is to be found in rocks
or soil, or in the water or in the air. No distinction in nature is
so absolute as that between the inorganic and the organic realms, the
nonliving and living things, so far as our senses can perceive them.
When, however, we consider the two prime divisions of the living
world--animal and vegetable--so diverse in their higher developments,
we find them springing from the same base in a single cell of almost
structureless protoplasm, and so alike in this simplest form as to
be in some cases indistinguishable--mere drops of living matter
whose functions are so limited that they present no discriminative
characteristics. Indeed, marking a definite boundary between animals
and plants may be difficult in cases much higher in the scale than
these primitive globules of protoplasm.
A fundamental distinction between plants and animals as we now know
them is the exclusive possession by plants of the green substance
chlorophyll, by the presence of which their food is transformed under
the influence of sunlight into vital energy in a manner essentially
different from that by which animals assimilate their substance.
Chlorophyll is a complex, nitrogenous, colloidal substance, produced
by and always associated with, protoplasm, and related to the coloring
matter of the blood of animals. It is restricted to plants, and usually
resides only in definite portions of the cell; yet we have good reason
for believing, as Prof. William F. Ganong tells us, that our present
green plants were preceded in time by a colorless kind of the utmost
simplicity, and without chlorophyll, which yet could make their own
food from carbon dioxide and water by using the energy of chemical
oxidation of soil-minerals in place of sunlight. "We have precisely
such chemosynthetic organisms, a kind of soil bacteria, still living on
the earth at this day; and they are doubtless the lineal descendants
of the ancient forms, which probably lived in the mud of shallow seas
that may be full of them yet." These ancient chemosynthetic organisms
were neither animal nor plant, but both and between. They must have
expanded, varied, evolved, thus originating a great many branches, most
of which perished.
Now, from this biochemical borderland of life, let us turn our
attention to the living world as we know it to-day, or as preserved
for us in the "record of the rocks," pausing only to fix well in our
minds the main distinctions between animals and plants. Plants have no
special organs for digestion or circulation, nor any nervous system.
Most plants absorb inorganic food, such as water, carbonic acid gas,
nitrate of ammonia, phosphates, silica, etc. No animal swallows any
of these minerals as food. On the other hand, plants manufacture from
such materials the food on which animals exist, by the production and
storage in their tissues of starch, sugar, and nitrogenous substances.
The two kingdoms supplement one another. They are mutually dependent,
and probably originated simultaneously.
CHAPTER II
THE SEA A VAST AQUARIUM
No results of investigation in natural history have been more amazing
than those that show the marvelous richness of the sea in plant and
animal life--not merely at its warm margin, but far out in the centre
of what the ancients used to call "the desert of waters"; not only at
its surface, but in its profoundest depths, and under the polar ice as
well as amid the tropics. Sea populations differ somewhat according
to situation, those of the shallow shore lines, which are of the
"littoral" fauna, differ largely from those living in the open sea
and belonging to the "pelagic" fauna, and there are surface swimmers,
and others confined to the abysses; but virtually every class and
subdivision in the animal kingdom is represented in greater or less
variety in the zoölogy of the ocean. The list stretches from the merest
monads to the huge sharks and still bigger whales.
This multitude and diversity of animal life is possible in the sea
because of an even greater plenitude of plants there, which furnish
a never-failing food resource. Bacteria and blue-green algæ are at
the base of this. Bacteria exist in all seas, as in all soils, and
the fertility of nature above ground and under water depends on these
microscopic organisms, whose numbers in the ocean are as incalculable
as the grains of sand on its brink. In equal multitude are the
diatoms, unicellular algæ with flinty cases, by which the waves are
sometimes discolored over broad areas; and millions of other green
plants, living alone, or in chains, minute in size, but each a chemical
laboratory converting the salt water they absorb into meals for the
animals that swallow them--animals in most cases almost as small and
simple as the things they eat, and themselves destined to be sucked
into the mouth of something a little bigger, to be in turn a tidbit for
a third hungry mouth, and so on to the broiled mackerel for our own
breakfast.
THE PLANKTON AND ITS PHOSPHORESCENCE
The assemblage of plants and animals that together float or swim at or
near the surface of the ocean (or other water), say within a layer of
water one hundred fathoms thick, is scientifically called _plankton_
of the sea. In the open ocean, the pelagic plankton is much alike all
round the world of waters, although it varies a little in composition,
and still more in relative abundance, being denser in temperate than
in either tropical or polar latitudes; but nowhere is it absent. The
"waste of waters" teems with life. The plankton of the shallow waters
near continental shores, however, presents a decidedly different
assemblage from the pelagic plankton.
In the pelagic plankton, single-celled animals of the groups called
foraminifers and radiolarians are exceedingly prominent, and play an
enormous part in the economy of the sea, although almost or quite
microscopic in size. They are incased in chambered shells of lime or
flint; and over vast areas in warm latitudes the ocean floor is so
thickly covered with the dead shells of one kind that the mud is
called globigerina ooze. They are the eaters of the microscopic plants,
and themselves are food for a wide variety of hydroids and jellyfish,
large and small, whose silvery forms are often visible to the voyager,
and which are mostly responsible for the pale stars of phosphorescence
that shine about his prow and glorify his wake in dark nights. The
queen of these far swimmers is the radiant Portuguese man-of-war. In
the night a dragging fine-meshed net will capture more than by day of
the plankton, because many little creatures that in daylight sink to
considerable depths come to the surface at night.
Rising a step to the worms, we find them comparatively rare, but one
kind of marine flatworm that abounds in midocean is rose-red and
several inches long. Much more numerous is another flatworm, Sagitta,
"which along with copepoda, salpæ, pteropoda and radiolaria, everywhere
constitute the bulk of the small pelagic organisms" captured by towing
nets. Like almost all of these usually defenseless creatures they
are perfectly transparent, but some of them depart from the rule of
pale blue in tint and shine in bright red. A longer step takes us to
the Crustacea, represented in the pelagic plankton by queer little
shrimplike forms that in countless hosts of individuals play a part in
the ocean comparable to that of insects on land. The copepods are the
most numerous probably--little things only a fraction of an inch in
length, but amazingly abundant, and the principal users of plant food.
Their relatives, the little ostracods, have similar habits, and are
noted for their intense phosphorescence. Haeckel relates that on his
way to Ceylon he saw the entire sea like a twinkling ocean of light,
and his microscope showed him that it was made by throngs of ostracods,
with some jellyfishes, salpæ and worms. Crustaceans of higher rank
abound also. In northern waters species of Schizopoda, small,
transparent prawns with red spots around the mouth and big, black eyes,
swarm in enormous numbers, and are known to the fishermen as "kril."
An important part of the pelagic plankton consists of certain small
mollusks; and "as regards abundance of individuals few groups of
pelagic animals can compare with the winged snails, or Pteropoda."
These are minute, rapidly swimming creatures with thin, glassy shells,
and in some parts of the warmer oceans these discarded shells are so
numerous on the bottom that they give the name pteropod ooze to the
mud. One kind (Limacina), with a coiled shell about the size of a
pinhead, which abounds in the north Atlantic, is much feared by the
Norwegian fishermen because they very often spoil the herring that
feed on them. Another kind (Clione), looking somewhat like a reddish
butterfly an inch or so long, swims in shoals in the icy seas of the
far North, and is known as "whales' food." Some larger mollusks, of
which the beautiful purple Ianthina is most conspicuous, live among the
vast patches of floating seaweed in the Sargasso Sea.
Great numbers and variety of tunicates or ascidians and their larvæ
are taken in the surface nets of the sea naturalists, among them the
salpæ--free-swimming, barrel-shaped, transparent animals well known
to all seafaring people, and often seen crowding the surface of the
ocean. One genus of them is Pyrosoma, which has from the earliest
days excited the interest of mankind, mainly on account of the strong
phosphorescent light emitted, the name, indeed, meaning "fire animal."
These salpæ aggregate into colonies often several yards in length which
glow like fiery serpents as they move sinuously on their way.
This property of luminosity, so widely possessed by marine animals, is
one of the unsolved mysteries. It is called "phosphorescence," because
it resembles the cold light given by phosphorus when undergoing slow
oxidation, but phosphorus has nothing to do with the manifestation
here, or in such insects as the firefly; nor is it owing to bacteria,
as in the case of shining wood or decaying fish. What it really is no
one knows, but it has, at least, been learned that in animals the power
of emitting light is always attributable to certain structures of a
glandular nature that secrete a slimy, luminous substance, or, rather,
two substances, one luciferin and the other luciferase. When both
together are exposed to seawater phosphorescent light results.
As a rule, the light organ is surrounded by a layer of black pigment
that acts as a reflector, and often the light is projected through a
transparent lens; and there is reason to believe that in the case of
the higher animals, such as deep-sea fishes and squids, the rays may
be thrown when and where the creature desires, as a man handles an
electric flashlight. But for what purpose? Is it to illuminate the
surrounding water so as to perceive, or to attract prey, or is it to
avoid foes? A learned oceanographer replies that no one certainly
knows. "At all events," he concludes, "the answers would probably tend
to show that the many different kinds of light organs serve different
purposes."
PRISONERS IN THE DARK AND ICY DEPTHS
So much for the surface population of the ocean--the plankton layer is
regarded as a hundred fathoms thick. We have considered only that over
the mid-oceanic depths, but that of the shallow margins is different
simply in the absence of some purely pelagic creatures, and in the
presence of vast hordes of eggs and larvæ of the animals rooted in the
sand or attached to the rocks and weeds from high-water mark down to a
comparatively short distance below low-water mark. These I shall speak
of more completely hereafter.
Before that, however, I want to say a few words in regard to the
extraordinary inhabitants of the ocean's depths--depths which in some
places exceed the elevation of the highest mountains on the land.
The conditions under which animal life exists there are vastly
different from those at the surface, and it is not surprising to find
these creatures of an extraordinary character. The pressure exerted
by water on anything lowered into it increases at a rapid rate as the
object sinks, so that at a depth of only 500 fathoms it equals about
100 times the pressure at the surface. This contributes to the density
of underlying waters; the saltiness of the sea also adds to the water's
density, but this decreases slightly from the surface downward. More
important than density in its effect on living things is temperature.
In the Sargasso Sea in summer the water at the surface will indicate
about 52 degrees F., and at 100 fathoms of depth 48 degrees, below
which it diminishes slowly to a little below the freezing point--32
degrees F. The water below a few hundred fathoms may therefore be
regarded as a series of layers measured by degrees of density,
temperature, etc., and this means a series of biological strata in
each of which the denizens are more or less limited by unfavorable
conditions above and below them.
A fourth factor conditioning deep-sea life is that of light. The
sunlight penetrates to a much greater distance than was formerly
believed; and experiments with photographic plates show that the blue
rays may sink as far as 800 fathoms, but the red rays go much less
down. Below that glimmer is absolute darkness, illuminated only by the
phosphorescent glow of the lanterns carried by the animals moving about
in that Stygian and icy abode--which would seem to us the most dreadful
fate to which any creature on the globe is born.
It has been said that the ocean depths seem to be divided into
horizontal zones, certain groups of animals being confined, when
adults, within limits of depth determined by conditions suitable
to them, one zone above the other. Practically, however, these
intermediate life-zones can hardly be defined, and vary in different
seas, and under changing conditions, as of season, and so forth.
Animals taken only by deep hauls of the nets within the tropics,
for instance, may be captured in cooler latitudes near the surface;
furthermore, the vertical distribution of fishes, as a class, may
differ from that of crustaceans as a class. Nevertheless it is true
in general that many sorts of pelagic animals dwell at intermediate
depths, from which, when they have become mature, they cannot either
rise or descend any great distance. Among them are representatives of
all the classes of marine life.
Let us now consider the creatures of the lowest level--those abysmal
depths where eternal cold, stillness, darkness, and equability unite
to make an environment so forbidding that human imagination would
refuse to people it with living beings; yet where life and strife do
actually exist, although by no means uniformly distributed. We know
most about it as it exists in the bed of the north Atlantic.
The real bottom animals are mainly fixed--sponges, hydroids,
sea anemones, bryozoans, brittle-stars, crinoids, brachiopods,
holothurians, worms and mollusks. They are nowhere numerous remote
from a shore, and below 2,500 fathoms are very scarce, to judge by
the results of dredging. Their food comes wholly from the surface,
apparently, some catching it as it falls and others sucking it out of
the ooze. Moving about among these, and feeding on them, is a scanty
population of snails, squids, crabs, and fishes, making their living
upon or close to the bottom; and a larger and more varied company of
relatives swim in the water above them up to, say, the 2,000-fathoms
line. All these are of forms different in many respects from kindred
species at or near the surface; and some brought up by the deep-sea
dredge can hardly be distinguished from fossils entombed in the oldest
fossiliferous rocks--so unchangeable is the environment in which their
race has been propagated for perhaps fifty millions of years.
Through these dark abysses swim fishes with extraordinary and grotesque
adaptations to their conditions. All are small, rarely six inches long,
often less than an inch, yet armed to the teeth. This is especially
true of the families Stomiatidæ and Sternoptychidæ, in which one finds
fishes of the queerest shape, with big heads and a savage array of long
sharp teeth. All are voracious, for food is scant and must be fought
for; and some, as Chiasmodus, have mouths so capacious that they often
swallow fishes larger than themselves, when their stretched stomachs
hang beneath their slender bodies like the yolk sacs of newly born
trout. All are dark in color, brown, blue or violet marking the abyssal
species. Some of them have light-giving organs; and this was formerly
regarded as a peculiar possession of deep-sea fishes, enabling them to
see their prey in the gloom of their habitat, but it is now known that
light-giving organs are especially characteristic of pelagic fishes of
the region between the surface and 250 fathoms of depth. It must be
remembered, however, that the sedentary invertebrates of the bottom
glow with phosphorescence.
This outline of a vast body of information shows that the waters of the
oceans are everywhere inhabited, to their uttermost deeps, by living
beings; that these are adapted to various circumstances, and so form
faunas of local extent and character; and that probably the sea derived
its wealth of population--at least all that part superior to the
monads--from the land, beginning with the earliest dawn of life on the
globe.
CHAPTER III
A CHAPTER OF FOUNDATIONS
THE NATURAL BASIS OF CLASSIFICATION
I mentioned in my introductory chapter that the simplest form of animal
was one whose whole being was contained within a single envelope, or
"skin," called a cell. Such a cell contains nothing but that strange
primitive life-substance named protoplasm, condensed at one point into
a nucleus, and it is precisely of such cells that the bodies of all the
animals we commonly know are made up; nevertheless an immense variety
of creatures still exists, especially in the plankton of the sea, that,
like those at the dawn of life, consist of one cell alone. Here then we
stand at the first grand division of the animal kingdom:
A. Animals consisting of a single cell--_Protozoa_.
B. Animals composed of an aggregation of cells--_Metazoa_.
This distinction, you see, is one of structure, as must be all the
subdivisions that follow, if they are to be natural; and it is the
clearest possible illustration of what we mean in zoölogy when we
speak of "lower" and "higher" rank, for it is evident that it is a
step upward, an advance from utter simplicity to greater and greater
complexity, to proceed from a single-celled, all but helpless
animalcule to one composed of many cells, with so vast a division of
labor and extensive power of action as belong to such a combination of
forces.
I do not propose to describe the Protozoa, because both of lack of
space and lack of popular interest; anyone may learn about them in any
good zoölogical textbook. But I do want to mention one very important
point, on account of its bearing on the history of the higher animals.
The protozoans reproduce their kind by simply splitting into two
individuals, and these again split into another two, and so on; the
process is called "fission." There comes a time, however, when the
ability to do this ceases, and the protozoans of this strain will die
out unless one or more of them meets with the same kind of animalcule,
and the two "conjugate," or merge into one another, thus renewing their
power to go on dividing.
Turning now to the Metazoa, or animals in general, we may say that
they are flexible and usually motile beings, needing a supply of solid
food which they convert by digestion into a fluid form, and then
diffuse through their tissues. This accounts for the fact that all
animals consist essentially of a tube, which in the simpler forms is
very apparent. This typical tube consists of at least two layers--an
outer, protective, and sensitive coat (ectoderm), and an inner,
digestive one (endoderm). This two-layered condition is the limit for
a few fresh-water and a vast number of marine animals therefore called
"coelenterata," of which the jellyfish and corals are examples. The two
coats are separated, and at the same time connected, by a greater or
less amount of a jellylike filling called the "mesenchyme." Into this
intermediate mesenchyme both ectoderm and endoderm bud off cells which
have certain functions--that is, they circulate the digested food,
perform the creeping movements when such occur, expel the waste of the
body, and most important of all, provide the germ cells by which the
race is perpetuated.
Now in animals superior to the jellyfishes and the flatworms, the
mesenchyme is replaced by a definite hollow tissue that produces a more
efficient system of muscular, excretory, and reproductive organs. This
hollow tissue is the "coelom," and in the most advanced animals, such
as the chordates, "the coelom and its products are of the greatest
importance, for they give rise to the vertebræ and the muscles, and
in so doing mold the shape of the fish, amphibian, reptile, bird, and
mammal."
In this brief sketch of some broad distinctions among the masses of
animals we have a hint of the basis of their classification.
ANIMAL LIFE IN ORDERLY ARRANGEMENT
Classification is really only a sorting out of things into groups of
the same kind. It may be artificial, according to fancy or convenience,
or it may be by discovery of nature's inevitable development. It has
been done crudely ever since men began to show curiosity about the
things around them. They spoke of animals of the land, of the water,
and of the air; of those that lived on vegetable fare as different
from the flesh eaters; and in a more particular way they recognized
various obviously like and unlike groups within the larger ones. All
these distinctions were made on external appearance or behavior, and
closer observation presently showed bad combinations, such as placing
bats with birds simply because both flew, or whales with fish because
both lived in water. Slowly it became evident that the only proper way
to classify animals was by putting together those of like structure,
and this could be accomplished only by intense comparative study of
the interior anatomy of their bodies. Even here, however, progress
was limited until the great light from the idea of organic evolution
fell on biological science, by which it was perceived that the true
criterion by which the proper place of any animal could be determined
was its line of descent--a matter wherein the student of fossils
could render, and has rendered, vast assistance. In other words a
real, natural classification is according to ancestry, just as human
relatives are grouped into families according to their known descent
from the same forefather.
In this evolutionary light zoölogists have now perfected, at least in
respect to its larger divisions, a classification of the animal kingdom
which is generally accepted, and is followed in this book. It proceeds,
reading downward, from the simpler and older forms of animal life to
the more complex and more recent forms.
As to the names and relative order, or rank, of the subdivisions that
we shall have occasion to mention, a few words are desirable. The only
real fact is the individual animal. A collection of these so similar
that they cannot be divided, and which will interbreed, but usually are
sterile as to other animals, is termed a _species_. A number of species
closely similar are bracketed together as a _genus_ (plural _genera_),
and this done, every individual is given a double name, as _Felis
leo_ to the lion, the first part of which indicates its genus, and is
called its "generic" name, and the second indicates its species, and
is called its "specific" name. This "scientific name" is given in Latin
(or Latinized Greek) so that it may be unmistakably understood in all
parts of the world, for a local name in one language would mean nothing
to a student speaking some other language, or perhaps speaking the same
language in another country; thus the name "robin" is applied to half
a dozen very different birds in separate parts of the English-speaking
world, and endless confusion would result were not each animal labeled
in a language understood by everybody; and this must be a dead
language, so that the significance of the terms applied shall not vary
in place or time.
Several similar genera may form a _family_; families that agree in
essential characteristics are united as _orders_; orders are grouped
into _classes_; and finally like classes are assembled into a _phylum_
(Greek, "a leaf": plural _phyla_), which is the largest division except
the primary distinction of Protozoa and Metazoa.
CHAPTER IV
THE HUMBLEST OF ANIMALS--SPONGES
At the foot of the arrangement of phyla in the metazoa stand the
Porifera, or sponges, fixed, plantlike, queerly shaped beings living
in the sea, except one family in fresh waters, and abundant in all
the warmer parts of the world on rocky bottoms. Whatever its size or
shape, a live sponge (of which the commercial article is the more or
less perfect skeleton) is coated with a thin fleshy membrane perforated
by minute "inhalant pores" and larger holes termed "oscula," or
mouths. Through the inhalant pores the sea water, with its burden of
microscopic food, enters one of many spaces beneath the surface from
which incurrent canals penetrate the interior of the sponge, constantly
branching and growing smaller until lost to sight. The fine tips
communicate with small cavities lined with cells that are fitted to
seize and assimilate the nourishment brought them by the water. From
these rudimentary stomachs go similar excurrent ducts that unite near
the surface into trunk canals that carry out the used water and waste
products. This system of circulation, bringing nutrient water strained
through the pores, and expelling it forcibly after it has been cleared
of food value, is kept in motion, with occasional periods of rest,
by the action of "flagellate cells" that line certain tracts in the
canals. These are elongated cells from which project whiplashlike
filaments, one to each cell, whose movements in concert "resemble
those which a very supple fishing rod is made to undergo in the act
of casting a long line"--the movement being much swifter from without
inward.
Beneath the outer skin, and all among the canals and cavities, is a
filling of gelatinous materials, largely protoplasm, in which are
formed great numbers of variously branched and strengthening spicules,
of limy material in one group, and in others of a flinty or glassy
nature, or in the absence of these, a network of "spongin," such
as forms the skeleton of our common washing sponges. Spongin is a
substance allied to silk in chemical composition, and the threads are
felted together in such a way as to form a firm, yet elastic structure.
"In some Noncalcarea, which are devoid of spicules, the place of these
is taken by foreign bodies--shells of Radiolaria, grains of sand, or
spicules from other sponges. In others again, such as the Venus's
flower basket (Euplectella), the glass-rope sponge (Hyalonema), and
others, the skeleton consists throughout of siliceous spicules bound
together by a siliceous cement."
Sponges are reproduced both by budding in some form, which is an
asexual way, and by the sexual method of eggs and male cells; these are
formed in the same sponge, but rarely at the same time, and the early
stages of development are passed in a brood-cell within the body of the
parent sponge. Finally, the embryo escapes through one of the outgoing
canals, swims about awhile, becomes thimble-shaped, and settling down,
fastens itself by the closed end to some patch of mud, a rock, dead
shell or seaweed, closes the open end of the "thimble," and proceeds
to grow.
Sponges do not appear to be eaten by fishes or anything else. Countless
lower animals, such as marine worms, mollusks, and so forth, burrow
into them, however, in search of shelter; and in reversal, certain
small sponges, such as the cliona of our shores, burrow into the shells
of mollusks, which explains the honeycombed appearance of many of the
shells picked up on the beach. Sponges have a large part in that very
interesting and widespread phase of marine life called "commensalism,"
in which two animals become intimately associated in a mutually
beneficial way, and are thus spoken of as messmates. Some kinds of
sponge are never found growing except on the backs or legs of certain
crabs; the sponge conceals and protects the crab, while itself benefits
by being carried from place to place, with constantly new changes of
fresh water and food. This sort of partnership occurs in many different
groups of marine animals.
The capture and preparation of sponges for market employ thousands
of men and boats in the eastern Mediterranean, whence the best are
derived, and in the West Indies and Gulf of Mexico, where the sponges
are of a coarser kind, and are gathered and prepared by rougher
methods. They are taken commercially also in other seas, and frequently
dredged from vast depths.
CHAPTER V
FLOWERS OF THE SEA
JELLYFISHES, NAMESAKES OF THE FABLED MEDUSA
The type and simplest form of that great division of aquatic,
and almost exclusively marine, animals constituting the phylum
Coelenterata, is the polyp. It consists of a soft-skinned body,
typically cup-shaped, containing a baglike digestive cavity, or
primitive stomach, open at the top, and surrounded by the soft
mesenchyme. The open upper end is the mouth, which is usually encircled
by few or many tentacles--hollow outgrowths from the wall of the
tubular gullet. Currents of water are drawn in by waving cilia at one
end of the slitlike mouth, and pass out as waste at the other side;
they bring food and oxygen from which nourishment is absorbed by the
cells of the wall of the stomach (endoderm). Certain outgrowths within
the mesenchyme act as feeble muscles for lengthening and shortening the
body and tentacles; but there are no blood vessels or excretory organs.
Most polyps are fixed on some support, but in many the young pass
through a free, swimming stage before settling down for life. All
coelenterates, and these only, are provided with "stinging cells," the
nature and importance of which will be explained presently.
The simplest class is that of the hydroids (Hydroida), the type of
which is the fresh-water hydra, so-called because, like the Hydra
of ancient myth, when it is cut to pieces each part will grow into a
new animal. It lives in ponds and pools of stagnant water, and is so
small that a magnifying glass is necessary to study it, especially
in the case of the green one of our two common American species--the
other is brown. Indeed, similar hydroids of salt water are often taken
and dried by unscientific collectors under the impression that they
are feathery seaweeds. It is stalklike in shape, has long tentacles
which always turn toward the greatest light, influenced like certain
plants by heliotropism, and feeds on minute crustaceans and other
minute organisms. Sometimes hydras are so abundant as to form a velvety
surface in warm pools. The sexes are combined in the same individual,
and the embryo forms within the body, then protrudes as a bud, which
finally breaks away and after a time sinks, attaches itself at the base
to some support, and grows into a perfect hydra. When quiescent or
alarmed the tentacles are withdrawn, and the whole animal shrinks into
a little lump.
Such is the general natural history of the group; but the oceanic
hydroids have developed a vast variety of forms, and, with increased
breadth of life, have added many interesting features and habits.
Many of them are single, rooted in mud, or upon seaweeds, rocks or
shellfish both dead and alive, and look like flowers of lovely tints;
and they reproduce by putting forth separate reproductive parts, called
"zooids," of various kinds. Others are in colonies that spread by
extensions of the base from which arise other hydroids until a bunch
of them are growing side by side; but these groups consist of hydroids
differentiated into separate functions, for some devote themselves
to capturing food which nourishes all, through the common base, while
others produce the buds and eggs by which the colony is increased.
[Illustration: JELLYFISHES
(_Medusa aurita._ _Rhizostoma cuvieri._ _Cyanea capillata._)]
The most remarkable of these processes of reproduction is that which
is represented by the jellyfishes so abundant in all seas, and so
beautiful either when seen floating along just at the surface of the
summer sea, or when at night they glow with phosphorescence like
silvery, greenish rockets in the dark waves. Sometimes they occur in
enormous "schools"--as we say of fish--all of one kind, filling the
water thickly as far as one can see, and now and then in late summer
are cast on the beach in long windrows. They range in size from a
pinhead to ten or twelve feet in diameter. So big a Cyanea would
probably weigh fifty pounds, but after a thorough drying would yield
only a few ounces of semisolid matter, 99 per cent of the creature
being water absorbed in its spongy tissues. Some are egg-shaped, others
like a bell with a long clapper, but the ordinary form is that of an
open umbrella, usually fringed about the edge with tentacles, sometimes
short and fine, sometimes few and long, again a crowded circle of
long snaky appendages. These elastic hanging tentacles are the means
by which the medusa (as such a jellyfish is appropriately termed in
science) captures its food, which consists not only of the minute
things swarming in the plankton, but of other coelenterates, small
crustacea, fishes, anything in fact that it can entangle in its sticky
net and sting to death. Every one of the filmy tentacles is thickly
studded with microscopic cells (cnidocells) covered by a mere film,
and having a spinelike trigger projecting from it. If this trigger is
touched, or the film broken, out springs the coiled thread dart which
is barbed and carries into the wound it makes a poison that benumbs.
Thousands of these microscopic darts may prick the skin of a captive,
and paralyze its strength--as it does that of a man who gets caught
naked in the trailing net of one of the great northern medusæ. Being
thus captured, the prey is drawn up to the mouth, which opens in the
center of the under side of the umbrella float.
At intervals around the margin of the umbrella are small organs by
which, it is believed, the creature maintains a sense of balance and
direction, and perhaps of temperature or light, or both; for many
medusæ sink out of sight by day and come to the surface at night; and
when the sea is rough they descend to quiet depths. Thus they have
the power not only to move ahead by the alternate contraction and
dilatation of the disk, but to so alter their specific gravity as to
sink or rise at will. They thus show the rudiments of both a muscular
and a nervous system.
Very interesting, and often of great beauty, are the free-swimming,
colonial, hydroid polyps called siphonophores. On a long stem or
string are arranged, at the top, a bulb filled with gas or air, as
a float, then a series of swimming bells whose pulsations carry the
colony about, beneath which are various polyps and tentaclelike
appendages, some to gather food, whose digested products circulate
through the whole colony, others performing reproductive functions.
The variety of form is considerable; and one of the most peculiar,
and the only siphonophore familiar to most persons, is the exquisite
Portuguese man-of-war, whose prismatically tinted bulb, as big as
one's fist, is commonly met with in the Gulf Stream in the North
Atlantic, and often is seen in great flocks in the tropics, bobbing on
the surface of the waves in calm weather. Beneath that bulb trails a
long tuft of tentacles and zooids, performing various functions, and
so foreshadowing the division of labor that in the higher animals is
effected by the different limbs and organs.
SEA ANEMONES, CORALS, AND SEA FANS
Sea anemones are simply large polyps of more complicated structure
than the hydroid polyps. Instead of a simple, baglike, enteric cavity,
the slitlike mouth admits food into a flattened gullet which leads
to an enlarged digestive cavity. The gullet does not hang free, but
is joined to the outer wall of the body by a series of radiating
partitions, between which shorter ones extend from the inner surface
of the ectoderm; and below the gullet the stomach wall extends in lobes
between these partitions, through which holes permit the nutritive
juices to circulate throughout the whole body. The whole upper surface
of the polyp is covered by short tentacles arranged in circles. A
current of water, induced by waving cilia, is constantly flowing in
at one corner of the mouth and out at the other, supplying the animal
with oxygen and a certain amount of minute food, and carrying off
waste; but the anemones capture by means of their tentacles small
fishes, mollusks and everything that can be caught and swallowed. As
some anemones exceed a foot in diameter, large and powerful prey may
sometimes be taken. It is interesting to note that anemones distinguish
very quickly between what is good to eat and what is not. Most of them
are sitting near shore on rocks or in tide pools, or are clinging to
the larger seaweeds or clustered on the supports of wharves where the
waves and tidal currents are continually washing about them, often with
much violence, and dashing against them strands of weed or the small
wreckage always floating in such a place. None of this is seized, or at
least is not swallowed; but whether we are to conclude that this choice
is made by intelligence, or only by chemical perception is a matter for
study. When harm threatens, or when they crave rest, they withdraw all
their gorgeous tentacles, infold them within their mouth, and shrink
down into roundish gray lumps that attract neither the eye nor the
appetite of any marauder.
[Illustration: CORALS
Tree coral (_Dendrophyllia nigrescens_). Tuft coral (_Lophophyllia
prolifera_). Fan coral (_Euphyllia pavonia_). Cup corals and skeleton
(_Carophyllia smithii_).]
The coral polyps differ from anemones only in details of structure that
we need not consider, except to note the striking difference that here
the base and the radiating partitions instead of being membranous
secrete a firm skeleton either of lime or of the horny material termed
chitin. The flesh overflows the walls, folding down from the top, so
that the skeleton becomes really internal, although naked at the broad
base. Some of the tropical stony corals are like big anemones, several
inches across; and it is only when they infold all their richly colored
tentacles and become a dull and shapeless lump that their stony cup is
revealed. These are solitary, and form loosely lying corals, like that
called the "mushroom." New ones are produced by the parent throwing
off buds which for a time remain attached by a stalk, but finally fall
off and settle down to grow--a process that may go on for a score of
years. In the case of the huge coral masses called madrepores the buds
remain attached to the parent. If they spread out naturally, W. Saville
Kent explains, they build up by accumulation the large rounded masses
known as "brain" corals and "star" corals, which are most numerous
on coastline reefs, or form the base of the outer barrier reef. On
the other hand, where the budding is terminal, or oblique, branching,
treelike growths result in "staghorn" and similar forms.
The coral animals do not alone construct the reefs. Stony hydroids
(millepores), shells of all sorts of mollusks, limy sea mosses
(Bryozoa), animalcules and diatoms and various algæ stiffened or cased
with lime or flint, and blown sand, contribute to build them up,
especially when they near the surface of the sea.
The distribution of reef-building corals is interesting. At present
they are limited to about 35 degrees each side of the equator, but are
irregularly distributed, owing mainly to differences of temperature in
the water, which must not be colder than 68 degrees F. Hence they exist
farther away from the equator in the path of warm ocean currents. The
Gulf Stream accounts for the coral islands along the coast of Florida
and in the Bermudas, which is their farthest point on the American
coast; and the warmth of the water accounts for their extensive
presence along the eastern coasts of Australia and Africa, when few
exist on the western sides of these continents; similarly the western
coasts of South and Central America are nearly free of coral banks.
Other causes of limitation exist. For example, the noticeable absence
of coral growth along the coast of South America is largely, if not
altogether, owing to the fresh water and silt brought down by the great
rivers there--both prejudicial to coral life.
Coral colonies increase and ultimately form banks wherever warm,
pure sea water is constantly present, and not more than about 125
feet deep. Here, spreading and continually rising on the skeletons
of dead generations, they form a long line close to the land called
a "fringing" reef; and outside of this, beyond a space swept by the
currents, may arise a second, still more flourishing bank, termed
"barrier" reef. The great barrier reef that extends for 1,200 miles
along the eastern coast of Australia--a vast chain of banks and
islands--is an amazing example of what these minute animals can
accomplish, given time; and geology can point to still more stupendous
results of their work in the early history of the globe.
Very characteristic, in the great coral-growing region of the South Sea
archipelago, is the ring-shaped island or "atoll," which incloses a
quiet lagoon, usually with an open entrance. The reason for such a form
has excited much discussion, one explanation being that its origin was
about a small island that slowly subsided, the coral keeping pace in
rising as the island sank, until finally the land disappeared; another
that the circular reef arose from a submerged elevation, and when it
came near the surface ceased to grow except on its outer border because
it ceased to get suitable water and food, until after a time the
central part died out, leaving a ring. Both explanations may be true of
different situations.
When a reef comes near to the surface the branching coral is knocked to
pieces by the waves, and there are added to this breakage shells and
bones, calcareous seaweeds, and what not; and all this is ground into
sand by the surf, washed high on the top of the ridge and manured by
dead plants and animals, and by the droppings of birds, until finally
a soil forms beyond the reach of the tides. Then, if it is in the far
southern seas, a drifting coconut may lodge there and be rolled high
enough to be left to strike its roots into the sand and begin the
grove that by and by will make the islet attractive to men. The thick
husk of the coconut resists harm from sea water, near which this palm
prefers to grow in just such a sandy, shelly soil as the uprising reef
affords. The nuts that so often fall into the surf or are carried
out by rivers make long voyages without losing their vitality. Here,
again, the situation of most coral islets in the course of currents
is advantageous, for thus not only these nuts but other useful seeds
and colonizing elements drift directly to their doors, as it were.
Birds, wandering widely over the waters, espy the bit of land, and
aid by their visits to increase its fertility and often add to its
flora. Reefs near shore, especially in Florida and southward, become
jungles of mangroves, which not only spring from floating seeds but
send down from their branches sprouts that become rooted in the mud and
spread the growth interminably. Such a "mangrove key" soon attracts
an extensive population of plants and animals and speedily becomes a
considerable island.
A great variety of corals, however, are not reef builders, and some
species secrete little if any lime; these solitary relatives are found
scattered all over the oceans, in deep water as well as shallow,
wherever the bottom is suitable, and an immense amount of interesting
information about them is to be found in books devoted to this
beautiful group of animals.
The class includes two or three other orders of coral--polyps that
grow in a solitary way or in groups, forming those elegant objects
called sea fans, sea pens, and so forth, which can be referred to
only briefly. One of these is the order Alcyonaria, in which some are
soft-bodied, others are strengthened by a network of spicules. A very
beautiful one is the "sea pen," which takes the shape of an ostrich
plume; another is the strange mass of parallel tubes called organ-pipe
coral; and some of them are very large, the great tree coral of the
eastern Atlantic depths being sometimes as tall as a man, while it
looks like a sturdy, leafless tree. As in all the others, however,
it is covered by a living fleshy coat of protoplasmic substance
studded with polyps whose gay colors and waving tentacles give it the
appearance of being clothed with minute sessile blossoms. The best
known of this group, probably, is the red coral of commerce, which
is the scarlet, ivorylike interior stem of a branching alcyonarian
colony. This coral has from the earliest time been cut into cameos
by lapidaries, as well as used for making necklaces and other toilet
ornaments.
CHAPTER VI
UNINVITED GUESTS
FLATWORMS, FLUKES AND TAPEWORMS
The phylum Platyhelminthes follows the coelenterates in the ascending
series of zoölogical classification, and includes a baneful company of
creatures badly called "worms," which show none of the segmented or
ringlike form of body that characterizes the true worms of the phylum
Annulata to which we shall come presently. On the contrary, they are a
group of small, soft-bodied, flattened animals, which first show that
two-sided character, or bilateral symmetry, which has apparently been
absent from all the groups we have studied hitherto, whose members are
circular or globular in shape, and whose organs, in the adult, are
arranged radiately.
The simplest are the planarians (Turbellaria), which live a free
life, as a rule, although some are parasitic. They are little, thin,
leaf-shaped creatures that creep on the bottom of ponds and even of
deep lakes, or swim in the sea, and feed upon algæ and minute animals.
Similar to them in appearance are the flukes (Trematoda), of which the
best known of a large variety is that which infests sheep. Most of the
trematodes are parasitic.
The third class of flatworms is the Cestoda, the members of which are
universally parasitic, and are known principally as "tapeworms" in
reference to their form.
The phylum Nematothelminthes contains an assemblage of related worms,
some marine, but mostly living in fresh waters or on land, which are
eellike in form, very slender, and often have amazing length. The first
and lowest class is that of the nematodes, of which the minute "vinegar
eels" and "paste eels" are familiar examples. The remainder of the
nematodes are parasitic, and many of them are dangerous parasites.
In an allied family and genus (Trichina) is placed one of the most
dangerous of human parasites, the _Trichina spiralis_.
Here, too, comes that "hairworm" (Gordius), which most country folks
call "hair eel" or "hair snake." Many assert with the most positive
faith that if you will soak a horsehair in water it will "turn into a
snake," and will show you this long threadworm in a horse trough to
prove it. I never knew a cautiously made experiment in that direction
to succeed; nevertheless the fanciful error survives. The gordius,
which does look like a hair from a gray mare's tail, is somewhat
aquatic in its habits.
CHAPTER VII
DWELLERS BETWEEN TIDE MARKS
THE COLONIAL MOSS ANIMALS
Seaweeds and rocks at and below the limit of the ebbing tide are often
covered with small bushy growths, or with lacelike incrustations that
are alive. These are moss animals, representing the class Polyzoa of
the phylum Molluscoida. They are minute, soft creatures that live in
colonies formed by the repeated budding of the members, all connected
by a fleshy base so that each contributes to the nourishment of all.
"Each little animal occupies a separate stony or horny capsule, into
which it may withdraw and even close the opening with a lid.... The
mouth is surrounded by tentacles that in many species arise from a
horseshoe-shaped or disklike base. These tentacles are always beset
with hairlike bristles which by their movements serve to set up
currents, and thus to drive minute organisms into the mouth."
A typical example of these polyzoans (or bryozoans) is _Bugula
turrita_, so abundant wherever our northeastern coast is rocky that
the rocks below tide level appear covered with its mossy tufts, which
are often ten inches long and profusely branched. The main stems are
orange-yellow, while the terminal branches are yellowish white. The
delicate tracery so frequently seen on the fronds of kelp, and on
shells and stones along both shores of the Atlantic indicate colonies,
or their remains, of the lace coralline (Membranipora); and the dull
red or pinkish crust so common on shells and stones in shaded tidepools
represents successive colonies of the "red-crust" polyzoan (_Escharella
variabilis_), layer crusting over layer. A similar history accounts
for the curious nodules called "false coral" so common in moderately
deep water in Long Island Sound. Similar polyzoans, which exist in
great variety, both modern and fossil, contributed extensively to the
formation of the older strata of sedimentary limestones.
ANCIENT LAMP SHELLS
Associated in structure with these minute colonists is the ancient race
of brachiopods (Brachiopoda, "arm-footed") or lamp shells, although
they much more nearly resemble bivalved mollusks, whence, by the way,
comes the name of the phylum to which both belong--Molluscoida, which
means "mollusklike."
The race of the brachiopods goes back to the beginning of the geologic
record. A few living examples are still found in the ocean, some of
which, as lingula, have changed so little that they can hardly be told
from the most ancient fossils of their family. Certain species are
dredged abundantly on both coasts of the Atlantic from water a few
fathoms deep where the bottom is rocky. They look like small mussels at
first sight, but on examination show a vast difference in structure.
The bivalve shells, instead of growing on the right and left sides of
the animal, as in bivalve mollusks, cover its back and front, and the
head parts are at the gape of the valves. At the hinge end of the shell
the lower valve overlaps (it is the shape of this lower shell, like
that of an old Roman lamp, which suggests their common name, "lamp
shells") and the hinder end of the body projects as a stalk, by which
the animal fastens itself to the rock. "The mouth in the brachiopods is
flanked by two curiously coiled and feathered arms which lie within the
cavity between the shells, and are supported by skeletal rods attached
to the upper shell. These serve as gills, and also to capture the
minute creatures upon which the brachiopod feeds."
Owing to their great abundance, world-wide distribution, and remote
antiquity, as well as their excellent state of preservation,
brachiopods occupy a very conspicuous rank among extinct invertebrates,
and furnish us besides with a large number of important index fossils.
They are to be found in immense variety from the Cambrian to the
present, most numerously in formations from Silurian to Permian times.
[Illustration: STARFISH AND OTHER TYPICAL LIFE IN A TIDE POOL
Photo, American Museum of Natural History]
STARFISHES, SEA URCHINS, AND TREPANGS
We have now arrived at the point (phylum Echinodermata,
"spiny-skinned") where a distinctly new type of interior structure
appears in the possession by animals of a hollow space (coelom) between
the outer skin and the wall of the digestive tube which now becomes
occupied by definite organs instead of by an almost uniform mesenchyme,
as in the sponges and coelenterates. These organs arise from an
interior lining membrane called "mesoderm."
Henceforth, therefore, we shall deal with coelomate animals, among
which the echinoderms are lowest in rank. The simplest of them is the
"sea lily" which lives rooted on the bottom in deep water, and sways
about on a slender, jointed stalk, looking much like the flower after
which it is named. It is of interest chiefly as a survivor of the tribe
of crinoids that were so varied and numerous in early Paleozic times
that massive Devonian limestones are composed largely of their remains;
and the type has changed little through the ages. It consists typically
of a cup, mounted on its stem like the calyx of a flower, and composed
of circles of calcareous plates, definite in form and in relative
position, that contain and protect a well-organized body. Surrounding
the open mouth of the cup is a circle of long, jointed, much-branched
tentacles that sweep the water, capture passing prey, and bring it into
the mouth of the crinoid within the circling base of the arms.
[Illustration: CORAL FORMATIONS OF THE GREAT BARRIER REEF, AUSTRALIA
Photo, American Museum of Natural History]
If now you were to cut off its stalk, lay the crinoid on the sand,
mouth down and arms outspread, beside a brittle star or a basket fish,
which also have many-branched arms, it might be difficult to tell them
apart, yet they represent different orders; and from this, by way of
the naked serpent star, it is but a short transition to the starfish,
where the arms are no longer tentaclelike, but are simply pointed
extensions of a central body; this, in fact, is the case, for now they
are no longer prehensile organs, but are supports, mainly serviceable
in locomotion, and the stomach and ovaries are partly lodged in them.
The main point just now, however, is the fact that here, and in the
successive changes of form to be shown, the pattern of plates that form
a strengthening mosaic in the skin of the central part of the body
remains identical.
All starfishes are not as prettily symmetric as our familiar
five-finger. Some are shorter in the arms, and much broader and
thicker in the body; and if you will examine a collection of preserved
specimens of the echinoderms you will see that you can trace gradation
of form right around to the bun-shaped cake urchin, on whose top the
five-pointed star is printed, and thence to the globular sea egg,
which the French called "sea urchin," using one of their names for the
hedgehog. Furthermore, the five sections of the shell of the urchin,
which represent the five arms of the starfish folded forward and grown
together into a spherical case, are to be traced again, outlined by
appendages, in the elongated and leathery hide of the trepangs and sea
cucumbers of the order Holothuria.
It is as an illustration of homology, that is, the resemblance between
parts that have the same relation to the typical plan of structure,
and as an example of how almost endless variations of form may arise
within a single type, that the echinoderms are of most interest.
Otherwise it may be said that they serve as food for fishes and some
other creatures, including coastwise savages, and as curiosities in
geological museums and in aquaria; and that starfishes are sadly
destructive of cultivated oyster beds. We may therefore dismiss them,
and devote a page or two to the worms.
EARTHWORMS AND BEACHWORMS
Although various parasitic creatures have been described as flat
"worms," round "worms," and so forth, naturalists regard as true worms
only those of higher organization classified in the phylum Annulata, or
annelids, the distinctive characteristic of which is that its members
have elongated bodies divided into ringlike sections. These represent
a division of the internal parts into a series of structural segments
or "matemeres," each supplied with its own set of organs, yet connected
by blood vessels and nerves, and the whole traversed by tubular organs
serviceable to the entire animal. The nervous system consists of a
"brain" in the head, and a double, ventral nerve-cord with a ganglion
in every segment, foreshadowing the nervous system in insects and other
arthropods. The phylum embraces three classes: 1. Chætopoda--earthworms
and marine annelids; 2. Gephyrea--marine worms, otherwise called
sipunculoids; and 3. Hirudinidæ--leeches.
The earthworm or "angleworm" (that is, angler's worm, bait worm)
of the "common garden variety," to use the phrase of old-fashioned
encyclopedias, is a typical example of the first class, whose Latin
name refers to the bristles (setæ) on the flattened lower surface of
the body that serve the worm as "feet." A magnifying glass shows them
in four double rows allowing eight to each of the rings into which the
body is so plainly divided; their extremities are directed rearward,
and by their means the worm pushes itself along, and is able to cling
to and climb not only the walls of its burrow but vertical surfaces
when not too smooth. Thus they are found frequently on roofs and in
other elevated and surprising places, to which they have crawled in
the night, when, as well as in warm, rainy weather, they are likely to
wander a great deal. The long and greatly extensible and elastic body
tapers almost equally at each end, but the head end is that which goes
forward in crawling, and a lens will show a mouth on its lower surface,
beneath a sort of thick lip. A long gullet leads into an expansion
called the crop, and that into a large, tough-walled stomach, beyond
which an intestine leads to the last segment. The thirty-third to
thirty-seventh segments are swollen, forming the "belt" (clitellum),
which denotes maturity, but seems to have no special functions. The
senses are few and dull. No eyes exist, nor sense of hearing, but
the skin is extremely sensitive to vibrations, and to bright light,
as might be expected in a nocturnal animal. The sense of taste is
discriminating. The eggs are extruded in such a way as to form a
glutinous ring about the body, which, when complete, is slipped over
the head of the worm, and left to hatch in warm soil under a stone.
Earthworms live underground in burrows that are sunk well below the
frost line. In digging they work head downward, gnawing--although they
have no hard jaws--and swallowing the earth that is not easily crowded
aside and then throwing it out and perhaps heaping it up as "castings."
The tunnel must be wide enough to let its occupant turn around in it,
and it ends in a deep chamber in which one or more worms may pass the
winter without freezing. These worms naturally seek a loose, damp soil,
not only for ease of working, but because moisture is a necessity,
as they breathe through their skin; hence they abound in meadows and
cultivated soil, and are not found on high, dry plains. During the
day they lie near the surface, often with the head just protruding.
Here they are discovered by sharp-eyed birds and garter snakes, and
sacrificed by thousands, notwithstanding the strength with which they
hang on to their retreats by the tail. When it retires to the depths of
its burrow this worm plugs the mouth of the tunnel with leaves which
it draws always by the base, exhibiting considerable intelligence in
manipulating the various shapes of leaves to that end.
The world-wide distribution of the earthworm is to some extent owing
to man's agency. On our northwestern plains, for example, these worms
originally were absent, but are now widely distributed and flourishing
there, having been carried from the east, as eggs or small worms, in
the soil packed about the roots of trees and shrubs transplanted to
western orchards and gardens. This fact may have something to do with
the recent westward spread of the robin, which, more than any other of
our birds, is a hunter of them. Except where excessively numerous these
worms do far more good than harm in a garden.
The naids (Naidæ) are small transparent worms that creep about on
vegetation in fresh water, and, besides laying large eggs, they
occasionally divide into two at a place in the body that appears
arranged for this purpose, for it consists of a zone of very elementary
tissue. "Gradually," as Minot records, "the tissue of this interpolated
zone transforms itself into muscles, nerves, etc., and, growing
meanwhile, it forms in front a new tailpiece to patch out the anterior
half of the worm, and behind it forms a new head for the posterior
half of the original body. The zone then breaks and there are now two
worms." A relative, the lumbriculus, does the trick in a much more
prosaic way, breaking in two first, and letting the separate halves
acquire head or tail as best they may. This ability to reproduce lost
parts is of much service in the life of the species and often of the
individual, which may still live after some water tiger has bitten it
in two--and these worms are at the base of the food supply of rivers
and ponds, and would soon be exterminated were they not capable of
rapid and profuse multiplication.
Worms of this class dwell in great numbers and variety in the sea and
in salt-water meadows and beaches, and are often beautiful as well as
interesting objects of study for the visitor at the shore. The sea
mouse (Aphrodite), for instance, which is about three inches long and
of oval shape, is covered with hairlike bristles that glisten with
brilliant green, red, and yellow iridescence; it is to be looked for on
the mud just below the low-tide line, and inhabits both coasts of the
North Atlantic. The body of the common "clay worm," dug for bait at low
tide, which is olive in general tone, gleams with pearly iridescence,
while its innumerable feet bear gills that are green and salmon-red.
Another (Lumbriconereis) is known as "opal worm" for good reason; and
our sands abound in slender scarlet worms of the same genus named
"red thread." All these worms bury themselves in the sand, or wander
through it in search of prey, for they are carnivorous, and do not
hesitate to kill and eat each other. Some are fairly sedentary, and
protect themselves against fishes, crabs, mollusks, and bigger annelids
that seek them, by forming tubes by means in some cases of a shelly
secretion, but more usually by cementing bits of shell, stones, and
grains of sand into an irregular tube lining the burrow; the slender,
limy serpentine tubes often seen on stones or dead shells in tide
pools, are, or were, the homes of such protected worms, most commonly
of the "shell worm" (Serpula). "Often a number of these calcareous worm
tubes are seen clustered together. When undisturbed the worm protrudes
its beautiful feathered gills, which resemble a little passion flower
projecting from the mouth of the tube. These gills are variously
colored in different individuals, some being purplish brown, banded
with white and yellow, while others are yellowish green, orange, or
lemon-yellow. At the least disturbance, such as a shock or a shadow,
the gills are instantly withdrawn into the stony tube, and the opening
stopped by a horny disk." In the Gulf of Mexico extensive colonies of
these worms often form, and as the early generations die others erect
their tubes above them; as this goes on sand and shell fragments fill
around and between the tubes, and after a long time the whole mass
becomes a solid reddish, loose-lying rock, composed chiefly of serpula
tubes, which in Florida is dragged up from the beach and used as
building stone.
The third class (Hirudinidæ) of Annulata is that of the leeches, those
ugly, but useful, worms of land and sea. In spite of their sluglike
appearance the leeches are segmented worms, although the wrinkles on
their gray, mottled skins do not indicate the position of the segments
beneath. The mouth on the under side of the head is armed with jaws
and sharp teeth that make three or more cuts through the skin, whence
the blood is sucked; there is also a holding sucker near the tail.
Their attacks cause little pain, and that fact has led physicians to
put them into use when bleeding is required. The eggs of leeches are
laid in moist earth in little packets, and hatch in five or six weeks.
The growth to maturity is slow, and continues during a long life. Many
species abound in ponds and stagnant waters. Asia has terrestrial
leeches, swarming in moist vegetation; and in Ceylon the minute
leeches are a terrible plague in certain regions. Many also are wholly
marine. Some of the larger forms attack fishes directly, and quickly
kill them by sucking their blood away; others are true parasites. On
the other hand the leeches of our lakes are fed on by the whitefish and
similar fishes. They are a great pest to our fresh-water turtles.
CHAPTER VIII
BUILDERS OF THE PEARLY SHELLS
The mollusks, or "shellfish" (phylum Mollusca) are a homogeneous
group of soft-bodied, unsegmented, typically bilateral, elaborately
organized animals, mainly aquatic and marine, whose origin--probably as
a derivative from a wormlike stock--is lost in the mists of geologic
prehistory. In most cases the mollusks secrete from a larval gland
an external shell which serves as skeleton and defensive armor; are
bisexual and produce eggs, or if monoecious are never self-fertilizing.
They possess a heart, and blood circulation (usually colorless);
breathe in the water by means of gills, or, in the air, by a primitive
kind of lung; have a nervous system and senses in some cases of a high
order; the organs are normally paired, and protected by a general
covering integument called the "mantle"; and the creeping species move
by a muscular, elastic, ventral organ styled the "foot," while the
swimmers are provided with a variety of swimming organs. Mollusks vary
in size from all but microscopic minuteness to a bivalve weighing 500
pounds or a squid half as big as a right whale. They occur in all seas
at all depths, abound in fresh waters both swift and stagnant, and are
scattered over the earth wherever vegetation flourishes.
The phylum Mollusca is divided into five classes, as follows, and it
will be noticed that four of the names refer to the locomotive organ
or "foot" (Greek _pous_, "foot"):
I. _Pelecypoda_, the Mussels--mollusks inclosed in a bivalve shell
fastened by a muscular hinge, the adjacent part of the valves being
generally more or less toothed; the foot is as a rule roughly
comparable to the shape of an ax head.
II. _Amphineura_, the Chitons--flattened, bisymmetrical mollusks
whose shell consists of eight crosswise, overlapping plates.
III. _Gastropoda_, Snails, whelks, etc.--mollusks that crawl on the
flat undersurface of the body, or distensible foot.
IV. _Scaphopoda_, Tusk shells--mollusks that possess a long tubular
shell open at both ends; with their small and elongated foot they
are supposed to _dig_ into the mud in which they live.
V. _Cephalopoda_, Cuttlefishes, and Octopods--mollusks with
tentaclelike "arms" arranged about the mouth, and either an external
or internal shell. These are the highest in rank.
THE OYSTER AND ITS RELATIVES
The lowest in rank of these classes is the Pelecypoda, containing
the "bivalves"--mussels, clams, oysters, and the like, in which the
shell is in two parts or valves hinged together over the "back" of
the animal, and attached to it on each side by a powerful muscle,
the "adductor," by the contraction of which the shell may be tightly
shut. Within the shell the body is enveloped in a "mantle," or fleshy
membrane falling like a cloak on each side; and from it is secreted
the outer shell, which grows by additions to its ventral margin. These
additions are in a general way annual, so that the concentric lines of
growth on its exterior are an indication of the years of the mollusk's
life, which is slow in growth, and long-lived. The interior of the
shell is usually pearly, and marked with microscopic rugosities, which,
by breaking up the light, as if by innumerable prisms, gives the
iridescence so beautiful in the pearl oyster, the fresh-water unios and
many others. These pearly layers are called "nacre."
Bivalves were formerly classified in conchology as Acephala, because
they have no proper head, but at the posterior end are two openings of
tubes, provided with cilia. In one, the cilia induce a constant current
of water which after leaving the gills brings into the animal's stomach
floating microscopic food, both plants and animals, including eggs and
larvæ, where it is captured and assimilated while water is ejected
through the other (dorsal) pipe. This food includes bacteria, and if
the mollusk lives and feeds in water polluted by sewage, or otherwise
containing germs of disease, it becomes dangerous as human food; hence
oysters and clams exposed to such bad conditions ought never to be sent
to market because of the disease germs remaining in them.
In bivalves such as the oysters, horse mussels, piddocks, and others
that are sedentary, and often fixed in place, or that, like river
mussels, scallops, etc., move about freely, the mouth tubes are short;
but many bivalves, as the clams, pinnas, razor fish and so forth,
bury themselves in the sand of the bottom, by means of the strong
distensible foot protruding from the forward end of the shell. These
are provided with a double-barreled tube, called the "siphon," which
may be contracted within the protection of the closed shell, or may
be stretched out several inches; the animal may thus sink its body
deep in the sand while its siphon reaches to the surface and inhales
food-bearing water. The little squirts of water often seen jetting
out of the beach at low tide as one walks along it are from clams
so buried, and which, alarmed by the vibration of one's footsteps,
hastily eject the water and withdraw their siphons.
The old name for this class, Lamellibranchiata, referred to the gills,
two of which, on each side, hang like curtains inside the mantle and
between it and the saclike body containing the viscera; when the shell
is open they are laved by the water, and extract from it, by some
quality hardly understood, the oxygen necessary to regenerate the blood
that flows through them; and, in addition, respiration is carried on
through the skin.
The nervous system is very primitive, and the sense organs consist of
an otocyst (a minute sac in which a hard particle floats in a liquid)
in the foot, by which, it is believed, a sense of direction is had,
and which also serves the purpose of an ear; an organ that tests the
water; and in some, as the scallop, rudiments of eyes are situated on
the margin of the mantle. Most pelecypods are of two sexes, but some,
such as our American oysters, are hermaphrodite. Eggs in vast number,
and a cloud of spermatozoa, are thrown out in midsummer, and a little
of the latter succeeds in reaching and so fertilizing fortunate eggs,
but almost all merely serve as food for the host of mollusks, worms,
sea anemones and what not that subsist on such provender. The few
fertilized larvæ drift about and happily escaping multiplied perils,
presently settle to the bottom to attach themselves to some fixed
object, or otherwise get a chance to grow big enough to defy ordinary
enemies. Some interesting variations in this rather commonplace larval
history occur, however, in certain families.
It will be possible to name only a few of the most useful or otherwise
conspicuous bivalves, beginning with the oyster, concerning which
an immense amount of detailed information is accessible to the
reader in the reports of the United States Government (Tenth Census,
and documents issued by the Fisheries authorities) and in those of
States, like Connecticut, New York, and Maryland, where oyster culture
is an extensive industry, said to be worth in the aggregate about
$20,000,000. The oyster of the eastern American coast is to be found
in the Gulf of St. Lawrence, but not in considerable numbers between
there and western Maine, whence it is present southward to the Gulf of
Mexico, except on the shifting sands of the outer beaches. It seeks
protected waters and a rocky or weedy bottom furnishing objects to
which it may, when young, attach itself, and later will not be torn
adrift by storms, for where an oyster establishes itself in infancy it
means to stay all its life. Hence the sheltered waters of Buzzards and
Narragansett Bays, Long Island Sound, and the lagoons and inlets that
lie behind the outer line of sandy beaches from Long Island to Florida
are the sources of our supply--especially Chesapeake Bay.
A full-grown oyster will produce about 9,000,000 eggs, each being about
one five-hundredth of an inch in diameter. When the little oyster
(spat) is about one-eighth inch wide shells begin to form on its
sides, and it settles to the bottom with its left side down, usually
where other oysters are; and hence extensive colonies, or "reefs," of
these mollusks form, and "rise on their dead selves" to a level where
they may be reached by the oysterman's rake. Many years ago, however,
it was discovered that large, marketable oysters were becoming very
scarce. Oystermen therefore sought favorable places, and raking the
natural beds transplanted their catch, little and big, to new ground,
where they were left to mature. This crude method was next improved
on by sowing thickly over the new ground, just before spawning time
in midsummer, a great quantity of empty oyster and other shells.
These were favorable to the catching of "spat," and would result in a
new bed that in about four years would furnish salable oysters; and
annual plantings produced, after a time, an annual crop. These are the
essential facts of oyster culture everywhere, although methods differ
somewhat in other parts of the world--in France, for example, fascines
of twigs are spread over tidal flats to catch the spat, instead of
shells.
Our eastern American oysters are undoubtedly the largest and finest for
the table of the many species that exist all round the globe. Those of
the Pacific coast of the United States are excellent, but small; and
the same is true of the European species; nor is the use of oysters
abroad so general and extensive as in the United States.
The pearl-bearing oysters are somewhat distant relatives of the edible
oyster (Ostræa), the thorny oysters (Spondylus), the hammer shell, the
windowglass shell (Placuna) and others. The pearl oyster of commerce is
named _Meleagrina margaritifera_ and is found in scattered localities
within the tropics on both continents. The chief fisheries are in the
Persian Gulf, around Ceylon, in Australia, among the Sulu Islands
and on the west coast of Panama. The Pearl Islands, south of Panama,
yielded to the early Spanish adventurers riches in gems that rivaled
those their competitors obtained from gold mines; but now they are a
field of small importance. In fact, the pearl fishery is carried on
now far less in hope of a profitable collection of gems than for the
profit in the shells, which have a nacreous interior of remarkable
beauty--the mother-of-pearl--and the great advantage of offering this
in almost flat surfaces, sometimes eight or nine inches broad, making
it useful in the arts as well as in the more practical line of buttons,
knife handles, etc. Sometimes the whole surface of a fine shell has
been carved, cameowise, with cunning art and an exquisite effect.
CHAPTER IX
BUILDERS OF THE PEARLY SHELLS--_Continued_
MUSSELS, SCALLOPS AND CHITONS
The familiar marine mussels of the family Mytilidæ will some day become
of great importance in this country as a food supply, as now they are
useful in resisting encroachment by the sea on certain parts of the
coast. They exist in vast numbers on both our coasts, and elsewhere in
the world, in two genera, Mytilus and Modiolus, which differ a little
in form, but not in habits. They have acquired the stationary habit,
and in place of a "foot" of serviceable size have developed a gland
that secretes an exceedingly tough, fibrous bunch of threads known as
a "byssus," by means of which the animal may not only attach itself
firmly to any sort of object, but may actually move about. The common
species of Modiolus, the "horse mussel," lives in great numbers north
of Cape Hatteras at and below the line of low water, and is much larger
than the edible mussel just described. A smaller species of Modiolus
is extremely numerous on the New England coast, and down to the
Carolinas, forming dense tangled beds on muddy patches as well as among
rocks, and serving to bind the mud and plants together and hold them
from disintegration by stormy waves, in spite of the thin and brittle
character of their shells. A southern species is bright yellow, with
dark rays; and the common modiola of the Pacific coast is dark, glossy
brown. Such mussels are eaten regularly in Europe, and come to us in a
pickled condition as a luxury. There is no reason why we should neglect
to add our own to our long list of sea foods.
The next useful mollusk to be considered is the scallop, one of
the many species of the family Pectinidæ, of which we eat only the
adductor muscle. The commercial species is _Pecten irradians_, the name
referring to the (nineteen) ridges that radiate from the flattened
hinges to the scalloped margin of the shell, which is prettily colored.
This species is common in sandy, shallow places from Cape Cod to
Florida, but the fishery is most productive about the eastern end of
Long Island and in Narragansett Bay. Farther north is a very much
larger species (_P. islandicus_) especially abundant on the Grand
Banks, off Newfoundland, where it forms an important food of the cod
and other fishes. It is well known to cooks, who use it in baking
their fish confections _en coquille_. A large number of other species
are distributed throughout the world, one (_P. jacobæus_), inhabiting
the Mediterranean having the name "pilgrim shell" in allusion to the
fact that in the days of medieval religious pilgrimages, those who had
visited the shrine of Saint James at Santiago de Compostela, Spain, to
pay homage on July 25, were accustomed to wear a scallop shell in their
hats in token of the fact--this mollusk being connected with traditions
of that saint.
Turning to the fresh-water mussels, or naids, as some books call
them, one is staggered to learn that more than 1,500 species have
been named, a large proportion of which belong to the United States,
which is peculiarly hospitable to them because of our many rivers and
lakes, together with the prevalence of limestone rocks, whose constant
dissolution in water supplies the store of calcareous matter that these
thick-shelled mollusks require. All belong to the family Unionidæ, in
which two divisions are noted--one (Anodon) in which the mussel has a
comparatively elongated thin shell with no "teeth" in the hinges; and
the other (Unio) in which the shell is thick, various in shape from
an oval to a triangle, and has prominent umbones, beneath which the
valves (which are always alike) are hinged together by interlocking
teeth embedded in a somewhat elastic gristle. The interior of all these
unios is richly nacreous, and consequently pearls are produced in the
same way as in the marine pearl-bearing shells; and some of the finest
known gems have been derived from them, in this country and abroad, as
well as innumerable specimens of moderate value. These mollusks like
clear streams or lakes with a sandy bottom, and are not to be looked
for in stagnant weedy waters. They keep an erect position, the nibs of
the shell half buried in the sand, and move slowly about, plowing a
path and dragging themselves along by means of the powerful foot, but
keeping the short siphons at the other (or longer) end of the shell
well above the mud.
We come next to our market clams. These are of two distinct
kinds--"hard" and "soft," or quahog and long clam, as they are
distinctively called. The quahog is a thick-shelled, roundish mollusk
with a distinctly heart-shaped outline when looked at endwise. It
dwells in fairly deep water, standing on its nibs half buried in the
sand, like a wedge, and moving slowly about. Young ones become the
"little necks" of our summer tables.
The soft clam belongs to a different race. Its elongated shell is thin
and chalky, is loosely hinged, and gapes widely at both ends, and
although it is used much as food, especially in chowders, it is by no
means as good as the hard clam. Its principal value, indeed, is as
bait in the cod fisheries, and for this purpose enormous quantities
are gathered. It lives in, rather than on, muddy beaches, sometimes
in crowds of thousands, its shell deeply buried, and its long siphons
reaching up to suck in water and food when the tide covers the flat.
When the tide is out, a tiny hole in the sand and a spurt of water show
the clammer where to dig, and his spade quickly unearths the clam.
The second class, Amphineura, contains the chitons and their relatives.
These chitons are flattened mollusks protected by an armature of eight
crosswise plates, overlapping like shingles, which creep about the
rocks close to shore, and when lifted curl up like sowbugs. The most
interesting thing about the chitons is the fact that they are provided
with excellent visual organs, "the whole dorsal surface of some forms
being studded with eyes, of which not less than 8,000 occasionally
exist on a single specimen." Many of them are complete, with cornea,
lens, and a pigment layer within the iris.
SNAILS AS TYPES OF GASTROPODS
The gastropods (Gastropoda), including the snails and slugs, limpets,
whelks, periwinkles, sea hares and the like, are Mollusca having the
mantle completely enveloping the body, and the shell, when present, in
a single piece, and usually in spiral form. There is a well-developed
ventral foot, on which the animal creeps, and in front of it a distinct
head bearing eyes and tentacles. These organs retain their normal
bilaterality, but the body is, as a rule, inequilateral. The cause
of this is the fact that on the animal's back is developed from the
first a shell, which, with its contents, amounts to a relatively
large weight, and it naturally falls over to one side. The mouth is
armed with a flat, distensible, ribbon-like organ, studded with rows
of chitinous teeth, that serves as a rasp and a boring instrument,
and which is called an odontophore, or, in snails, a radula. Most
gastropods are carnivorous.
The lowest in rank are the shell-less, or "naked" gastropods known as
"sea slugs," "sea hares," and so forth. One Mediterranean species of
Aplysia secretes a purple liquid utilized by the ancients as a dye, and
this is still sought for in Portugal, where storms sometimes cast vast
quantities of the mollusk on the beaches.
We come now to the great group of mollusks inhabiting fresh waters
and dry land--the snails, whose group name is "pulmonates," that is,
possessors of lungs, and breathing air. On the generally accepted
theory that all these are descended from marine ancestors, and have
gradually acquired the faculty of living on land, it would be natural
to look for a series of mollusks that were amphibious, and, as it were,
half-way fitted for a terrestrial existence, and such intermediates
exist in all parts of the world. The little black Melampus, which
covers the mud of tide flats on both the Atlantic and Pacific coasts
in tens of thousands, and seems just as happy when the tide is out as
when it is in, or when it is simply refreshed by the spray, is a good
example. A near relative, Carychium, is still more emancipated from the
sea.
First among these pulmonates are those common in ponds and still
streams the world over, of the family Limneidæ, called limneids or pond
snails. They are in various forms. Some are limpet-shaped (Ancylus),
some are flatly coiled (Planorbis), but most of them have shells drawn
out into a graceful spiral; in all cases the shell is not composed of
lime, but of the thin, fragile, horny substance "chitin." The best
known one is _Limnea stagnalis_, which sometimes reaches a length of
two inches, and inhabits almost every quiet piece of water in North
America, and in Europe and all Asia except India and China.
These water snails of our ponds and ditches are exclusively vegetable
feeders, and must come to the surface at frequent intervals to breathe,
letting out a bubble of vitiated air, and taking in a fresh supply.
Should the pond dry up in summer the limneids burrow down into the mud,
and remain in that heat trance called æstivation until the autumnal
rains refill the basin and let them come forth. The small kinds
called "physas," exceedingly common everywhere in this country and
Europe, differ from Limnea in having the shell partly enveloped in the
turned-up fringed edges of the mantle, and by being coiled from right
to left instead of clockwise. This reversal occasionally occurs in
individuals of all gastropods, which are then said to be "sinistral,"
as opposed to the normal "dextral" coiling; but in the physas it is the
rule.
Next come the wholly terrestrial pulmonates--snails and slugs,
distinguished from the pond snails, which have only one pair of
tentacles at the bases of which the eyes are embedded in the skin,
by having two pairs of "horns," one of which carries the eyes on
their tips--good eyes, which may be quickly withdrawn out of harm's
way by inversion of the tubular stalks. The thick, extensible foot is
surmounted by a body coiled within the shell; and this foot secretes a
viscid fluid that lubricates the creature's path, and often leaves a
silvery trail.
Snails are mainly vegetarians. The mouth lies just under the front
tentacles, and its upper lip is armed with a horny, crescentic "jaw."
Within the mouth is the lingual ribbon, which may be brought up
against the cutting edge of the jaw. This tongue is studded with rows
of infinitesimal, flinty teeth, the radula of our big white-lipped
snail, a quarter of an inch long, furnishing room for 11,000 of these
denticles; and as all of them point backward the tongue easily seizes
and draws into the mouth whatever the jaw nips off. Substantially
the same sort of "tongue" is possessed by all the gastropods, but
the arrangement and shape of the microscopic denticles is different
in every species, and this is one of the "characters" used in
classification. With it the carnivorous rasp away their food; and by
bending it double and using it as a gimlet bandits like Nassa, the
oyster pest, drill through other shells and devour the occupant. You
may pick up on any seabeach scores of examples of the work of these
borers. In Europe some kinds of slugs and snails do great damage in
gardens, but we have little to complain of in this respect.
Largely dependent on moisture, the young snails that are hatched in
midsummer at once seek retreats, and may be looked for under leaves,
logs, and loose stones in the woods and pastures. Most American
snails are solitary, and will be found lurking in the moss beside
mountain brooklets--a favorite spot for the glassy vitrinas--hiding
in the crevices of rocky banks and old walls, crawling at the edge
of swampy pools, creeping in and out of the crannies of bark on aged
trees, or clinging to the underside of succulent leaves. Some forms,
very beautiful in their ornamentation when magnified, are so minute
that they might be encircled by the letter o in this type, yet you
will soon come to perceive them amid the grains of mud adhering to the
undersurface of a soaked chip or rotten log.
For fresh-water species various resorts are to be searched. Go to
the torrents with rocky bottoms for the paludinas and periwinkles
(Melania); to quiet brooks for physas and coil shells (Planorbis); for
limneas to the reeking swamps and weedy ponds. By pulling up the weeds
gently, you may get small species that otherwise easily escape your
dipper or net. In the Southern States and in the tropics certain forms
are to be picked off bushes and mangrove trees like fruit, especially
the round "apple snails" (Ampullaria) as big as your fist.
SEA SHELLS IN NATURE AND ART
Other familiar forms of gastropods are the limpets, keyhole and
half-deck; the abalones, so much used in the making of ornaments; and
the many small sorts of "periwinkles" studding the rocks and hiding
among the seaweeds of every coast. Then there are the pyramidal top
shells (Trochus), the bulging, wide-mouthed turbans (Turbo), and the
open-whorled wentletraps (Scalaria) which years ago were so rare that
collectors paid $100 or more for a good specimen. The two former
kinds are on sale in all seaside shops, with the natural rough brown
exterior ground away until they gleam outside in the prismatic glory
of the nacre layers that lie underneath. A group of heavy shells of
carnivorous tropical mollusks furnishes ornaments for the mantelshelf
also. These include the knobby volutes, often richly colored in
marbled patterns or in spiral rows of round spots; the olives, whose
ovate shells are sometimes dark purple, sometimes beautifully marked,
and always glossy, because enfolded during life inside flaps of the
mantle that completely protect them; the miters, that take their name
from their resemblance in shape to the headdress of a bishop, and
show splendid decorations in tints of red and orange; and the strong,
spiny murexes, a small Mediterranean species, which is the principal
source from which the ancients derived their Tyrian purple dye--a
coloring matter yielded by treatment of the blood of many species,
including one of the commonest little mollusks (Purpura) on our own
coast, which old-fashioned New Englanders yet utilize sometimes for
making an indelible ink for marking clothing. To this family belong the
"drills" that destroy thousands of dollars worth of oysters annually
in Long Island Sound by boring through them. Near relatives are the
whelks (Buccinum), extensively eaten in England; and two of the largest
and commonest shells on our eastern sand beaches, known to northern
fishermen as "winkles" and along the southern coast as "conchs."
These (Fulgur and Sycotyphus) are big, pear-shaped creatures with
chalky white shells that crawl about near shore, seizing and devouring
anything they can overcome, and working havoc on planted oyster beds;
they deposit their eggs in parchmentlike capsules shaped like gun wads
and connected into a long chain that are often thrown up on the beach,
where they are called sea necklaces.
Of great beauty in their rich variety of color and pattern are the
tropical cone shells, of which a large number of species are known,
some so rare as to bring great prices in the conchological market.
Their bite is poisonous. Equally numerous in species are the charmingly
decorated auger shells, some (Pleurotoma) spindle-shaped, others
(Terebra) that would serve as models for a church spire. Near them is
classified that white mollusk (Natica) whose globular shell is perhaps
the commonest relic of the sea seen on our northern beaches, and
sometimes is as large as a man's fist; to it belong the curious "sand
saucers" to be found in August, which contain its eggs. These naticas
are predatory, and burrowing their way through the loose sand come upon
and devour other shellfish, boring a circular, nicely countersunk hole
through their armor and feeding on its inmate; their depredations on
the northern oyster beds are a serious matter.
Well known and always admired are the cowries, smooth, brightly colored
shells, shaped like an olive with a gash down the length of one side.
This long and narrow aperture is usually toothed, and it is only in the
young that any indication of a typical spiral growth is discernible.
The money cowrie of Africa is small and cream-white.
Lastly a word must be said about the largest of known gastropods, the
big "conchs" or wing shells (Strombus), the helmet shells (Cassis),
and the tuns (Dolium). They are West Indian. The species most commonly
seen in the United States, forming a border for flower beds in seaside
villages, is _Strombus gigas_, with a delicate orange-red or pink
interior, from which are cut most of the shell cameos offered to art
lovers. This shell, like the great spiral triton of the South Seas, is
also converted into a horn much used in foggy weather by the spongers
and small coasters of Floridian and West Indian waters. The helmet
shell, a heavy, rounder and smoother mollusk than the Strombus, is also
extensively used in cameo cutting, especially the African black helmet,
in which a white outer layer covers an almost black underlayer on the
broad lip. Dolium has a large, globose but thin shell, ornamented with
revolving ribs.
The class Scaphopoda is composed of a single family (Dentalidæ) known
as tusk shells, because the little shells, one to two inches long, are
shaped like an elephant's tusk, open at both ends. The structure of the
occupant is so singular, the animal lacking head, heart, gills, and
some other ordinary features, that naturalists believe it is a hopeless
degenerate. One of the species of the Pacific coast is famous as the
shell strung as ornaments and serving practically as money among the
northwestern Indians until very recent times, under the name "hiqua."
NAUTILUS, DEVILFISH, AND SQUID
We have now arrived at the last and highest division of the
Mollusca--the Cephalopoda, the class of the nautilus, ammonite, and
other fossil forms, and of the squid, cuttles, and octopuses of our
modern seas. The cephalopods are very different in shape, activity, and
in their higher organization and intelligence, from other mollusks,
but their general anatomy is the same. The special characteristic,
as indicated by the name, is the fact that the head is surrounded by
tentaclelike extensions of the "foot," which is here fused in part
with the head, and divided into the long "foot arms," which are the
instruments by which these predatory creatures obtain their prey. The
underpart of the foot forms a tube called the funnel (or siphon).
Through the funnel the animal expels water from the mantle cavity, and
thus propels itself through the water. When the siphon is in its normal
position the animal swims backward; but it can be turned back over
the edge of the mantle, giving a forward movement. In cephalopods the
sexes are separate, the male being often much smaller than the female.
The eggs are usually laid in gelatinous capsules, commonly known in
New England as "sea grapes," and the development is direct, that is,
without any free-swimming larval stage.
The class is divided into two subclasses: 1. _Tetrabranchiata_,
cephalopods with four plumelike gills inside the mantle; and 2.
_Dibranchiata_, with only two such gills. In the first subclass belong
all those very ancient cephalopods called in a general way ammonites,
goniatites, orthoceratites, etc., that are found in such great numbers
and astonishing variety in the Paleozoic rocks, from the Ordovician
age onward, although but few groups survived beyond the Carboniferous
period, and only two families can be traced as high as the Tertiary
deposits, one of which--that of the nautilus--survives to the present
day as the final remnant of one of the conspicuous and interesting
populations of the primitive ocean.
The pearly or chambered nautilus is one of several species inhabiting
the East Indies and the coral region of the South Pacific seas,
creeping along the bottom in deep water, most numerously at the
depth of about 1,000 feet. Hence the animal is not often taken
alive, although the smoothly coiled and handsome shells are cast
on the beaches in great numbers; and little is known of its habits
or embryology. It is a soft lumpish sort of creature, with a great
number of short arms and tentacles around the mouth, none armed with
suckers. It begins life as a mere globule covered by a minute hood of
shell; but presently, growing too large for this hood, it enlarges it
by additions to the rim, and then forms behind its body a partition
(septum) across the shell, cutting off the part in which it was born.
As growth advances, this enlarging and partitioning continues until the
nautilus has attained its full size. Then, as before, it occupies only
the outermost chamber, behind which the whole interior of the shell is
divided by the septa into chambers, abandoned and empty, but filled
with a gas that buoys it up in the water. Oriental artists are fond of
grinding away the dull exterior of the shell and exposing the gleaming
nacre underneath; and of carving in this mother-of-pearl picturesque
designs, examples of which are often to be seen in curiosity shops.
This is not only the last remnant of the great group of ancient
nautiloids, but one of the smallest, for some of the Paleozoic coiled
forms were as big as a washtub, and the straight ones were often six
feet long.
The Dibranchiata, on the other hand, are comparatively modern, as their
ancestry dates back only to the Trias, and our seas still harbor a long
list of living representatives. This subclass has two divisions: 1.
Octopoda--octopods, the eightarmed argonaut and other octopuses; and
2. Decapoda--decapods, the ten-armed cuttlefishes, or calamaries, and
the squids.
[Illustration: THE CHAMBERED NAUTILUS--SECTION
_H_, Head. _T_, Tentacles. _E_, Eye. _M_, Muscles. _S_, Shell. _A_,
Air Chambers]
The octopods have a saclike body with eight arms of about equal size,
in some kinds thick and short, in others long and snaky. Every arm has
along its underside a double row of round, muscular suckers without
horny rims; and whatever is seized by one or more of these arms is
drawn into the mouth at their base, where it is bitten by a beaklike
jaw of sharp horn, and further devoured by means of a toothed tongue
similar to the radula of gastropods. Nearly all are tropical, but some
species exist in deep water considerably to the northward. Certain
species are used as food in many parts of the world, and are considered
a delicacy in Italy and other Mediterranean countries. The fishermen
of Japan and the Philippines capture them by the simple process of
lowering big earthen urns and leaving them on the bottom overnight;
when they are hauled up in the morning many will contain entrapped
devilfish, as sailors call them, which at once go to market.
A very singular octopod is the little argonaut, or "paper sailor." Its
body is not larger than a walnut--that is the body of the female, for
the male is only a tenth of that bigness. Its home is mainly in the
tropics and in deep water, but in the summer spawning season it rises
to the surface, and is occasionally met with far northward on the Gulf
Stream, drifting, apparently, in a snug little boat. The two dorsal
arms are expanded into broad, roundish membranes at their ends, and old
stories said that they were used as sails--a supposition of much use to
poets; but the "boat," shaped somewhat like the shell of the nautilus,
is not a shell proper, but a membranous pouch secreted by the mantle in
spawning time, and not vitally attached to the body, but held in place
beneath it by the two broadened arms, and serving as a receptacle for
eggs and a cradle for the embryos hatching from them.
Turning now to the Decapoda, we treat of things much nearer home and
familiar on both sides of the continent, for these are the cuttlefish
and squids, none of which have an external shell, but possess an
interior brace to their muscles either of lime or of chitin. The
cuttlefish proper, or calamaries, are those of the family Sepiadæ,
which have an oval, flattened body bordered by a fin; and two of the
ten arms are, in the female, in the form of long, slender tentacles.
In addition to being edible and easy to get, as they stay near shore,
their calcareous back brace is the "cuttlebone" fed to cage birds; and
they furnish the substance from which the drawing ink called "sepia"
is made--principally in Rome. This is a brownish black liquid that the
animal jets out through its siphon when it thinks itself in danger in
order to make an inky cloud in the water behind which, as a sort of
smoke screen, it may run and hide. Other cephalopods use this means of
escape.
The squids, however, are all elongated in shape, and have finlike
expansions of the mantle only on the tail. Two of their arms are long
and slender, and are broadened at the tips, and studded with suckers.
These suckers in some squids are strengthened by a horny rim, or by
recurved hooks, or by both. The eyes are large, perfectly formed,
and as serviceable as those of the fishes on which they prey. These,
and some other animals, including small ones of their own kind, they
capture by darting backward, swinging quickly to one side and seizing
the victim in their sucker-bearing arms. They themselves are devoured
by whales, seals, and many kinds of fishes; and enormous quantities
of squids of various species are annually collected by fishermen for
use as bait in the Newfoundland fisheries. In place of the calcareous
cuttlebone of the sepia the squids have their bodies stiffened by an
internal strip of chitinous substance called the "pen."
Squids are of all sizes from an inch to twelve feet in length; then
there is a surprising jump to the giants (Architeuthis) of the North
Atlantic, which, when the tentacles are stretched out in front, may
measure seventy-five feet from tip to tail. These are little different
in structure or habits from their smaller brethren that exist in so
many species near all coasts and throughout the midseas right around
the globe; but their huge size makes them fit antagonists of the sperm
whale, which hunts them, and whose hide often bears a record, left by
their powerful suckers, to show how hardly some big squid struggled
for life. These monsters are the greatest invertebrates known in
present or past time; and it is probable that the long wriggling arms
of one and another, glimpsed at the surface, may account for some of
the sea serpent stories brought home by apparently perfectly honest
sailors, especially those which in many cases recount that the supposed
"serpent" was in conflict with a whale. Carcasses of these gigantic
squids are occasionally cast on the shores of Labrador and Greenland.
CHAPTER X
ANIMALS WITH JOINTED FRAMES
The phylum Arthropoda embraces an immense assemblage of small animals,
inhabiting salt and fresh waters, the land, and the air above it.
The typical members of this group have a body divided into segments,
jointed limbs, some of which are modified into jaws, and a more or
less firm external skeleton. The general organization is complex,
with the nervous system and senses well developed, in some divisions
showing powers of perception and brainwork of a very high order. The
chief divisions, or classes, of the Arthropoda are given below in the
order of rank, from those simplest in organization to the most complex.
Members of the first three classes breathe by gills, and are termed
Branchiata, the remainder are air breathers or Tracheata.
_Crustacea_--Crabs, lobsters, shrimps, barnacles, beach fleas.
_Trilobita_--Trilobites; eurypterids (fossil only).
_Xiphosura_--Horseshoe crabs.
_Onychophora_--Peripatus.
_Myriapoda_--Centipedes; millipedes.
_Arachnoidea_--Spiders, mites, ticks, scorpions.
_Insecta_--Insects.
As several of these classes contain many subdivisions, and thousands
or even tens of thousands of species, all that is possible is to give
the reader such an account of each important group, as will enable him
to assign to their proper place such arthropods as he may encounter in
his rambles, or in his reading, and to learn something of the manner of
life in the various groups.
CRABS AND THEIR SMALL RELATIVES
"Everyone," says Dr. Calman, "has some acquaintance with the animals
that are grouped by naturalists under the name Crustacea. The edible
crabs, lobsters, prawns, and shrimps are at least superficially
familiar, either as brought to the table, or as displayed in the
fishmonger's.... Many, however, will be surprised that the barnacles
coating the rocks on the seashore, the sand hoppers of the beach, and
the wood lice of our gardens, are members of the same class. Still
less is it suspected that the living species of the group number many
thousands, presenting strange diversities of structure and habit, and
playing an important part in the general economy of nature."
The great majority of crustaceans are aquatic animals, breathing by
gills or by the general surface of the body, having two pairs of
"feelers," or antennæ, on the front part of the head, and at least
three pairs of jaws. Most crustaceans are hatched from eggs, usually
in a form very different from their parents; and they reach the adult
state only after passing through a series of transformations quite
as remarkable as those that a caterpillar undergoes in becoming a
butterfly. All crustaceans, except a few much modified land forms,
breathe by means of feathery or platelike gills which are always
an appendage of the legs, where they appear as one or more lobes.
Colorless blood propelled by the heart wanders into spaces in these
lobes, and there lies separated from the water by a mere film
of tissue, through which oxygen is absorbed from the water. Most
crustaceans are covered, at least in part, by some sort of shelly coat
composed of a combination of the horny substance "chitin" with lime,
which reaches its highest state in the big lobsters and crabs. This not
only protects and gives support to the internal organs, but also to the
muscles by which the animal moves. In other words it plays the part of
a skeleton. As it does not increase in size after it is once formed,
and cannot stretch much, the crab must cast its shell at intervals
as it grows. The new covering, which had been formed underneath the
old, before molting, is at first quite soft, and the animal rapidly
increases in size owing to the absorption of water. The shell then
gradually hardens by the deposition of lime salt.
The reader who may not hitherto have understood the difference between
"hard" and "soft-shelled" crabs is now instructed; and it is observable
that the figurative expression "a hard-shell," when applied to a man,
signifies that he must undergo a complete change before his ideas will
be enlarged.
The simplest of the crustaceans are those small creatures of the
subclass Branchiopoda (gill-footed) that swarm in our waters, both
salt and fresh. Lakes, ponds and ditches abound in a variety of minute
or even microscopic species that, in gathering food from equally
small bits of dead organic matter, as well as from living plants and
animalcules, perform an important service as scavengers--a service,
in fact, performed by all crustaceans in a greater degree than by any
other single group of animals. They also furnish the basis of food
for the whole body of aquatic life, since it is upon these minute
crustaceans that fish fry, tadpoles, insect larvæ, caddis flies, and
so on, must mainly depend. One of them is Daphnia, familiar to keepers
of aquariums. Another is Cyclops, a favorite with microscopists and
abundant in stagnant ponds, which is a member of the group called
copepods that form an important part of the oceanic plankton, where
they are the chief consumers of the minute algæ; but they also occur
at all depths. In arctic waters the copepods are so abundant that
they form the principal part of the food of certain fishes and of the
whalebone whales. These, and their minute relatives, the ostracods,
produce a large part of the phosphorescence of the sea, and some of
them exhibit bright colors.
All these are free swimmers, but nearly related to them are the
barnacles (Cirripedia) whose larvæ float about for a time near shore,
and then settle down and attach themselves by their hinder parts to a
rock or some other support, and begin to secrete an armature of limy
overlapping plates that forms a strong cup in which they sit, often in
a crowd that whitens a big rock. When the tide is low these sessile
"acorn shells" are tightly closed, but when the water returns, bringing
its load of invisible food, the animal stands up, as it were, and
thrusting out its feathery legs sweeps the water to capture a meal--a
beautiful sight to watch. The relation of the plates in the barnacle's
cup to those in the coat of the higher Crustacea is more easily seen in
the more pelagic "goose barnacle," whose hinder part is extended into a
tough, flexible stalk, while the fore part is covered by plates. This
kind is fond of attaching itself to floating timber, to ships' bottoms,
or even to the surface of whales, and thus floats or is carried
all over the watery globe. To it belongs the ridiculous myth of the
barnacle geese.
Great numbers of crustaceans of more advanced types live in the open
sea, and at all depths; and many of them assume extraordinary shapes.
The space between tide marks, and the mud of salt marshes and tidal
creeks abound in a wide variety of species, some of which are familiar
to everyone who lives at or visits the seashore. Thus the sand and rows
of drifted seaweed on all our eastern beaches are likely to harbor
flocks of amphipods, well called "sea fleas" or "sand hoppers," which
sometimes jump away before you in hundreds as you walk along.
Here, too, are to be found the pretty, burrowing "mole crabs," or
"ivory crabs," so called from their shining white jackets; and a host
of other species with strange forms and habits haunt the margins of
tropical and Oriental seas. All these are bandits, preying on whatever
they can catch, and between times guarding themselves from capture
by fishes, bigger crabs, and other enemies, by lying in mud burrows,
to the bottom of which they are quick to retreat. The big arm of the
fiddler crab, held across its face, closes its burrow like a door. One
sort, the hermit crab, has all its hinder parts naked, and so backs
into an empty snail shell, curling its taillike soft abdomen around the
central column of the shell and so dragging it about with it, with its
armored head and thorax sticking out of the mouth of the shell. As it
grows it becomes too large for its first shell, and from time to time
must leave it and find a larger tenement in which to ensconce itself--a
perilous transfer. Let me quote some notes I made on a New England
shore to give a picture of crustacean life there in summer.
"The lady crabs were plentiful, always alert, and inclined to be
pugnacious at our intrusion. The first one I met instantly rose upright
at the surface of the water, and when I made an advance it sprang
half way out of the water and cracked its pincer claws together as if
supposing it would reach, or at any rate frighten me. Perhaps it was my
shadow it clutched at so viciously. If so, the crab probably concluded
its huge antagonist to be an intangible ghost upon which the most
powerful claws could have no effect, for an instant later it _backed
down_--literally and swiftly--to the bottom, and in a twinkling had
wriggled tailwise into the mud and out of sight. When with my shovel
I routed madame out of that retreat, she indignantly scuttled off
too briskly to be followed, and will have great tales to tell of her
adventure.
"The stone and fiddler crabs were as common and comical as usual;
and I made the acquaintance of a new one called Gebia, which was a
small, semi-transparent, bluish white, washed-out, bloodless specimen,
shaped somewhat like a crawfish and carrying bunches of roe beneath
its abdomen. It looked like a miniature lobster made of glass and
filled with milk. Then in the eelgrass there was a funny isopod, called
Caprella. It was half an inch or so long, and clung by its hinder feet
to the grass, waving its body up and down in search of minute prey.
Other isopods and amphipods were exposed by turning over stones or
digging in the sand at the edge of the water--small, pale, shapeless
crustacea, which are flattened laterally so that they must lie on
their sides, and when uncovered will kick about with feet and tail in
laughable anxiety to get under something. Under the stones we found
the tubes made by a certain species; and when we captured the active
little architect and put him in a bucket of clean water, he instantly
began to gather grains of sand and stone and to join them together Into
a shield under which he might hide. We found that these grains were
joined together by spiderlike threads, which the amphipod spins from
two pairs of small legs under the middle of his body, secreting a fluid
that hardens in the water. Another (Hippa) about the size and shape of
a robin's egg, but with a thin shell of mother-of-pearl (so to speak),
gave us great amusement by its extraordinary celerity in burrowing, so
that we could hardly seize it before it had squirmed down out of reach
into the wet sand."
The edible crabs (Cancer) live in the shallow region just below ebb
tide, for they cannot endure exposure to air as well as other species,
and live by scavenging. The lobsters are inhabitants of still deeper
water, especially where it is somewhat rocky, and devour more carrion
than living fish. That miniature of the lobster, the fresh-water
crawfish, which is also edible, dwells in deep burrows in wet
lands--burrows that are really wells half filled with water. Various
species of these and other edible forms of Crustacea are found all over
the world.
MILLIPEDES AND CENTIPEDES
The myriapods (class Myriapoda) are those unpleasant creatures more
commonly known as centipedes, millipedes, or thousand-legged worms.
They have a wormlike form, with the body divided into segments, a
distinct head with antennæ, jaws and several single eyes, and a
varying number of air tubes, or tracheæ; two sexes exist, and eggs are
laid in the ground within cases formed by the mother of pellets of mud.
They vary in size from an almost invisible minuteness to a length in
some tropical species of six or more inches. The centipedes (Chilopoda)
are those flattened forms so often seen in and about rotting wood and
vegetation or in moist ground, their bodies looking like a chain of
plates joined together by flexible skin, each section having a single
pair of legs, usually very short, but in one sort (Cermatia) each leg
is longer than the body, and the hinder pair twice as long, matched by
two very long feelers. Most of them are predacious, feeding on anything
they can catch, and their strong jaws exude poison. The larger ones may
inflict a very painful bite if incautiously handled.
[Illustration: GIANT CENTIPEDE
(_Scolopendra gigas_)]
Another group, the Diploda, are known as galley worms, or millipedes,
and have two pairs of bristlelike legs on each segment. Here the
body is as round as that of an earthworm, and is incased in a hard,
chitinous shell, usually red-brown in color; and when disturbed they
coil up and emit an acrid, unpleasant odor as a defense.
WEAVERS OF SILKEN TRAPS
The class Arachnida, which contains the scorpions, spiders, mites
and their allies, connects the Crustacea with the Insects; and
some naturalists include within it the eurypterids and king crabs,
classified in this book with the Crustacea. All live on land and
breathe air except a small group of allies (Pycnogonida) which are
marine, and may be found on the rocks, and clinging to wharf piles,
etc., on our coasts as well as elsewhere; they appear to be all legs,
and are known to New England fishermen as "no-body crabs." The class
includes seven orders, the lowest in rank of which is that of the
scorpions (Scorpionida).
Scorpions are inhabitants of warm countries, and some tropical American
species are six inches in length, but those of our Southern States
are smaller. They have slender bodies consisting of a cephalothorax
and a long abdomen ending in a sharp sting through which two poison
glands inject poison into the wound made by it, the effect of which
may be very severe on a man, and is fatal to the insects and other
small creatures on which scorpions prey; this "tail" with the sting
is usually carried curled up over the back. The body is protected by
chitinous plates above and below. The legs are four. From the head
spring two great, crablike, pincer claws. When these seize an insect
they hand it back to two small but powerful appendages at their base
which act as jaws. Between them is a small mouth. Scorpions are
nocturnal in habit, hiding by day in crevices, and wandering about at
night; thus they are likely to seek such dark retreats toward morning
as a person's boots; and in hot, dry regions travelers must be cautious
about examining their clothing and baggage to avoid being stung. The
scorpions retain their eggs until hatched. The young when born differ
little except in size from their parents, and are cared for with much
solicitude by the mother, who carries them around with her for some
time, hanging by their pincers to her body. The race is ancient, fossil
remains occurring as early, at least, as the Carboniferous age.
The second order, Pseudoscorpionida, includes the "book scorpions,"
a series of minute, stingless, scorpion-shaped creatures found in
moss, under the bark of trees, or more often on flies. A third order,
Pedipalpida, is that of the scorpion spiders, or "whip scorpions" of
the tropics; the fourth, Solpugida, contains certain ugly creatures
intermediate between scorpions and spiders; and the fifth order,
Phalangida, is that of the small-bodied, vastly long-legged things
called "harvestmen" in England and daddy longlegs by us, which run
about in the summer heat, and feed on minute insects. They abound in
all the warmer parts of the world, and in great variety, South America
showing some very bizarre forms. This brings us to the sixth order,
Araneida--the spiders.
THE SPIDERS AND THEIR WEBS
Spiders are usually thought and spoken of as "insects" by the layman.
Many persons call almost every creature an insect that is small and
supposed to be useless, or suspected of harmfulness. But spiders
are different from insects properly so called in many important
particulars of structure and habits. Spiders have four pairs of legs,
while insects have six legs. The spherical abdomen, which is cut off
from the head by a deep constriction, shows no segmentation, and on its
floor are large glands (the arachnidium) producing the silk which is
exuded from three pairs of tubes with sievelike openings, at the end
of the abdomen, called the spinnerets. Their nervous system is highly
developed, and they show much intelligence. Spiders are of two sexes,
but the male is usually much smaller than his mate.
When egg-laying time comes the female forms a little silken bed
attached to grass, or underneath a stone, or stuck to some object,
or placed in a burrow, or hung like a hammock by long guy lines, and
deposits in it eggs like drops of jelly. One sort places this under
water, forming a nest like an inverted cup and filling it with bubbles
of air, and spending much of its time in this real diving bell. A
common garden spider (Lycosa) forms globular cocoons, and drags them
around attached to the spinnerets, regardless of jars and bumps. In
a large section of the tribe this is all the use that is made of the
silk, which differs from that of insects (caterpillars) in being made
up of a great number of finer threads laid together while soft enough
to unite into one.
It is a common habit with spiders to draw out a thread behind them as
they walk, and in this way they make the great quantities of threads
that sometimes cover a field of grass. This is the gossamer often so
annoying to us in late summer, but a thing of beauty when glistening
with dew.
The gossamer of autumn, however, is made by the very small spiders of
the genus Erigones, which hide in the herbage, but in the fine weather
that comes after the first frosts climb to the tops of posts, fences
and tall weeds, in company with the young of larger kinds, and "turning
their spinnerets upward allow threads to be drawn out by ascending
currents of air, until sometimes the spiders are lifted off their feet
and carried long distances." These are the "ballooning spiders" of
which one hears. In this way the whole country is overspread with lines
and tangles of trailing silken threads that whiten our clothes and
stick to our faces.
Three or four hundred species of spiders might be obtained in almost
any locality in this country by diligent search, and thousands of
foreign species are known; hence only a few conspicuous examples may be
mentioned here. The tribe may be divided according to habits into two
groups of families: 1. The hunting spiders, which run on the ground or
on plants, catching insects by chase or by strategy; and 2. The cobweb
spiders, which make webs to catch insects, and live all the time in the
web or in a nest near it.
In the former group are the Drassidæ, a family of small, varicolored
spiders that run about on the ground or in bushes, one large genus of
which (Clubiana) includes pale, or purely white species; their cocoons
are baglike or tubular. The most conspicuous genus is Misumena, in
which the species are white or brightly colored, and which spend their
days among flowers, waiting in rigid attitude for an insect to alight
near them on which they may pounce. Spiders can see well for four or
five inches, but not much beyond that. The Attidæ are small, hairy, or
scaly jumping spiders, often brightly colored, that are found in open
places and on the tops of low plants, whence they leap on their prey,
or make long jumps to escape danger. To the next family, Lycosidæ,
belong the large spiders most often seen in fields and pastures. They
are fond of dry, sandy places, where the females live in silk-lined
holes. These lycosids are long-legged, rapid runners, and capture
their game by running it down. To this family belongs the famous
tarantula of southern Europe, fabled to produce a madness (tarantism)
in a person bitten that could be cured only by dancing to music of a
certain lively measure called "tarantella." (The so-called "tarantula"
of our southwestern desert region, is, however, another species.) A
common northern spider (_Lycosa carolinensis_) is its equal in size,
(the longest legs covering a spread of three inches), and in color,
black with gray legs. Still larger is another North American lycosid
(_Dolomedes tenebrosus_), gray with spiny legs ringed with dark and
light gray, which spreads four inches.
These big ugly creatures, and the bites of spiders generally, are
regarded with unnecessary dread by most persons. The jaws (mandibles)
are close together at the front of the head. They are two-jointed, the
basal joint stout, and the end joint or claw slender and sharp-pointed.
The claw has near its point a small hole, which is the outlet of
the poison gland. "The poison kills or disables the insects which
are captured by the spider. Its effect on the human skin varies in
different persons. Sometimes it has no effect at all; oftener it causes
some soreness and itching ... and cases have been known in which it
caused serious inflammation which lasted a long time. Spiders seldom
bite and only in self-defense, the bites so commonly charged to them
being often the work of other animals."
In the family Agalenidæ we meet with the first of the web makers. These
are spiders of moderate size, characterized by a big head marked off
from the thorax by converging grooves. Their natural home is in the
grass, where their flat, closely woven sheets of silk, almost invisible
by reason of their transparency, but brought into plain view when
coated with dew or dust, are spread everywhere. They also are fond of
getting into cellars and old buildings, and constructing webs across
corners, bracketwise. Somewhere the web sinks like a narrow funnel into
a short tube in which the owner hides, watching hungrily until a fly
alights on his silken platform.
"The Therididæ," says Emerton, "are the builders of the loose and
apparently irregular webs in the upper corners of rooms, in fences
and among rocks, and between the leaves and branches of low trees and
bushes. They are generally small, soft and light-colored spiders, with
the abdomen large and round and the legs slender and usually without
spines.... Most of the Therididæ live always in their webs, hanging by
their feet, back downward. The webs have in some part a more closely
woven space under which the spider stands." These spiders are quick
to avail themselves of any chance to spin their shapeless meshes of
almost invisible silk, which few regard as real "webs," in closets,
cellars, and all over the house or barn. Many of them are adorned with
gay colors or striking patterns, and some are much feared, especially
_Latrodectus mactans_, about half an inch long, which is black with
scarlet spots. It is common from Canada to Chile, and everywhere is
considered fatally poisonous--why, it is difficult to say.
Last of our list, and highest in rank, are the Epeiridæ, the "orb
weavers," as they are often called, who make those regular spiral nets
which are in our mind's eye when we think of cobwebs. Most of the
moderately large and handsome house and garden spiders are of this
family, and everyone can easily examine their work, although it is less
easy to watch them at it, as the webs are built and repaired at night.
Among the obscurer and foreign species the abdomen often shows humps,
points and long forward-reaching horns that make them exceedingly
grotesque, and doubtless difficult to handle by birds and other
creatures that seize them as food.
One of the round webs of the Epeiridæ consists of several radiating
lines, varying in different species from a dozen to seventy, crossed
by two spirals--an inner spiral that begins in the center and winds
outward, and an outer spiral that begins at the edge of the web and
winds inward. The inner spiral is made of smooth thread, like that of
the rays, to which dust will not cling; the outer spiral is made of
more elastic thread which, when fresh, is covered with fine drops of
sticky liquid.
"In beginning a web, after the radiating threads are finished, the
spider fastens them more firmly at the center and corrects the
distances between them by [inserting] several short, irregular
threads, and then begins the inner spiral, with the turns at first
close together and then widening ... until they are as far apart as
the spider can reach with the spinnerets [resting] on one and the
front feet on the next, and so goes on nearly to the outside of the
web, where it stops abruptly. The spider usually rests a moment, and
then begins, sometimes at another part of the web, the outer sticky
spiral.... As soon as the inner spiral is found in the way a part of it
is cut out, and by the time the outer spiral is finished the inner is
reduced to the small and close portion near the center.... The whole
making of the web seems to be done entirely by feeling, and is done as
well in the dark as in daylight. When the spider is active and the food
supply good, a fresh web is made every day, the old one being torn down
and thrown away."
[Illustration: AMERICAN GARDEN SPIDER
(_Epeira vulgaris_)]
As a rule these orb weavers do not stay in the web in the daytime, but
hide away in their nests made in some near-by but concealed place; and
their egg cocoons are hidden in all sorts of places.
All of the spiders that have been considered so far belong to the
division of the class that has but a single pair of lungs. A second
division has been made for those having two pairs of lungs, composed
of a single family, the Mygalidæ, consisting of the so-called
"bird-catching" spiders and the trapdoor spiders. The great mygale
of Guiana has a body sometimes two inches long, and its legs will
span eight or nine inches of space. It is hairy all over, intensely
black, and a terror to all small creatures, even catching small birds,
according to tradition; but proof of this is wanting.
The trapdoor spiders are those of the genera Cteniza and Atypus which
dig and inhabit vertical holes in the soil, lined with silk and closed
at the top by a hinged stopper or "trapdoor." Several species occur in
southern Europe, one of which has a second door hanging by a silken
hinge half way down the shaft; and in case of trouble the spider goes
below it and pushes it above its head, so that the intruder is deceived
into thinking it has opened an empty nest. _Cteniza californica_ is the
common species of our Southwest. The cover of the hole is made of dirt
fastened together with threads, and is lined, like the tube, with silk,
and fastened by a thick hinge of silk. The spider holds the door shut
from inside. These underground homes are safe retreats for the spiders
during the day, and nesting places in which their eggs are deposited
and young reared; at night the spiders go forth in search of prey.
MITES AND TICKS
Mites and ticks are classified with the spiders as degenerate relatives
of arachnoid stock. Ticks are large enough to be seen without a
magnifying glass, and some become half an inch long. Ticks are wholly
parasitic. The female lays several thousand eggs at one time on the
ground or just beneath the surface. "The young 'seed ticks' that hatch
from these in a few days soon crawl up on some near-by blade of grass,
or on a bush or shrub, and wait quietly until some animal comes along.
If the animal comes close enough they leave the grass or other support
and cling to their new-found host." These parasites are the agents of
the spread of several infectious diseases of cattle, the worst of which
is the destructive Texas fever, and of mankind, as spotted fever and
other ills resulting from the presence of blood parasites.
CHAPTER XI
FROM BUTTERFLIES TO BEETLES AND BEES
The generally accepted classification of the insects divides them into
more than twenty orders, and these into hundreds of families whose
species, already catalogued, are three times as numerous as all other
known animals together. "There are, for example," as Lutz remarks,
"15,000 species of insects to be found within fifty miles of New York
City; more than 2,000 of these are either moths or butterflies."
Insects as a class are characterized primarily by the division of the
body, when adult, into three clearly defined regions--the head, the
thorax or fore body, and the abdomen or hind body. All insects have
three pairs of legs, distinguishing them from the eight-legged spiders,
and from the many-footed myriapods and other arthropods, and most of
them have one or two pairs of wings, borne like the legs on the thorax,
the abdomen never bearing either. The head consists of four segments,
but in most cases the first three are consolidated into the hindmost,
and are represented only by the appendages they bear. The foremost of
these are the mouth organs, of which there are three pairs: the most
anterior are the mandibles, next the maxillæ, and then the labium,
the two latter bearing articulated prolongations known respectively
as maxillar and labial palpi. The mouth has an upper lip (labrum) and
contains a tongue. These mouth parts are variously modified, and by
these modifications insects may be classified in two groups: "First,
those in which the jaws and maxillæ are free, adapted for biting, as
in the locust or grasshopper; and second, those in which the jaws and
maxillæ are more or less modified to suck up or lap up liquid food, as
in the butterfly, bee, and bug." It is in this latter group that we
find those having those interesting relations with plants that result
in cross-fertilization of flowers.
[Illustration: A FLORIDA KATYDID
(_Cyrtophyllus floridensis_)]
From the forehead spring a pair of antennæ, which are not only
"feelers," but the bearers of other senses. They are jointed, and
exceedingly various in form and service. Some are mere stubs, others
long and slender as a whiplash, or they may be thickened at the end,
as commonly in butterflies, or bear rows of hairs on each side, giving
them in some cases a beautiful plumelike appearance. With their
antennæ insects inspect by touch whatever they come in contact with,
and test the shape of what they may be constructing, such as cells
for their eggs. They recognize one another, and apparently exchange
communications, or become aware of a stranger, and the ants induce
their captive aphids to let down the honeydew by stroking them with
their antennæ; but in many of these cases, if not all, additional
information is derived through the antennæ by reason of the senses of
hearing and of smell which many of them certainly possess. Ears, or
organs sensitive to vibrations, and delicate hairs and other processes
connected with nerves responding to touch are found in various other
parts of insects' bodies, but the feelers are preeminently the seat of
the sense of smell.
The eyes of insects are of two kinds, simple and compound. The simple
eyes are small and practically useless single ones (ocelli) situated
in a triangle of three on the top of the head. The compound eyes are
on the side of the head, and are covered by a transparent layer of
the chitinous skin (cornea), divided by delicate lines into square
areas (facets). Beneath each facet of the cornea is an "ommatidium,"
optically separated from its neighbors by black pigment, and consisting
of an outer segment or "vitreous body" and an inner segment or
"retinula" formed of sensory cells. In some such eyes the ommatidia
are few, but in others extremely numerous, so that the eyes cover a
large space; some hawk moths are said to have 27,000 facets. The
nature of the picture conveyed to the mind by such an eye has aroused
much discussion. Photographs taken through the eye of a dragon fly show
that, though the eye is compounded of many lenses and sensitive areas
(retinulæ) corresponding to them, yet the whole eye throws one image
on the retina. However complex such an eye may be, it is devoid of any
focusing arrangement and can only receive a clear image when the retina
and the object are separated by the focal length of the lenses. Hence
the need for active movement on the part of creatures having them.
The head is connected with the thorax by a neck often protected by the
overlapping front of the "tergum," or chitinous plate that covers the
thorax. The thorax consists of three segments, named from the front
backward "prothorax," "mesothorax," and "metathorax." These and a few
other technical terms are in such constant use in describing insects
that it is important to know them. The under (ventral) surface of the
thorax is protected by another plate named "sternum." The armor is not
continuous all around the body as in the crustaceans, but that on the
upper surface is connected with the sternum by a seam of soft skin
along the sides of the body.
Each segment of the thorax bears a pair of legs, each of which consists
of a stout, flattened "coxa," nearest the body; a small second part,
the "trochanter"; a third, the "femur"; a fourth, the "tibia"; and
finally the "tarsus," or foot, terminating in a pair of claws, bristly
on their under surface to give adhesive power. It is by means of these
stiff hairs, and not by any suction or stickiness, that flies are able
to walk on the ceiling and on vertical surfaces.
The wings of such insects as fly arise from the tergum of the thorax,
and are in two pairs except in the flies, where there is but one,
the hinder pair being represented by two little protuberances called
"halteres." Usually the wings are strengthened by rods called "veins,"
and the patterns of venation vary in different groups, and form one of
the means of classification.
The abdomen consists normally of ten segments, and contains most of the
digestive and all of the reproductive organs, above which runs the main
blood vessel, and below it the highly organized nervous system, the
chief ganglion of which, in the head, is termed "brain."
The breathing of insects, although rhythmical in its inhalation and
alternate exhalation, is not to the same purpose as ours. Respiration
goes on by means of a system of branching tubes (tracheæ) that ramify
throughout the body, and to which air is admitted through nine or more
openings in the side of the body guarded by valves called "spiracles."
The buzzing of flies, "singing" of mosquitoes, and the like, are sounds
made in these spiracles, not by their rapid wings. At intervals the
tracheæ are enormously enlarged to form air sacs. These no doubt,
lighten the body, but they probably serve also to provide a reservoir
of air from which the fine branches are filled by diffusion, and into
which the carbon dioxide is discharged. The circulation of oxygen in
adult insects, however, is never by means of the blood, but simply
by absorption by the tissues into which the excessively attenuated
tracheal tubes penetrate.
Insects are bisexual, and male and female are always separate
individuals. Except in a few abnormal cases among the most lowly, eggs
are produced and deposited in some favorable place for hatching.
SOME PRIMITIVE GROUPS
Insects go back in geologic history to the middle of the Paleozoic
age, and their remains are numerous and much differentiated in
Carboniferous rocks, when the orders Aptera, Orthoptera, Neuroptera,
and Hemiptera (the last represented in the Silurian by ancestral forms
of the bedbug and the cockroach--the oldest fossils yet discovered)
were flourishing. The beetles and ants first appear in the Trias, the
true flies, in the Jurassic, and the butterflies and moths, wasps, and
bees not until the Tertiary. This indicates an evolutionary progress
in structure with advancing time, as elsewhere in biology. The most
primitive type (Aptera) is still with us in the skipping silver fish
and snow fleas, or spring-tails, that annoy us in various situations.
They are wingless, very simple in organization, and without any
larval metamorphosis. Not much better are the Mayflies, or dayflies
(Ephemeridæ), that sometimes in early summer arise in enormous numbers
from lake shores and rivers, and then quickly disappear. Most of them
live, in truth, only a single day (or night), a single one of the many
American species surviving three weeks. During their brief life the
female drops into water several hundred eggs where they presently hatch
into swimming or crawling larvæ that next year, or perhaps not until
the third spring, creep out on land, molt, and fly abroad in ephemeral
crowds.
It is not a long step from these Mayflies to the dragon flies and
damsel flies (Odonata), which also belong to the water spaces of the
country, and are among the most interesting of all the insect tribes,
and the most beautiful, as they dart and curvet over the surface of
some glassy pool that reflects the steel-blue or peacock-green sheen
of their long slender bodies, and the black bars that alone make their
narrow and almost transparent wings visible. They are known by many
ridiculous names, as "darning needles," "snake doctors," etc., but
there is no harm in them; on the contrary they are to be encouraged,
for they consume, especially in their larval stages in the water, a
vast number of mosquitoes, gnats, and other troublesome "bugs." The
adults capture their food on the wing, and are hawklike in the agility
with which they turn and dodge in pursuit of their active prey. The
actual catching is done with the feet, which curve far forward, and
are studded with spines that give a sure grip on anything caught
between them; they assist, too, in clinging to plants, but the legs
are ill-adapted to walking. The wings are very powerful; are of a
glassy texture, and never folded; they are crossed by a great many
veins, breaking the surface into innumerable small squarish areas, and
bear markings that distinguish each of the two or three hundred North
American species.
Dragon flies, and their cousins, the smaller and more graceful,
low-flying damsel flies, pair as a rule in flight. In some of the
families the female descends below the surface of the water, and is
able by special apparatus to insert her eggs beneath the skin of a
plant; others place them in plant stems above the water, or simply drop
them at the surface, whence they sink to the bottom. The "nymphs," as
aquatic larvæ like this, with incomplete metamorphosis, are termed, go
about preying on anything they can seize and eat, and possess some very
peculiar temporary adaptations to their underwater career. After a time
the nymph (which is the "dragon" in dragon fly) changes from a rather
slender to a broad and flattened creature and crawls out of the water.
Soon its skin splits, and an adult dragon fly emerges.
Closely allied to the dragon flies are the stone flies, or alder flies
(Percoptera), whose ugly and predacious nymphs are so well known
to anglers as "dobsons," "crawlers," and by many other local and
opprobrious names, because they make excellent bait for still-water
fishing. The adult is that great, thin-winged creature called
"hellgrammite" (_Corydalis cornuta_), with a wing spread of four
inches, and possessed in the female of powerful biting jaws, which,
as in all insects, work horizontally and not up and down as among
vertebrates. In the male the jaws are extended into long, curved,
piercing organs which cross when at rest, and which are fully an inch
in length, but fortunately they are not used as jaws, but for holding.
Related to these is a group of well-known insects belonging to the
old order Neuroptera, but now placed in separate orders, all with
lacelike wings and an incomplete metamorphosis. They include the ant
lions, the useful aphis lions, the scorpion flies (Panorpa), the lovely
lace-winged flies, and the caddis flies, which make larval cases of
bits of stick, or of shells or fragments of stone, in the bottoms of
rapid streams. From somewhere in this group, probably, the ancestral
Lepidoptera branched off to develop into the butterflies and moths of
the present day. Next to them are the earwigs (Dermaptera), beetlelike
insects very conspicuous in Europe, but little noticed in this country.
A MUSICAL TRIBE
Out of this confusing array of rather primitive groups we come to an
extensive and well-defined order, the types of which are familiar to
the most careless of observers in all parts of the world. This is the
order Orthoptera, "straight wings," which includes the cockroaches,
mantids, walkingsticks, grasshoppers, locusts, katydids, crickets, and
their humbler kinfolk.
Cockroaches are native to all the warmer parts of the world, and we
have a common large brown one, and some others of our own; but the pest
of our kitchens is the small Oriental species whose origin was Asiatic,
and which probably accompanied the earliest westward wanderings of
mid-Asian men, and established themselves as boarders by the camp fires
of the cave men. At any rate, the "black beetles," as the British call
them--wrongly in both particulars--are now settled wherever ships have
gone or civilized goods have been carried. As they first began to be
really troublesome in New York City about the time when the Croton
water was introduced (1842) they got the local name "Croton bug," but
they are the world-wide _Blatta orientalis_, scampering around where
they are not wanted, carrying a queer packet of eggs under the tail.
[Illustration: TWO WALKINGSTICKS
(_Diapheromera femorata_)]
The mantids--of which a common species in the Southern States is known
as "mule killers" because of the superstition that its saliva poisons
stock--and the gaunt "walkingstick" insects that mimic twigs so well
that they are not seen as often as they might be, introduce us to the
great tribe of grasshoppers or locusts--two words that it has worried
bookmakers to keep straight. The grasshoppers fall into two families,
distinguished among other points by the length of the antennæ. The
short-horned ones (Acrididæ) are properly called locusts, and the
long-horned family (Tetigonidæ) are better known as grasshoppers,
despite the fact that until recently the books called this family
Locustidæ. To the Acrididæ belong the locusts that in years past have
worked such havoc now and then in the West, when vast swarms came from
the Rocky Mountains to the new farms along the eastern border of
the plains, and ate up the young grass and crops, leaving the ground
looking as if swept by fire. It is a story older than written history
in all plains districts of southern Asia, Asia Minor, Egypt, and
northern and south-central Africa, where no earthquake, or tornado,
or other reaction of nature against man's interference with natural
conditions, is so dreaded as a visitation of migratory locusts. In
this country any such "plagues" as half ruined Kansas forty years or
so ago need no longer be anticipated, because the plowing on ranches
and other disturbance of the ground in which the locusts lay their eggs
is now so extensive, and the methods of checking small flocks are so
well understood, that the vast surplus generations that constituted a
migration in search of food in the old days are no longer born.
All the Orthoptera are musical, or at any rate noisy, and make their
rattling or piercing notes as instrumentalists, not as vocalists.
"Some species," writes Frank E. Lutz, "make a rasping sound by rubbing
their hind legs against their front wings (tegmina). Others rattle,
while flying, their hind wings against the tegmina. These sounds
are primarily amorous serenades, and Nature's serenades without
attentive ears would be even more curious than the ears for which the
grasshoppers perform. In this family there is an auditory organ on each
side of the first abdominal segment, just above and back of the place
where the large hind femora start. Notice the clear round spot on the
next grasshopper you catch.... Few have not heard the masculine debates
as to whether Katy did or didn't, but many do not know by sight the
small, green, long-horned, stockily built disputants, both of whom
usually stay high in trees. The musical apparatus of the male--the
musician--is at the tegmina, and the leaflike wing covers, broadly
curving entirely around the body, act as sounding boards. The female's
wing covers do not have the thick rasp veins at their bases."
A third family, the Gryllidæ, contains the crickets--burrowing mole
crickets, ordinary black crickets dwelling in the herbage, and several
kinds of tree crickets that look like ghosts of their kind. All add to
the noise of a summer evening by rubbing the roughened surface of their
wing covers together--chirping to ears that are situated in the shins
of the listening cricketesses.
THE TRUE BUGS
Skipping the white ants or termites, which are few and comparatively
harmless in this country, but in the tropics make vast trouble for
house-holders; the various sorts of lice and the little black thrips
that destroys onions and some fruits, we come to the great assemblage
that entomologists call "bugs," limiting the word to the order
Hemiptera, which now must be considered.
The two features, basally common to all the immensely diverse members
of the order, are the character of: 1. The feeding organs; and 2. The
wings--in each case very distinct from that of all other insects. The
bugs have highly developed piercing and sucking jaws. The mandibles and
first maxillæ are transformed into stylets, often barbed toward the
tip; these work to and fro within the groove of a stout-jointed beak
(rostrum) which is formed by the union of the second maxillæ. The head
is usually triangular in shape, as viewed from above.
As to the second characteristic, the bugs are distinguished by the
modification of the fore wings into partly horny covers for the
entirely membranous hinder wings. This feature divides the order into
two suborders, Homoptera and Heteroptera. In the first this hardening
is little evident; but in the Heteroptera--where not wingless, as in
certain families--the fore wings are stiff and lie flat on the back
when closed, whereas in the Homoptera they are somewhat humped over the
back, and droop down on each side a little. The triangular space marked
on the back by the closed wings is a ready mark by which to recognize a
hemipteran, or true bug.
The Hemiptera display a greater diversity of form than any other order
of insects, and vary in size from almost microscopic scales to fat
cicadas and "giant" water bugs. "Some pass their lives in the upper
parts of trees, others chiefly on the lower limbs; still others prefer
the protection of roots, stones or rubbish on the ground; a large
number of species select a home beneath the surface of the earth,
often in the holes of ants or other insects; a conspicuous assemblage
of dull-colored forms occurs only in the crevices or under the bark
of trees and shrubs; while a host of others skim over the surface of
placid waters, and a few are found remote from land upon the rarely
disturbed waves of the tropical and subtropical oceans.... While the
greater number derive their food either from the sap of vegetables,
or the blood of fishes, animals and man, there are others which are
satisfied with the strong fluid that accumulates beneath damp, decaying
bark of trees, or still others which enjoy the juices of fungi or
ferns.... Those which creep about in search of living prey are often
furnished with curved or hooked forelegs, suitable for seizing and
holding creatures when in motion, such as caterpillars and other larvæ."
The Homoptera include the immense and destructive family Coccidæ,
the bark lice, scale insects, and mealy bugs, among which, however,
are the useful producers of lacs and such dyes as cochineal. Related
to them are the Aleyrodidæ, the destructive "white flies," and the
Aphidæ, almost infinite in number and in harmfulness to fruit trees and
cultivated plants; also the queerly shaped leaf hoppers and similar
minute, plant-sucking forms.
It is one of the curiosities of zoölogy that associated with these
minutiæ we find a family of bugs of large size--the cicadas, whose loud
"singing" by the male in autumn gives them the name "locust," and often
becomes annoying when one wants to sleep where trees are near by. The
noise is made by vibrating membranes stretched over a pair of sound
chambers, situated, one on each side, near the base of the abdomen.
The cicada lays its eggs in slits cut in the bark. The newly hatched
young drops to the ground and, burrowing into it, feeds by sucking the
juices of roots. The time spent in the ground varies according to the
species in various parts of the world. In the case of our "periodical"
cicada it lasts about seventeen years, whence we call that species
"seventeen-year locust," and know it, when a great swarm comes out of
the ground and ascends the trees, by the humming of the crowd which
sounds like the vibration of telegraph wires in the poles.
[Illustration: SEVENTEEN-YEAR LOCUSTS
1-4, pupæ, increasing in age; 5-15, the locust imago struggling out
of the pupa; 16, 17, 18, the imago stretching its wings; 19, empty
pupacase; 20, 21, perfect locust. (Smithsonian Institution.)]
The Heteroptera, or proper "bugs," are a much larger assemblage, a few
kinds of which have attracted popular notice. The long catalogue
begins with the small "water boatmen" that live an active predatory
life on the bottom of streams and ponds. Other common aquatic families
are the Notonectidæ, that swim on their backs, the Nepidæ, or "water
scorpions," one of whose genera is that of the slender, long-legged
"skaters" that glide so swiftly across the glassy surface of still
waters. Then there are the great water bugs (Belostoma), which all
over the world are the tigers of quiet rivers and ponds, pouncing from
their concealed lairs on even minnows, small frogs, and anything else
they can catch and kill. These great brown bandits are sometimes two
inches long. Some of the tropical species are strange in form and have
extraordinary habits in caring for eggs and young.
Leaving the aquatic group, we come to certain troublesome plant-sucking
bugs, and to the bedbug, which claims the longest lineage of any known
insect, for the remains of perfectly recognizable ancestors are found
in Ordovician rocks dating from early in the Paleozoic time. Skipping
the lace bugs, red bugs, or "cotton stainers," and others, we come to
a series of families that are among the worst pests of the farmer and
gardener, the chinch bug, squash bug, cabbage bug and many others, the
aggregate effect of whose ravages causes a loss of millions of dollars'
worth of crops every year, not only in this country, but everywhere
that grain, vegetables, and fruit are cultivated; and in most cases it
is not the native but introduced species that does the most damage.
GILDED BUTTERFLIES AND DUSTY MOTHS
The butterflies and moths, whose beauty attracts more collectors than
any other group of insects, constitute the order Lepidoptera, the
meaning of which term is "scaly winged," in reference to the fact that
the hairs that clothe and ornament the wings are scalelike. Butterflies
have club-shaped antennæ, and belong to the division Rhopalocera.
Moths are Heterocera. Some of the moths, especially the males, have
feathered antennæ, some threadlike, while a few tropical ones have
"club" antennæ, so that this distinction is not perfect. The pupæ
of butterflies are not protected by cocoons, as are those of most
moths, and are usually called "chrysalides" (singular, "chrysalis").
Butterflies in general only fly during the daylight, when few moths are
stirring, and usually hold their wings erect when at rest, while moths
hold them flat or folded against the body.
The Lepidoptera undergo a complete larval metamorphosis, and the
process is more familiar to general readers than in the case of
other insects. From the eggs, which are often objects of great
beauty when examined through a lens, are hatched wormlike creatures
that grow rapidly by repeated moltings of the skin into full-sized
"caterpillars"; those of certain moths develop in community nests,
but ordinarily they live singly. All have three pairs of thoracic
legs, and a variable number of temporary "prolegs" near the rear
of the body. Caterpillars may be smooth, round, and colorless, or
coated with a heavy fur, or bristling with knobs, tufts of hairs, and
other appendages, and brightly ornamented with color; and many of
these peculiarities appear to be wholly defensive in purpose. Some
caterpillars give off, when alarmed, disgusting and acrid fluids, and
the hairs of others irritate venomously the skin of anyone handling
them, and probably account for the fact that few birds will touch
certain species. All caterpillars feed voraciously--in fact, this is
the only time in the life of many species when food is taken, the adult
moths and butterflies as a rule being neither willing nor able to eat.
At a certain time, having completed its final molt, the caterpillar
arranges itself according to the custom of its race, and subsides into
a pupa.
[Illustration: CATERPILLAR OF THE MILKWEED BUTTERFLY
(_Anosia plexippus._) (Smithsonian Institution.)]
A century ago men interested in butterflies spoke of themselves
as aurelians, explaining that "aurelia" was a proper name for the
butterfly pupa because of the golden ornaments it usually bore. Really,
however, this characteristic, so marked in the gilt "buttons" of our
common milkweed butterfly, pertained to only a single family--the
Nymphalidæ. When the nymphalid caterpillar reaches the turning point,
it withdraws the abdomen a little from the cracking skin, exudes a
little sticky silk which it fastens to its support, then hooks the tip
of its abdomen firmly into this silk; this done, hanging thus by its
tail, the caterpillar finally shakes off its coat and, as a chrysalis
(a Greek word of the same general sense as the Latin _aurelia_) the
pupa hangs, head down and inert, until the following spring.
The butterflies of greatest size and most splendid coloring belong to
the family Nymphalidæ, whose hundreds of species are scattered all over
the warmer parts of the world. Here belong those gorgeous tropical
ones, whose wings, sometimes with a spread of five inches, emulate the
prismatic hues of the "eyes" in a peacock's tail, and which are so
often seen mounted as lovely ornaments in curiosity shops; and here
also is classified that strange "leaf butterfly" of Malaysia, whose
wings when closed so perfectly imitate a leaf of the tree on which it
alights that the sharpest eyes can hardly find it. Here, too, belong
our brown-streaked "fritillaries," such as the vanessas, and darker
ones like our mourning cloak, and many others well known to amateurs.
[Illustration: FINAL MOLTING OF A NYMPHALID CATERPILLAR
(a) Before shedding skin. (b) In act of shedding skin. (c) Trying to
catch hold of silk button. (Smithsonian Institution.)]
All of this family have their chrysalides hung by the tail; but in
the remainder of the butterfly families they are held in an upright
position by a loop of silk that passes around them like a girdle. Such
are the "coppers," the "blues," the "hair streaks" and many other
small, gayly colored species (Lycænidæ) common in summer, to which
season they add so beautiful an interest. In another large family, the
Papilionidæ, are found the great yellow and black "swallowtails," which
are almost exclusively American, and several dark blue or purple-marked
species, with "tails" to their wings, that attract the attention of the
most careless as they lazily flit among the flowers. In this family,
too, are the sulphur-yellow butterflies that dance over the roads and
fields in little flocks; and, alas, the white ones whose caterpillars
are so injurious to cabbages and similar vegetables. The last family
(Hesperidæ) contains small, rather obscurely marked, butterflies that
connect the Rhopalocera with the Heterocera, or moths.
[Illustration: CATERPILLAR BEGINNING ITS COCOON
Photo, A. N. Mirzaoff]
In fact the distinction between the two divisions of Lepidoptera is
one of convenience rather than of science, for it marks difference of
habits rather than of structure. Instead of a naked pupa, that of the
moth is inclosed in some sort of envelope called a "cocoon." This may
be an earthen cell underground, or a woolly tuft fastened to some such
support as the bark of a tree, or a leaf rolled and tied by silken
threads into a tube, or a burrow in dead wood, or a paperlike case
fastened to a twig; but in every case some special provision is made
for the easy emergence of the imago when the time comes for its birth
as a moth. The moths themselves do no harm. Their few weeks of life
are devoted entirely to mating and putting their eggs in just those
places where the larvæ they will never see can have the food proper for
them and the best chance for life--a matter of marvelous instincts and
adaptations. Few of them, except the hawk moths, eat at all. That is
done in the caterpillar stage, when many sorts become destructive of
the labor and hopes of the farmer and gardener and orchardist, or make
havoc in stores of grain and meal, and in garments of wool and fur,
carpets, and cabinets of natural history specimens.
[Illustration: MOTH AND EGGS
Photo, A. N. Mirzaoff]
Most of the moths are small, inconspicuous, grayish or brownish
creatures whose markings, very lovely when closely examined, so closely
resemble in their mottlings the places where the moths rest during the
day, that they are comparatively safe from the birds, monkeys and other
enemies that seek to catch and eat them. Some, however, are of large
size and brighter hue. Thus the silkworm moths of the Orient (and of
our own land) may measure four or five inches across the outstretched
wings, as does the cecropia and others that flit about evening lights;
and a near relative among us is the exquisite, long-tailed, luna moth,
which is pale green with chestnut edgings; many others in this group
are almost as "richy bedight" as butterflies. It is these that make the
large papery cocoons so easily seen in the fall in trees and bushes.
A remarkable family (Bombycidæ) is that of the hawk moths, which much
resemble in shape and action humming birds. They are day flyers,
but most active in the morning and evening twilights, and hover on
whirring wings before a flower, while with their long, tubular tongues
they suck its nectar, for these moths feed as well as do their fat,
uprearing, bulldoglike caterpillars, to which they owe another common
name for the family--that of sphinx moths. Their pupæ are lodged under,
on, or near the ground in a loose cocoon, and are to be recognized
by an appendage, curled around like a jug handle, in which lies the
chrysalis' long tongue.
FLIES AND THEIR HYGIENIC IMPORTANCE
Flies, scientifically speaking, are only those insects of the order
of Diptera, distinguished by having only one pair of fully developed
wings. They pass through a complete metamorphosis, and the larva is in
all cases a "grub" or "maggot" destitute of legs. It is rarely enclosed
in a cocoon but lies buried in the ground, floats in the water, or is
protected by the last larval skin which, separating from the pupa skin,
remains around it as a hard case. Flies and their larvæ live in the
most diverse manner. Some flies attack backboned animals and suck their
blood, some prey on smaller insects, some suck honey, and some find
their food in decaying animal and vegetable matter. A large number of
dipterous larvæ eat refuse, many feed inside growing vegetable tissues,
and some prey, or are parasitic, on other insects. More than 10,000
species of true flies have already been named in the United States
alone. The order contains all the different species and varieties of
fleas, mosquitoes, sand flies, gnats, midges and gall flies. Then come
the blood-sucking gadflies, and half a dozen families allied to them;
the scavenging syrphus flies, the bots that trouble cattle, the house
flies and stable flies of deservedly bad repute; and, lastly, the
horseflies, bee parasites, and botflies. The popular interest in these
insects is confined to the flies of our houses and stables, and to the
mosquitoes. In fact it is in the relation that the flies mentioned,
and some others, bear to public health and comfort, that this group of
insects is important at all to any but the special student.
BEETLES AND THEIR GRUBS
The beetles (order Coleoptera) make up a very distinct and natural
group of insects, characterized by the horny or leathery texture of
their forewings, or "elytra," which serve as cases for the folding
membranous hind wings alone used in flight. These elytra, when closed,
usually cover the whole hind body. They are strengthened with ridges
around their edges, and marked with a series of longitudinal furrows
and often also with impressed dots. The hind wings are sometimes very
small or wanting; in such cases the elytra are often fused together
along their middle edges (suture). The head is usually extended from
behind forward, having therefore a large crown and a small face; the
feelers are very inconstant in form; the mandibles are always developed
as strong biting jaws; the prothorax is free and movable; its tergite
(pronotum) is a very prominent feature in all beetles, reaching back to
the origin of the elytra.
The beetles undergo a complete metamorphosis, and the larvæ, called
"grubs," have various shapes, while the pupa is "free," that is,
closely similar in development and appearance to the adult. Beetles
are world-wide in distribution and more than 100,000 species have been
catalogued. They are divided into a great number of families, among
which those mentioned below contain the most noteworthy forms.
The tiger beetles are large-headed, predacious forms, most numerous
in the tropics, which live in holes in the soil and rush out to seize
passing prey. The ground beetles (Carabidæ) are a very extensive
family, represented in all parts of the world, and are insect hunters,
destroying hosts of injurious insects. Most of them are black or brown.
The Dyticidæ and Hydrophilidæ are aquatic families, including some
of the largest and fiercest of carnivorous beetles, the terrors of
ponds and marshes, where they prey not only on other insects and their
young, but on tadpoles, small fishes, etc.; and their grubs are quite
as savage. The rove beetles (Staphylinidæ) are a very large family of
narrow, elongated species, which are very active; they feed mostly on
small insects, worms and snails. The carrion beetles belong to the
family Silphidæ, the smaller among which live in moss and under tree
bark, and the larger genera contain the noted "burying beetles." Some
groups of very minute, ground-keeping species lead to the familiar
"ladybirds" (Coccinellidæ), a large and world-wide family of small,
rounded beetles, usually brightly spotted, which frequent plants of all
sorts, and feed chiefly on aphids. Some quaint superstitions pertain
to these pretty insects, that should be attracted rather than repelled
when they visit window gardens and greenhouses, which they will
endeavor to clear of the "greenfly" and similar injurious plant lice.
Passing over several inconspicuous families we come to the dermestids,
very small, dark-colored beetles of elliptical outline, some of whose
genera are among the worst of household pests, and have been spread by
commerce throughout the civilized world.
Some of the dermestids are troublesome as museum pests; others attack
food in the pantry, store, or warehouse. "Drugs do not escape their
attack, species devouring even cantharides and tobacco; woolen and silk
goods, feathers and furs, are ruined if left long exposed to their
depredations; and one species is accused of biting young doves....
_Anthrenus scrophulariæ_, probably introduced into America from Europe,
has received the names carpet beetle and buffalo bug, on account
of its habit, both as larvæ and imago, of destroying carpets. This
beetle measures about four-fifths of an inch in length, and is black,
brick-red and white, the last crossing the back in two zigzag lines.
The point of attack is the nailed-down edge or the lines of the seams."
Who has not been amused at the labors of the big black beetles that
one meets in summer on dusty paths rolling balls of fibrous material.
These "dung beetles" are the American cousin of the scarab of the
ancient Egyptians, which typified to them many mystical ideas connected
with life, present and eternal. With its shovellike head and broad
forelegs the beetle gathers and compacts the material it wants, and
begins to roll it, sometimes with the help, more often against the
struggles, of another beetle toward a prepared nest-hole. Arrived there
an egg may be inserted into it, and then the rounded mass is left as
food for the grub to be hatched from the egg; if no egg is inserted,
the ball becomes simply a mass of stored food to be eaten by its
maker. Processes vary among the 7,000 or more known species of this
cosmopolitan family.
Not all of this great family are dung beetles, however, or scarablike.
Here belong the May bugs and June beetles that come blundering around
lighted country residences in the evenings; and it is their fat white
grubs that, hatched from eggs buried in the ground, devour the roots
of the grass and other plants, spoiling the lawns and strawberry beds.
The robin is their most effective enemy. Among the lesser genera are
those of the rose bugs, hated pests of the horticulturist and fruit
grower. In that section of the family known as the cetonians are found
the giants of the race, the West African "goliaths," four inches long;
the tropical American Hercules beetle, exceeding six inches long, half
of which belongs to the forward-reaching horn of its helmet, the South
American elephant beetle which is even more bulky, and several other
giants, the males of which have the head ornamented with fearsome
protuberances.
Other families of beetles are the Buprestidæ, whose larvæ are injurious
to trees by boring into their wood; the Elateridæ, or snap beetles,
which arch their bodies and leap when they happen to fall on their
backs, and among which are found the many varieties of brilliant
"fireflies" for which the American tropics are famous. The larvæ of
the elaters mostly live in decaying wood, and are the justly hated
"wireworms" of our gardens. Then there are the Meloidæ, that include
the blister beetles, or oil beetles, one of which is the cantharides of
the pharmacopoeia; and there are a great many more.
HONEY MAKERS AND PLANT STINGERS
A long shelf is required in the naturalist's library for the books
relating to the Hymenoptera of America alone--our wasps, bees, ants,
and their smaller relatives, which engage everybody's attention by
their social habits and amazing display of instincts. Besides these
three principal and familiar groups the Hymenoptera include a host of
other insects of great but inconspicuous importance. In large part
these are parasitic on other insects or their larvæ, or even on their
eggs, and some are the most minute insects known, virtually invisible
to the unaided eye. Scarcely larger are the makers (Cynipidæ) of the
galls so commonly seen on trees and plants in which they breed. Another
group (Chalcidoidea) cause the swellings that disfigure plants by
placing their young within their tissues, such as the "joint worms"
that ruin grain; and here, again, many species are parasitic on grubs.
Then there are the sawflies (Tenthredinidæ), resembling bees, whose
ovipositors are like a pair of saws with which these insects are able
to bore holes into wood, within which the egg is placed and the young
larva burrows; of these are many and various kinds, all injurious to
trees, garden shrubs and plants, each kind restricted to a particular
sort of plant.
Perhaps even more numerous are the ichneumon flies, whose service in
the world seems to be to keep the insect hosts down to the number
possible to exist and at the same time to allow men and other animals
to live. Their method of life is to deposit their eggs on or in the
bodies of other insects, usually in the larval stage, where they
hatch and thrive by the slow death of the host. The ichneumon flies
are the dread of all other insects, most of whose adaptations for
self-preservation are directed against this insidious and universal
enemy to insect life.
None of the foregoing Hymenoptera live in colonies or by social
methods. That plan belongs to the four most advanced divisions--wasps,
bees, termites, and ants. Even among the wasps and bees, however, the
larger number of species live alone or in single families, each female
constructing a solitary receptacle for her purpose underground, in
soft wood or otherwise. Most species store with the egg placed there
half-dead insects, or pollen, etc., as food for the grub, which
receives no further attention; but a few, such as the big digger wasp
(Bembex) take food to the grubs daily. Another class of both wasps and
bees form nests of several cells containing eggs, and thus in spring
families are originated by fertilized females that have survived the
winter. As the larvæ develop in succession they are fed by the mother,
and presently mature sufficiently to aid her in caring for the younger
grubs. Out of such family nests, or "combs" of paper cells, often
attached to the ceilings of sheds and porches of rural houses, have
apparently developed the mutually helpful societies of bees and ants,
which are often of surprising extent and permanency.
The prosperity of these social insect communities, whose instincts,
habits, and products amaze us, is due to an organized division of
labor in the community between three classes of "citizens"--(1) the
comparatively few males, whose whole duty is to fertilize the queen
mother and supply the community with progeny; (2) the selected and
specially nourished "queen"; (3) a vast number of nonreproductive
females, the "workers," that build and guard the nest, gather and
preserve stores of food (honey), and nurse and rear the young. In
some groups the duties of the workers are subdivided among classes
that differ in size and equipment. It is these female workers, or
their correlatives among the solitary bees and wasps, that sting,
their useless ovipositors having been transformed by the addition of
poison into deadly weapons by which they procure their prey, or defend
themselves, or both. It is this division of labor, and attendant
habits, that especially characterize the higher Hymenoptera, and give
to the order the supreme rank it occupies among insects.
CHAPTER XII
AT THE DOORWAY OF THE "UPPER CLASSES"
PRIME SIGNIFICANCE OF THE NOTOCHORD
We have been considering up to this point one of the two primary and
natural divisions of the animal kingdom--that into Invertebrates and
Vertebrates. Although these are terms made familiar by long usage, and
refer to the absence or presence of a backbone composed of jointed
sections (vertebræ), a truer conception of the distinction is had by
regarding the first as animals whose skeleton, or frame, that gives
support to the muscles and other soft parts of the body, is exterior;
and the second as animals whose skeleton is interior. The one is, in
scientific language, an "exoskeleton," or more or less hardened outer
shell from the inner surface of which the organs grow and maintain
their attachment and leverage for work or protection; and the other an
"endoskeleton," around which the organs and integument are accumulated
by growth, and by means of which the animal's strength is maintained,
the interior bones--of which the chief is the spinal column, or
backbone--giving a firm fulcrum for the operation of the muscles and a
support and protection for the vital organs.
* * * * *
All the vertebrates are included in a single phylum--Chordata. This
term has supplanted in zoölogy the old term Vertebrata (now reserved
as a class name only), because it is more comprehensive and precise.
Professor Harmer says:
"The axis of the backbone of all vertebrates is formed by an elastic
rod known as the 'notochord,' which lasts throughout life in some of
the lowest forms, but in the higher forms appears only in the embryo.
The universal occurrence of this structure has been regarded as the
most important characteristic of the Vertebrata and their allies, which
are accordingly grouped together in the phylum Chordata. The members
of this phylum are further distinguished from other animals by several
important features. Of these one of the most important appears to be
the existence of lateral outgrowths of the pharynx, which unite with
the skin of the neck and form a series of perforations leading to the
exterior. These structures are the gill slits, and in the fishes their
walls give rise to vascular folds or gills. With the assumption of a
terrestrial life the higher vertebrates lost their gills as functional
organs, respiration being then performed by entirely different organs,
the lungs. But even in these cases, the gill slits appear in the
embryo.... Another fundamental characteristic of the Chordata is given
by the central nervous system, which lies entirely above the alimentary
canal, just dorsal to the notochord. Not only does this position of the
nerve centers distinguish the Chordata from the Invertebrates, but a
further point of difference is found in the development."
This definition requires the inclusion of various creatures very unlike
"vertebrates," and the phylum therefore embraces three subdivisions:
1. Adelochorda--marine wormlike creatures having a notochord in
the anterior of the body, and gill slits, both persistent; 2.
Urochorda--the ascidians or tunicates, small marine creatures, some
fixed along shores, others free-swimming and in some cases united into
swimming colonies (e. g., the salpæ), the tadpolelike larvæ of which
show a notochord in the tail; and 3. Vertebrata.
This last great subphylum is divisible into seven grand natural groups
with the rank of classes, namely:
1. _Acrania_--Lancelets (Amphioxus).
2. _Cyclostomata_--Lampreys; hags.
3. _Pisces_--Fishes.
4. _Amphibia_--Amphibians.
5. _Reptilia_--Reptiles.
6. _Aves_--Birds.
7. _Mammalia_--Mammals.
The first of these seven classes, the Acrania, has usually, heretofore,
been set apart as a subdivision equal in rank to the subphyla
Adelochorda and Urochorda, and the remaining six classes were grouped
into a coordinate subphylum Craniata, denoting that they alone have
a distinct head (cranium); the reason was that its members, the
lancelets, have no spine, but only a notochord, which, however, extends
from end to end of the body above the digestive organs, and persists
in the adult and throughout life. The lancelets (amphioxus) are small,
fish-shaped creatures that burrow in the sand of the seashore, usually
leaving only the head exposed, and sucking in a continuous current
of water which brings with it minute food. They breathe through gill
slits. The reproduction is bisexual, and by eggs.
The significance of the Acrania in this phylum is that they represent
a very early ancestral stage of the stock from which the higher
vertebrates (Craniata) have developed, and from which they themselves,
of course, have also diverged to a certain degree; and it is because
they retain many primitive characteristics that the study of their life
histories has engaged the attention of so many eminent zoölogists and
has thrown so much light on the evolutionary history of the "higher
animals," or vertebrates.
THE ROUNDMOUTHS--LAMPREYS AND HAGS
Popularly included among fishes, the lampreys and hags of the class
Cyclostomata (roundmouths) differ from true fishes by the possession of
a suctorial mouth devoid of functional jaws, by the single olfactory
organ, and by the absence of lateral appendages, or paired fins.
They have an eellike form and method of travel, and some species are
a yard in length. They are bisexual, discharging both eggs and milt
into the water to become fertilized by accidental contact. Lampreys
ascend the rivers to spawn, however, and there make little heaps of
pebbles, carried and piled with the mouth, in which the eggs find some
protection from the many egg-eaters in all streams. Most, if not all,
of the migratory parents die after spawning. From the eggs hatch larvæ
that undergo a metamorphosis. Lampreys live on small crustaceans,
worms, and so forth, eat carrion, and also attack living fishes. The
tongue, like the interior of the mouth, is armed with teeth. They
are in the habit of attaching themselves to stones in order to hold
themselves against a river current, breathing meanwhile by taking water
directly into the pouchlike gill chambers and expelling it, instead of
sucking it through the mouth and passing it out of the gill slits. In
ancient Rome the big sea lampreys of the Mediterranean were eaten as a
delicacy, and even cultivated in landlocked ponds, and they are still
highly prized in some parts of Europe.
The hags are an even more primitive group of cyclostomes that live in
the mud of shallow seas and are too abundant on both our coasts, where
they are a pest of the fisheries. Their general habits are similar
to those of lampreys, but wherever possible they attach themselves
to fish on which they feed. The hag is particularly destructive to
fishes caught on "set lines" of hooks, or in nets, and the loss thus
resulting on the coasts of California, in Japan, and in some European
fisheries is very serious. As these cyclostomes have no scales or
other hard parts to be preserved except a few teeth, no fossil remains
are certainly known, but it is the opinion of paleontologists that
otherwise the class might be traced to the earliest Paleozoic time.
CHAPTER XIII
FISHES--THE ARISTOCRACY OF THE WATERS
In beginning, with the fishes, an account of the typical vertebrates,
it will be well to point out the structural features in which all
agree. Vertebrates are bilaterally symmetrical animals, with an
internal skeleton, the axis of which is composed of similar segments
(vertebræ) and divides the body into a dorsal and a ventral portion.
This skeleton is first formed in cartilage, and remains so, or it
may become more or less hardened by deposits of lime, or completely
transformed into bone. The anterior end of the vertebral column
(backbone) carries a capsule (the skull) inclosing the brain. When
limbs are present there are never more than two pairs. The nervous
system consists of a brain and spinal cord from which trunk nerves
arise and ramify throughout the body. The blood is first driven to the
gills, or to the lungs, as the case may be, by means of a heart having
either one or two auricles, and after it has traversed the body through
arteries and veins it returns to the heart. The stomach, liver, and
other viscera, lie in the ventral part of the body. The skin produces
a protective covering characteristic in each division of the class, as
scales for fishes, feathers for birds, and so forth.
Fishes are vertebrates fitted to live in water. Their typically
fusiform shape is that best adapted to progress through the rather
dense medium they inhabit; and their limbs are swimming organs, or
"fins." These are of two kinds, "paired" and "median." The former are
the pectorals, one on each side of the forward part of the body, and
the pelvic, or ventral fins on the belly and near together; these four
serve, like the bilge keels of a ship, to maintain stability--prevent
rolling over--rather than for progression. The median fin is vertical,
and extends around the tail from the middle of the back to the end,
when it is complete; but in most cases it is represented by an upright
fin, the "dorsal" on the back, by the "caudal" fin fringing the tail,
and by the "anal" fin at the vent. The powerful caudal fin is the
principal agent in swimming, aided by undulatory movements of the
dorsal and ventral fins; and it has a twisting action that drives the
animal forward as does the rolling of the oar in "sculling" a boat.
The median fins are developed from the skin, and are supported by a
skeleton system of their own, not connected with the spine. In most
fishes the upper and lower halves of the caudal fin are alike, and the
tail is symmetrical, but in sharks and some others the end of the spine
curves upward and the lower wing of the tail is much larger than the
upper; in the former case the caudal fin is said to be "homocercal,"
and in the latter "heterocercal."
The fins of fishes are in many species modified and adapted to purposes
remote from swimming or balancing. Thus it is the first dorsal fin of
the remora that has become the sucker on its crown; in the angler the
first rays of the back fin are lengthened and lobed to form its "lure,"
and elongation of various fin rays as feelers, or light bearers, etc.,
may be found elsewhere. The pectorals are enormously enlarged to make
wings for the flying fish and the gurnard, and to give a substitute for
legs to the Oriental gobies that like to go ashore, while the ventrals
are transformed in certain fishes of swift streams into organs by which
they can fasten themselves to the bottom or climb against a cataract.
The skin of fishes is rather thick and tough, and abounds in glands
that secrete mucus, and in cells that secrete the hardening, or
protective, denticles and scales that form the coat of most species,
and which differ widely.
Louis Agassiz distinguished four kinds of scales--placoid, ganoid,
cycloid and ctenoid. The first named occur only in the selachians
(sharks and rays) and are variously shaped particles of lime that
prick through the skin, which makes excellent polishing material when
prepared as "shagreen." These "denticles" in the skin become teeth in
the mouth without change of structure, and the great spurs with which
the "saw" of the sawfish is armed are only extreme instances of this
special adaptation.
Ganoid scales are such as formed the armor of the great extinct tribe
of ganoid fishes, a remnant of which survives in our gar pikes, or
billfish. In some of the fossils they are roundish, and overlap, but
in modern ganoids they are rhombic in shape and plate the body edge
to edge, connected by toothlike processes that articulate with the
adjacent scales, and permit flexibility in the body. The outer face of
the scales is enameled, like teeth, beneath which is a layer of bone
substance and the teeth in the mouth are only modified scales.
Cycloid and ctenoid scales are those of ordinary fishes, and are
precisely alike, except that the hinder, or attached, end of the latter
is split into a comblike fringe. They have a rounded or often polygonal
form, are composed of lime, and are translucent, thin, elastic, and
overlap like shingles on a roof. The scales of fishes increase in size
with the animal's growth by additions to the exposed rim, and as these
accessions may be observed, by counting them the age of the fish may be
computed, when checked by certain other considerations.
The colors of fishes are produced by pigment cells, both in the skin
and on the outside of the scales; and by a peculiar tissue composed of
secretion products called "iridocytes." These, by their various ways
of reflecting light, and by the color elements contained in them, give
rise to the different hues of fishes.
Fish show their inferiority as a class by retaining the method
of respiration by means of gills characteristic of the aquatic
invertebrates. The gills are composed of bright red tassels set on
hoops that encircle the throat, and are usually covered by a movable
flap--the "gill cover." Under this flap, the neck of the fish is
perforated by crescentic slits. The fish normally breathes by taking
gulps of water into the mouth and throat, and squeezing it out through
the gill slits; during its rhythmical passage over the thin gills the
oxygen of the dissolved air is absorbed by the hæmoglobin of the red
blood, and is carried away to incessantly revivify the body; and at the
same time carbon dioxide is set free and got rid of in the outgoing
stream.
An organ peculiar to fishes is the air bladder--a sac lying under the
backbone and communicating by a duct with the stomach. It is not only
of service in respect to buoyancy, but is accessory to respiration. In
spite of its name, however, it does not contain air, but a gas rich
in oxygen and nitrogen which is secreted by certain arteries and is
carried away when needed by other blood vessels, as fat and starchy
substances are stored elsewhere and may be drawn upon when food falls
short. Nevertheless, the chief function of the "swim bladder," which is
exceedingly varied in shape, is to render the fish of the same weight
as the water in which it lives. In this condition of equilibrium the
fish swims with a minimum of muscular effort. A consequence of the
organization, however, is to restrict the vertical range of each fish
and kind of fish, because any considerable movement up or down means a
change of pressure. This will bring about the expansion or contraction
of the volume of gas in the air bladder and thus alter the specific
gravity of the animal. Such automatic adjustment is limited, however,
and practically prevents a fish rising or falling far above or below
the depth to which it was born; and the fatal effects of violent change
are seen in those fishes brought up in explorers' dredges from great
depths, the air bladders of which are invariably so distended as to
kill the animal. Nevertheless, some species seem able to migrate from
and to great depths; and temperature is perhaps a greater factor in
vertical distribution than the air bladder, the adjustments of which
must be slow. The great body of fish life in the sea resides within
about 300 fathoms of the surface.
Fishes have a brain and a system of nerves and sense organs varying
according to rank, and outlining the higher developments of the nervous
system as found in mammals. Of the sense organs the most peculiar are
the small sensitive bodies scattered in various parts of the skin,
fins and mouth, called "end buds," each at the terminus of a nerve
fibril. These buds seem to carry the sense of feeling, and are said
to be represented in mammals by the taste buds in our tongues. They
are aggregated in a narrow band along the side of the fish, and in a
maze on the side of the head, called the "lateral line," the course
of which is plainly visible on many fishes, as for example, on the
sunfish of brooks and ponds. This lateral line consists of canals in
the skin, opening to the surface by pores, and reached by branches
of large nerves. The use of the lateral line to the fish is not well
known, but it is believed that its cells are of service in balancing
the body. As blind fishes are able to avoid obstacles with the greatest
ease when swimming, it is possible, in the opinion of Dr. Bridge, that
these organs enable their possessors to appreciate undulatory movements
in the water in the shape of reflex waves from contiguous surfaces or
objects.
One feature of the lateral line on the head are the "auditory organs,"
varying with the kinds of fish, which contain semicircular canals, with
otoliths, in the more or less complete form of an internal ear. Each is
reached by the auditory nerve from the brain and is also connected with
the air bladder in many cases. Whether this is a true organ of hearing
in the ordinary sense, or whether it serves some other purpose, as, for
instance, the regulation of the distension of the air bladder, is not
known. The old question of whether fishes hear sounds made above the
water is not yet answered scientifically; but it is probable that they
can feel the jar of sounds made in the water, which is equivalent to
hearing, as far as it goes. Fishermen have a saying that if you swear
you won't catch any fish--a good precept, anyhow; but more effective is
the care anglers take not to step heavily, nor to make loud, jarring
noises, near the bank of the stream in which they mean to cast their
lines.
The great majority of fishes have good eyesight, and the eyes
themselves are similar in structure to those of the higher land
animals; but it seems probable that the range of vision is short.
The eyeballs are usually large in proportion to the size of the
head--sometimes strikingly so--and are movable; while the situation
in the head is naturally such as to give the most advantageous vision
according to the habit of life. Thus those of sharks, and other
predatory sorts that live by the chase, are well forward; while those
of bottom-feeders, and especially rays, flatfish, anglers and the like,
are in the top of the head, looking upward. Nocturnal species have the
largest eyes, but the unfortunate cave fishes, whose whole life is,
and has been for unnumbered generations, passed in the total darkness
of caverns and underground streams, have lost the use of their eyes
altogether, and the organs themselves have disappeared by atrophy.
Blindness is found also in oceanic families that dwell far below the
penetration of daylight; yet many fish of the Stygian depths, which, so
far as we know, never leave that region of utter blackness, possess big
and apparently efficient eyes. Most of the blind or nearly blind sea
fishes thus far obtained have been in hauls from a depth of about 1,200
fathoms. It is believed that the ability to see in deep-sea fishes is
connected with the light-giving (phosphorescent) organs possessed by
many of them, and with the fact that animals of all sorts on the sea
bottom in deep water are luminous, and so reveal themselves to the
predatory creatures that feed on them, while the fishes' own "lanterns"
enable them to chase moving prey, avoid enemies, and find mates.
Fishes have efficient olfactory organs situated near the snout, and in
the higher families they are in pairs and become true, but internal,
nostrils. The sense of smell is strong, and perhaps more useful on
the whole than the sense of sight, especially among the carnivorous
species. Sharks seem to follow their prey by scent like hounds.
All these senses serve instincts related to the necessities of the
individual and the race in each kind of fish. This is sometimes
manifested in what appears to us as cunning means of safety or of
provision for young; but discriminative intelligence is small in
fishes, which probably are able to learn little more than that at
certain places and times food may be had, as is illustrated in
cultivated fish ponds, where the captives from infancy onward are fed
regularly. Anglers tell of old trout that refuse year after year to
be beguiled by their experiments in flies; but it is doubtful whether
this is anything more than an increased wariness due to frequent
disturbance. The remora is, or has been, used by the Caribs of the
West Indies and the negroes of Zanzibar for catching sea turtles, a
line being fastened to a captive and comparatively tame remora carried
in the boat, and the fish turned loose as soon as a turtle is seen
at the surface. The remora will make a bee line for the turtle and
attach itself firmly to the shell so tenaciously that both animals
may be dragged to the boat. It is to be noted that the fishermen
see the turtle near by before they dispatch their living grapple,
and it is doubtful whether the remora has any notion of what it is
doing. It simply obeys repeatedly an instinct. This very low degree of
intelligence is doubtless owing to the almost invariable environment of
piscine lives, in which virtually nothing occurs to suggest any change
in traditional habits or arouse into activity any rudiments of mind a
fish may possess. Mental inertness is characteristic of aquatic animals
of all kinds, as contrasted with the correlated activity of body and
mind of land animals stimulated by varied and changeable surroundings.
The breeding habits of fishes furnish one of the most interesting
chapters in their natural history, and many surprising facts have been
learned within a few years in regard to the reproduction of marine
species, of great value to the sea fisheries.
In all fishes the sexes are separate. As a rule females are larger than
males, and more numerous. The size of the egg in any group depends on
the amount of food yolk stored for the sustenance of the young, which
must thrive by its absorption until it is able to eat by its mouth. The
largest are the eggs of sharks, etc. (Elasmobranchii), which resemble
fowls' eggs. The European dogfish, perhaps two feet long, has eggs an
inch in length, each in a flattened leathery "purse" having tendrils at
the ends that twine about weeds and anchor it like a rocking cradle.
The similar egg capsules of skates, dropped on the sand, are common
objects on all beaches. Elasmobranch eggs are deposited at intervals
throughout the year and, as they are exposed to comparatively little
danger, are few in number. In most other orders spawning, as the egg
laying of fishes (and aquatic amphibians) is termed, is limited to a
short period, the eggs are small, and the number of eggs produced is
often enormous--five or six millions in a large cod, for example.
In the majority of Teleostomi--a group name embracing all the modern
bony fishes--the eggs are voided broadcast into the water, the males
at the same time emitting clouds of milt. These eggs are of two kinds,
one that sinks and, often being glutinous, sticks to some object on or
near the bottom, and is called "demersal"; and another that contains an
oil bubble, making it so buoyant that it floats, and these latter are
called "pelagic." The fertilization of such spawn must be accidental,
but as the milt and the eggs sink or drift together the number that
come into fertilizing contact is no doubt considerable. Nevertheless,
an extremely small percentage ever reach the point of hatching, and
still fewer survive to become mature, for in addition to unfavorable
circumstances of water and temperature, every living thing, almost, in
the ocean, including the parent fish themselves, is a devourer of the
eggs and young of fish; and it has been said that the vast number of
eggs dispensed by certain species, only a single pair of which on the
average survives to maturity, is one of nature's methods of providing
food for the inferior forms of marine life.
CHAPTER XIV
SHARKS--THE TIGERS OF THE SEA
Only a rapid systematic sketch of the class Pisces, fishes, is
possible, distinguishing the main divisions, alluding to their history,
and touching here and there the most characteristic genera and species
of the thousands that have been described by ichthyologists. The
primary division is into three subclasses:
1. _Elasmobranchii_--Sharks, skates, rays, etc., having a
cartilaginous skeleton.
2. _Teleostomi_--Ordinary fishes, having a bony skeleton.
3. _Dipnoi_--Lepidosiren, and many extinct, primitive families.
In the Elasmobranchii, or selachians, the skeleton consists of
cartilage, as in the embryos of all fishes--a sign of their primitive
and inferior rank; but parts of it in various species become hardened
by depositions of lime, especially in the vertebræ, in spines and
teeth, parts often well preserved as fossils. Sharks' teeth are among
the best known of fossils, and before science established their
true character were commonly called "birds' tongues," or "snakes'
tongues." The sharks, first to be considered, are a very ancient race,
originating in early Paleozoic times. Of the many curious extinct forms
that terrorized the Silurian, Devonian, and Carboniferous seas, a few
representatives still exist in the South Pacific, notably the cow
sharks; an eellike Japanese species with frilled gills that Dr. Garman
thought might easily fill the rôle of "sea serpent"; and the quaint
bullhead, or Port Jackson sharks of Australian waters; all these are of
small size and the last named represents the principal race in Mesozoic
seas. Their flat teeth form a sort of pavement of the mouth, enabling
them to crush the mollusks and crabs on which they chiefly feed.
Next in a rising order of classification, and of somewhat more recent
origin geologically, is the European family of dogfishes (Scyllidæ),
which includes also the "ground sharks" of warm seas--deep-water fish
eight to twelve feet long, that creep about near the bottom in search
of prey. Next come the large pelagic sharks of the family Carchariidæ,
which contains about sixty species, scattered over all the seas,
and one confined in the fresh water of Lake Nicaragua. One section,
that of the "topes" and "hounds" of temperate and warm seas, are
bottom-feeders, and have pavementlike teeth adapted to crushing and
grinding the shellfish on which they subsist; but most of the family
are swift and powerful hunters of fishes in the open sea, such as the
dreaded tiger shark of the West Indies, which is variegated in color
and sometimes twenty feet long, and the equally big blue, white, dusky,
and other ferocious bandits ranging not only the tropical seas, but
more common in northern oceans than is generally supposed. The teeth in
these and other hunting, fish-catching sharks, are shaped somewhat like
arrowheads, in some cases smooth-edged and single-pointed, in others
with sharply notched edges and side cusps. They are set in the flesh of
the jaw, unattached to the underlying bones, in concentric rows, one
close behind the other, all round the front of the mouth, both above
and below, and look and act like a set of saws, a sidewise movement of
the jaws sawing through an object seized in a single bite. As fast as
the front row of teeth are lost they are replaced by those of the row
immediately in the rear. But all gradations exist between these and the
mosaic of "pavement" teeth in the topes. The mouth of these hunting
sharks is on the underside of the head, and they must turn on their
backs to seize anything floating or swimming near the surface.
This is the group that furnishes the "man-eater" stories--tales
that have been substantiated by so many terrifying examples that
no precaution of safety against them should neglected, even on our
northern coasts, where the ravenous blue shark, or the dusky species,
may appear at any time, even in harbors. A few years ago a man was
seized by one of these sharks in a little inlet of New York Bay, at
Freeport, New Jersey.
Blue sharks are nocturnal in habit, and are sometimes seen asleep
or resting in the daytime, with the tips of the two dorsal fins,
characteristic of this family, in sight above the surface of the
water. "So gentle are they in their movements," says one authority,
"that, unlike many other monsters of the deep, they do not disturb
the luminous creatures, which at the same time will be lighting every
wavelet with their phosphorescence. Blue sharks are not very particular
as to what fish they take as food, though those which are gregarious in
their habits, like mackerel, pilchards, and herring, are most commonly
hunted by them." A curious relative of these "man-eaters" is the
hammerhead, in which the sides of the head are extended in two great
lobes, with eyes at their extremities; this kind of shark is greatly
feared in the East Indian seas. In spite of it, and the prevalence of
other huge and voracious sharks, the Arabs about the entrance to the
Red Sea, and the natives of other Oriental shores, will swim and dive
in the open sea, apparently without fear, where Europeans would be
devoured almost instantly. Another peculiar shark is the thresher, well
known in the North Atlantic as elsewhere for its strategic maneuvers.
It grows to a length of fifteen feet, of which the tail forms at least
one half. Quite inoffensive to man, the thresher feeds on the shoals
of smaller teleosts, such as pilchards, herrings, and sprats. When
feeding it swims in gradually diminishing circles around the shoal,
splashing the water with its long tail, and keeping the victims so
crowded together that they become an easy prey. Hammerheads and their
relatives, the "bonnet" sharks, frequently visit both our shores in
summer.
The porbeagles are big, fierce sharks of the family Lamniidæ, the
giant of which is Rondelet's shark, known to attain a length of more
than forty feet. The triangular, saw-edged teeth of such a one measure
nearly an inch across the base; but similar fossil teeth, and also
others dredged from the bottom of the South Pacific, are much larger,
indicating sharks beside which Rondelet's would be small, and in all
probability these monsters survived to a comparatively recent date. A
remarkable lamnoid shark of Japanese deep waters has the snout produced
into a long, flat, flexible, leaflike blade.
Closely related sharks, almost as big, are well known in the North
Atlantic. Two of them, the "bone" and the "basking" sharks, are killed
by fishermen whenever encountered for the sake of the oil in their
livers. The name of the second refers to its habit of loafing and
sleeping on the surface on fine days, when a boat may go so near it
that a harpoon may be planted in its hide before it will move. The real
"basking shark," however, is a gigantic species of Rhinodon, of the
Indian and South Pacific oceans, with a very bulky body that may exceed
forty-five feet in length. Both of these ponderous fishes are sluggish,
and are not dangerous to man, except that a blow of the tail may smash
a boat when an attempt is made to harpoon them at close quarters. They
feed on small fishes that go in shoals, and also, perhaps, on seaweeds.
The last sharks to be mentioned are American dogfish of the family
Squalidæ (another family, Scyllidæ, are known as "dogfish" and "hounds"
in Great Britain), which are numerous and greatly hated along both our
northern coasts. The common gray dogfish of the North Atlantic and
California coasts is the spiny one (_Squalus acanthias_), the larger
females of which will weigh about eight pounds. It makes its home in
deep water off the New England coast, approaching the shore when the
mackerel come in and disappearing when they depart; but dogfish are
to be found all summer in shoal places such as George's Bank, and
irregularly in shore inlets. In the late autumn they become numerous
on the Grand Banks, and stay there until the winter's cold drives them
away into deeper water. Everywhere these small sharks are a nuisance
to the fishermen, by tearing nets and by eating the cod, etc., hooked
on the trawl lines. Formerly they were regularly hunted for the oil in
their livers, which is especially valuable for certain purposes, as in
harness making, but the price of this oil is now low, and the fishery
has declined.
The economic use of sharks is not great except as producers of oil.
The flesh is good food, but not popular. In China sharks' fins are a
favorite substance for delicate soups and sauces, and a very large
trade in catching sharks for their fins is carried on near Bombay, and
in East Indian waters.
The ugly angel shark, with its squat, toadlike body, big, winglike side
fins and thick tail, occupies an intermediate place between the sharks
and the rays. It creeps along the bottom, and is remarkably voracious.
The chimæra is another queer "monster" of the deep.
CHAPTER XV
THE FEARFUL DEVILFISH AND OTHER RAYS
The rays (order Raiæ) differ from the sharks superficially rather than
in structure, where the most important difference is the position of
the gill clefts, which are lateral in the sharks and ventral in the
rays and skates, as the smaller members of the order are called. The
majority of them have a flattened, depressed body, from which the
broad, expanded pectoral fins are scarcely distinct, while the tail is
usually long and slender, in one family so much so that they are known
as "whip rays;" and in some a horny point at the tip is connected with
a venom gland so that its pricking is poisonous, and these are called
"sting rays." All the rays are carnivorous, but only the sharklike
forms (sawfishes and the Rhinobatidæ) actively pursue their prey. The
true rays live on the bottom and feed on shellfish and small fishes.
Most of them bring forth a few young alive, but many lay eggs in
squarish, oblong, leathery cases with tendrils at the corners by which
they become moored to eelgrass, etc; they are frequently cast up on
beaches, and go by the name of "sea purses," In the earlier stages the
young ray is much like a shark, and the enormous development of the
pectoral fins does not occur until nearly the time of hatching.
[Illustration: CATERPILLAR PROTECTED BY FORM AND COLOR RESEMBLING THE
TWIGS OF A TREE]
[Illustration: SEA HORSE PROTECTED BY FORM AND COLOR RESEMBLING THE
MARINE PLANTS AMONG WHICH IT LIVES]
The sawfishes, of which several tropical species are known, besides
one common in the Atlantic and Mediterranean, are among the most
remarkable of oceanic fishes. The body is slender, sharklike, and of
great power. The head is flattened, and the snout projects into a hard,
flat, sword-shaped beak, the edges of which are thickly studded with
sharp teeth; and this singular weapon places all the large inhabitants
of the ocean at the mercy of this powerful marauder--it is the worst
enemy of whales, even, in the warmer seas, as is the "killer" in the
Arctic region. With it the sawfish cuts and slashes, tearing off pieces
of flesh, or ripping open the abdomen of its opponent, then seizing the
detached pieces. One can easily picture to himself the slaughter when
a sawfish dashes into a school of fishes, squids, or porpoises, and
slashes right and left with his ripsaw of a beak. Some of the Oriental
species reach, and even exceed, twenty feet in length, and Dr. Day, the
Indian ichthyologist, says that such monsters have been known to cut
bathers completely in two. The saw of a twenty-foot fish would measure
six feet in length and a foot across the base.
[Illustration: THE GILA MONSTER, FEARED THOUGH ITS BITE IS NOT ALWAYS
DEADLY TO MAN
Photo, Elwin R. Sanborn, N. Y. Zoological Society]
[Illustration: THE IGUANA, A REMARKABLE LIZARD OF THE NEW WORLD
Photo, Ewing Galloway]
The most famous of the rays, probably, are the torpedos, a family with
a rounded, instead of the customary triangular outline, and a rather
short tail, species of which occur on all tropical and temperate
coasts, and are noted for their power to give electric shocks to any
living thing touching them.
The electric organs are a pair of large masses lying between the head
and the pectoral fins. These are derived mainly from four nerves, which
originate from an electric lobe of the medulla oblongata. By means of
the electric shocks which they are able to administer at will, the
torpedo rays are able to ward off the attacks of enemies, and to kill
or paralyze their prey. The action is that of a galvanic battery. The
dorsal surface is positive, the ventral negative, and the discharge of
a large torpedo is sufficient to temporarily disable a man; yet it is
not so powerful as that from a big electric eel.
The huge "sea devils" of which thrilling stories are related are the
eagle rays of the family Myliobatidæ, some of which are fifteen or
twenty feet across the "wings"; and they are among the most frightful
of the dangers to which pearl divers are exposed in their perilous
occupation. They are savage beasts, and will even attack a small boat
with men in it. The worst of these belong to the vicinity of Panama.
CHAPTER XVI
BONY FISHES--TELEOSTOMI
We come now to the fishes proper--those with skeletons of bone,
although in some of the lower forms the ossification is incomplete. The
mouth contains supplementary tooth-bearing bones that form secondary
jaws corresponding to the functional jaws of the higher craniates;
hence the group name "Teleostomi," or perfect-mouthed fishes. The body,
as a rule, is coated with scales, and a gill cover (operculum) is
always present.
The Teleostomi include four orders, the Crossopterygii, the
Chondrostei, the Holostei, and the Teleostei.
The crossopterygians are mostly strange extinct fishes found as fossils
from the Devonian down; but some have survived, and live in the
sluggish African rivers an eellike existence, of which the bichir of
the Nile is a familiar example. The Chondrostei also are largely fishes
of the Paleozoic time, but two families survive to the present--the
spoonbills and the sturgeons. Of the former one species is Chinese,
and the other is the shovel-nosed spoonbill or paddlefish of the lower
Mississippi River. It is a big, sluggish creature, that stirs up the
mud with its long flat beak, and consumes it, getting sustenance from
the minute organisms it contains. They make caviar from its eggs. As
for the sturgeons, we have five species in the United States, and one
abounds in the Black Sea and the rivers that drain into it, from whose
eggs the Russian caviar is made. One or two species are exclusively
fresh-water, but most sturgeons are migratory fishes, living in the
sea, but ascending rivers for spawning. Their food consists of worms,
mollusks, the smaller fishes and aquatic plants; and in feeding the
mouth is protruded downward in the form of a cylindrical, spout-like
structure and thrust into the mud. Our common eastern-coast sturgeon is
also a native of the Mediterranean and French coasts, and was formerly
in England a "royal" fish, reserved to the king's use.
Of the third order, Holostei or "ganoids," whose history may be traced
in fossils almost to the earliest of fossiliferous rocks, we possess
in our rivers the only two survivors: one is the many-named bowfin of
the Mississippi Valley, and the other the widely distributed billfish
or gar pike. Both these relics of a very ancient order are of great
interest to naturalists; and the names "mudfish," "John H. Grindle,"
and many others, show how well known the bowfin is to the farmer boys.
The bowfin attains a length of about two feet and a weight of twelve
pounds, and, unlike its cousins the garfishes, is covered with hard,
rounded scales; the forepart of the body is cylindrical, the head stout
and blunt, and the mouth filled with powerful teeth. It is exceedingly
hardy, enduring absence from the water for a long time, as well as
grievous injury; hence the young are the favorite bait of anglers in
the Mississippi Valley, and make interesting captives in an aquarium,
where, however, nothing else but snails can remain alive. These fish
are strong, active, voracious and gamy. They feed on all sorts of small
aquatic creatures.
The garfish (or more properly gar pike, Lepidosteus, because certain
sea fishes of another sort are also called gars) is an elongated active
fish of our rivers, covered with hard, flat, ivorylike scales set in
oblique rows, and its snout is prolonged into a bill filled with sharp
teeth. They have many peculiarities of structure indicating their
ancient ganoid lineage; and besides our common species two others are
known, one of which, the alligator gar, belongs to the Gulf Coast and
Central American rivers. These gars are nocturnal and predatory in
their habits, and in early summer resort in large numbers to shallows
to lay their eggs, which are covered with a sticky envelope that
adheres to any object on which they fall. The long bill develops after
infancy.
CHAPTER XVII
MODERN FISHES--TELEOSTEI
The lower orders of teleosts retain many characteristics of the
Holostei, and several of their families are known only as fossils in
the Cretaceous and Tertiary rocks. The most primitive survivor of these
ancient forms is the great tarpon of Florida and southward, another
species of which occurs in India--such wide differences in habitats
being an evidence of antiquity in nearly all cases among animals. The
extraordinary mormoids of northern Africa, and the eellike gymnarchus
of Gambia, are other relics of the past, as also are several other
queer African families, the barramundi of Australia, and the arapaima
of the Amazon region. The one last named is the largest fresh-water
fish known, specimens exceeding fifteen feet in length, and weighing
400 pounds, all of which is excellent food. The mother protects her
offspring which, when young, swim in front of her. Several of these
old-fashioned teleosts, like our bowfin and the primitive Dipneusti,
make elaborate nests in which their eggs are deposited, and they and
the fry are carefully guarded by the parent. In this same suborder come
the most familiar and useful game and food fishes--the shad, herring,
trout, salmon, whitefish, smelt, etc.
The shad family is a very large one, numbering about 200 species, most
of which are marine, but a few are "anadromous," that is, they ascend
rivers of fresh water to spawn in the shallows near their sources.
This is the habit of American shad, of which there is only one species
in spite of the many local names in use; and it is regarded by the
fisheries authorities as the most valuable river fish in the country
except the Chinook salmon; but the supply of it would have been
exhausted long ago had it not been for the incessant and energetic
methods of replanting of fry, artificially bred, in all the eastern
rivers, and the transplanting of them to rivers on the Pacific Coast,
the credit for which valuable public service belongs to the United
States Bureau of Fisheries.
The shad is to be found from Florida to Newfoundland. Little is known
of its life in the ocean, but in spring it approaches the coast in
great numbers, and may be had in the St. John's River in Florida in
winter, but it is not numerous until March. It next appears in the
Savannah and Edisto Rivers, and so successively northward, the height
of the run in the Potomac being in April, in the Delaware early in
May, and in the Miramichi River in New Brunswick late in May. The main
body ascends when the water temperature is 56 degrees to 66 degrees.
They come in successive schools, the males preceding the females. They
ascend the rivers, often nearly to their heads, and deposit their eggs
on suitable spawning grounds, pouring out about 30,000 in most cases.
The eggs are very small, semibuoyant, and usually require six to ten
days for hatching, depending, as does the whole operation, on favoring
temperature. After the spawning the shad show hunger, and will often
bite at an angler's fly.
"The herring is beyond question the most important of food fishes in
the Atlantic, if not in the world," declared the late G. Brown Goode,
formerly Assistant U. S. Fish Commissioner. It affords occupation for
immense fleets of boats, and thousands of men, nowhere more numerously
than in the North Sea and along the Norwegian coasts. Professor Huxley
once gave 3,000,000,000 as the number of herring taken annually from
the North Atlantic; but Dr. Goode showed that this was far too low an
estimate, and added that it probably was "no greater than the number
contained in a single shoal if it covers half a dozen square miles, and
shoals of much greater size are on record. And ... at one and the same
time scores of shoals must be scattered through the North Sea and the
North Atlantic, any one of which would go a long way toward supplying
the whole of man's consumption of herring." Herrings are surface
swimmers, and their food consists of the small organisms, chiefly
crustaceous, which have been described as "plankton" in the early pages
of this book. They themselves afford food to every predatory fish,
squid, whale, and bird that frequents their region (mainly north of the
fortieth parallel of latitude), and which has the wit and ability to
seize them. They move here and there in shoals for food, and in spring
migrate to the shallows and rivers of the northern coasts to spawn.
Besides the Atlantic herring, a very similar species throngs in the
North Pacific, and several others live in the Great Lakes and other
waters of this country.
No fishes are better known in America than the salmon, trout, and
whitefish, which are near relatives. Of the salmon there are many kinds
in all the northern parts of the world and in the open ocean. Some
ascend rivers to spawn, and some do not. Our Atlantic salmon, once so
abundant in every river from Connecticut northward, is the same as the
salmon of Europe, and the king of game fish. Now it is at all numerous
only in the Maritime Provinces of Canada, climbing the waterfalls of
those mountain streams to their very springs to deposit its eggs,
whence few individuals survive to return to the ocean. The heaviest
salmon on record is one of eighty-three pounds captured in England in
1821; an American example of forty pounds is considered very large.
The salmon of the North Pacific are of a different genus
(Onchorhynchus) and consist of several species, some Asiatic. On the
American side we have five species, and most of them have been seen in
all the rivers from central California to Alaska, Siberia and Japan;
but the blueback predominates in Fraser River and in the Yukon; the
silver salmon in Puget Sound; the quinnat or Chinook salmon in the
Columbia and Sacramento; while the comparatively worthless dog salmon
is seen everywhere. The quinnat and blueback enter and "run" the
rivers in the spring, and are caught when in prime condition, whereas
the other three run in the fall, and are more usually caught after
deterioration; hence "spring" salmon are best in fact and in trade.
The habits of the salmon in the ocean are not easily studied, but
Jordan, Evermann, and other diligent students have come to certain
conclusions from a great number of facts. They believe that the king
and the silver salmon probably remain not far from the rivers where
they were born. The blueback and dog salmon probably seek deeper
water. It is the prevailing impression that the salmons have some
special instinct which leads them to return to spawn on the same
grounds where they were hatched, but Dr. Jordan says:
"We fail to find any evidence of this. It seems more probable that the
young salmon hatched in any river mostly remain in the ocean within
a radius of twenty, thirty or forty miles of its mouth. These, in
their movements about in the ocean, may come into contact with the
cold waters of their parent river, or perhaps of any other river, at a
considerable distance from shore. In the case of the quinnat and the
blueback, their 'instinct' seems to lead them to ascend these fresh
waters, and in a majority of cases these waters will be those in which
the fishes in question were originally spawned."
As to the fate of the spawning fish, after the eggs and milt have been
voided, and their duty is done, the salmon begin to float downstream
tail foremost. The great majority of them die--certainly all at the
headwaters of the big streams; and it is the opinion of the best
judges that none ever get back from anywhere alive into the ocean
after spawning, but that the race is sustained wholly by the escape of
the young each year. It is supposed that non return from the sea, or
attempt to ascend the rivers until at least three years old.
Trout are in most cases simply small species of salmon, and a great
number of kinds inhabit the ocean, lakes, and rivers of all northern
countries, for none of this great family occur in the tropics or in
the southern hemisphere. Our western trout--the widely distributed
and variable cutthroat, the steel-head of the northwestern coast, the
beautiful rainbow trout of the Coast Ranges, and others are examples.
The common brown "brook" trout of Great Britain belongs here; but
our brook trout, the "speckled beauty" of anglers and poets, is of a
slightly different kind (genus Salvelinus), for it is classed with the
European charrs. The Dolly Varden trout of the Rocky Mountains and the
Sunapee trout are also charrs. The graylings, namaycushes, and smelts
are members of this family, whose final representative among us is the
numerous and very valuable section of whitefish and lake herrings of
the Great Lakes and Canada generally.
No family of fish is of more importance as food for man, not to speak
of the sport many of its members afford, than this; yet, doubtless, it
would have been nearly destroyed by this time had it not been for the
intelligent and patient work of fish culturists and the farsightedness
of governments, both Federal and State, and Canadian, in supporting and
extending economic replenishing of depleted waters. The organization
and breeding habits of the salmon tribe lend themselves to this work.
Passing by some families of deep-sea fishes, of small size and most
bizarre outlines, we come to the suborder that contains the carps,
catfishes and "minnows" of our lakes and streams. Here, the first
to present itself, in the large family Characinidæ, is that fierce
little brute of South American rivers, the "piranha" or "caribe," of
which Col. Theodore Roosevelt had so much to say in describing his
explorations in Brazil in 1913 and 1914. One of his companions was Leo
E. Miller, who has since published another account and increases the
bad reputation of the caribe by what he has to tell of its ferocity:
"In the Orinoco they attain a weight exceeding three pounds, and are
formidable indeed. The natives will not go in bathing except in very
shallow water, and I know of two instances where men were attacked and
severely bitten before they could escape. The fish somewhat resembles a
bass in shape, although the mouth is smaller; the jaws are armed with
triangular, razor-edged teeth; and as they travel in immense shoals
they are capable of easily devouring a man or large animal if caught in
deep water.... Usually they are slow to attack unless their appetite
has been whetted by a taste of blood from a wound; then, however, their
work is done with lightninglike quickness.... To catch them we used a
large hook secured to a long wire leader and baited with any kind of
raw meat, and they always put up a good fight."
A related fish in the Rio La Plata is almost equally dreaded because of
its much greater size and formidable teeth, but it works singly; and
Africa has many similar characinids, whose flesh is good food, though
full of bones. In this order, too, is now classified the family of the
"electric eels" (Gymnotidæ) which are not, however, eels, but merely
long, cylindrical fishes, naked and almost finless. The well-known one
of the Amazon region grows to a length of eight feet and the thickness
of a man's thigh, and is justly feared. It is found only in marshes and
in comparatively shallow parts of rivers, to the annoyance of travelers
who have to ford at such points, beasts of burden being frequently
knocked down by the electric shocks. About four-fifths of the length of
the fish is occupied by the tail, which contains the electric organ.
This consists of two huge masses filled with a jellylike substance,
below the spine, and separated by a narrow median septum. This
apparatus is under the control of the fish, which by it may stun or
kill an enemy or an intended prey, even at a considerable distance.
The family of the cyprinids--the carp, goldfish, chubs, shiners,
loaches, and other "minnows" of this and other countries--contains
about 1,300 species, scattered over the whole world except South
America, Madagascar, and Australasia. All are fresh-water fishes,
feeding on vegetation and small animals; and they vary in size from two
or three inches to a six-foot carp--the original home of which, now the
cosmopolitan giant of the family, was Asia.
Next to these are placed another extensive fresh-water family, that of
the catfishes (Siluridæ). More than 1,000 species, mostly tropical,
have been described; these are grouped in eight subfamilies, among
which there is a wide diversity in shape and habits--in fact, few of
those of foreign lands look at all like the catfishes with which we
are familiar in America. Most of them are sluggish, but some actively
inhabit swift streams. They can exist not only in foul water, but
will live a long time out of this element, and some even make long
migrations overland from river to river. One or more fin rays are sharp
and poisonous in many species, as boys know who handle the little
bullhead incautiously, and an African species is able to administer
a strong electric shock. Its apparatus is not a battery of modified
muscular tissue, as in other electric fishes, but consists of a thick
coat of greasy material surrounding the whole body just beneath the
skin. Another general characteristic is the protection and assiduous
care given to their eggs and young, most species making some sort of a
nest in which the eggs are deposited and the fry kept safe from attack.
The third suborder of teleosts contains eellike fishes of the tropics;
and the fourth contains the true eels and their relatives. Our common
eel is also "common" in most of the temperate countries of the world,
but there are perhaps 150 other species of the family Anguillidæ, a
large proportion of which live altogether in the sea, many of them at
great depths, and showing strange shapes. The generation of the eel
was, until recent years, one of the great mysteries of zoölogy, as
no propagation, or any symptoms of it, ever appear in fresh water.
Finally it was discovered that a queer, almost transparent, compressed
creature, a fraction of an inch long that abounded in the surface
waters of the ocean, and which had been a puzzle to naturalists, who
called it Leptocephalus, was the larva of some sort of eel. This and
other discoveries made it plain that when the eels (of the age of four
or five years) leave the rivers and bays of all countries and coasts
in the autumn, and go out to sea, they do so to spawn, leaving their
eggs on the floor of the ocean, mostly south of Bermuda, according to
J. Schmidt. From them hatch the minute larvæ that, as they grow, rise
to the surface, and when about a year old appear as the silvery young,
called "elvers," that drift on the northward-running currents to the
coasts of Europe and North America, and ascend the streams by millions
in spring. It is not probable that any of the adult eels that go down
to the sea to spawn ever come back; and if any remain in landlocked
waters whence they cannot migrate to the salt water, they do not breed;
but it must be remembered that eels are able to travel a considerable
distance overland, at night, from one piece of water to another, and
so many may finally reach the sea.
The next suborder illustrates the remarkable difference in size and
external appearance that often marks fishes grouped together by
similarity of structure. It includes the muskellunge and all the other
pikes and pickerels, and the tiny shiners and "bait minnows" of our
rivers and brooks, and those of the Old World, one of which is the
smallest fish known; it includes several families of deep-sea fishes,
often of quaint form and with curious appendages; here, too, is the
valuable blackfish of Alaska, the amphibious, phosphorescent little
fish of Indian bays and estuaries which when salted and dried forms the
Oriental delicacy called "Bombay duck"; and here are the blind fishes
of the Mammoth and other American caves. The Heteromi and Cateosteomi
are almost equally miscellaneous assemblages, the most notable members
of the latter being the funny little pipefishes and sea horses that
lurk in the eelgrass near shore, and the males of which carry the
eggs and young about in a pouch on the belly. In the next suborder,
Perceosces, we find more strange denizens of the mid-oceanic depths,
especially the family Chiasmodontidæ, besides some surface ones of
ancient lineage, such as the gar and snakeheads of tropical waters,
the flying fish and the mullets. The Anacanthini is a small group
containing the remarkable pelagic and abyssal macrurids, the fierce
barracudas, and the most valuable single family of food fishes in the
whole list--the cods.
The cod family (Gadidæ) has many species in northern seas and a few
south of the equator. It includes, besides the cods, the haddock, hake,
whiting, coalfish, capelin, ling, and several other market fish of
importance. The cod is a deep-water fish which goes about in great
schools whose movements are not well understood, but in winter they
approach the northern shores of the continent, seeking shallows on
which to spawn, and it is then on the "banks," off New England and
Newfoundland, that the most profitable fisheries are followed. The cod
is extraordinarily prolific, and in addition to this it is propagated
artificially more extensively than any other fish.
Thus we come to the last suborder, Acanthopterygii, or "spiny-finned"
fishes, in which are classified the greater number of really modern
and more or less familiar swimmers in the "briny deep." Among American
members are the sunfishes and black bass, the perches and darters;
the great family (Serranidæ) of sea bass, snappers and West Indian
groupers; the tilefish, which appears and disappears in a puzzling
fashion; the grunting drums and their relatives of the Scienidæ; the
porgies, sheepshead, and other Sparidæ; the brilliantly colored angel
fish of the coral reefs of Bermuda and southward; the surf fishes, so
important in California; the wrasses, parrot fish, and globefishes, or
boxfishes, that inflate their horny hides when alarmed, until they bob
about on the surface like corks.
FISHES WITH PRIMITIVE LUNGS
There remains the fourth subclass--Dipnoi or Dipneusti, the lungfishes.
The reason why these creatures, whose organization is on an antique and
lowly plane, judged by fish standards, have been elevated to subclass
rank is that here the air bladder is modified into a single or double
elongated sac with many cellular spaces, and is connected by a short
tube with the mouth, and thus serves as a lung. The peculiar structure
of the heart, narial openings, and the power of existing for a
considerable period out of water, are extremely amphibianlike, and they
have by various naturalists been regarded as scaly sirens--a sort of
connecting link between the fishes and the amphibians. They are found
fossil in Paleozoic rocks, especially in the Old Red Sandstone of Great
Britain, and also in the Upper Jurassic strata in Colorado.
[Illustration: AN AFRICAN LUNGFISH
(_Protopterus annectens_)]
The surviving species (family Lepidosirenidæ) are widely scattered,
as is characteristic of all these very ancient families. A celebrated
example is the barramundi of Queensland--an elongated, flat-sided fish,
covered, except on the head, with large roundish scales, and having
paired fins that look more like flippers than fins. It becomes four
or five feet long. It lives in still pools in which the water in the
dry season becomes extremely stagnant and overladen with decomposing
vegetable matter; and it is only by rising to the surface occasionally,
and taking air into its lung, that it is enabled to obtain sufficient
oxygen for purposes of respiration. The barramundi does not leave the
water, nor can it live long in the air. It is easily captured, and is
eaten by the blackfellows.
Equatorial Africa possesses three species of the genus Protopterus,
which dwell in marshes, and feed voraciously on young fishes, frogs,
and small animals. The form is somewhat eellike, and the paired fins
are soft, slender appendages of little use, locomotion being effected
by the powerful tail. Like the barramundi this fish rises at intervals
to take a breath of air; its "lungs" are double, while that of the
barramundi is single. In the dry time of summer the protopterus burrows
deeply into the mud of the dried-up marshes, where it curls up with its
head highest and subsists wholly by breathing air until the autumnal
rains bring water enough to enable it to wake up and resume its aquatic
life. A similar eellike species abounds in the swamps, sluggish rivers
and marshes of northern South America, named Lepidosiren, and all its
habits closely resemble those of the African lungfishes.
CHAPTER XVIII
AMPHIBIANS--A CONNECTING LINK
We have now come to a class of vertebrates that in their manner of
life, and presumably in their history, connect the dwellers in the
waters with those on the lands of the globe. Dr. Gamble cites examples
from various groups of animals to show that adaptation to a terrestrial
existence is an advance on that requisite for aquatic life, and that
the critical point in the evolution of the vertebrate phylum was passed
when its members migrated from water to land. "When we come to land
animals," he says, "the problem of weight has to be considered before
that of locomotion. The lateral undulations of the body, even when
aided by unjointed paddles, or fins, are not sufficient to insure rapid
movement on land. Hence a system of levers has to be evolved, partly to
support the body, and partly to propel it. The use of joints becomes
a necessity, and we find that all active terrestrial animals, except
snakes, have jointed limbs. The critical point in the history of this
phylum is passed when its members migrated from water to the land. The
step was taken by the ancestors of the Amphibia (that is, the frogs,
toads, and salamanders). In them the breast fins of the fish have
become the jointed forelegs, the pelvic fins have become the hind legs."
How this great change from the fish fin to the five-fingered hand
occurred is, at present, just as obscure as the mode of conversion
of the arms of reptiles into the wings of birds. The answer can only
be supplied by further discoveries in the geological history of the
order, and though this history can be traced back to the time of the
Coal Measures, we find the earliest Amphibia as sharply marked off
from the fishes by their feet as they are to-day. These forefathers
(subclass Stegocephalia) are the earliest known four-footed animals,
and their fossil skeletons are found from the Carboniferous up to the
Trias, after which the race disappears. They had the general form of
newts, and many were only a few inches in length. That some of these,
at least, were terrestrial in habit is shown by the fact that they are
often found in stumps and hollow logs of sigillarias and other fossil
trees of the coal beds, especially in Nova Scotia. But there were also
species several feet in length, with formidable teeth, which were no
doubt carnivorous and predatory, so that it was well for the little
ones to seek places of safety. These stegocephalians were unmistakably
amphibians, with two condyles supporting the skull, but their skeleton
contains many features that suggest reptilian anatomy, and it is agreed
that the reptiles sprang from this stock. The peculiar feature of this
group is that their flattish heads were covered by a broad shield of
bony plates (ossified skin); and similar armor protected their bellies,
and in a few cases the back also.
Geological formations furnish no ancestral connection between the
Stegocephalia and modern salamanders; but the limbless, wormlike,
burrowing and blind cæcilians of the tropics exhibit certain
stegocephalian characteristics, especially a scaly skin, which put them
into a division (Apoda) by themselves. The remainder of the class,
that is, Amphibia (also called Batrachia) in general, have a soft,
moist, naked skin, and are naturally divisible into two orders:
1. _Urodela_--Tailed amphibians: newts and salamanders.
2. _Anura_--Tailless amphibians: frogs and toads.
Modern amphibians in general are animals fitted for life both on land
and in water. All are born from eggs hatched in water, and the young,
at first in a larval form unlike the adult condition, have external
gills adapted to breathing in that element; but in most cases they
lose their gills, and as adults acquire lungs for breathing air. This
metamorphosis of the young, comparable to that of the nymph-producing
insects, is the especial characteristic of the class. The skeleton is
of the vertebrate model, but in the Urodela is largely cartilaginous.
The skin is smooth, soft, moist, and covered only with a filmy coat
of horny texture that is molted from time to time as the animal needs
room to grow. The skin abounds in sense organs about the head and
along the sides of the body--an inheritance from the lateral line of
fishes--which are most active in the larvæ, and disappear altogether
with age in most frogs and toads, although they revive in salamanders
in the breeding season.
The skin also contains many mucus glands and other larger glands,
especially on the back. These emit under provocation a poisonous liquid
that is fatal to small animals, and very irritating to the eyes, nose,
and throat of larger ones. Most, if not all, Amphibia, says Dr. Gadow,
are more or less poisonous, and it is significant that many of the most
poisonous exhibit a very conspicuous yellow or orange upon a dark
ground, which is so widespread a sign of poison. There is no venom in
their bite--in fact, their teeth are too small, although numerous, to
let anyone fear their biting. The skin is heavily laden with pigment,
and this is displayed in many amphibians in striking patterns of bright
coloring. Certain groups possess in a high degree the power of altering
their colors to conform to their surroundings.
An interesting feature of the amphibians is that power of repairing
mutilations of the body and replacing lost parts which is so well
known in worms, hydroids, and other lowly creatures, and is termed
"regeneration." This ability is most active in young specimens.
Tadpoles frequently have their tails bitten off, whereupon new ones
grow quickly. Salamanders fight bitterly, tearing off each other's
gills and limbs, and turtles and fishes frequently bite off their
tails. New tails are generated speedily, and usually in good and
effective form, although they contain no regenerated caudal vertebræ,
but only a rod of cartilage. The ability to rebuild lost parts is much
less among the frogs.
Another notable fact is that here for the first time we meet with a
voice organ, and a real voice expressing emotions, although in an
extremely limited way. This is most noticeable in the tree frogs, which
are the most advanced of the Amphibia in organization.
NEWTS AND SALAMANDERS
The Urodela are represented throughout the whole northern hemisphere
except in desert regions, as far in North America as southern Canada,
and also southward to Panama; and in the Old World, northward to
the line of very cold winters and southward to the Mediterranean and
Indo-China. In the main, however, our genera are different from those
of Europe and Asia.
The largest and best known of American urodeles is a member of the
family Proteidæ and genus Necturus, and is widely known as "water
dog" or "mud puppy," because of the doglike shape of its head. It is
a brown, robust creature, sometimes two feet long, with bushy gills,
retained throughout its life, springing from open gill clefts in
three bright red tufts on each side of the head. It inhabits cold,
rapid streams, hiding under stones by day, and moving about at night
in search of crawfish, worms, insect larvæ, frogs, etc., and dodging
hungry snapping turtles. But little smaller, and even more ugly in
appearance, is the "hellbender," representing the family Amphiumidæ.
These blackish creatures are to be found in mountainous regions, and
hide during the day under loose rocks. By the time they are about
three years old their gills have been absorbed, and their lungs are in
service, so that they are compelled to rise to the surface occasionally
for drafts of air. They hunt at night for food, preferring crawfish
and, fishermen say, fish eggs. The breeding habits of this animal
have only lately become known, and Mr. B. G. Smith, who has made a
special investigation of them, says that the breeding season begins (in
Pennsylvania) in August, when hellbenders of both sexes come out more
freely from their rock shelters and roam about, frequently in small
companies. The small number of eggs produced are hidden in a pocket
under a loose stone; and the young, which are more like tadpoles than
the form of their parents, breathe by gills which do not completely
disappear until the animals have reached nearly their maturity.
Otherwise our salamanders are small species found in brooks, ponds, and
wet woods, and often getting into cellars and wells. Uninformed persons
think them to be lizards, and foolishly fear them, but except for the
irritation of the hands that may follow rough handling they are utterly
harmless to man or his property, and serve him by devouring great
quantities of insects and worms.
A common species in damp, neglected woodlands is the little red-backed
fellow that is so light and leaping in its movements when disturbed,
even throwing off its tail in its panic of fear. It is more terrestrial
than most, laying its few eggs in rotting wood instead of going into
the water for that purpose; and the young carry gills but a few days.
This red-backed Plethodon must not be confused with the small newts,
bright vermilion with a row of glowing spots along the sides, that are
found in woods in summer. They are young specimens of _Diemyctylus
viridescens_, which is common all over the eastern part of the United
States and southern Ontario. The parents are green, and wholly aquatic
in habits. The larvæ have gills and swim about until early autumn,
by which time their gills have been gradually absorbed, and they go
ashore, where their coats change in color from a mottled green to
scarlet. This red condition and their residence on land continue until
the autumn of the third, or the spring of the fourth year of their
lives, when they become sexually mature, resume a greenish dress, go
back to the water, and pass the rest of their lives there.
Mention can be made of only one more species--the black, yellow-spotted
"tiger triton," which is the most widely spread and often seen of
our terrestrial salamanders. It is especially noteworthy because of
the extraordinary condition of suspended development exhibited by its
larva, the famous edible axolotl of Mexican lakes, which, while still
retaining larval gills and aquatic habits, grows nearly or quite to
the size of its parents--three to four inches--and becomes capable of
breeding. Similar cases are known in certain lakes in southern Europe;
and it appears that this arrested development, together with natural
growth of body, occurs occasionally in many other amphibians. The
condition is termed "neotony," but the biological explanation of it is
not clear.
CHAPTER XIX
AMPHIBIANS--_Continued_
FROGS, TOADS AND TADPOLES
The frogs and toads of the order Anura differ from the inferior
batrachians principally in form. The tail is absent, and instead of
long, slender bodies and small legs, or none, they have short, squat,
triangular bodies and hind legs, at least, of relatively great size and
strength, whereby they progress when on land by leaps instead of by
running or creeping; some are almost wholly aquatic in habit, others
almost wholly terrestrial or arboreal. The ossification of the bones is
far more complete, the eyes and ears (represented by the large tightly
drawn membrane, the "tympanum," on each side of the head, covering the
internal ear) are well developed, and the voice is louder than in the
urodeles, which can do little more than squeak. The mouth is usually
large and cleft to beyond the eyes. The tongue, used to capture prey,
is not thrust straight forward, but thrown "overhand," as it were,
catching the insect aimed at in its curling and sticky tip.
All frogs and toads are flesh eaters, mainly of worms and insects
and larval or small water animals; but the big species, such as the
bullfrog, may seize prey of considerable size as it comes within
reach, such as young ducklings. None hunt about for prey, but, aided
by the concealing nature of their colors, wait quietly until a victim
comes within reach of their quick and accurate tongues. All lay their
eggs in still water, varying in number from a few score to several
thousands, according to the species. In all cases the young are hatched
in a larval form, called "tadpole," having a tail and gills, and
this gradually changes into the adult, tailless form of the adult.
On emerging from the egg the embryo has a very large head and body.
In a frog the external gills and the long, compressed tail are only
feebly developed when the tadpole is first hatched, while the mouth is
provided with a much developed adhesive apparatus, by means of which
the young attach themselves to plants or other objects. The tadpole
changes by regular stages into the adult form, the tail being slowly
absorbed into the body from which the legs grow out.
The Anura are separable into two suborders:
1. _Aglossa_--Having no tongue.
2. _Phaneroglossa_--Possessed of a tongue.
The Aglossa are few in number, and belong to southern Africa and
tropical America, where the group is represented by the famous Surinam
toad, whose eggs are fixed in separate pits or "pouches" in the spongy
skin of the mother's back, where they are placed as fast as laid, by
aid of the male.
The Phaneroglossa contains several families, the first of which,
Discoglossidæ, is characterized by the round, nonprotrusible tongue,
and includes species of toads belonging mainly to the Mediterranean
region, two of which are familiar to most readers of natural histories.
It may be well to say at this point that the terms "toad" and "frog"
do not express scientific distinctions, although generally applied by
naturalists to the first three families of the list, and especially
to the Bufonidæ; but mark the facts of popular observation that the
members of these families are more terrestrial than the members of the
families that follow them, and that they have rough warty skins in
place of smooth and shiny ones; but many exceptions confuse both the
classification and the use of the words--as, for example, in the case
of the hylas, which you may call either "tree frogs" or "tree toads,"
according to your liking.
The two species mentioned above are the "unke," or firebellied toad
of Germany, which when alarmed displays its scarlet underparts by a
peculiar attitude calculated to surprise and frighten away an enemy.
The other is the "midwife toad," most common in Spain and Portugal.
The spade-foot toads (Pelobatidæ) are a strangely distributed family
inhabiting the western United States, Mexico, eastern Europe, and the
Indo-Malayan region. Their special characteristic is the fact that
the inner tarsal tubercle is large and is transformed into a shovel,
which is covered with a hard, sharp-edged, horny sheath. Having this
excellent tool these small and noisy toads rapidly excavate deep holes
in the soil, preferring sand, and lie hidden during the day, but come
forth at night to hunt. They resort to water only for a week or so
of egg-laying in the spring, and remain unknown to most persons in
whose neighborhood they are really numerous. Our common American one
(_Scaphiophus solitarius_) is about two inches long, and brown above
with darker patches.
This brings us to the typical toads, Bufonidæ, represented in all parts
of the world except certain islands. A hundred pages might be filled
with interesting accounts of the manners and customs of the hundred or
so species, many very different from those familiar to us.
All breed in water, resorting to ponds and pools in the early spring.
Where many broods have hatched the young can be met with in myriads,
the ground literally swarming with them; and as they are naturally
stirred up by a sudden warm rain, perhaps after a drought, people will
occasionally affirm as an observed and well-ascertained fact that "it
has rained toads"--something that never occurs except in the very rare
cases when a cyclone has scooped the water and everything in it out of
a pond and scattered it abroad.
Most of these young, migrating toads disappear as food for birds,
snakes, etc., or die of disease. The food of young and old consists of
insects, worms, snails, and the like; and it is an easy thing to tame
toads and have much amusement in watching them at work in the early
evening, for they are crepuscular in habits; and the wise gardener will
see that they are not disturbed in their beneficial service of catching
and devouring insect pests, unless they are so numerous as to be a
nuisance.
The smallest North American toad is the oak toad of the Southern
States, which is only an inch long. When, in the breeding season, these
diminutive toads flock to the pools in great numbers, they keep up an
ear-splitting chorus of shrill _peeps_, like so many young chickens.
FROGS AS NURSERY MAIDS AND WEATHER PROPHETS
The tree frogs are a very large family (Hylidæ) distributed all over
the world, except Africa, but most of the species belong to the
steamy forests of tropical America. All are of small size, have smooth
skins, normally greenish, but very changeable in color to adapt the
creatures to the hue of their surroundings, as a protective device;
and most of them inhabit trees. To enable them to do this the toes end
in expanded, padlike disks, the contraction of which, when the foot
is pressed against a surface, produces one or more furrows and, in
addition, causes the exudation of a little mucilaginous liquid. The
foot pressed against the surface expels the air, and this fact, aided
by the stickiness of the pad, enables the frog to hold on to even a
vertical plane of glass. All Hylidæ have a voice, often very loud, and
enhanced by membranous sacs under or on each side of the throat, or in
some cases internal; this sac, when blown out may be almost as large
as the creature's body, as may be seen in our common gray tree frog
when "singing." This species, like most others, becomes very noisy in
the evening, in cloudy weather and before rain, with its not unmusical
croaking; and a similar European species is kept in confinement by some
people as an interesting pet and weather prophet.
The most interesting thing about the Hylidæ is their various methods of
breeding, for while most of them lay their eggs, up to a thousand in
number, in the water, many produce but a few, and attach them to the
body.
A large tree frog called in Brazil "ferreiro" (smith), makes a sound
like a mallet slowly and regularly struck on a metal plate. This frog
actually builds a nursery in the shallow edge of a pond, where a
basin-shaped hollow, with a rim, is formed by the broad-handed female.
Here she leaves her eggs, safe from egg-eating fishes or insects, as
the rim forms a wall higher than the surface of the water. A Japanese
frog makes a similar basin, then produces a liquid which she kicks into
a froth, and into the midst of this the eggs are dropped, and there the
hatched larvæ develop, and remain until the gradual collapse of the mud
rim sets them free.
In these and similar cases the eggs and tadpoles are abandoned by the
parents; but many frogs watch over and care for their young. Some carry
the young in a pouch on the back, but how it is accomplished is not
known. A West African species carries its eggs in its mouth; and the
male of Darwin's frog, of Chile, carries the eggs in a great vocal
pouch beneath its throat, which subsequently forms a nursery for the
tadpoles until they emerge as young frogs.
It must be noted, however, that some of these examples belong to
the related family Cystignathidæ--a very extensive family largely
represented in Central and South America.
The remainder of the tailless amphibians are assembled in the numerous
and widely distributed family Ranidæ, which is that of the "true"
frogs. The typical subfamily, Raninæ, is cosmopolitan, except as to
Australia and South America south of the Amazon basin; but some less
typical forms are confined to the tropics, and include several strange
species, such as the little arboreal Dendrobates frogs of Brazil, one
of which is famous for furnishing in the secretion of its skin a dye
that when properly applied turns the green plumage of tame parrots into
yellow--a fashionable tint. These small and pretty frogs are noted for
their solicitude for their young, carrying baby tadpoles on their
backs--where the infants creep and become attached--from place to
place, as safety or better water conditions suggest.
The North American frogs are good examples of the ranine race, and
those more commonly seen are the following:
Leopard frog (_Rana pipiens_), green with irregular black blotches,
mostly in two rows on the back; legs barred above; belly pale. Eastern
specimens are more olive than bright green.
Pickerel frog (_R. palustris_), light brown with two rows of large,
oblong, square blotches of dark brown on the back, a brown spot above
each eye, and a dark line from the nostril to the eye; upper jaw white
and black. Habitat, eastern United States among mountains.
Wood frog (_R. sylvatica_), pale reddish brown; a black band across the
pointed face. This smallest of our species is to be found only in damp
woods, resorting to water only in early spring to deposit its eggs; and
it is almost silent.
Green, or spring frog (_R. clamatans_), green or bronze-brown, brighter
in front, with more or less small black spots; yellowish white below.
This is a rather solitary frog, living in springs and small ponds,
where it utters the familiar "chung" at frequent intervals. It is
distinguished by the enormous size of its eardrum.
Bullfrog (_R. catesbiana_), greenish, brightest on the head, and with
small dark spots on its back; legs blotched; eardrum large; toes
broadly webbed. Length five to eight inches, breadth four to five
inches. It utters a roar not unlike that of a distant bull, and a
company of them on a still summer evening will awaken the neighborhood.
Bullfrogs are present throughout the eastern United States and Canada,
west to the dry plains; and furnish the market with "saddles" (their
hind legs) as a table delicacy when fried. These frogs may lay 12,000
eggs apiece.
All our frogs lay their eggs in water in rounded masses, not in
strings, as do the toads, usually attached to some submerged stick or
plant stem. The tadpoles, light in color, are very voracious, and feed
on every sort of flesh that they can bite off and chew with their horny
jaws. On the approach of winter the frogs--except the wood frog, which
hibernates in the loam of the forest, or in some rotten stump--sink
into the mud of the pond or marsh where they live, and pass the cold
months in torpidity. Their food is almost exclusively insects, caught
by the tongue, but the big bullfrogs seize with their mouths any small
creature that comes their way.
CHAPTER XX
REPTILES--MONARCHS OF THE MESOZOIC WORLD
What is a reptile? It is a cold-blooded, air-breathing vertebrate, with
one occipital condyle, complete right and left aortic arches, red blood
and a covering of scales. The classification of the class (Reptilia)
recognizes the existence of many distinct subdivisions, as follows:
_Proreptilia_ (extinct).
_Prosauria_ (extinct, except the tuatara).
_Theromorpha_ (extinct).
_Chelonia_--Turtles; tortoises.
_Dinosauria_ (extinct; dinosaurs).
_Crocodilia_--Crocodiles; alligators.
_Plesiosauria_ (extinct).
_Ichthyosauria_ (extinct; fish lizards).
_Pterosauria_ (extinct; pterodactyls).
_Pythonomorpha_ (extinct; mososaurs, etc.).
_Sauria_--Lizards; snakes.
This surprising diversity of groups, each so widely isolated, as is
implied by separation as subclasses--divisions of almost the highest
rank--shows that the class developed in favorable circumstances that
stimulated enterprise, so to speak, and resulted in rapid variation of
habits, terrestrial, aquatic, arboreal, and aerial, and consequently of
adaptive structure. The fact that most of the subclasses are extinct
also shows us that the story of the Reptilia is mainly a tale of the
departed glory recorded in the archives of the rocks; and we shall
hardly be able to understand living reptiles properly without knowing
something of their prehistoric development into the dominance to which
they rose in the Mesozoic era, which we call Age of Reptiles, and their
subsequent decadence.
The first subclass covers certain most ancient skeletons and parts
of skeletons that naturalists are not yet agreed are true reptiles,
some considering them stegocephalian amphibians. Anyway, they
indicate plainly that it was from that group of Amphibia that the
variety sprang that developed into what, in time, became the distinct
reptilian type. The first distinct product of this departure from
the stegocephalian stock appears in the fossils of a division of
the second subclass, the Prosauria (_pro_, "before"; _saurus_, a
"lizard"), named Rhynchocephalia ("beakheads"), which, although
lizardlike in general form, retain many amphibian characteristics of
structure. Now the amazing and extremely interesting thing about this
is that a representative of this earliest of true reptiles is still
living--probably the premier peer among all vertebrates, reckoned by
length of ancestry. This most primitive of reptiles, illustrating how
hundreds of ancient species known to us only by a few bones must have
appeared and acted in life, is the tuatara of New Zealand, catalogued
in science as _Sphenodon punctatum_.
It has the shape and general appearance of a big lizard, dull in color
and with a granulated rather than scaly hide, and an oddly shaped
head, toothless in the adult, when the jaws become somewhat like a
horny beak. Yet it is not a lizard any more than it is a crocodile or
a turtle, but combines features of all three in its anatomy. Hence it
is what naturalists term a synthetic or generalized race (as is the
case with all very primitive creatures) out of which more and more
specialized groups and species may be, and are, developed, each sorting
out and strengthening some particular characteristic of structure,
continuously modified by adaptations to habits and environment until
a separate type results. The ribs, for example, in the tuatara are
remarkable for the presence of hooklike processes that project backward
from each rib over the next rib behind it; such processes occur
elsewhere only in the crocodiles and the birds. Behind the breastbone
are rodlike bones embedded in the muscles of the belly; they occur
again in the ancient fish lizards and modern crocodiles, and probably
gave rise to the under shield of the turtles. And so on.
The tuatara is verging on extinction. It has nearly disappeared from
the mainland of New Zealand, but is now protected on some small
adjacent islands where it dwells in burrows which it digs and then
shares with petrels. During the greater part of the day the tuataras
sleep; and are fond of lying in the water, being able to remain
submerged for hours without breathing. They feed only upon other
animals.
The third subclass (Theromorpha, "beast-shaped") comprises very ancient
reptiles whose remains lie in the rocks of Permian and Triassic age,
principally in South Africa, and exhibit a skull, and especially teeth,
so much resembling those of carnivorous mammals (for instance, those of
a dog) that at first their true nature was mistaken. These creatures
have excited the most profound interest, not only because they present
so many differences from the Prosauria, but also, and chiefly, because
it is from their ranks that we are able to trace, with no small degree
of certainty, the origin of the Mammalia.
THE SOURCES OF TORTOISE SHELL AND TERRAPIN STEW
The turtles and tortoises are of a very ancient group (Chelonia) and
one very distinct among reptiles, by reason of their armor. What is
known as tortoise shell is the series of horny plates, in some species
of beautiful texture, in others thin and dull, or even leathery
in character, that covers the underlying bones that form the real
protection to the animal's body. In embryo (unhatched) turtles the
skeleton is much like the ordinary four-footed type, with the vertebræ
separate, a full series of ribs, and the limb bones in their proper
places. As growth proceeds, however, changes occur rapidly, but least
in the oceanic "leathery" turtle, in whose skin nodules of bone expand
and join into a mosaic of plates covered with a thick, coriaceous
hide. But this skin remains quite separate from the skeleton beneath,
which fact places this animal in an order Athecæ ("lacking a case"),
quite by itself. All other chelonians are classified in a second order
Thecophora ("case-bearing"), and in them the changes that go on in the
skin to produce the turtle's shell are far more complete.
If you peel off the horny shields on the upper shell, or "carapace,"
you will find beneath them a central, lengthwise row of squarish plates
of bone, on each side of these a row of similar plates, and outside of
these a marginal row of small plates--all knit together at the edges,
the zigzag lines of juncture, or "sutures," being plainly visible.
When we dissect a turtle we find no layer of skin or flesh beneath
these plates, but discover that they lie directly on the bones of
the skeleton and are a part of it. This is what has happened: The
vertebræ have grown together, and the backbone is a tube upon which
the original nodules in the skin have become fixed, and have broadened
into the central line of plates. Those nodules that lay above the
ribs have become fused with them so that no trace of ribs is left,
except where their heads have become fused with the backbone, and they
have broadened into the side rows of plates; and the marginal skin
has become transformed into the marginal plates. Similar alterations
have produced the under shell, or "plastron," replacing the skin; and
adaptive changes have altered the usual relations of the limb bones
to the rest of the external skeleton. The carapace and plastron are
usually connected by a "bridge" of bone.
Into the space within this shell most tortoises may withdraw the head
and tail which, like the feet, are covered with horny scales. The head
has good eyes, and a nose with a lively sense of smell, which the
creature utilizes in selecting its food; but its hearing appears to
be dull. The mouth has no teeth, but the lips are coated with horn,
making a parrotlike beak that can inflict a severe bite. Horny spines
often grow on the legs, or tail, or both, assisting in both defense and
offense.
The chelonians are a very ancient race, and one that has changed
remarkably little since its beginning. The great age accounts for the
very wide distribution of turtles closely related, and also for the
fact that they inhabit land, fresh and salt water; those of the land
being, no doubt, the oldest. All turtles lay eggs, the shell of which
varies, according to kind, from a parchmentlike envelope to a hard,
shining shell; but the process of generation is slow and curiously
complicated.
The respiration of the Chelonia is interesting. The lungs are spongy
masses, attached to the upper shell. As the rigid case does not permit
of their expansion by breathing, the necessary vacuum is made partly
by the neck and limbs, which act like pistons as they are drawn in and
out, the air being swallowed or pumped into the lungs. Most chelonians
may exist for a very long time without breathing, and can stay for
hours or even days under water. No animal, perhaps, is harder to kill;
and all turtles have long lives, the giant turtles of the Galapagos and
their kin living more than 100 years.
The list of Thecophora begins with the suborder Cryptodira, whose
members have the carapace covered with horny shields, and consists
of the family Chelydridæ, composed of our two snapping turtles, the
familiar northern one, and the southern alligator snapper. They inhabit
stagnant pools, especially deep channels in swamps and slow rivers such
as the bayous of the lower Mississippi Valley, and often show only the
tip of the nose as they prowl about close beneath the surface in search
of prey--anything they can seize. They take the hook readily if baited
with fish or flesh, but stout tackle and a strong arm are needed to
land one when full grown; and the act is dangerous to the catcher, for
they are the ugliest brutes in the country, and to be bitten by one
is a very serious experience. Nevertheless, the young are caught for
market in large numbers, for they are excellent food. One curious fact
about them is not generally known, namely, that when lying still, like
a piece of old log covered with mud and moss, they protrude a pair of
wormlike filaments from the tip of the tongue, whose wavering attracts
fishes to their doom. Louis Agassiz says of the great alligator snapper
of the Southern States, which when walking on land carries its body
high on the long legs, much like an alligator:
"They are as ferocious as the wildest beast of prey, but the slowness
of their motions, their inability to repeat the attack immediately,
their awkwardness in attempting to recover their balance when they have
missed their object, their haggard look, and the hideous appearance of
their gaping mouth, constitute at such times a picture as ludicrous
as it is fearful and revolting. Their strength is truly wonderful. I
have seen a large specimen bite off a piece of plank more than an inch
thick.... Fishes, salamanders and young ducks are their ordinary prey.
They lay from twenty to forty or more round eggs, only about the size
of a small walnut, in holes which they dig in sloping banks not far
from the water."
These snapping turtles probably represent well the disposition and
habits of the extinct predatory reptiles; and give us a hint of why the
race succumbed to the more active and intelligent mammals that were
growing up around them toward the close of the Mesozoic.
This brings us to the great family Testudinidæ, which is scattered over
the whole world except Australia, and contains almost all the ordinary
tortoises, mud turtles and terrapins, some of which are entirely
aquatic, others amphibious, others wholly terrestrial. Among the most
typical and widely distributed are those of the genus Chrysemys, to
which "mud turtles" belong. The commonest species in the Eastern
States is the painted turtle _Chrysemys picta_; in the West, _C.
marginata_. These and other species of North and South America are very
pretty when young, the ground color of the upper shields being green,
variegated with yellowish or blackish markings, often in delicate
patterns. They are carnivorous, depend mainly on fish, but eat many
insects and their larvæ. In winter they hibernate in holes in a bank of
their pond.
[Illustration: TERRAPIN
(_Malaclemys palustris_)
(After Babcock. Boston Society of Natural History)]
To the genus Clemmys is credited the "sculptured" wood tortoise, the
keeled plates of whose back are marked with fine concentric grooves
and radiating black lines; and the equally common speckled one, black
with round, orange spots. Both spend long periods wandering in woods
and fields in search of worms and insects. Closely related to them
are the salt-marsh tortoises known as terrapins, which are so much of
a luxury in the eyes of those fond of good dinners that probably the
favorite one, the "diamond back," would be extinct had not protective
measures, and cultivation in captivity, saved the life of the species.
Several other terrapins are to be found in the marshes of the Southern
States, but not in other countries. Another relative is the interesting
little "box tortoise," which is often kept as a pet, and will become
very tame; its highly convex shell is colored black and yellow, or
orange-brown, but no two are alike. The eyes of the male are red, those
of the female yellow. It is naturally enough a "box" tortoise, for,
by means of a flexible joint line across the plastron, the fore and
hinder halves can be brought up to the ends of the carapace, shutting
the whole body inside a tight box that will defy all enemies not strong
enough--as are wolves, bears, and big cats--to tear it to pieces. This
tortoise is exclusively American. It has become, as a species, wholly
terrestrial, so much so that, although it is fond of drinking often,
if it falls into the water it will drown. It thus leads us to the true
land tortoises that fill the remaining genera of this family.
[Illustration: BOX TORTOISE
(_Cistuda carolina_)
(After Babcock. Boston Society of Natural History)]
The typical and most numerous of these belong to the genus Testudo,
with about forty species scattered over all warm or temperate parts of
the world except Australasia. Typically grazers and fruit eaters, they
occasionally vary their diet with worms, snails, and insects. The eggs
are hard-shelled, and the males are usually smaller than their mates.
Most land tortoises hibernate in the ground during the cold half of
the year, or they æstivate during the hot and dry seasons when in the
tropics, but this is not an invariable rule. Several species of these
land tortoises are common and well known in Europe and also in India,
and are often kept as pets. They show considerable intelligence, and
are decidedly fond of listening to music. Our best known American
representative is the "gopher" (_Xerobates polyphemus_) of Florida,
Georgia, and Texas. This turtle is nearly a foot long, with a high,
rounded shell, dull brown in color, and the forefeet covered with
hornlike scales and some spines--an armature for digging. The deserts
along the Mexican border have several local species.
In this family belong the "gigantic" tortoises of the islands east of
Africa and west of South America, now all but extinct, save a few in
captivity in zoölogical gardens. In fact they differ from ordinary land
tortoises mainly in size and in such minor points as distinguish the
various species; some of them, indeed, are not excessive in bulk. The
largest on record is a male of _T. daudini_, of South Aldabra, whose
shell was sixty-seven inches long, and whose living weight was 500
pounds. A fossil species of the late Miocene in India had a shell six
feet long, and then and later tortoises almost as big inhabited both
Europe and North America, and more recently Madagascar. Their survivors
are now restricted to two widely separated regions--the Galapagos
Islands, 600 miles off the coast of Ecuador, and the Mascarenes and
other western islands in the Indian Ocean. The most interesting thing
about this matter is the presence of these tortoises on these widely
scattered islands, and the effects of their isolation. It must be noted
that when discovered by European voyagers no one of these islands,
except the Comoros, was inhabited by men, and none had any large or
harmful beasts of prey.
On these peaceful islands plenty of food, an equable climate, and
absence of enemies, enabled the tortoises in vast numbers to grow to a
size impossible to their relatives on the mainlands. "Scattered over
the many islands they were prevented from interbreeding, and thus it
has come to pass that not only every group of islands, but, in the case
of the Galapagos, almost every island has, or had, its own particular
kind." How did these huge chelonians get to these islands? None like
them is found on any continent at present, although they had a wide
distribution in geological ages. We must conclude that those of the
Madagascar region, at least, are the descendants of tortoises once
populating "Lemuria," that land area which until mid-Tertiary time
occupied the region of the western Indian Ocean, and of which the
existing islands are the remains. A similar theory, for which there
is geological evidence, may account for the survival of the Galapagos
giant tortoises after those of the mainland had died off.
The next family is that of the big sea turtles (Chelonidæ), such as the
green turtle, whose flesh is so highly prized a substance for delicate
soups (but almost all turtle flesh is good eating), the hawksbill and
the loggerhead. They abound in all warm seas, and reach a large size,
the green turtle often having a shell three to four feet long, but
smooth, while that of the hawksbill is covered with horny plates with
high keels and an overlapping arrangement, which are the tortoise shell
of commerce. The green turtle is wholly vegetarian in diet, feeding on
the large seaweeds, while the others are carnivorous, devouring fishes,
mollusks, etc. All three resort in summer to sandy beaches, dig holes,
and bury a great quantity of eggs.
There remains a large group of fresh-water turtles, distinguished,
in addition to other important structural peculiarities, by the fact
that they withdraw the head under the shell by a sidewise bending
of the long neck. They are entirely carnivorous, and occur in all
tropical and some temperate countries, the ferocious "soft shells"
of the Mississippi Valley and northeastward belonging here. A very
curious one is the matamata of Guiana and northern Brazil, the biggest
of its tribe, becoming more than three feet long. It gets its living
by stratagem rather than by activity. The back of its shell is so
roughened by coarse bosses that it looks like the bark on an old log,
and ragged flaps of skin project from head and neck. These are kept in
constant motion, and attract the attention of passing fishes and other
creatures, whose curiosity often takes them too near the treacherous
jaws of the concealed monster.
Our list of turtles ends with the one probably of most importance to
mankind of all the kinds in the world. This is the "arrau" of the
Amazon and Orinoco basins, where it is very abundant, and not only
an essential element in the subsistence of the native Indians, but
of great commercial importance on account of the eggs, which are
periodically collected in enormous quantities, chiefly for their oil.
This oil is eaten, like the eggs themselves, or is used for burning
in lamps, or as an addition to tar. The turtles are likewise eaten by
man and beast. This turtle is large, sometimes three feet long; and it
deposits a great number of soft-shelled eggs in the sand.
[Illustration: HORNED DINOSAUR
(_Monoclonius nasicornus_)
Skeleton restored from bones found in the Red Deer River region,
Canada. (American Museum of Natural History)]
DINOSAURS--ANCESTORS OF BIRDS
No class of the extinct reptiles is so familiar, by name at least, as
is that of the dinosaurs, mainly because of the enormous size of some
of them, and the fact that their prodigious skeletons are exhibited
complete in many museums. No other land animals ever approached some
of them in bulk. A great number of species have been exhumed, yet as
a group these reptiles are only imperfectly known, for the fossils
are not scattered throughout the whole extent of Mesozoic deposits,
but only in two limited periods of that era separated by two or
three millions of years. All of them had short, compact bodies, long
tails, and long legs for a reptile, and instead of crawling they
walked or ran, sometimes upon all fours, more generally on the hind
limbs, like ostriches. They ranged in size from that of a cat to the
prodigious bulk of the diplodocus or the brontosaurus, seventy feet
long and perhaps twenty feet high at the hips, while an East African
species appears to have been even far bigger. Some were herbivorous,
and dwellers mainly in marshes and swamps; others ranged the uplands,
armored for defense against huge predatory kinds, and still others had
horny beaks like birds. It is believed, in fact, that our birds are
descended from the same stock as these creatures, through an early
offshoot.
[Illustration: MONOCLONIUS RESTORATION (DECKERT) IN TYPICAL LANDSCAPE
(American Museum of Natural History)]
CROCODILES AND ALLIGATORS
These repulsive and ferocious reptiles (Crocodilia) are the bulkiest
of the whole class, and most resemble the ancient aquatic dinosaurs,
with which they are undoubtedly allied, although their precise
derivation is undetermined. Their general shape is in conformity with
the reptilian model, rather than indicative of any close relationship
to lizards; indeed their closest living relatives are the tuatara and
the chelonians. They have four legs of nearly equal size in modern
examples, but in some of the older extinct forms of the Lias and
Jurassic strata the hind legs were much longer than the fore pair, and
broadly webbed, while other features indicate a purely marine life;
but it appears plain that the crocodilians originated as land dwellers
whose descendants, early in the history of the group, took to an
amphibious method of life.
The eyes, nostrils, and external ears are situated on the upper surface
of the head, so that breathing, seeing, and hearing are unimpaired in
the water, the upper part of the head being usually raised above the
surface when swimming. The nostrils and ears have valves which are shut
when the animal is under water.
Crocodiles and alligators are mainly carnivorous, feeding on mammals
and waterfowl, for which they lie in wait close to the edge of the
water, sweeping them in by a blow of their tail, but the gavials
feed almost exclusively on fish. All are oviparous, laying oval,
hard-shelled eggs.
The order is represented by a single family, Crocodilidæ, including
six genera scattered through the tropical and subtropical parts of
the globe in the strange fashion that characterizes many of the
ancient groups of which present species are mere relics. Thus the
American genus of alligators has also a species in China; and the Old
World crocodiles are represented by a single, narrowly restricted
species in the region of the Gulf of Mexico. Our common alligator (_A.
mississippiensis_) inhabits the low coastal rivers and swamps from
North Carolina to the Rio Grande, and remains abundant in the steaming
bayous along the lower Mississippi, and in the swamps of Louisiana, but
in Florida has been killed off, not only by the demand for its hide (as
leather), but in a wanton way by tourists and sportsmen, until now its
numbers are greatly reduced. It would have become nearly extinct were
not its prolificness great, each female depositing thirty-five to forty
eggs in the layers of the cone-shaped heap of a nest she makes on the
bank.
Young alligators feed mainly on fish, but the old ones take more and
more to getting birds and beasts for their dinner, stealing on them
quietly as they swim, or when they approach the water to drink. The
prey is dragged down and drowned. In the crocodilian throat the passage
for air from the nostrils reaches much farther back above the mouth
than in other animals, and the entrance of the windpipe may be closed
by pressing together the base of the tongue and the soft palate,
enabling the alligator to drown its prey without drowning itself. In
two particulars our alligator is singular--its fear of man and its
voice. When surprised basking on shore, as it likes to do, it will
rush with awkward haste for the water; and there will get away or out
of sight whenever a man appears. Hence it is safe to bathe in waters
infested by alligators, which will retreat from the feared bather
as far as possible. Nevertheless when an alligator is cornered it
can and will make a very dangerous fight with jaws and tail that are
truly formidable. But it rarely attacks unprovoked, except where a
mother finds you tampering with her nest. As to its noise-making, the
alligator is unique among reptiles in giving voice to a really loud
noise, or bellow, which may sometimes be heard for a mile or more. It
varies according to the size of the reptile from the gentle "mooing" of
a small one to a "thundering and tremendous blast" by a big male.
In the half-submerged morasses of Florida, from Lake Worth southward,
dwells a true crocodile, closely allied to that of the Nile, and first
discovered there by William T. Hornaday in 1875. It differs from the
alligator in the pattern of scales, in the relative length and vertical
flatness of the tail, and especially in having a long, pointed snout
instead of the broad, spade-shaped head of the alligator. Its general
habits present no novelty, but it is more agile and, in captivity, more
vicious than its cousin, while showing a similar dread of man in its
wild home. This crocodile is found from northeastern Mexico south to
the coast of Ecuador, especially in salt marshes.
Central and South America are the habitat of several species of
caymans, which differ from alligators mainly in their teeth and the
fact that protective scales cover the belly; they are blackish in
color, and vary in size and markings, the largest, known on the Amazon
as the black cayman, or "jacare usassu," growing to be twenty feet
long; but the Indians pay little attention to it.
Crocodiles proper (genus Crocodilus) are distinguished by the fact that
some of their foremost teeth fit into a notch of the upper lip, and
are therefore exposed, as is not the case with alligators or gavials.
One species lives in West Africa, another in India, another is wholly
marine in habits (as were some of its extinct progenitors) and ranges
from eastern India and southern China to northern Australia, a fourth
is Australian, and a fifth Central American; but the best known of all
is the so-called Nilotic crocodile of the upper Nile and the rivers
of east central Africa. Formerly it occupied the whole course of the
Nile, and was one of the sacred animals of the priestcraft of ancient
Egypt. In Madagascar it is extraordinarily abundant, and has there the
peculiar habit of digging long, ventilated burrows in the river bank,
in which it lies, and where it stores its prey. Large old specimens
may become fifteen feet in length, and their life is probably very
long, for new teeth grow as fast as the old ones are lost, and when
adult they have no known enemies except one another, but their eggs are
sought for by several kinds of birds, lizards, and so forth, and the
old ones devour many infants.
Crocodiles abound in all the sluggish rivers and estuaries of central
Africa, and are more destructive of human life than even lions or
leopards, and kill much game and many domestic animals. Lying in wait
close to the bank, they make a rush, seize by the nose or leg any
animal as it stoops to drink; or, stealing close to an antelope or goat
standing at the edge of the river, they will, with a sweep of the tail,
knock it into the water, and grasping it with their jaws bear it down
to a horrible death. The crocodile does not at once tear its victim to
pieces, as do the alligators, but pushes it into some hole in the bank
to decompose before being consumed. Major J. Stevenson-Huntington says:
"At Sheshike, on the Zambezi, a paramount chief, who lived some forty
years ago, used to derive great amusement from watching slaves and
criminals being thrown to the crocodiles, his chair being brought
to the river's bank in the cool of the afternoon that he might
enjoy the spectacle in comfort. The crocodiles at this place never
forgot those halcyon days, and, until very recently, it was almost
certain death for anyone to drink at the river, or attempt to draw
water, except within one of the protecting screens of logs which
were erected for the purpose.... On the other hand there are some
large pans in Amatongaland, which, although full of the reptiles,
are said to be quite safe to bathe in, attacks on human beings being
unknown.... Always cunning and suspicious, the crocodile at times
evinces considerable audacity in the pursuit of his prey. Natives are
occasionally knocked off the gunwales of their canoes by a flick from
the tail. I recollect Major Gibbons, standing upright in the stern
of our little aluminum steam launch on the Zambezi, with the tiller
between his feet, nearly losing his balance through an attack of this
kind. I have heard of a native, sleeping on a hot night in the doorway
of a hut close to the river, being attacked and dragged in."
Despite this frequent attack on large prey, fishes are the main
reliance of the African crocodiles for subsistence.
As opposed to this terrifying record from eastern Africa, the
"long-snouted" crocodile of the west coast rivers offers a mild
reputation, since it is content with fish, frogs and water birds as
food, and fears men more than it is feared by them. The natives hunt it
for the sake of its flesh. Crocodile meat is considered good in all
uncivilized parts of the world, but most white men dislike its musky
flavor; the same may be said of the eggs of these reptiles.
The Orient possesses a variety of crocodiles, the best known of which
are the marsh crocodile, a near relative of the African species, and
the gavial, placed in the genus Gavialis, and distinguished by its
long, slender snout and weak teeth. This gavial abounds in the Ganges
and other rivers of northern India and Burma, where it is numerous,
and frequently exceeds twenty feet in length. A second species is
found in the Malayan archipelago. It feeds almost exclusively on fish,
and so rarely harms man or beast that it is regarded as harmless. The
marsh crocodile, or "mugger," is also of great size, and inhabits the
rivers and marshes of India, Ceylon, and the Malayan islands. It is
a fish eater and an arrant coward, feared by no one under ordinary
conditions. It was, perhaps, originally, as a matter of gratitude for
this harmlessness, that the custom arose among the Hindus of venerating
this reptile. In some places, as notably near Karachi, large numbers of
muggers are kept captive in ponds, and attended by priests and devotees
who guard and feed them.
A third species is the formidable "estuarine" crocodile, which
frequents the tidal portions of rivers from the Bay of Bengal to China
and Australia. It exceeds all of its race in stature, usually exceeding
twenty feet long, and one old specimen on record was thirty-three feet
from tip to tip. It is held in great fear by fishermen, for in many
cases it develops man-eater proclivities, and has all the ferocity
and resourcefulness of its Nilotic cousin. The salt-water habitat
of this species recalls the fact that among the many kinds of fossil
crocodilians known, from the Lias onward, one was a purely marine form.
The crocodiles are followed in the classification of the reptiles by
several extinct groups, known only as fossils of the Mesozoic Age.
The first of these is the subclass Plesiosauria, containing a series
of predatory creatures characterized by very long necks, short tails,
and feet that in the older forms indicate a terrestrial existence, but
later exhibit a progressive change to paddles, showing that finally
the plesiosaurs were wholly aquatic. This was accompanied by a steady
increase in size, until finally a length of at least forty-five feet
was reached--chiefly by extension of the neck--in the elasmosaurus of
the Cretaceous rocks of Kansas.
Another subclass, Ichthyosauria, restricted to the Mesozoic Age, were
large, swimming, marine "fish lizards" with a somewhat whalelike form,
the front limbs transformed into paddles, and the snout in the form of
a long bill filled with sharp teeth. They lived on fishes, cuttlefish,
mollusks, etc., and had the general habits of sharks. They died out
early in the Cretaceous epoch, and left no descendants.
A third extinct subclass is that of the pterodactyls, or "flying
dragons" (Pterosauria), which possessed the air throughout the Mesozoic
Age, and filled the place of birds in the fauna of that period,
although they had no relationship to the real birds that came later.
Some were no larger than sparrows, but later ones spread their leathery
wings twenty feet or more. The origin and real affinities of these
winged reptiles are unknown and they left no descendants.
We find in the Cretaceous formations skeletons of very long, slender
marine reptiles (Pythonomorpha) with a lizardlike head and all four
limbs in the form of paddles, of which the mososaurs are the best
known. These were the latest of the Mesozoic reptiles; and about the
time of their disappearance we begin to find the earliest fossil
suggestions of the subclass Sauria which contains our modern orders
Lacertilia, the lizards, and Ophidia, the serpents. Neither of these
owe their ancestry to any of the fossil groups just mentioned, in spite
of superficial resemblances, but "their origin has probably to be
looked for among the Prosauria, of which Sphenodon (the tuatara, see
page 183) is the only surviving member." They are also very distinct
from crocodiles in structure.
[Illustration: MESOZOIC FLYING REPTILE (PTERODACTYL)
(Restoration, after Owen)]
LIZARDS AND CHAMELEONS--TURNCOATS OF THE WOODS
Lizards (Lacertilia) are creatures of hot climates, and especially of
deserts, and they exhibit an almost endless variety of shape, size,
structure, and adaptations to their surroundings and a mode of life
that is primarily dictated by their food. The majority are terrestrial,
but some species are semiaquatic. There are climbing, swiftly running,
and even flying forms, while others lead a subterranean life like
earthworms. Most of them subsist on animal food, varying from tiny
insects and worms to birds and mammals, while others live upon a
vegetable diet.
Lizards, like snakes, have a scaly skin covered with a thin, horny
pellicle which is shed from time to time, flaking off in pieces except
in the wormlike species, where it is sloughed whole as by snakes. In
most lizards the scales are well developed, and "shingle" the back and
sides of the body, but in some they are like little tubercles, giving a
granular appearance--a good example of which is the "Gila monster" of
Arizona. Lizards are, as a rule, adaptively colored according to their
habitat, so that browns and grays prevail in the sand-running species
or those, like the monitors and iguanas, that are mostly aquatic; but
brilliant hues in varied, even fantastic, patterns adorn many of the
small, agile, tropical kinds, whose safety lies in their swiftness
of movement and cleverness in hiding. This is supplemented in most
species by the capability of changing color, a faculty that is most
serviceable in the chameleons, by rendering them more or less invisible
to the hawks and other animals that try to catch and eat them. Some of
the more sluggish, earth-dwelling kinds are further protected by many
spines sprouting from the skin, as is familiar in our western "horned
toad," and in the fearsome-looking "moloch" of Australia; and the
iguanas are provided with an erectile spiny crest along the ridge of
their backs, most notable in the basilisks.
A strange characteristic of most lizards with slender tails is the
power to part with them at a moment's notice. If an enemy seizes this
appendage, which often is held temptingly aloft, it breaks off and its
owner escapes before the would-be captor has had time to recover from
his surprise. Within a short time a new tail is developed, but it is
never so perfect as the original organ.
Most lizards lay eggs, few in number, and with shells hard in some
families, parchmentlike in others, that are hidden in a hole in a dead
stump or some similar place of concealment, and are left to be hatched
by the warmth of the sun. Many lizards retain their eggs until nearly
ready to hatch, and so are practically viviparous. The embryos have an
"egg tooth," as do turtles and snakes.
The Lacertilia are naturally divisible into three sections, namely,
geckos, typical lizards, and chameleons.
The geckos are a large and ancient family represented in all
tropical countries, and some species are common along both shores
of the Mediterranean, but none reach the United States. They are
small, plump, flat-headed, and mostly somber in color, but this is
changeable; the skin has a granular surface, but regular scales cover
the desert-dwelling species. One peculiarity of the group is the
adaptation of the foot to the habit of climbing about rocks and trees.
The undersurface of the toes has a series of plates, which serve as
adhesive pads wherewith the animal is enabled to climb not only trees
and the smooth rocks, but a windowpane or to run along the ceiling with
the ease of a fly. Another peculiarity is the fact that the eyeball is
covered by a "watch glass" of transparent skin, under which the little
animal rolls its eyes and stares at you with vigilant interest. Geckos
are nocturnal in habit, and as evening approaches come out from their
retreats and become active in hunting for insects, and in avoiding the
other lizards, snakes, and so forth, that would like to seize and eat
them; and it is then that are heard their low, two-syllabled, clucking
calls that give them the name "gec-ko." These funny little lizards
are utterly harmless, come into houses, and are easily tamed, yet are
regarded in many countries with superstitious dread and that foolish
fear of poison that is attached to most small lizards and newts. In the
Orient several strangely modified forms exist.
The lizards proper (Lacertæ) number several hundred species classified
in eighteen families, and differ vastly in size, shape, food, and place
and manner of life. Some, like the degraded slowworms, are limbless,
scaleless and in their serpentine form and underground life resemble
worms more than anything else. Others, such as the "flying dragons" of
Malayan forests, have developed great winglike expansions of the skin
on the sides, folded close to the body as they climb about the trees,
but capable of being spread as supports when they wish to take a long
gliding leap to some distant perch; and an Australian species has
similar skin expansions that can be raised into a broad ruff around the
neck that gives the little animal a terrifying aspect. The many kinds
that live in deserts have the dull hue of the ground, or may bristle
with spines, of which the squat "horned toad" of California is an
excellent example; while those that scamper about the trees and rocks
of the equatorial region are often brilliantly striped or spotted in
reds, greens and blues. Many are pugnacious and able to bite severely,
but the only one whose bite is poisonous is the heloderma of the
Mexican border. This is a fat, sluggish, black and yellow creature,
about a foot in length, that inhabits the hot desert sands. Fortunately
it is slow to anger, but when it does bite there flows into the wound
a poison which has the same effect as the venom of the rattlesnake,
although less copious and virulent. Severe illness, and in a few cases
death, have resulted from the bite of this ugly creature, which is more
commonly known as the "Gila monster," because it is prevalent in the
valley of the Gila River in southern Arizona.
As the great family Agamidæ is confined to the Old World, so the
Iguanidæ belongs to America, where several species are numerous in the
tropics, and reach a size of three to five feet, much of which is tail.
They live in trees, feed on vegetation, and haunt the banks of rivers
into which they jump on the slightest alarm. One traveler relates that
along the Mosquito Coast of Nicaragua, when a person is going in a
canoe up some of the narrow, unfrequented creeks, he encounters quite
a shower of iguanas, and runs some risk of getting his neck broken,
for a big iguana will weigh twenty-five pounds or more. Their flesh,
resembling that of chicken, is a favorite article of food and iguanas
are constantly brought to rural markets. The family contains about 300
species. Among them is the common little "chameleon" (Anolis) of our
Gulf States, so often sold to tourists as a curiosity, and brought
north to die of cold and neglect. It is golden green on the upper
surface, and white on the under, and the throat, when inflated, glows
with vermilion; it is a harmless, active little tree dweller, and will
change its colors to suit its surroundings with astonishing rapidity.
In another genus (Sceloporus) is placed the blue-tailed, variable,
"fence lizard," or "swift," which is known throughout the eastern
United States; but the common small lizards of the Pacific slope belong
to Gherronotus and other genera.
The largest lizards of all belong to the two families Varanidæ, the
"monitors" of Africa and eastward to Australia, and Teidæ, the "tejus"
of Central and South America. They are singularly alike in appearance
and habits--long-tailed, slender, smooth-skinned, carnivorous
creatures, living in all sorts of places, varying with the numerous
species, and both hated and utilized by the natives of the various
countries they inhabit. Some monitors are more than seven feet long.
The American tejus, such as the big "teguexin" of Brazil, frequent
forests and plantations, where their strength and speed enable them to
catch all kinds of animals, from insects to worms, frogs, snakes, mice,
and birds. "They take chickens and eggs from the farms, and they are
frequently hunted down by dogs for the sake of their flesh, which is
considered good to eat. They defend themselves with lashing strokes of
their long tail and with their powerful jaws."
The chameleons differ so much from other lizards that they have
been placed by some systemists in a different suborder. The chief
differences are three. First, the feet, terminating rather long legs,
have the fingers and toes so arranged that two digits oppose three
as do our thumbs the palm of the hand, and the animal can grasp a
branch just as we would, giving so firm a grip that chameleons are
exceedingly agile climbers, and may take as many odd attitudes among
the branches as would a monkey. Second, the eyes are very large, but
the eyelids have grown together over them, leaving only a small hole
out of which to look. The right and left eye roll about incessantly,
and independently, giving a most comical squinting effect--but no
lizard sees with both eyes at once! Third, the tongue has reached an
extraordinary development. When the mouth is shut it is withdrawn into
a tubular sheath at the back of the mouth; but when a fly is seen and
wanted it is shot out like a released spring, seizes the fly in the
flaps at its club-shaped extremity, and is quickly withdrawn. This
tongue may be thrust out to a distance equal to the length of the body,
less the long, tapering, prehensile tail, which is another important
part of the equipment of these active tree dwellers. The skin is not
scaly, but granular in appearance; and the skull is prolonged behind
into a pointed helmetlike form that is distinctive of the group.
Chameleons are most celebrated, however, for their remarkable power
of changing their color, but this is by no means always, or perhaps
often in direct response to the hue of their immediate surroundings.
Dr. Hans Gadow has made an extensive study of his captive specimens of
the common chameleon of the Mediterranean region, and confesses himself
baffled in the attempt to learn an explanation of the influences,
external or mental, that causes the alterations of hue. One judges
from his observations that they are mainly the expression of fleeting
emotions--but who can read the emotions of a lizard?
But if we do not know the _why_, the _how_ of these fluctuations of
color is well understood, and is briefly stated by Prof. Pycraft:
"The horny outermost layer of the skin is colorless; in the layer
beneath this are embedded iridescent cells with striated surfaces.
Below this, in the deepest layer of the skin, _cutis_, are a large
number of cells filled with refractive granules, chiefly guanin
crystals. These cause white color by diffuse reflection of direct
light. Nearer the surface are cells filled with oil drops, and these
give a yellow color. In the granular mass are embedded numerous
color-bearing granular sacs or chromatophores, containing for the most
part blackish brown or reddish pigment. The branches of these sacs
being contractile, the contained granules of color are drawn away
from or toward the surface of the skin, and thus, combining with the
stationary color, effect a corresponding change in the coloration of
the animal."
The chameleons are an African family, but a few of the fifty or so
species belong also to the western coast of India and Ceylon, and one
is a resident of southern Spain. They vary in size from that of a mouse
to a species in Madagascar two feet long.
The lizards and snakes are the most recent developments of the
reptilian line of vertebrate evolution. No undoubted lizard remains
have been discovered antedating the end of the Cretaceous epoch; and no
fossil evidences of snakes are much older than the mid-Tertiary, yet
these are surprisingly similar to existing forms. The affinities of
both groups seem to be with Pythonomorpha.
CHAPTER XXI
SERPENTS, GOOD AND BAD
Snakes (Ophidia) are the newest and most flourishing branch on the
reptilian family tree, whose trunk and lower limbs are dead or dying.
They differ from lizards mainly in their elongated and limbless form
(which, however, had been foreshadowed by certain lizards) and more
particularly in the formation of the mouth. Instead of a solid union of
the bones of the skull, many of the bones, especially about the mouth,
are connected by an elastic ligament, allowing the snakes to open their
mouths widely enough to swallow larger prey than otherwise would be
possible. The palatal bones, as well as the jaws, bear small, solid,
recurved and pointed teeth, replaced by others from the same root pulp
when lost; they have little chewing power, but are useful to seize and
hold food which is then slowly swallowed by the snake gradually working
its jaws ahead and over the object, until the muscles of the throat can
grip it and slowly work it downward into the tubelike stomach. Serpents
strive to turn their prey and swallow it headfirst.
The tongue in all serpents is a slender, extensible organ, forked at
the tip, usually black, and always seen protruded and waving about when
a snake is disturbed. Uninformed people call it a "stinger," but it is
merely the animal's tongue and used as such. It serves the additional
purpose of an instrument of investigation, the serpent informing
itself by touching with its tongue as to the nature of many things
with which it comes in contact. It has, however, no stinging or other
harmful purpose or power whatever. A rattlesnake's tongue would harm
you no more than one of the little love licks that you get from your
favorite puppy.
The eyes, which may be rudimentary in the burrowing species, or large
in those of nocturnal habits, have no eyelids, and are covered with
a transparent film of skin that is sloughed off whenever the skin is
shed, which happens frequently in young, growing individuals, but only
annually in adults, as a rule; and for a day or two snakes are blinded
by the loosening of this covering. No snake has ear openings, and their
hearing is dull. The sense of smell, however, is well developed, and
it is probable that these animals obtain much food by its aid, even
following a trail by the nose.
Serpents travel on their bellies, moving their bodies in lateral
undulations, and often running with amazing swiftness. Every pair of
ribs is connected at their lower ends with one of the large abdominal
scales, or "scutes," and it is generally believed that the creature
moves by the pressure and pushing of these scutes and rib points on
the ground; but Boulenger, a leading authority, thinks that their
importance has been somewhat exaggerated, although of undoubted use for
the purpose of climbing, at which some species are remarkably adept.
Some snakes lay eggs with a tough, parchmentlike shell; others retain
them within the body until the young are fully developed.
Snakes do not migrate nor wander far from their birthplace in search of
food. Desert dwellers burrow under the sand for protection from the
heat, and go abroad at night, as is the habit of many snakes. In the
colder climates the serpents hibernate, collecting in companies tangled
together like a ball in some animal's burrow, or in a den among the
rocks, the hardier ones occasionally appearing on warm days in winter.
When they come out in spring they are likely to make their way to wet
lowlands, in search of frogs, toads and mice.
The order is divided into nine families, which will now be considered
in the order arranged by G. A. Boulenger of the Zoölogical Society
of London. The first four families are small, wormlike, burrowing
creatures, with a large number of species distributed in warm countries
throughout the world, and regarded as relics of an ancient type. The
beautiful coral snake of South America, which grows to a yard in length
and is only partly subterranean in habit, leads from these to the great
family of boas and pythons (Boidæ) which contains the biggest serpents
that exist, or so far as we know, ever have existed. The members
of this family have vestiges of pelvis and hind limbs, appearing
externally as clawlike spurs. The Boidæ comprise sixty or seventy
species and the range of the family is world-wide. They mostly prefer
wooded districts, climbing trees, assisted by the short and partly
prehensile tail. Some are semiaquatic. All are rapacious, and feed by
preference on warm-blooded creatures.
The family is divided into two subfamilies, Pythoninæ and Boinæ, but
the difference between them is confined mainly to certain bones in the
skull. The pythons belong entirely to the tropics of the Old World,
except a single species in southern Mexico; and number about twenty
species. The Boinæ are chiefly American. None is venomous.
A famous python is the six-foot, tree-dwelling carpet snake of
Australia, black, beautifully marked with a pattern of yellow dots.
A very large species is the reticulated python of Indo-China and the
Malayan region, having an arrangement of dark lozenges on a lighter
ground. India has a similar species, reaching a length of thirty
feet, marked with reddish brown patches on a yellowish ground. This
(_Python molurus_) is the one most often seen in zoölogical collections
on account of its hardiness; but it is a savage creature, almost
untamable. Like others of these big serpents it is able to make very
long fasts; indeed their life, in this respect, seems to consist of
gorges, followed by long periods--sometimes several months--of fasting
and repose, entirely voluntary. It appears from observation of captive
specimens that they have individual preferences for a certain kind of
food, and perhaps wait for it; thus one in the Jardin des Plantes,
Paris, refused various toothsome animals for months until a goose was
offered, which it seized hungrily, and then sulked through long weeks
until another goose was given.
Africa has two pythons, one (_P. regius_) confined to West Africa, the
other (_P. sebæ_), common from the Sudan to the Cape. "The latter,"
William C. Scully says, "is the largest of African snakes, occasionally
attaining a length of more than twenty feet, with a circumference of
eighteen inches. One is recorded of twenty-five feet. It principally
frequents rocky chasms in moist, warm forests. It is not dangerous to
man, being quite nonvenomous, but it will fight fiercely if attacked,
and the long, sharp, teeth may inflict a severe bite. The python
usually preys upon small animals, such as minor antelopes, monkeys,
conies, and birds. Sometimes this snake coils itself at the bottom of
a stream and lies with its nose just emerging. When a small buck comes
to drink, the snake seizes it by the nose, the recurved teeth taking
an inextricable grip. After the buck has been drowned the python coils
itself around the body and crushes it for convenience in the process of
swallowing.... The python does not regard the horns, which sometimes
may be seen sticking out through the abdomen. These wounds quickly
heal, the snake apparently being none the worse for the perforations.
"So far as I know the python is the only snake which incubates its
eggs. Such, numbering from thirty to fifty at a brood, and weighing
about five and a half ounces each, are usually laid in a deep rock
crevice or in the deserted burrow of an ant bear or hyena. The mother
coils herself over and around them."
Let us turn now to the boas. Popularly the whole tribe is frequently
spoken of as "boa constrictors," but that is the scientific name of
only one among several species, the _Boa constrictor_ of the West
Indies and tropical South America. It is the one most common and best
known, and, as it is easily tamed, is the one often seen in the hands
of performers with serpents in circuses, and exhibited in menageries.
In many places in South America the natives, according to Leo Miller,
keep them running at large about their huts to catch rats. In forested
regions they spend most of their time in trees, but in an open country
lie about on the ground, retreating when alarmed into some hole, as of
a viscacha--their favorite prey on the plains.
Far greater and much more dreaded by the natives is the great water
boa, or anaconda (_B. murinus_), of the Amazonian region, which is the
longest of American snakes, and the worst foe of such river-loving
creatures as capybaras and iguanas. The color scheme of the anaconda
is greenish yellow above, with a single, or two alternating series,
of large, blackish transverse spots, and one or two lateral series of
blackish eyespots with white centers. The lower parts are whitish,
spotted with black. The anaconda is very aquatic, and is usually found
submerged close to the banks of the river, on the lookout for its prey.
Although mammals and crocodiles are occasionally eaten by this snake,
it prefers birds, these being constricted and eaten under water. Only
a single instance of an anaconda having attacked a man is on record.
Although it grows to a length of over thirty feet, it is sexually
mature when about half that length.
Various very slender and agile species, the tree boas, belong to
the tropical American forests, one of which is called the "rainbow"
boa because of its marvelous iridescence in the sunlight. Another
large species inhabits Central America and Mexico; and two small,
brown secretive snakes, the "rubber" boas, more commonly known as
"double-enders," because their blunt tails closely resemble their
heads, are found in California and northward to British Columbia. The
remainder of the family are scattered from Africa to the South Sea
Islands.
ORDINARY SNAKES (COLUBRIDÆ)
We now come to the family Colubridæ, which embraces nine-tenths of all
the modern serpents of the world. The more hardy species are to be
found north to about the summer isotherm of 41 degrees; and snakes are
absent only from some of the South Pacific Islands, New Zealand and
Ireland; Ireland never had any, despite the St. Patrick legend.
The best arrangement of the Colubridæ is that by Boulenger, who,
adopting Duméril's terms, has divided them into three series according
to the character of the teeth.
1. _Aglypha_--All the teeth solid and not grooved. Harmless, that is,
not venomous.
2. _Opisthoglypha_--One or more of the posterior maxillary teeth
grooved. Mostly poisonous; a few tropical species.
3. _Proteroglypha_--Anterior maxillary teeth grooved or tubular.
Deadly poisonous; cobras, coral snakes, etc.
The immense family Colubridæ is divided into several subfamilies,
the first and most extensive of which is the Colubrinæ, in which are
associated all the "harmless" snakes in the world except the boas
and pythons. None exceeds twelve feet long, and most of them are
much smaller. Nearly all lay eggs, but some bring forth large broods
of living young, among which are our water snakes, and the striped
"garter" and "ribbon" snakes so numerous in our meadows and gardens.
These striped snakes (Eutainia) exist in a great number of "species" or
varieties most confusingly varied in coloring, some having no stripes
whatever. They are very hardy, living far toward the north in Canada,
and are the last to go into hibernation and the first to reappear in
spring. For this winter sleep they burrow deeply into soft soil, or
where rocky places exist, seek deep crevices.
The water snakes of the genus Tropidonotus follow, with many
representatives in all temperate countries, one of which is the
"common grass snake" of England--the only serpent in Great Britain
except the viper and a rare little burrower. Ten species, with several
varieties, are credited to the United States, some of which are ringed
with irregular or broken bands of blackish on gray, others obscurely
blotched, and some black or brown with red bellies. They are the
ugliest of all our snakes both in appearance and in vicious temper;
and are of no service to mankind, for their food consists entirely of
fishes, frogs, toads, etc., obtained in or near the water. They live
altogether in rivers, ponds and swamps; and by their dark bodies, flat
heads, and keeled scales so resemble moccasins whose fierce, repellent
attitudes they imitate, that in the South they are almost as much
feared; hence it is well to note the differences. The harmless water
snake is more slender than the deadly moccasin and may be told by the
red spots on the abdomen; the undersurface of the poisonous snake is
straw color, with black or gray spots on younger individuals, but has
no red spots. The water snake has the plates on the underside of the
tail in two rows, the moccasin in a single row. These snakes are agile
swimmers and are able to spend a long time in hiding under water. They
produce their young alive in broods of twenty-five to fifty, and they
are as pugnacious as their elders.
Various small, ground-keeping snakes lead to another conspicuous
American group, the racers and black snakes of the genera Spilotes
and Zamenis, of which species and near relatives are numerous in
Europe and Asia, a Malayan example growing to a length of ten or more
feet--probably the longest of colubrines. Three different "black
snakes" are known among us. The largest is the "gopher snake" or
"indigo snake" of the sandy parts of the southeastern States, which
may approach eight feet in length, and it is a variety of the still
larger yellow "rat snake" or "cribo" of the tropics, which is protected
about villages and houses as a good-natured exterminator of vermin.
Our variety has a useful breadth of taste and lack of choler, and its
haste to escape into a gopher turtle's hole when a man appears gives
it one of its names, while its glossy, blue-black color, relieved only
by a reddish chin and throat, accounts for the other. They are real
pets, showing no fear and offering no harm; the closely related "rat
snakes" of India, on the other hand, although similarly protected as
ratters, are described as diabolical in temper, and thus usually remain
untamable. To some extent in the South, but principally in the Northern
States east of the plains, the commonest black snake is the "black
racer," which west of the Mississippi, instead of being pure satiny
black, with white chin and throat, appears in a bluish green hue,
often with yellowish belly, and is known as "blue racer." Third, we
have the less numerous and larger "pilot," whose scales are noticeably
keeled and have each a touch of white. Raymond L. Ditmars takes great
pains to relieve these snakes of various calumnies, as that they hunt
for rattlesnakes and copperheads (whence the name "pilot"), as that
they "constrict" their prey, as that they "fascinate" anything, and as
that they maliciously attack human beings--on the contrary, they make
frantic efforts to get away the instant their fears are aroused, and
few things on earth can make better speed than this black rocket. If
cornered, however, it will turn on the enemy, rear a third or more
of its length, and strike repeatedly with a force and rapidity hard
to avoid. Yet both the common and the indigo species quickly become
docile and show signs of recognition and partiality toward their human
friends. The long, slender "coachwhip snake" of the South and the
equally thin and swift striped "racer" of the Pacific coast are allied
species.
The genus Coluber, to which belongs the famous Æsculap snake of central
Europe, is represented among us by a series of large and gayly colored
species. One is the yellowish, brown-blotched fox snake of the prairie
States, which is a ground keeper and a great hunter. In search of
rats and mice it often haunts haystacks and barns where it should be
welcome. "One snake is worth a dozen traps, for the reptile prowls into
the burrows and nests of rats and mice and eats the entire brood."
Similar in size (six feet) and habits is the brilliant red-and-crimson
corn snake of the Southern States, which is a great mouser and also
an agile climber after nests of birds, whose eggs and young it likes.
Another, even larger, coluber of the South is the four-striped chicken
snake, useful in its pursuit of small rodents, but, like the pilot
black snake, with too great a fondness for hen's eggs and young poultry
to be liked by farmers.
The big, gray, blustering "bull snakes" of the southern and western
parts of the Union take their name from their habit of emitting a loud
and prolonged hiss when annoyed. They keep on, and under, the ground
in sandy regions, feed on small mammals and birds, and are powerful
constrictors; they are also noted for morose and savage dispositions.
Next to these repulsive reptiles come in classification the beautiful
and gentle green snakes--slender little creatures that hunt for
caterpillars and various insects through the foliage of bushes, among
which their gracefully festooned length is hardly visible. South
America has another group of very long and slender insect eaters and
nest robbers known as "tree snakes," whose habits are similar but on a
larger scale, and which have a wonderful power of riding securely on
the branches, no matter how violently they are waved by the wind.
Passing over a number of small, smooth-scaled serpents, of which
the pretty ringneck is an example, we come to the important genus
Ophiobolus, which contains the king snakes, milk or house snakes, coral
snakes and others, represented in the Old World by the genus Coronella.
They vary in size from fourteen inches to six feet, and in color from
gray with dark blotches to a ringed pattern of red, black, and yellow,
often of brilliant beauty; but there is much individual variation.
The king snake might easily furnish material for a long chapter. Its
name follows from its known disposition to pick a quarrel and fight
with any serpent it meets, big or little; and quite independent of
whether it is hungry, for it is as fond of eating its own kind as it
is of lizards, toads, mice, birds and anything else that comes in its
way on the ground, for it is not much of a climber. Our books are full
of incidents of its destruction of poisonous species, and the popular
belief is that it hunts for, and relentlessly pursues rattlesnakes,
copperheads, etc., but the authorities assure us this is not so.
If it accidentally encounters a rattler or moccasin, it kills, and
perhaps eats it; but it does the same with any other serpent. It is an
exceedingly quick and powerful constrictor, and careless of bites, for
it is entirely immune to venom. Captive specimens have been repeatedly
hypodermically injected with the poison of all sorts of American
venomous serpents, as well as bitten by them, and have shown little
if any effect. But wounds enrage it. Winding its lithe body round and
round the doomed creature, until every part of the shining length is
engaged, it tightens with such strength that the victim is benumbed,
unable to bite and quickly strangled. Nevertheless these snakes submit
easily to confinement and speedily grow perfectly gentle and friendly.
The common northern representative of the genus is the house snake or
milk snake--names given to several other species; it is also known as
"checkered adder," because of the general resemblance of its blotched
form to the dreaded copperhead. It is gray above, with a series of
large, chestnut-brown saddles on the back, smaller blotches alternating
with them along the sides; the belly is white, marked boldly with
square black blotches. The pattern and tints vary widely. This snake
is a lover of warmth and a hunter of mice and rats, wild and domestic;
and in search of them it frequents pastures and damp meadows, where
such wild game abounds, comes much about stables and houses, and often
creeps into the rural dairies that are usually close to springs.
Serpents with these inquisitive habits are familiar in all parts of
the world, and from time immemorial have been accused, among other
iniquities, of milking cows and goats, and of drinking and spoiling
milk and cream on the shelves in dairies and cellars. These beliefs
survive among country people to this day, as I found out a few years
ago by an extensive correspondence of inquiry, in which incredibly
absurd statements were made. Of course, well-informed persons know
better. The keepers of reptiles at the New York Zoölogical Park, for
example, find that snakes show no liking for milk. Captive specimens
cannot be induced to drink it unless suffering from great thirst. It
would be a feat beyond physical possibility for a serpent the size
of the largest milk snake to consume enough milk from a cow--if the
reptile should be so inclined--to produce an effect noticeable to the
most minute degree.
We will mention only one other sort of our harmless colubrines--the
"hognose," "puffing adder," "spreading adder," as it is variously
known; but the name hognose is the best. Its genus is Heterodon. Two
species are common all over the eastern half of the United States and
Canada, one an ugly mottled gray, the other black. They are about
two feet in length, thick-bodied, with roughly keeled scales, a flat
head and a pointed, upturned snout--altogether very unhandsome and
forbidding-looking reptiles; and they profit by this in an attempt to
frighten away whatever alarms them, while in reality themselves almost
(sometimes quite) paralyzed by fear.
CORAL SNAKES, COBRAS, AND SEA SNAKES
The flattening of the head and neck practiced by the hognose as a
gesture of readiness to fight, whether true or false in its implication
of ability, is found among several non-poisonous colubrids elsewhere
and indicates their approach in kinship to the "hooded" cobras that
are the foremost representatives of the venom-bearing members of
the Colubridæ. It will be recalled that we have been sketching the
"harmless" section (Aglypha), and have now to take up the two remaining
"dangerous" sections of the Colubridæ, the Opisthoglypha and the
Proteroglypha.
The principal tooth-bearing bone in a serpent's mouth is the forward
half of the upper jaw, termed the maxillary. The maxillary of each side
is connected with its fellow by a small, single bone in front (the
premaxillary) and otherwise is connected with the loosely connected
bones of the skull by those elastic cartilages that enable the mouth to
expand and take in prey of a size more than equal to the snake's head
when the mouth is shut. In the serpents that do not possess a poisoning
apparatus the teeth on the maxillaries are alike in size, and solid;
but in the venomous kinds some of the teeth are enlarged and grooved or
channeled to conduct a flow of poison into the wound made by biting.
This is the case with the poison-bearing sections of the Colubridæ
mentioned above, and their difference is in the relative position of
the poison-conducting teeth or "fangs" on the maxillaries.
In the Opisthoglyphs these teeth are situated near the posterior end
of the maxillary, and are grooved on the rear side, where they receive
the poisonous fluid from a sac in the cheek. The greater number of
species of this group are residents of the Old World, although we have
several representatives along our Mexican border, and more southward,
especially in the tropics. Most of them are little dangerous to
mankind, as it is difficult for them to inflict a wound by "striking."
They first seize their prey and then use their rather short fangs. The
poison has a paralyzing effect, reducing the victim to helplessness.
Some of these snakes must be regarded as decidedly dangerous, but
fortunately all the American species may be quickly recognized by the
peculiar marking on their heads, which has given the name "jew's-harp
snake" to a common species of Arizona. It is believed that the vipers
are an offshoot of an opisthoglyph ancestry, in spite of the forward
position of their fangs.
In the Proteroglypha, on the contrary, the poisoning teeth, in all
cases small, are situated near the front of the maxillaries, and they
are much more dangerous reptiles, for they include the coral snakes and
cobras (Elapinæ) and the sea snakes (Homalopsinæ), which are able to
strike their teeth into anything they successfully attack.
The coral snakes (genus Elaps) derive their name from the broad bands
of coral-red that encircle their bodies in most species, with narrow
rings of black and yellow between. These brilliant colors, combined
with the luster of the smooth scales, make them among the most
beautiful of serpents, and a common species of our Southern States is
called the harlequin. The genus is exclusively American, and nearly
all belong to the tropics, where the largest become five feet long,
and their bite is deadly to man. They keep to the ground, and much of
the time under it, and are cannibalistic in their diet. The body is
slender and cylindrical, the head small, and the eyes like beads. They
are indocile, quick-tempered, and very dangerous to handle, despite
the fact that they do not always resist being disturbed. Hence the
widely prevalent opinion that they are harmless is a perilous delusion
fostered by the fact that certain innocuous southern serpents closely
mimic the coral snakes in size and colors. It should be learned and
remembered, especially by visitors to winter resorts in Florida, that
the poisonous ones (Elaps) have the black rings bordered on each side
by the yellow ones, while in the harmless species the yellow rings
are bordered by the black; also, in the coral snakes the bands of
color completely encircle the body, but do not in the other kind. A
very elaborate illustrated account of the coral snake and its poison
apparatus, methods and serious effects, was given by Stejneger in the
"Annual Report of the United States National Museum," for 1893, Part II.
The remainder of the elapine serpents (about 125 species) belong to
Africa and the Orient. Typical of them are the cobras of the genus
Naja, of which the species (_Naja tripudians_) met with from Turkestan
to southern China and the Malay islands, and named by Portuguese
explorers "cobra de capello" (hooded snake), is world-famous. Several
species inhabit Africa and differ little from the Indian cobras, but
are equally deadly. The fangs in all this group are small and are fixed
in the extreme front of the upper jaw, not being erectile like the long
fangs of the rattlesnakes and vipers. Cobras vary much in coloration,
and Mr. Scully reports that he has killed South African specimens of
light yellow, jet black and all intermediate hues.
The cobra is a fierce fighter and, when reared up, with expanded hood,
looks very formidable. Anterior to the head the ribs lengthen and
then gradually shorten to normal dimensions. These lengthened ribs,
about twenty in number, lie, when the snake is quiescent, more or less
laterally along the spine. But when the snake becomes excited, the
neck bends and the ribs spring out at right angles. Over them the loose
folds of skin expand umbrella fashion. When much enraged, the cobra
spits drops of venom at its enemy. These are propelled a distance of
about four feet.
The cobra is found all over South Africa, but is especially plentiful
in the dry, sandy deserts northwest of the Cape. There extensive
colonies of large mice abound, patches of ground being thickly
honeycombed with burrows. In these the cobras dwell--apparently, as in
the case of the puff adders, on the best of terms with their hosts,
upon whom they principally feed, reminding one of the tenancy by the
Western rattlesnake of prairie-dog "towns."
A close relative of the cobra is the ringhals (i. e., ringneck), known
as the "spitting snake," the explanation of which Mr. Scully furnishes
from personal experience thus:
"The ringhals, when excited, exudes a quantity of venom, which drips
down the fangs and lodges behind the abrupt, horny, lower lip. Upon
this the angry snake directs a blast of air through its extensible
windpipe, with the effect that a jet of fine venom spray is emitted
toward an enemy. This jet may reach a height of six feet. That the eyes
are aimed at I have proved by experiment. If the poison reaches them
blindness, which may be permanent, results. The bite of the ringhals is
highly venomous, but the snake appears to prefer disabling its enemy by
means of the spray of venom."
The most novel and interesting of Mr. Scully's contributions to
African herpetology, however, is his story of the mamba (_Dendraspis
angusticeps_), which he calls "the head of the family." It is the
longest venomous snake in the world, probably running to fifteen feet
in exceptional cases, but is slender and primarily a tree snake. This
naturalist declares it to be the most dangerous of all snakes, as it
is highly aggressive at times and its speed is quite extraordinary.
If disturbed during the pairing season, the mamba attacks without
hesitation; and if at any time one happens to get between the mamba
and its dwelling, the snake rushes straight for its objective and, in
passing, strikes swift as lightning at the intruder. It progresses in
a series of bounds, suggestive of the successive uncoilings of a steel
spring. There are two varieties, one colored a vivid grass-green, the
other steely black, both so dreaded that the news that a large mamba
has been seen will cause the vicinity to be shunned--perhaps for months.
"The mamba has the habit of lying coiled among the branches adjacent to
a footpath in a forest. Woe to the passing wayfarer in such a case! If
he touch a twig, and thus impart the least tremor to the snake's lair,
a lightning-swift stroke upon face, neck, or arm seals his doom. Such
a stroke may be delivered either forward or sideways, with equal speed
and effectiveness."
The most feared of the cobra tribe in India and eastward is the king
cobra, or hamadryad, which often exceeds a dozen feet in length and
is "the largest, boldest and most dangerous of all venomous snakes,"
in Boulenger's opinion, "for when disturbed it does not content
itself with merely sitting up and expanding its hood, but will almost
invariably attack." Fortunately it is not numerous anywhere in its
range from the Himalayas to the Far East; and it is useful in that it
feeds exclusively on snakes, small pythons, kraits, rat snakes, and
the common cobra. Its bite will kill a man in an hour or two; and it is
recorded that an elephant bitten by one died in three hours.
Nearly all the serpents of Australia belong to Elapinæ, and are
exceedingly dangerous. Among them are the "black snakes," the females
of which are called "brown adders"; the "tiger," so called from
its colors; and most dreaded of all, the "death adder," which is
distinguished by a peculiar tail end, and by the fact that the head is
made distinct from the body by a narrow neck, giving it a viperlike
appearance. When disturbed it flattens out the whole body.
A few words about the sea snakes will close our account of the
poison-bearing colubrids. These are set apart in the subfamily
Homalopsinæ, on account of the structure of the tail, which is
flattened vertically into a combination of swimming organ and rudder,
for they live in the estuaries of Oriental rivers, and go far out to
sea in their search for food; and are to be met with from the Persian
Gulf to Polynesia and Japan. All are very poisonous, feed mainly
on fishes and produce living young; and all are clothed in varied
and brilliant colors. Living in the sea, or in tidal inlets, their
movements in the clear blue water are agile and elegant; and in the Bay
of Bengal they are sometimes seen congregating in large shoals.
We turn now to the last and most advanced family of serpents, the
vipers, rattlesnakes, moccasins, copperheads, and so forth (Viperidæ).
VIPERS, MOCCASINS AND RATTLESNAKES
"Viper" is an old French-Latin word, meaning "bearing living young,"
which was noted as distinctive from the egg-laying habit of other
snakes, and peculiar to the single species that the people of southern
Europe knew--the small _Vipera verus_, or asp, from which the large
and widespread family derives its name. The vipers differ from
the colubrids in important particulars. Their bodies are thick in
proportion to their length, which rarely exceeds six feet, and this and
their weight make them unable to run rapidly or (with one exception)
to climb trees. The sturdy body narrows into a slender neck supporting
a distinct head, given a flattened, triangular form by the expansion
of the hind head on each side to accommodate the great poison sacs
with which these snakes are provided. The maxillary is a stout bone
in the fore part of the upper jaw, and carries on each side a long,
backward-curved fang, which is tubular and is connected at its root
with the extremity of a duct from the poison sac. When the serpent's
mouth is closed, or it is swallowing anything, these fangs, which in
a large snake may be an inch and a half long, lie back in a fold of
the flesh out of the way; but when the mouth is widely opened they
spring forward, and when the head is darted forward to strike a prey
or an enemy, they are driven down into its flesh and the venom spurts
through them into the wound, with benumbing and deadly effect. They are
frequently broken or dragged out, and then new ones arise from behind
to replace them. The eye is large, dull, and catlike in its pupil; the
scales are strongly keeled and dull in hue in the desert dwellers, but
often gay with colors in intricate patterns in the forest dwellers;
and the short and stumpy tail may end in "rattles," or a horny tip, or
neither. Nearly all give birth to large broods, which are as vicious
at birth as are their mothers. The family has two sections, marked by
the absence in the first, and the presence in the second section, of a
deep pit in the broad scale on the head between the nostril and the eye.
The original little "viper" of Europe and Asia is more a nuisance than
a peril, for it is rarely more than a foot long, and its bite would be
fatal only to a small child. A larger species, the sand viper, ranges
from Italy to Armenia. India, Burma and Siam, however, have a member
of this group which is pronounced by Sir J. Fayrer as next to the
cobra the most dangerous serpent of the East--the daboia, or Russell's
viper. It is nocturnal, not aggressive, and makes a loud hissing when
anyone comes near it, so that it does not cause as many human deaths
as it might; but frequently kills grazing cattle by biting them on the
nose. The greatest and worst of these snakes belong to Africa, where
the northern deserts are infested with two greatly dreaded species--the
horned and the saw vipers. The former has two sharp hornlike
protuberances above the eyes, and Canon Tristram writes that its usual
habit is to coil itself on the sand, where it basks in the impress of
a camel's footmark, and thence suddenly to dart out on any passing
animal. Horses as well as men are in constant terror of it, for it will
attack without any provocation.
The worst of the African vipers, nevertheless, is the puff adder, which
ranges over the whole continent, and may grow to a length of six feet,
with a girth equal to a man's thigh.
"The coloration of the puff adder," Mr. Scully writes, "is in
groundwork a series of delicate browns, with more or less regular
curved transverse patches darkening to black and edged with vivid
yellow. Its scales are keeled; its short tail tapers suddenly to a
point. It is a sluggish creature, incapable of swift progression. When
disturbed, it flattens itself to the ground, the air expressed in the
process causing the warning hiss which has saved many a life. But if
the foot of the intruder touch it, or even tread in its immediate
vicinity, the puff adder lunges either forward or sideways, with
a swiftness that the human eye cannot follow, and, having buried
its fangs deep in the flesh, holds on like a bulldog, forcing two
streams of venom into the tissues. The expression of this snake--its
square muzzle and glaring, lidless eyes with vertical pupils--the
extraordinary gape of the jaws and the huge, erected fangs, form what
is probably one of the most fiendishly menacing combinations in nature.
Nevertheless, apart from its head, the puff adder is a creature of
great beauty. The 'night adder' (_Causus rhombeatus_) is much dreaded
on account of its habit of lying at night in pathways and failing to
move out of one's way. This snake is one of the exceptions to the
rule of the viper class, in that it is not viviparous. It has another
remarkable peculiarity: the poison glands, instead of lying compactly
embedded in the maxillary muscles above the angle of the jaw, are much
elongated, and lie one on each side of the spine."
All the pit vipers are American except a few species in southern Asia,
some of which are arboreal in habit and have red prehensile tails. Our
American species fall into two genera: Ancistrodon, the moccasins (no
rattles), and Crotalus, the rattlesnakes.
The "upland moccasin" of the South is the "pilot" or "copperhead" of
the North, where it still exists in forested and rocky districts from
Connecticut and the Great Lakes to Texas, and is particularly abundant
in the rough hills beside the Hudson River, and thence southward along
the Alleghenies. Its general hue is yellowish brown, becoming chestnut
or coppery red on the head and end of the tail, which terminates in a
hard point. Along the back, meeting irregularly on the midline, are
chestnut-hued blotches that divide on the sides, forming inverted Y's;
the belly is yellowish with distinct black blotches, leaving the throat
clear. After one has seen a copperhead he is not likely to confuse
it with the milk snake or any other. Its haunts and habits are much
the same as those of the eastern rattlesnakes, nor do I consider it
any more aggressive in spite of a rather over-blackened reputation,
nor so deadly in the effects of its weaker venom. It is bad enough,
however, and should be killed on sight wherever children or pet dogs
are likely to meet with it. This upland moccasin is named in science
_Ancistrodon contortrix_; its brother species, the water moccasin, is
_A. piscivorus_.
The moccasin is a larger, heavier snake than the copperhead, and a
dweller in the sluggish rivers and swamps of the Gulf States and
northward to North Carolina and Kentucky. The moccasins commonly lie
on the branches of bushes at the edge of the water; and if escape from
danger be possible they quickly drop into the water and swim away
beneath it to some hiding place. If suddenly surprised they coil and
open the mouth widely toward the intruder, showing its white interior
that has given them the name "cotton mouth" among the darkies, who
fear them greatly, especially as they work in the rice fields. Mexico
has a similar species.
Closely allied to the copperhead and moccasins are two very dreadful
snakes of the American tropics--the "fer-de-lance" of the French
islands of the West Indies, and the "bushmaster" of Brazil. The former
reaches a length of six feet, and the bushmaster, or surukuku, as the
Indians name it, to twice that length, thus rivaling the great viper of
India. Both have all the ferocity and power of their race exaggerated
to the limit, and hundreds of human lives are sacrificed to them every
year. Every traveler has thrilling tales about them. Leo Miller, a
cool-headed man of science, takes very seriously the fear this creature
inspires. He reminds us that a bushmaster ten feet long has fangs an
inch and a half long, and injects nearly a tablespoonful of poison at a
single thrust. A man would survive such a dose but a few minutes. When
once a bushmaster fell from a tree branch into his canoe everybody in
it sprang overboard, and some narrowly escaped drowning. Such deadly
creatures would make the tropical world unendurable were it not that
most of the time they are sluggish and peaceful; but a little fright,
or a protective instinct in regard to their eggs, sets them off with
the suddenness of a released spring.
In taking up the rattlesnakes we have a sure guide in Dr. Leonhard
Stejneger's "Report," describing all the species of North America (the
group Crotalinæ is confined to this continent, Central America, and
a single species in South America). The special peculiarity of the
group is the queer "rattle" (crotalus) at the end of the tail. This
consists of a series of loosely connected, somewhat cone-shaped, horny
capsules, each of which originally covered the terminal vertebra of
the tail. On sloughing the skin this covering remains, but is soon
pushed away by the new capsule formed beneath, and partly within it,
which in turn is pushed out and replaced by a third, and so on, until
sometimes a dozen remain linked together; and when the serpent vibrates
its tail, as most snakes do when excited, they rattle against one
another, the tone of the "music" rising as the excitement, and speed
of vibration, increases. The sloughing is irregular as to frequency,
however, especially in young individuals, and may not always produce an
addition to the rattle, and the appendage itself may be broken, so that
the number of pieces, or buttons, in the rattle is not a trustworthy
measure of the age of the snake.
The smallest of the crotalids are the ground rattlers (genus
Sistrurus), of which we have two species, and there is one in Mexico.
The northern kind, widely known by its Indian name "massasauga," ranges
from eastern Pennsylvania and Ontario to northern Minnesota and Kansas,
and thence to Texas. The Southern States have a second species commonly
called "ground rattler." Both are grayish brown with chestnut or darker
dorsal blotches, and are inhabitants of the prairies, with their swamps
and marshes. The largest do not exceed forty inches, and their bite is
correspondingly weak in effect.
The remainder of the rattlesnakes belong to the genus Crotalus.
The commonly seen species of the region east of the dry plains was
named _Crotalus horridus_ by Linnæus, and this is one of the few
instances in which his name has defied change by the systemists. It
formerly was to be found as far east as central Massachusetts, but
there, as elsewhere, civilization has killed it off, so that now it
survives only in the Appalachian glens, and in thinly settled tracts
farther west and south. Its general color above is yellow-brown, below
nearly white; and the body is banded with blackish, the bands taking a
zigzag form behind the neck, and the tail is black. It rarely exceeds a
yard in length, and is, as a rule, timid and nonaggressive; but a good
deal remains to be learned about its habits and breeding.
Far more formidable than this is the diamond-back (_C. adamanteus_) of
the low, coastal region from North Carolina to the lower Mississippi
River and throughout Florida, where it is far more common than is
desirable. This rattler may exceed eight feet in length, and has
corresponding power of harm. It is partial to the neighborhood of
water, where its ground-running prey is most numerous; hence it is
frequently spoken of as the "water rattlesnake," to distinguish it
from the banded species, or "timber rattlesnake" of the same region,
which is more habituated to forested districts, with rocks. A race of
_C. horridus_, usually large and vicious, exists in the coast swamps,
and is locally called the "canebrake rattler." The diamond back itself
takes its name from the lozenge-shaped patches of dark color formed on
its upper surface by the crossing of diagonal narrow bands of bright
yellow on a greenish gray ground. The literature relating to this
terrifying snake would fill hundreds of pages. Raymond L. Ditmars of
the New York Zoölogical Park, gives this description:
"Most deadly of the North American poisonous snakes, and ranking in
size with the largest of the tropical venomous serpents of both the
New and the Old World, this huge rattlesnake, with its brilliant and
symmetrical markings, is a beautiful and terrible creature. Ever bold
and alert, ever retaining its wild nature when captive, there is a
certain awe-inspiring grandeur about the coil of this formidable brute;
the glittering black eyes, the slowly waving tongue, and the incessant,
rasping note of the rattle.... The mere vibration of a step throws the
creature upon guard. Taking a deep inhalation, the snake inflates the
rough, scaly body, to the tune of a low, rushing sound of air. Shifting
the coils to uncover the rattle, this is 'sprung' with the abruptness
of an electric bell. There is no hysterical striking, but careful
watching, and if the opportunity to effect a blow with the long fangs
is presented, the result is generally mortal."
[Illustration: THE RATTLESNAKE
(_Crotalus horridus_)
Beside the snake is the skin it has just discarded]
A large and very showy western analogue of the diamond-back, known
by the sinister specific name _atrox_, occurs from central Texas to
California. One of its varieties is red, with darker red markings and
a white tail. The familiar rattlesnake of the plains east of the Rocky
Mountains is _Crotalus confluentus_, which is of moderate size and
dull hue; its mainstay of food is found among the prairie-dog towns.
A similar but smaller species (_C. oregonus_) takes its place west of
the Rockies, from British Columbia to southern California. The "tiger"
rattlesnake, yellow barred with black; the "horned" rattler, which,
like the Egyptian horned viper, has a trick of advancing sidewise, and
consequently has the popular name "sidewinder"; and the slender green
rattlesnake, are small species of the deserts along the Mexican border.
CHAPTER XXII
BIRDS--KINGS OF THE AIR
A bird is an animal clothed with feathers and having the forelimbs
adapted to flight.
The birds constitute a class in the phylum Chordata, and otherwise are
combined, in the group Sauropsida, with the Reptilia, with which they
agree more closely in anatomy than with any other group, one prominent
particular being that both have a single condyle, in contrast with the
mammals and amphibians where the condyle is double. In fact primitive
reptiles--probably of the stock of dinosaurs--are the ancestors of
birds, the divergence having occurred probably in Carboniferous time.
Of the earliest divergent forms, the rocks have as yet yielded no
specimens, the most ancient bird forms recovered showing a degree of
development in the new type that must have been preceded by a long
history of evolution from its reptilian source.
[Illustration: ARCHÆOPTERYX
Skeleton of Archæopteryx macrura with indication of feathers
(Reconstructed. After Andrea)]
The oldest fossil bird known is that named archæopteryx, whose remains
are found in the Jurassic slates of Bavaria, which represent the
beginning of the Mesozoic or Age of Reptiles. In much of its anatomy,
and in the possession of perfect feathers, it is a true bird, yet it
retains many reptilian features. Its body was about the size of a small
crow; its legs were rather long, with well-developed feet of four
toes suitable to grasping a perch; its wings were short and probably
feeble, for the shoulder girdle and ribs are weak and the sternum is
rudimentary. It is plain that it was arboreal in habits, but a poor
flyer, and was aided in scrambling about the branches of trees on whose
leaves and bark it may have fed, by the fact that three digits of the
rather lizardlike wing hand terminated in strong claws, while the
thumb was entirely free.
The practical value of this clawed hand is illustrated in a living
bird--the hoatzin, of northern South America--which exhibits in several
ways the probable appearance and manners of the archæopteryx. "It
haunts the sides of lagoons and rivers where a thick growth of low
trees projects over the stream or the mud left bare by the tide. When
disturbed the bird flies off awkwardly with a violent flapping motion,
or leaps from bough to bough, erecting its crest and expanding its
wings and tail. The note is sharp and shrill, and has been described
as a hissing screech. The food consists of leaves and fruit. The
conspicuous nest, placed on low trees or shrubs, is a loose platform of
spiny sticks and twigs with a softer lining, and contains from three to
five yellowish eggs, spotted with reddish brown and lilac. The young,
which can see and run as soon as they are hatched, have a claw on both
forefinger and thumb, by means of which they creep about the thickets,
and hook themselves over the branches, assisted by the bill and feet.
They can also swim and dive."
The most striking features of the archæopteryx were its head and
tail. The skull is fairly avine, and the rather short and blunt bill
was furnished with conical teeth, nearly equal in size, and set in a
marginal row in distinct sockets. Still more lizardlike was the tail--a
prolongation of the backbone nearly as long as the body, along each
side of which sprouted strong feathers forming a horizontally flat tail
with a rounded end.
[Illustration: TOOTHED BIRD
(_Hesperornis regalis_)
Skeleton of toothed bird (After Marsh)]
The next that we know of bird evolution is derived from the discovery
of the fossil remains of toothed birds in the Upper Cretaceous
formations of Kansas--that is, in the more recent half of the Mesozoic
Age. They differ greatly not only from archæopteryx but from each
other, and are represented by several species. One type (Hesperornis)
was a wingless, diving bird of great size, whose long, heronlike
beak was studded with small, sharp teeth, all alike, implanted in a
continuous groove; its legs were so hinged to the compressed pelvis
that they could be extended almost level with the back, and the lobed
toes thus became lateral winglike paddles of great power. The other
type, represented by Ichthyornis and its relatives, also had a long,
stout bill set with teeth, but each in a separate socket. Ichthyornis
was about the size of a pigeon, and its strongly developed wing bones
and deeply keeled sternum show that it was a bird of powerful flight,
and apparently gull-like habits. So far as we know neither of these
Cretaceous birds had any progeny. When, after an immensely long period,
other fossils come to light in rocks of the middle Tertiary period they
bear few traces of ancestry, and exhibit little relation to the great
mass of modern orders. They are the "flightless birds," possessing no
wings but running about on massive legs; and the group includes the
extinct æpyornis, dinornis, and moa, and the existing ostriches, rheas,
emus, cassowaries, and kiwis. Some ornithologists question whether this
"ratite" group, characterized by having no "keel" on the sternum, did
not have an origin and line of descent quite distinct from those of
both the Cretaceous toothed birds and the modern "carinate" type which
possess a medial crest or "keel" on the breastbone for the support of
the flight muscles; but the more general opinion is that they are a
variant from very early birds with wings.
HOW A BIRD IS BUILT
Since its feathers are the one thing that marks a bird, outwardly,
as different from other classes of animals, we ought first of all to
learn what feathers are, and what purpose they serve. A quill feather,
such as may be picked up in any farmyard, has a horny, hollow stem
or "shaft," which is bare at the closed large end or "base," but has
two soft, winglike expansions toward its tapering end that together
make its "vane." This thin, flat vane consists of delicate branches,
"barbs," studded with tiny hooks, the "barbules," holding each adjacent
branchlet in place, but letting the whole vane bend and spring. The
whole beautiful thing is really very strong and elastic, as it must be
to push as hard against the air as a bird's wing has to do. The vanes
vary much in shape, and in the degree to which the branchlets are
disconnected into a fluffy looseness. Ostrich plumes, and those of the
birds of paradise, owe their beauty to the fact that each branch in the
vane is loose, and bears little disconnected branches of its own; and
in many feathers no vane at all grows, so that they resemble hairs,
when fine, and bristles when coarse, as is seen about the mouth of the
whippoorwill and some flycatchers. The nestling plumage or "down" is
of this character. The lovely plumes of egrets are slender stems of
feathers having in place of a vane scattered soft hairs. In some sea
birds the feathers are so stiff and hard as to be almost like scales.
Those of water birds, and especially the divers, are wonderfully close,
thick, and greasy, so that the down that forms an undercoat for warmth,
and the skin beneath it, never gets wet.
Feathers, then, serve their wearers first of all as clothing--very
thick and warm in birds of cold places; and doubtless this beneficial
modification of the primitive reptilian scale, by reason of its
conserving the warmth of the body, and gradually increasing the
temperature of the blood, has been largely instrumental in enabling
birds to rise so far above the grade of their cold-blooded and sluggish
ancestors.
Most animals whose lives are spent in the open air and light show more
or less color in their coat, but none are more beautifully adorned than
birds. The most brilliant examples are to be found in the tropics, and
some of the gayest in our colder land, such as the tanagers and humming
birds, are strays from large tropical families noted for gaudy attire.
The color we see in plumage may be due to either of two conditions.
It may, as is usually the case, be simply coloring matter deposited
in the substance of the feathers. But where the plumage gleams with
changing rainbow lights, as on the fiery throat patch of the humming
bird, on the neck of a dove or on the purple-black coat of the grackle
(crow blackbird), these splendid reflections are caused by very minute
wrinkles on the feathers, that break up the light. It is the same
effect, called "iridescence," as is seen on the mother-of-pearl and on
a soap bubble. Blue is usually an effect produced by certain coloring
matter not blue underlying a thin covering of feather substance; and
when you pound a blue feather into dust that dust will be black or
gray--or, at any rate, not blue. Birds of the same group are colored
much alike, as a rule.
In some cases the style of colors worn appears to be the best for the
safety of the birds of the group by making them hard to see as long
as they keep still. Thus most birds whose lives are passed on or near
the ground, and which build their nests there, are dull in coloring;
they are in danger from more enemies than are tree-dwelling birds, and
must be able to hide better. No bird of nocturnal habits is brightly
colored. It is mostly among the small, quick-flying species, such as
warblers and finches, that we find the gayly dressed ones. They are
birds of the sunshine, and usually migratory. In most cases when birds
have a plain dress there is little difference in it between the male
and the female; but whenever you find a species of bird wearing a gay,
ornamental dress, it is almost always the male that sports these fine
feathers, while the female and young are clothed in dull yellow, drab
or brownish tints. This appears to be another measure of safety. The
males can wander about, look out for themselves, and take to flight
when danger threatens; but their mates must sit quietly on their nests,
and trust for safety for themselves and (what is really more important)
their eggs or young mainly to not being seen. In their plain colors
they blend into the foliage and the shadows amid which they sit, and so
are more likely to escape the sight of prowling foes.
Feathers are not intended to remain permanently; they become worn and
faded, or are lost, so that at regular intervals the bird needs a new
suit of clothes. Twice a year, therefore, in spring and autumn, they
are pushed out by new ones sprouting in the same feather-growing pits.
This shedding of the feathers is called "molting," and it is analogous
to the shedding of the outer, horny pellicle of its skin by a snake or
lizard. Their molting is not very noticeable in land birds, because
the feathers drop out little by little; otherwise the poor creatures
would be left quite naked, and unable to fly. In most birds the new
feathers that come in are the same in pattern and color as those they
displace, so that the new plumage differs little if any from season to
season; but some birds acquire a new coat for winter that is decidedly
different, and sometimes snowy white, making them inconspicuous amid
the snow.
The largest and most important feathers in a bird's outfit are those
of the wings and tail, by means of which it flies and controls its
progress. How birds are able to keep themselves aloft in the air,
and move through it at will, is not yet understood. That it requires
great strength of wing muscles, and rigid support for them is evident.
Therefore we find the head of the arm bone (humerus) fastened by stout
ligaments to a great shoulder blade sunk in the flesh beside the fore
part of the spine, and also braced in two directions by other interior
bones, one of which extends down to join its opposite fellow at the
front end of the breast bone, and form the "wishbone" (the united
coracoids). This solid bracing by bones and tying by ligaments gives
the needed firmness to the wings; and enables their powerful muscles to
work them.
How great these muscles are you will know when I tell you that the
thick mass of "white meat" in the breast of the fowl carved at your
table consists only of the two principal muscles that move the wings
when a downward stroke is made. They, in their turn, are attached at
the base to the broad surface of the breastbone, or "sternum" and its
projecting keel. Beyond the wrist joint stretches a large, misshapen
hand, which consists mostly of one great forefinger, in the tough flesh
of which the big quills, or outer flight feathers, called "primaries,"
are rooted. Lying over their bases, when the wing is folded, is a row
of somewhat smaller quill feathers called "secondaries." Above those
are the small and close "wing coverts."
The tail is very important in guiding and checking a bird in flight,
and is useful in various other ways, and may also be extremely
ornamental. The tail quills are always in pairs, making an even number
of feathers. This results from the reduction to a mere stub of the
long clumsy tail worn by the archæopteryx and its fellows. The quills
continued to grow in pairs out of the side of the tail as it diminished
until all that there is room for (ten or twelve pairs) are now rooted
side by side around the edge of the condensed coccygeal bones.
Birds are, as a class, the most active of animals, and their
temperature is highest; this means a large consumption of oxygen, and
the windpipe is usually capacious, yet the lungs are not large, but
are supplemented by another apparatus for aeration. Opening out of the
lungs are several pairs of air sacs, amplest in those birds that are
much on the wing, which not only occupy spaces between the muscles and
organs within the chest, but in many cases extend into the neck and
head, and even into the limb bones, which in most birds are hollow.
[Illustration: THE PELICAN, NOTABLE FOR ITS THROAT POUCH
Photo, Keystone View Co.]
Here is a suitable place to say a few words about how a bird sings. The
breath enters and leaves the windpipe through the larynx in the back of
the mouth--an organ which, in our throats, contains the vocal cords and
voice-producing apparatus; but in birds the larynx is unimportant, for
their voice organ is near the lower end of the windpipe, and is called
"syrinx" or music box. It consists of an enlargement and modification
of the bony rings about the windpipe at the point where it forks into
the two branches to the lungs; and incloses vibrating membranes. It is
also furnished with small muscles that act to expand or contract the
tube and its inner fixtures, thus regulating the column of air forced
through the syrinx when the bird calls or sings. These muscles thus
control the space and the shape of the opening, and the tension of
the membranes that serve as vocal cords. The muscles of the syrinx vary
greatly in number and efficiency among birds; and many kinds classed as
"singing birds" (Oscines) do not sing melodiously or tunefully because
their music box is imperfectly supplied with the proper muscles. They
have the instrument, but are unable to play upon it.
[Illustration: PEACOCK WITH BRILLIANT TAIL SPREAD
Photo, Keystone View Co.]
[Illustration: SACRED PHEASANT
Photo, A. N. Mirzaoff]
* * * * *
The 10,000 or more different kinds of birds now living in the world are
classified in fifteen orders, of which the lowest in rank is that of
the ostriches, and allied ratite birds, mostly extinct, that stand in a
place apart by reason of their archaic structure and inability to fly.
The ostrich is still wild in the arid districts of Africa, Arabia, and
Mesopotamia; the rhea is Patagonian; the emus and cassowaries belong
to Australia and New Guinea; the apteryx, or kiwi, still survives in
New Zealand; and several gigantic ratite birds have recently become
extinct in New Zealand and in Madagascar, where egg shells, laid by the
prehistoric æpyornis, that will hold two gallons are still found. Some
species of these birds were seven feet in height.
CHAPTER XXIII
SOME NOTABLE WATER BIRDS
From these relics of geologic antiquity the remainder of the birds now
living, and their fossil ancestors as well, differ fundamentally, and
are united in a division whose badge is the keel on the sternum; hence
they are termed "carinate" birds (Carinatæ). The list begins with the
most archaic order, that of the loons, of which three or four species
are named, but they are hardly separable. They are as big as geese,
have black backs checkered with white spots, white undersurfaces and
heads purplish black, variously marked; and these heads and necks have
a very reptilian look, as they stretch forward their heads inquiringly,
or utter the "wild laughter" that seems so consonant with the lonely
waters they frequent. The reptilian suggestion is even stronger
in their cousins the grebes, known to gunners as "die-dappers,"
"hell-divers," etc., on account of the quickness with which they will
disappear when alarmed. The family badge is on the feet, where the
toes are not connected by a full web, as in loons, but every toe is
margined by a flange of firm skin with a scalloped margin. Grebes have
a way of swimming with the whole body under water, when the exposed
head and neck look very "snaky." The brown and white plumage of grebes
is exceedingly close and dense, and their indifference to wet and cold
is shown by the fact that their nests are mere rafts of sodden weeds
often so loosely tied to the rushes that they go adrift. Grebes abound
on all northern waters and are rarely shot since the taking of their
silvery breasts for hat ornaments has been stopped.
The penguins constitute an order limited in range to the antarctic
region. Their picture is in everybody's mind--a bird that stands as
erect as a soldier on two almost invisible legs and a short stiff tail,
and carries a small head, sometimes plumed, with a strong pointed bill.
The picture usually represents the great flocks that resort in the
brief summer to their rocky breeding places on icy shores, each female
guarding and incubating her two eggs in the rudest of nests on the
ground. These antarctic "rookeries" sometimes hold tens of thousands.
During the rest of the year the penguins are at sea, or under it,
behaving more like seals than birds, for their scalelike plumage is
impervious to water, and their stubby wings are in effect flippers by
which they swim under water, the strong-webbed feet acting only as
rudders until they come to the surface and can paddle. Penguins feed on
crustaceans and mollusks mostly, but also on fish and sea weed.
Next comes that group of wide sea wanderers, the albatrosses and
petrels, united in the family Procellariidæ, whose special mark is
found in the two bony tubes along the top of the beak that contain
the nostrils. Of the albatrosses many species are known, nearly all
inhabitants of the southern oceans, although two or three of the
largest regularly visit the North Pacific coast, and more rarely one
strays into the North Atlantic; certain small species frequent the
western coast of South America. The one best known is the "wandering"
albatross, whose wings spread nine or ten feet, yet are only nine
inches wide. They spend their whole lives on the open ocean, and
undoubtedly sleep there, regardless of storm or calm; but in summer
land on some lone antarctic island or lofty shore, and construct a heap
of mud and rubbish on top of which they deposit two chalky eggs.
Their relatives, the oceanic petrels, are much smaller as a rule,
and some no bigger than sparrows. They are of many kinds, including
fulmars, shearwaters, etc., and nearly all are black or sooty brown,
usually with touches of white. Most of the group are denizens of the
southern hemisphere, but some belong to the north and are migratory;
and the eastern Atlantic and Mediterranean are the home of the original
stormy petrels, which sailors call "Mother Carey's chickens" and regard
with mingled superstition and affection; Leach's white-rumped petrel,
of our New England coast, shares this name. Some of the far-southern
species are almost as big as albatrosses. Petrels get their food from
both the waves and the shore and follow ships on long voyages in hope
of scraps of flesh thrown overboard. Most of them breed in holes dug
in the topsoil of sea-fronting cliffs, and lay white eggs; many hide
in these holes by day, and go out only at night, filling the air with
wild cries while they hunt; but fulmars and shearwaters, which make
rude nests on rough shores or on cliff ledges, often in vast colonies,
go abroad in daylight, and throng on the Grand Banks and wherever else
fishing is going on.
Next, in the classification based on structure rather than on
superficial resemblances, comes a large assemblage of water birds,
some exclusively marine, others of inland waters. Here are placed
those long-winged, graceful, oceanic flyers, the tropic birds, and the
many kinds of gannets, snowy white, that soar and plunge like falcons
as they sweep over the waves and pick up incautious squids, fishes,
etc. Most of them are tropical, but one gannet is well known on both
shores of the North Atlantic where it nests in thousands on the cliff
faces that bound such lofty islets as the Bass Rock near Edinburgh, the
Hebrides, and Bird Rock in the Gulf of St. Lawrence. The flight is easy
and powerful, and the food is caught by a hawklike plunge.
The nearest relatives of these white birds are the cormorants, which
are shining black, glossy, with blue or green reflections. They are
scattered over the whole globe, most of them along seashores, but many
breed on inland lakes and swamps, usually in large companies. Unlike
the sweeping and beautiful flight of the far-wandering gannets, these
birds appear heavy on the wing; and instead of snatching their food
from the surface they dive after the fishes on which they feed, and
pursue their slippery prey under water, swimming with both wings and
feet, and dodging here and there in a most surprising way. Their bills
are peculiarly well adapted to holding what they catch; and a near
relative of the West Indies and southward often spears its prey with
its bill. This is the darter or snakebird, so called because its long
neck and small head give it a peculiarly snakelike appearance as it
swims with nothing above the surface but the slender head, and that
making scarcely a ripple.
Far more of a wanderer is the tropical long-tailed, long-winged, black
frigate bird, which is the hawk of the sea, for it hovers about the
flocks of fishing birds and forces them to disgorge their catch, which
it appropriates as it falls. Among the birds that suffer most from its
robberies are the pelicans, several species of which live close to salt
water in various parts of the world, while others prefer the lakes and
swamps inland. We have two common species in the United States, the
white pelican, seen all over the interior of the country in summer,
and the brown, which is southern and maritime; both are gregarious not
only in their annual migrations but in their breeding, building nests
on bushes in large companies. Their food is mainly fish, caught both by
diving and by scooping them up as they swim. The well-known peculiarity
of the pelican is the bag of naked skin that hangs from the underside
of the bill, and serves as a receptacle for the catch; when it is
filled the bird returns to its resting place to consume its food at
leisure, or to open wide its mouth and allow its nestlings to pick out
the contents of the bag.
All the foregoing are mainly marine and have short legs and webbed
feet, used principally in swimming; but we now come to the fresh-water
"waders"--the herons, bitterns, storks, ibises, and the like, whose
bodies are perched on stiltlike legs, and whose habits require them
to wade about in marshes and swamps in search of their miscellaneous
food; hence the neck also is long and the bill straight and sharp-edged
to fit it for seizing and holding the active prey by a sudden thrust.
All warm and temperate countries possess herons in a great variety of
species, varying in size from a bird three and one-half feet long, such
as our great blue heron, to one a few inches only in length; but the
colors are usually light and prevailingly bluish or greenish; while the
marsh-loving bitterns are streaked brown. Some are pure white, as is
our elegant egret, which has been all but exterminated in the United
States by men who kill it in the breeding season, when the beautiful
plumes that then adorn its back are at their best, and are marketable
as ornaments for hats and military shakos. Every plume bird so killed
means the loss of a family of young. Herons are shy, solitary birds, as
a rule, nesting on trees in remote swamps in "rookeries" to which they
return year after year from their winter retreats in the tropics; and
they get their food, which includes every sort of living thing they can
find, mostly by standing motionless in the water until it comes near
enough to be picked up by a swift stroke.
The storks are similar birds, but with rather heavier bodies and a way
of standing erect, and of holding the head straight out in flight (the
herons draw it back by curving the neck), which distinguishes them.
They are white and black as a rule, and mainly Oriental or African,
no typical species occurring in the United States. Storks are more
inclined to search the land for food than are the herons, and an
Egyptian species is locally called "a bird of blessing," because it
cleans the villages, while the stately "adjutant" of India is carefully
protected as a similar scavenger. The most familiar of the storks,
however, is the white one that in Europe nests on the roofs of houses,
chimney tops and similar places, and is generally regarded with an
affection that has been expressed in many a poem and story. Ibises are
much like storks, the common "sacred" ibis of Egypt probably owing
its religious distinction to its fondness for lizards and snakes--a
service highly appreciated in that country. Several ibises inhabit
America, one of which is not uncommon along the border of the Gulf of
Mexico, while another is noted for the splendid scarlet of its plumage.
In the same family is the beautiful spoonbill of our Gulf Coast, whose
name refers to the spatulate expansion of the end of the beak. Its
richly roseate hue is reproduced in the dress of the flamingos, that
need not be described.
[Illustration: FLAMINGOS
(_Phoenicopterus ruber_)]
We pass from the flamingos to the ducks by an intermediate form--the
curious chahas and horned screamers of northern South America--large,
turkeylike birds, often tamed and made of service on country places,
where they guard the poultry against hawks and other enemies.
The ducks are a cosmopolitan family (Anatidæ) of about 200 species,
divisible into five groups, namely, mergansers, river ducks, marine
ducks, geese and swans. These have many features in common, one of
which is that in the early autumnal molt all the wing quills drop
out at once, so that for a time none of them is able to fly. The
mergansers, sheldrakes, or "saw bills," are fish eaters, catching their
prey under water, where they move expertly, by means of the narrow,
tooth-studded bill that reminds us of the ichthyornis. They frequent
rivers, and most of them prefer rushing streams. Of our three species
two breed only in the Far North, the third on the Pacific slope. During
the winter they resort to a marine life in warmer latitudes. The river
ducks (Anatinæ) are distinguished from the seafaring ducks (Fuligalinæ)
not only by their preference for inland lakes and marshes, but by the
fact the hind toe bears no lobe, while in the sea ducks it is somewhat
webbed and functional. This group includes such well-known species as
the mallard, black duck, gadwall, widgeon, baldpate, teals, shoveler,
pintail, and the exquisite wood duck, to speak of American species
alone. The mallard and wood duck breed all over the continent, the
latter having the peculiarity of making its nest in trees, but the
others rarely nest south of Canada, except among the mountains of the
Pacific slope.
The seafaring ducks in North America also include several species that
are found on inland bays and salt marshes, such as Chesapeake Bay and
its borders, and do not limit their migratory routes to the seacoast,
but fly overland. Such are the redhead and canvasback, the scaups and
golden-eyes and the ringneck; but the eiders, the scoters, and some
others are truly oceanic. Most of these breed in the Far North, always
nesting on the ground, as is the rule of the whole family, except the
golden-eyes, which choose hollows in stumps and trees. None of the
ducks lays spotted eggs.
While among the ducks the male is likely to wear, at least in the
breeding season, more gayly colored plumage than the female--often
of extraordinary beauty--among the geese both sexes are alike, and
either white throughout, as in most of our species, or brown or gray,
with more or less black, as in the brants, and in our common "wild" or
Canada goose. Geese are far more terrestrial than ducks and visit the
land to nip the herbage, young corn, or cereals; in California doing
serious damage to growing crops. All our species breed in arctic lands
except the Canada goose, which still makes its nest in the northern
parts of the United States and throughout Canada; and most of them
spend the winter south of our country. They represent to most persons
the idea of bird migration. "We see the living wedge of long-necked
birds," says Chapman, "passing high overhead; the unbroken sound waves
bring the sonorous 'honks' with unexpected distinctness to our ears;
and we receive an impressive lesson in the migration of birds. They are
embarked on a journey of several thousand miles, but they come and go
as surely as though they carried chart and compass."
As these geese are larger than the ducks, so the swans surpass the
geese in size and are indeed the largest of water birds. The eight
species are distributed all over the world, everywhere frequenting
fresh waters alone; and all are white except a black-headed Argentine
species, and the wholly black swan of Australia. Before the discovery
of this Australian curiosity a black swan was the proverbial _rara
avis_--something incredible! Swans live mainly on weeds and roots
pulled up from the bottom, but also eat snails, and so forth. Two
species, the whistling and the trumpeter swans, belong to the American
fauna, but both are now rare.
CHAPTER XXIV
VULTURES, FALCONS AND GAME BIRDS
The so-called "birds of prey" include three quite distinct groups, the
American "vultures," the hawk and eagle tribe, and the fish hawks.
All agree in having strong, hook-pointed beaks, in many cases with a
toothlike point on the cutting edge of the upper mandible, and covered
at the base by a fleshy "cere"; and in having claws of great strength
termed "talons." This catlike armament, adapted to seizing and holding
living prey, and tearing its flesh, indicates the predacious nature and
practice of the tribe, but it is developed to its fullest extent only
in the falcons and powerful eagles, since a large part of the order are
carrion-feeders or catch nothing larger than grasshoppers. Among the
carrion-feeders are the condor of the Andes, and his almost extinct
cousin the California condor, which are the largest flying birds in the
world. Near relative to them are the turkey buzzard and carrion crow
of our Southern States, besides some tropical species. The vultures
of the Old World are, as a rule, big birds inhabiting mountainous
and desert places, and capable of overcoming almost any disabled or
weak animal. A small one that in North Africa plays the rôle of town
scavenger, as does our turkey buzzard, is famous under the Egyptian
name of "Pharaoh's chicken." The partial nakedness of the head, often
accompanied by a great neck-ruff, is a characteristic of all these
birds.
The lammergeier of the Alps and eastward to India connects in its
structure and habits the vultures (Vulturidæ) with the real predatory
family (Falconidæ), in which are placed the hundreds of species of
buzzards, harriers, hawks, eagles and sea eagles, that subsist by
killing and eating every kind of creature that it is within the power
of each one to overcome. The bulk of their prey consists of small
rodents; and in pursuing them they rid the land of vast numbers of
little gnawers most injurious to agriculture; it should be the business
of every farmer and orchardist to learn to recognize the three or four
fierce little poultry-catching falcons in his locality, and refrain
from killing any other sort of hawk.
It is a hopeless task to give any detailed description of the game
birds, which are world-wide in their distribution and practically of
the greatest importance to mankind, for in this group are found the
originals of our domestic poultry (the jungle fowls of India), and the
quails, partridges, grouse, pheasants, turkeys, curassows, and many
more of hardly more interest to the naturalist than to the sportsman.
The sportsman is willing to count the toothsome rails as "game" when
he goes after them in the marshes of the middle coastal States. They
are plain-colored birds that run about amid the salt grass and reeds,
and are an interesting example of adaptation to this special station
in life, for their bodies are notably compressed, so that a rail can
slip through a narrower space than any other bird of its size; hence
the proverb: "Thin as a rail." A common species in Europe is known in
literature as "corn crake"; and American relatives, the gallinules of
fresh-water marshes, go by the name of "mud hens." The rails belong to
the crane family, which includes many large tropical birds besides our
own two kinds of cranes, both becoming rare in the United States.
Good sport and delicate fare are afforded also by the great tribe of
"shore birds"--plovers, yellowlegs, curlews, snipe, and the various
sandpipers that feed along the seashores or frequent the inland marshes
of every part of the world, nowhere more numerously than along our
much embayed eastern coast. The plovers are especially interesting,
and one of them, the noisy killdeer, is familiar all over the country,
breeding in upland fields, where four brown and spotted eggs are
laid in a little hollow of the open ground, plover fashion. Another
notable species, the golden plover, is a cosmopolitan, and a remarkable
migrant, journeying from its arctic breeding place to the tropics, not
only overland, but across thousands of miles of ocean, as from Nova
Scotia direct to Bermuda, and Alaska to Hawaii. The crested "lapwing"
of Europe is another famous species. The plovers have short bills and
live on insects; but the sandpipers that in greenish or brown-streaked
coats flit along the shores pick up a more miscellaneous fare from
the edge of the sea and on exposed tide flats. Here too, are the very
longed-legged "stilts," the phalaropes with lobes along their toes like
a grebe, the curlews, with their long, upcurved bills, the willets
that alarm all the rest by their cries as soon as they espy a gunner,
the big, gray godwits and many others. Various snipes form a group of
small, swift fliers that haunt boggy land, where they probe the mud
with long bills furnished with nerves of great delicacy at the tip
by which they can feel the hidden worms buried in the mud that are
their favorite fare; and one of them is the swamp-haunting woodcock,
beloved of gourmands on both sides of the ocean. Europe and Asia have
several other kinds of birds in this class not known here, such as
the coursers, and the Egyptian "ziczac" that now and then picks the
crocodile's teeth, and is almost the same as the historic lapwing, so
familiar in Scotland.
CHAPTER XXV
FROM GULLS TO KINGFISHERS
Our scientific arrangement introduces next the gull family, followed
by a series of groups that seems to the layman most miscellaneous. The
gulls are a world-wide family of sea birds, seen also near bodies of
water in the interior of continents, especially northward, which live
on fish and floating edibles. They are mostly glistening white, often
marked with black about the head and wings, except the big brownish
skuas that live by robbing other gulls of their catch and their nests
of young. A very distinct group in the family are the smaller terns,
whose slender forms, long wings, and graceful flight give them the
suitable name of "sea swallows." Another distinct lot is that of
the low-flying black "skimmers." All these birds normally breed on
sandbanks near shore, laying four handsomely variegated eggs in a mere
shallow of earth, but a good many nest in colonies on the margin of
fresh-water lakes. The gulls serve well as scavengers, but are not good
to eat.
Related to the gulls, but very different in appearance, are the small,
dark-colored, quaint auks, guillemots and puffins of northern coasts,
that look like miniature penguins, for they stand erect on two big
feet. They are fishers, with great skill in swimming and diving, and
breed in companies of thousands, sometimes, on the ledges of the
sea-fronting cliffs of Labrador, northern Scotland, Alaska, and Arctic
islands. The extinct "great auk" of the North Atlantic coasts was a
giant of this race.
Passing the sand grouse of Africa and Russia, we come to the pigeons,
represented in a bewildering variety of forms in every part of the
world. The United States has several species--the common wood dove, or
mourning dove, the extinct "wild pigeon," once here in millions, the
banded pigeon of the Pacific Coast, and several kinds of ground doves
in the southwest. The rock dove, which is the original of the domestic
varieties, is still wild in Europe, together with several other
species; and the Orient abounds in representatives of the family, some
of them large and extremely handsome, especially in the division called
fruit pigeons. To this family belonged that famous bird of the past,
the "dodo" of Mauritius.
There follow two big groups, the cuckoos and plantain eaters, and the
parrots, which together have the peculiarity of two toes in front and
two behind, instead of the customary three toes in front and one,
or perhaps none, behind; the woodpeckers have the same "yoke-toed"
arrangement, but are distinct otherwise. The cuckoos are mainly
Oriental and very varied, although all show the slender form, long
tail, and long curved beak that we see in our two American species, the
black-billed and yellow-billed; the most aberrant one in our country
is the queer, lizard-catching road runner of southern California. None
of the cuckoos seems a good nest maker. The nests of our common ones
are loose platforms of twigs, and both species often drop eggs in
each other's cradles; but they, in common with almost all the other
cuckoos of the world, do at least incubate their eggs and care for
the nestlings, instead of leaving that task to some foster parent, as
does the similar cuckoo of Europe. The most extraordinary feature of
this parasitic habit is the fact that the cuckoo often, if not always,
first lays its egg in any convenient place, and then, taking it in its
beak, carries it to another bird's nest and puts the egg into it. This
accounts for the frequent finding of a cuckoo's egg in nests into which
so large a bird could not have crept.
To record the fact that about 500 different kinds of parrots are
catalogued will be a sufficient explanation of their dismissal with a
few general remarks. The larger number and most striking examples--the
great cockatoos for instance--belong to Australia and the Malayan
islands, but the Indian region, Africa, and tropical America abound in
parrots. Probably the northernmost of the whole family is our Carolina
parakeet, which formerly ranged in summer even to the Great Lakes,
but now is almost exterminated even from the great swamps of the Gulf
Coast. Of the two kinds most often seen in cages--a custom that is
almost prehistoric in antiquity--the gray parrot is African, and the
green or green and yellow "Amazons" come from South America.
Parrots are gregarious, nest in holes in trees, although a few live
in holes in the ground or among loose rocks, and feed on all sorts
of vegetable productions, including some very hard fruits cracked in
their powerful bills, as is the habit of the gorgeous macaws of Central
and South America. The lories of Australia are provided with tongues
brushlike at the tip, and besides eating seeds they lick the honey out
of the blossoms of the eucalyptus and other flowering trees, and in so
doing effect the cross-fertilization of these trees in a country which
has no bees to do that service.
Passing the brilliant rollers of the Old World, and the motmots and
little gemlike todies of the New, we come to the extensive tribe of
kingfishers, of which our blue and white example is a very modest
specimen--but the only one we have, while 150 other species are counted
in the rest of the world, most of them in the Austro-Malayan region
and in Africa. They vary immensely in size, colors, food and habits.
A large section are not "fishers" at all, but dwell in wooded places,
and subsist on insects caught on the wing, and on reptiles, mice, etc.,
like birds of prey. Few groups are so diversified and entertaining as
this one. Related to them are the bee-eaters, hoopoes, hornbills and
others that bring us to the owls, a suborder of which contains the
great nightjar family to which our whippoorwills and nighthawks belong,
with the swifts and humming birds as near relations. Then come the
woodpeckers, much alike all over the world (but absent from Australia),
followed by the gorgeous trogons of Mexico and some other tropical
beauties.
CHAPTER XXVI
PASSERINE BIRDS
We have now run through the list of all the orders of birds except
the last and largest--the "passerine" birds, the ordinary songsters
of the fields and woodlands of the northern hemisphere. There are
fifty families contained in the order. Here, among our North American
migratory birds are to be found the kingbirds, pewees and other
"tyrant" flycatchers; the larks of our western plains and eastern
seashore; that sprite of the Rocky Mountain brooks, the ouzel; the
waxwings, the butcher birds; the pretty greenish vireos that build
those exquisite, cup-shaped hanging nests made of grapevine bark and
spider's silk; and the swallows that become so friendly every summer
about barns, paying rent by diligent service in insect killing. Then
there is that interesting little group of small and cheerful climbers,
the nuthatches, chickadees, and creepers, that rid trees of hosts of
injurious insects which they dig out of crevices of the bark as they
scramble up and down the trunks, some of them continuing the good work
all through the winter. These have their counterparts in Europe, for
in respect of our common song birds, as of the birds of prey and game
birds, the avifauna of Europe and North America is virtually one. The
differences are mainly in the few representatives of tropical groups
that visit northern countries in summer, those of Europe partaking of
the African or Indian families, while we have wandering species from
groups that are properly inhabitants of Mexico and southward. Such, in
fact, are our few humming birds, hundreds of species of which belong
to the American tropics (and none to the Old World), our two tanagers,
members of a very large tropical family, and our blackbirds and
orioles, far more numerous in species south of the United States.
While we have many delightful vocalists, the best singers of all
our birds are no doubt the thrushes, and that is true of thrushes
elsewhere, for the European blackbird and mavis, the celebrated
nightingale, the solitaire--both that of the West Indies and that of
our northern Pacific Coast--and several noted musicians in the Orient,
are of this melodious family. Which is the best singer of them all
will never be settled, for the citizen of each country likes best that
to which he is most used; but to Americans nothing can be better than
the evening carol of the wood thrush, the serene hymnlike music of the
hermit, or the sweet and wavering call of the veery. Yet in the South,
where these northern thrushes are rarely heard at their best, the palm
is given to the mocking bird, which, like the northern brown thrasher,
rivals all in turn by simulating their notes in a liquid melody that,
especially when heard in the calm of a moonlit summer evening, seems of
surpassing beauty.
CHAPTER XXVII
THE BEASTS OF THE FIELD--SOME PRIMITIVE TYPES
We have now arrived at the highest rank in the scale of animal
life--the four-footed, hair-clad, milk-nursed denizens of our woods and
fields--the subclass Mammalia, mammals.
These are the "animals" of popular speech, but accuracy requires a
more distinctive expression, for every living thing not a plant is
an "animal." Unfortunately no such distinctive term exists in our
language, and hence we must borrow from the Latin the word "mammal" for
this group. It is correct, easy to remember, and there is no reason why
it should not be used popularly as well as scientifically. It is good,
because it is exact, and expresses the one great distinction which
separates mammals from all other animals--the feeding of the young on
milk secreted by the mother. The milk-producing glands were called
in Latin "mammæ," whence our word "mammal" and the technical term
Mammalia--animals that suckle their young.
Another peculiarity of the group is the coat of hair--persistently
growing threads of horny substance produced from the skin in greater
or less abundance and of varying quality and color. Its chief purpose
appears to be that of keeping the body warm; and, as in the case of the
feathers clothing birds, it enables the blood to rise to and maintain
a temperature much higher than that of the air; hence the mammals are
"warm-blooded." This condition, gradually acquired, stimulated their
activity and hence their brain development, the result of which is a
higher degree of intelligence than is manifested, as a class, by any
other animals, and a moving cause of their progress to the highest
plane of organic evolution.
The history of the evolution of the Mammalia may be traced back to
obscure beginnings in the Triassic, the oldest of the three divisions
of the Secondary or Mesozoic era. Just preceding that time there
flourished a group of reptiles, the Theromorpha, whose skull, teeth,
and forelimbs were very like those of a modern beast of prey; and
zoölogists consider it "altogether probable" that the origin of
the mammalian branch must be looked for among their number. It is
not doubted, however, that true mammals, although very small and
inconspicuous, existed throughout the whole Mesozoic era, despite the
fact that the world at that time was filled with ravenous reptiles.
Indeed, it is believed that their steady development was an important
agency in destroying the reptile population, largely by eating
their eggs. At any rate, before the end of the Mesozoic era the two
grand divisions of Mammalia, Prototheria and Eutheria, had become
established; and also the two primary divisions of the latter, the
Marsupials and the Placentals, had been separated. Then came that
extraordinary change in the physiography of the globe that marked the
end of Mesozoic conditions and introduced those of the succeeding era
named Tertiary. In the broader and higher land areas and the drier
and more invigorating climate that followed, producing a vegetation
tending constantly to become like that of the present, mammals found
increasingly favorable conditions, and became the dominant race of
animals.
RELICS OF PRIMITIVE TYPES
There live in Australia and New Guinea two curious little animals that
most nearly represent in their low and generalized organization the
primitive mammals, and differ so essentially from all other mammals
that they are classed by themselves as Prototheria ("first beasts").
They are the duckbill (Ornithorhynchus) and the spiny anteater
(Echidna). The duckbill is a small, softly furred, web-footed creature,
as aquatic in its habits as a beaver, which finds its food in the worms
and other things that live in and on the mud of its chosen stream, and
digs a burrow in the bank for its home, where it stays most of the
daylight hours, and where its young are born. Its special peculiarity
is that instead of the muzzle and mouth of an ordinary mammal, it is
furnished with a bill like that of a duck, and each jaw is armed with
horny plates to do the work of teeth; in the young ones true molar
"milk" teeth are present, but are soon shed. The cheeks contain pouches
in which a quantity of food can be stored, the animal carrying it in
to the safety of its burrow to be eaten, and so avoiding the danger of
being out for a long time of feeding.
[Illustration: OPOSSUM MOTHER AND YOUNG
Photo, American Museum of Natural History]
The echidnas are equally small, about eighteen inches long, covered
with a mingled coat of hair and strong spines, and mounted on short
legs and feet armed with powerful claws, for this animal dwells on
land, and not only burrows, but must tear to pieces the hills of the
ants that form its only food. Its round little head terminates in a
long, slender snout containing a ribbon-shaped tongue with which it
licks up the ants from their ruined nests.
[Illustration: ANTEATER, WHICH LIVES ON INSECTS CAUGHT IN THE STICKY
SALIVA OF ITS LONG TONGUE]
[Illustration: SLOTH, AN ANIMAL WHICH KEEPS TO TREES AND IS ALMOST
HELPLESS ON THE GROUND]
The striking peculiarity of both these queer creatures, however, is
the fact that they lay eggs. These are few--sometimes only one--and
recall those of reptiles in their relatively large size, parchmentlike
shells, and abundance of food-yolk. The duckbill deposits her eggs in
her grass-lined burrow nest and covers them with her body until they
quickly hatch. The blind and naked young then apply their lips to the
nearest part of the mother's abdomen, and suck milk through the pores
of the skin. In the echidna one sees a little advance on this extremely
simple beginning of nursing; for here, instead of being laid in a
burrow nest, and covered by the mother, the echidna's egg is placed by
the mother within two parallel folds of skin which at that season form
a deep groove in the abdomen inclosing the nursing area, and is held
there until it hatches. When the young has attained a certain size the
mother removes it from the "pouch," but takes it in from time to time
to suckle it.
Such are the Prototheria--one of the grand divisions of Mammalia, set
apart by reason of their laying the eggs from which the young will
afterward be born, whereas in the other division or Eutheria ("proper
mammals") the "embryos," or unborn young, escape from the eggs in a
less or greater degree of development before their birth from the
mother. This period between the conception of life in the egg and its
emergence at birth is called the period of gestation, and is much
longer in large animals than in small ones. Fundamental differences in
method of birth divide the Eutheria into two groups, designated as
Nonplacentals and Placentals.
THE MARSUPIALS
The word marsupial means "pouched," and refers to the most
characteristic peculiarity of the nonplacental division (order
Marsupialia), which is the possession of a more or less pocketlike fold
in the skin of the abdomen of the females within which the extremely
immature young are nourished.
The egg-laying mammals, also nonplacental, have the young inclosed in a
protective shell that they keep warm, as do the birds, until the embryo
is sufficiently matured to be safely born. In the marsupials nature
meets the difficulty another way. The embryo is but little advanced
when born, in fact it is utterly helpless and minute, being, even in
the case of the largest kangaroos, hardly as big as a mouse. It would
be fatal, of course, to turn it loose upon the world; and therefore the
mother is provided with the pouch already described.
The instant an embryo is born the mother picks it up and places
it within the pouch, where it crawls about until it touches and
instinctively takes hold of one of the threadlike teats. As it gets
stronger it leaves the pouch now and then, but returns to it for
nursing, sleeping, and protection when alarmed, until finally it
departs altogether.
This description applies to the most advanced families of the order.
In the oldest and most generalized families of marsupials, such as the
banded anteaters, there is virtually no pouch at all.
As almost the whole marsupial tribe are natives of Australasia, it is
odd that the family with which we must begin a list of them--the true
opossums--should be American, and quite unknown in Australia. This is
explainable when it is known that this family (Didelphidæ) is the most
archaic of this ancient tribe, and was well established in Cretaceous
times, and then and later was widely distributed in Europe and on this
continent; yet so little change has occurred in the race that teeth
from the Laramie formations of Wyoming are hardly distinguishable
from those in the jaws of our 'possum-up-a-gum-tree to-day. No wonder
the quaint creature is hoary and wrinkled; he is a very Methuselah
among mammals, and looks it! All opossums seem to have disappeared
from Europe before the close of the Miocene, but continued to survive
numerously in South America. They probably owe their long career, in
competition with animals of so much higher grade, to their small size,
forest life, nocturnal habits, ability to eat all sorts of food, and,
most of all, to their great fecundity. Our common opossum is the most
northern of its kind, and ranges over the whole country as far north
as the latitude of Lake Erie; it appears never to have crossed the
Hudson River until comparatively recent times, but is now frequently
met with in New England and on Long Island. It is at home in all sorts
of places, except, perhaps, on the dry plains, for it is primarily an
arboreal animal, aided in climbing about trees by its naked, prehensile
tail, by which it may hang to a branch while using its forefeet to rob
a bird's nest or gather fruit. It will eat anything it can get hold
of, and with its sharp teeth, which number fifty, will kill animals
as large as itself; hence it is a destructive raider of henroosts and
sitting birds as well as a seeker of mouse nests and insects.
Opossums are amazingly prolific, and have broods of a dozen or more
in many cases. These often crawl on the mother's back, and cling with
claws and twisted tails to her fur and tail, and so are carried about.
Burdened by these kittens she hunts daily--or rather at night, for the
most part--and defends them savagely and bravely against foxes and
other enemies, often successfully standing off the farmer's dogs. With
a family to defend, or when faced by any foe that is at all equal to
its powers, the opossum does not resort to "playing 'possum," for this
is a last resource when surprised and "cornered" by an overwhelming
danger that it can neither avoid nor cope with.
The proverbial feigning of death by this animal (many other small
animals do the same) has excited much popular interest, and has
received many explanations. I have suggested that it is a survival of
a practice which in past ages had been an advantageous ruse of the
ancestors of the opossums.
Several other species of opossums exist in Central and South America,
some much smaller than ours and one hardly bigger than a mouse. One
kind, the "yapock," is aquatic, dwelling on land only during the
infancy of its progeny, and until they are old enough to be taught
to swim. All the marsupials inhabiting the Americas (except a rare
little molelike one in Patagonia), belong in the family Didelphidæ; but
this family is not known in Australia, where the so-called "opossums"
belong to a different tribe. They were named after our common northern
opossum, which was known to science before Australia and its pouched
fauna were discovered.
One of the extraordinary things in zoölogy is that Australia, and
the near-by islands that constitute with it a faunistic province,
has no indigenous mammals (except a few mice and bats) other than
marsupials, which have become so diversified as to represent the varied
kinds of animals seen elsewhere; and no marsupials live anywhere else
in the world except our single and primitive American family. This
curious situation has caused much discussion. It is known that in late
Mesozoic times marsupials were scattered all over the globe, but became
exterminated everywhere outside of Australasia and America long before
the present era. The Australian marsupials are supposed to be the
survivors, flourishing in a favorable region; but why no other mammals
survived there is still a puzzle. Another theory is that Australia,
regarded as formerly a part of a much larger southern continent, is the
original center from which the ancestors of the Marsupialia spread,
but failed to maintain their race outside of their original home, with
which South America was then connected.
The most archaic of these marsupials is the celebrated Tasmanian
"wolf," or thylacine, which resembles in size and shape a pointer
dog, but with a longer muzzle, and that long tail which seems to be a
general characteristic of the Marsupialia. It is brownish gray, with a
row of darker bands crossing the hinder half of the back, and is one of
the most swift-footed and savage hunters in the world. It is confined
to Tasmania, where it became so destructive to sheep when the island
was settled that it was killed off until almost exterminated. This
island was the home, also, of another smaller beast, looking somewhat
like a wolverine with the head of a hyena, which was so morose, savage,
and untamable that the settlers named it "Tasmanian devil," and
destroyed it as rapidly as they could. It hid by day in some rock den
and made its forays at night. This truly diabolic creature belonged to
the family of dasyures, which is represented in Australia by several
small, predatory beasts called "native cats." They fill the rôle there
of our northern martens and weasels, and most of their time is passed
in trees, although some are fond of hunting amid rocks and brush. They
like to come about ranches and villages, where they are the pest of
poultry keepers, but are rarely domesticated, even partly. Another
carnivorous group (phascogales) contains the "pouched mice," which are
not mouselike, except in size, but have more the nature of shrews that
live in trees and hunt birds and any small creatures they can catch.
Of the phalangers a curious specimen is the wombat, named "native bear"
by the early colonists--an animal about the size of our woodchuck,
shaped like a miniature bear, and living mainly on roots, which it
digs at night with its powerful claws; its thick fur makes its skin
valuable in market. Related to it structurally, but much like our gray
squirrel in shape, and having an even longer and more bushy tail, is
the charming sugar squirrel, which dwells in trees, and sails in long
flights from tree to tree in the twilights and on moonlight nights just
as do our flying squirrels; there are also tree phalangers so small
they are called "flying mice." Other tree-living phalangers are the
"opossums" of Australia, whose soft gray pelts are exported in great
numbers to foreign fur markets.
[Illustration: A KANGAROO MOTHER
Showing young carried in the abdominal pouch]
The kangaroos and wallabies (Macropodidæ) represent the highest
development of the marsupial type, and number some fifty species spread
over all Australia and New Guinea. While the majority inhabit open
grassy plains, others brushy districts and rocks, and a few dwell in
trees, the kangaroos proper include half a dozen of the largest kinds,
the commonest of which is the great gray "boomer" or "forester," of
the colonists, often seen in menageries. It stands four to five feet
tall, with a tail thirty to thirty-six inches long; but this size is
considerably exceeded by that of the red or woolly kangaroo, of eastern
and southern Australia. Furthermore, fossil remains show that in the
Pleistocene era kangaroos far bigger than even these existed there in
numerous extinct species--one, for instance, whose skull alone measured
nearly a yard in length. These animals take the place in Australia
of the deer of northern countries. They are very gregarious, and
are always to be met with in droves. Each drove frequents a certain
district and has its particular camping and feeding grounds. The animal
has a dreadful weapon of defense in the powerful hind claw, which it
can use like the tusk of a boar.
The smaller kangaroos are called "wallabies," or brush kangaroos, and
frequent scrub jungle and rocky places. These furnish most of the skins
and leather sent to European markets and, like the big species of the
plains, have been greatly reduced in numbers by hunters and sheep
herders. Some of them are confined to the rough deserts and mountains,
where they jump about the rocks with astonishing agility. One small
genus includes the swift harelike species that resemble our jack
rabbits in habits; and there are also the "dorca" kangaroos, which are
arboreal in habit and handsomely colored. Another group are ratlike in
form, colors, and manners, running rather than leaping, and dwelling
among scrub and grass, scratching the ground all day in search of the
roots upon which they feed, and making havoc in the frontiersman's
potato patches. Several kinds have prehensile tails, which they use
apparently only to carry to their underground homes the long grass of
which they make their beds. They associate in connected burrows like a
rabbit warren.
In the varied forms and functions they present, as beasts of prey, as
grazers or root diggers, as ground-running, tree-climbing, burrowing
or cave-haunting forms, some solitary and slow, others agile and
gregarious, the marsupial tribe in its isolated corner of the earth
exhibits an epitome of the whole mammalian world. It shows in a
conspicuous way how the necessity and habit of making a living in
varied circumstances, and exposed to lively competition, restricting
every species to a particular manner, brings about a suitable
modification of structure.
THE EDENTATA--ANTEATERS, SLOTHS, AND ARMADILLOS
At the base of the great division of Eutherian mammals, to which
belong all that remain to be described, is found the order Edentata
("toothless"), whose modern representatives are few and unimportant
in comparison with those of past ages, when gigantic ground sloths,
armored glyptodons, and other fossil species flourished in a luxuriant
world. The name is not well chosen, for many of these animals possess
at least a few teeth, but always composed of vasodentine and not
coated with enamel. Although the origin of this race is obscure, it
was certainly far in the past, for its characters are archaic in many
particulars, and its members are often far separated in structure,
and also in their geographical distribution. Two families belong to
the Old World, one in the Orient and another in South Africa, but all
the other edentates are American. The Oriental one includes most of
the "pangolins," or scaly anteaters, which are covered from head to
foot in a coat of mail formed of overlapping horny plates, and can
roll themselves into a ball that will defy any jaws not big enough to
tear them to pieces; while the African family consists of the naked,
long-nosed aard-vark ("ant bear"), which burrows in the ground, and
cuts its way at night into the mud forts of termites and other ants in
search of its favorite food. These two ancient creatures differ so much
in their anatomy from the American edentates that they are classified
by some naturalists in a separate order (Fodentia); and they differ
almost as radically from one another.
It should not be surprising to find most of the modern edentates in
South America, since that is the most ancient and unchanged of all the
continents; but a few sorts of anteaters, sloths, and armadillos alone
remain where once their race, in its heroic age, dominated the world
of its time. The puny survivors look and act like the relics they are.
The "great" anteater, or tamandua, standing eighteen inches or more in
height, has flatfooted, bearlike hind feet, and short forelegs that
end in huge claws bent under, or backward, so that the animal walks
on the outer face of its toes. Its tail is a great bushy mass of hair
with which the animal may cover itself as with a blanket, and its long
neck tapers off into a head with a very long nose and little room for
brains. The big claws are not used for burrowing an underground home,
but for digging up the nests of ants and termites which it licks up
with its long, sticky tongue. When one realizes the enormous colonies
of ants in the tropics it is not amazing that so large an animal should
subsist exclusively on these minute creatures. The claws are formidable
weapons of defense also, the animal throwing itself on its back and
defying the foe, or rising on its hind legs and giving a tearing,
bearlike hug that even a man might well fear. This is a slow-moving
creature, more fond of open country than forests; but a smaller
tamandua belongs wholly to the woods and spends both days and nights in
the tree tops, tearing open the burrows and nests of arboreal insects
and devouring their inhabitants and their stores of honey and young.
A third species is the rare little yellow two-toed anteater of the
Isthmus region, which appears to live almost wholly on wasp grubs.
Much like these in organization are the two species of sloth, hairy
creatures that hang all day long by their long, muscular limbs and
two or three curved claws, underneath a branch of the tree through
whose top they slowly creep about at night, collecting, crushing with
their peglike teeth, and swallowing the leaves that constitute their
fare. Their long hair, naturally gray, becomes green by accumulating a
coating of minute plants that thrive on it, and this helps to conceal
the sloths amid the foliage, yet they are killed by eagles and by all
sorts of beasts of prey, against which they have no means of defense.
These listless creatures are the degenerate descendants of a very long
ancestry. The early Tertiary rocks of Argentina contain the bones of
small slothlike animals that apparently were ground dwellers and must
have been active diggers. Later that region became filled with larger
ground sloths, apparently their descendants, that are believed to have
browsed on bushes and trees; and some of these became the megatheres
of the late Tertiary, which were as big as elephants. Similar giants
inhabited North America.
Even in the earliest days known to paleontologists the anteater-sloth
group had become well separated from their fellow edentates, the
armadillos, arguing a far-preceding origin. In the later Tertiary
the latter type developed such huge and heavily armored forms as
the glyptodon, on whose bony shell the teeth of even the great
saber-toothed tigers of the time could make little impression. These
grotesque tortoiselike glyptodons, of which there was a great variety,
were vegetable eaters, and some survived to a time so recent that
there is evidence that they were finally killed off by human hunters.
Beside them were smaller armadillos, more like the modern ones, which
are armored with overlapping belts of horny material between which
coarse hairs sprout; but the amount of this armor varies greatly among
the several species scattered from Patagonia to northern Mexico. In
some it is a continuous shell, in others it consists of several belts,
in still others is nearly absent. Armadillos are carnivorous, digging
out worms, grubs and the underground nests of wasps, catching insects
of all sorts, stealing eggs and young from ground-nesting birds,
killing serpents by leaping on them and sawing their bodies in two by
means of the rough edges of their plates. In some places on the pampas
armadillo burrows are so numerous as to make riding dangerous.
CHAPTER XXVIII
THE GNAWERS
The great order Rodentia--rats, mice, rabbits, porcupines, squirrels,
beavers, etc., derives its name from the Latin verb _rodere_, to gnaw,
or eat away (something), and is characterized by the great development
of the front (incisor) teeth, by means of which rodents get their
living by biting off, or gnawing through, the plants and woody stems
on which they feed, or which they use in constructing their dwellings.
All are primarily vegetable eaters, yet none will refuse a meal of
flesh when opportunity offers to get it, and some are decidedly
carnivorous, especially as to fish. They are distributed all over the
world, including the Australian region. They are chiefly terrestrial,
and often burrow or live in ready-made burrows. Some are aquatic, such
as the voles; others, like the squirrels, are arboreal. In perhaps
a majority of the forms the hind legs are much longer and stronger
than the forelegs, giving the animals great leaping power, while the
forefeet, with their long and flexible fingers, are constantly used
as hands. Many are beautifully marked in varied tints of gray, brown,
red, and black, so that their pelts have value in the fur market;
and their flesh is an important element in human food. On the other
hand the activity of these animals, when numerous, causes serious
damage to gardens, crops and orchards and one of them, the rat, is
unquestionably the most dangerous animal to human health and prosperity
in the whole animal kingdom. The fecundity of the smaller, murine
species, is great, and from time to time they increase inordinately in
favorable places, and swarm abroad in vast and destructive migrations.
Were it not for the fact that the rodents furnish the principal part
of the food of predatory mammals, reptiles, and birds, and are thus
kept down, the globe would soon become so populous with this tribe that
hardly anything else could maintain existence.
The distinguishing anatomical characteristic of the rodents is the
dentition. The canines, so essential to carnivorous, predatory animals,
are here completely absent, and a long empty space intervenes between
the incisors and the molars, or cheek teeth, which vary greatly in
number and form among the different families. The incisors consist
of a single pair in each jaw, very large and strong, and composed of
vasodentine, _faced only_ with hard enamel, often yellow or red. As the
softer substance behind the facing wears away more easily, the incisor
takes a chisel shape, leaving the hard enamel in front projecting
slightly as a cutting edge; thus these teeth always remain sharp. The
rodents are traced back in their lineage to the order Tillodontia of
Eocene time. The oldest family of modern type in the order is that of
the squirrels.
Let us begin with the rabbits and hares (family Leporidæ). The name
properly applies to the Old World species _Lepus cuniculus_, the
burrowing wild rabbit from which all our various domestic rabbits are
descended, whose special characteristic is the fact that they live
in holes in the ground of their own digging, and in large colonies
called warrens. All the other species make their breeding beds and
resting places on the surface of the ground, in the best concealment
(outside of forests) that they can find. Such a home is called the
animal's "form," and when it contains a litter of young the mother
covers them with a blanket of hair which at that season she is shedding
copiously. Strictly speaking, all the Leporidæ, except the _cuniculus_,
are "hares"; but the general term "rabbit" is now so common that the
scientific distinction is of no consequence. Europe and Asia have
two kinds of hares, and several exist in this country, such as the
familiar "cottontail" or bush rabbit of the east, the southern swamp
rabbit, and several species of large, long-eared, swift-footed hares
of the western plains called "jack rabbits." The most important one,
however, is the large northern one named "snowshoe rabbit," because
in winter it receives a broad growth of hair on the feet, aiding it
in traveling over the snow. This rabbit turns white in winter, the
hairs losing their color with the advent of cold, as also does the big
arctic hare which wanders as far north as land extends. These northern
hares are the chief dependence for food in winter of all the Canadian
fur-bearing animals, and indirectly of the native Indians. Consequently
when, as happens at intervals of a few years, the rabbits of a
district all but wholly die off by an epidemic, a famine and dreadful
distress occurs--or used to when civilized aid was less available than
now--in northern Canada, and the commercial outcome of furs is greatly
diminished.
As the hares feed on herbage and bark, obtainable all the year round,
they are abroad in winter; but they have a family of small cousins, the
pikas (Lagomyidæ) that inhabit our western mountain tops above timber
line and must hibernate. Other species abound in the Himalayas. They
are little, short-eared, tailless creatures that make their homes in
companies among loose rocks, and store in their deep crevices enough
dried grass and flowering plants to keep themselves alive until the
late spring of those cold heights. Western folks call them conies.
The porcupines are large, plantigrade rodents notable for the mixture
of quill-like spines with the hair. This is most conspicuous in the
European species, which bristles with spines reaching far beyond the
hips and concealing the tail, forming an excellent defensive armor.
Some smaller African and East Indian species are less well armed, and
have longer tails, at the end of which are tufts of spines, making
an effective weapon. All of these pass their time and get their food
on the ground. Our American porcupines (family Cercolabidæ) differ
somewhat anatomically and live for the most part in trees, although
our common eastern porcupine wanders about a great deal in summer,
especially at night, feeding on herbage, and rejoicing in a find of
bones or other saline food here and there. It is defended by a coat of
long black hair in which spines are plentifully mingled, and the short,
flat tail, covered with thick spines, may give a sidewise stroke that
makes man or beast cautious about attacking an animal that otherwise
seems so lethargic and helpless. The porcupines of this family,
however, really belong to trees, where they slowly consume the foliage
and tender bark, and remain quietly through even Canadian winters. The
Pacific side of the country has a similar species in the yellow-haired
porcupine; and several smaller kinds exist in Central and South
America with scanty spines and long prehensile tails.
Closely allied to the porcupines are the gregarious viscachas of the
South American plains, that live in "villages" of burrows, and much
resemble prairie dogs in appearance and habits; also the chinchillas of
the high levels of the Andes, whose soft gray coat is one of the prizes
of the furrier. Here, too, come the swift-footed, slender agoutis and
pacas of South America, many species of which exist and are useful as
food; and a neighboring family contains the little cavies, from one of
which are derived our pet "guinea pigs," which are not pigs and do not
come from Guinea; also their cousin, the almost aquatic capybara, which
measures three feet long, and so is the biggest known rodent. This is
much hunted for its flesh, and is the principal prey of the jaguar.
This brings us to the world-wide tribe of rats and mice formed by
a group of eight families, of which the typical one (Muridæ) alone
contains a third of all Rodentia, and the other seven creatures
differing greatly from these familiar models. Many are small, such as
the house mouse (originally a native of southeastern Asia, as also
were the rats that commerce has carried all over the civilized globe),
and the even tinier harvest mice, gray or brown in plain color, and
with long, slender and nearly hairless tails and legs fairly equal in
size. Thence in size they grade up to the stature of the rat, and from
that on to the South African "springhaas" which is as big as a rabbit,
and to our muskrat, two feet long, counting in its tail. Although
essentially alike in structure some have varied widely from the
ordinary type. Thus the jerboas, several species of which inhabit the
plains of Asia and Africa, have the hind legs so long that their bones
are considerably longer than the distance from the root of the tail to
the nose; and they progress in long rapid leaps, balancing themselves
by long tails, often tufted at the end. The big "jumping hare" of
South Africa has much the appearance of a kangaroo with a squirrellike
tail; and a genus of exquisitely dressed mice in our sandy Southwest
are called "kangaroo" mice. In fact one of our commonest reddish field
mice, found all over the country, has similar proportions, and is
remarkable for its long leaps when hurried.
A shortening of the tail is seen in the voles, to which the common
meadow mice of various species belong, and still more in the lemmings,
in the Old World mole rats, and in our pouched gophers. All these are
not only ground-keeping kinds, but burrowers, and have no use for a
long tail, save in the case of the muskrat, which is really a big vole
that has taken to an aquatic life, and needs an oar to scull himself
through the water; for muskrats swim more by means of their tails than
by their feet. The foremost burrowers are the pouched gophers, whose
long tunnels, and food-getting, do so much damage to crops in the
central plains region of this country. They must be distinguished from
the ground squirrels, also called "gophers."
An interesting diversity of habits may be met with here. Some rodents
live in deeply excavated burrows, others in shallow diggings or holes
in stumps and rock crevices; some, like the water voles, reside in
holes in the banks of streams, or, like the muskrat, heap up "houses"
in a marsh in which to pass the winter in security; while still others
construct ball-like nests among the herbage, or in bushes and trees.
Some truly hibernate in cold countries, like the famous dormice of
Europe, and our equally sound sleeper, the American jumping mouse;
but mostly they stay in snug habitations and live through the winter
on collections of food, or, like field mice, gather seeds abroad even
in the coldest weather, or poke about under the snow for food, as do
the lemmings. From time to time certain species, especially of the
short-tailed field mice and the lemmings, multiply excessively in some
district, and then are forced to spread away from their birthplace in
those migrations of myriads which form the "plagues" that devastate
large tracts of country. They march on until an accumulation of enemies
and an epidemic of illness combine to kill them off.
SQUIRRELS, WOODCHUCKS AND BEAVERS
Squirrels in form and activities are much alike all over the world,
and are absent only from Australia and Madagascar. The long, bushy
tail that makes so excellent a blanket as it is wrapped about their
bodies when curled up asleep, is the badge and pride of the tribe. They
inhabit hollows in the trees or sometimes holes among their roots, and
in summer make globular nests of leaves and twigs in which the young
are nursed and trained. Nuts form their staple food, but berries,
fruits, roots, funguses, insect grubs, etc., offer changes in fare
with the recurring seasons. Sometimes great ingenuity is displayed in
getting at this food. Some species are arrant robbers of birds' nests,
and now and then kill and eat small birds and mammals; and the older
males are resolutely kept away from their babies by the mothers for
fear of cannibalism. This catholic appetite, and their willingness to
wander from place to place in search of things seasonable, enable
squirrels to find food of some sort every month of the year, yet most
species have the forethought to lay up in more or less secret places
a winter supply of provender; consequently no species of Sciurus
hibernates, strictly speaking.
This storing of winter provender is a matter that has been regarded
with more general interest, perhaps, than any other feature of animal
economy, and is mainly manifested among the rodents, although practiced
in a limited way by some others, as for instance, by weasels and foxes.
It looks like conscious foresight of the famine time to come, but it
is no doubt in the main, if not wholly, instinctive, since the young,
who have had no experience of the winter's scarcity or imprisonment
ahead, make suitable preparations. It seems to me that this habit,
so necessary to the existence of small, vegetarian creatures in cold
climates, arose in some such way as this:
The little animals that store supplies designed to keep them alive
through the winter are those whose food is for one reason or another
unobtainable then. Remember, also, that they are feebly endowed with
powers either for defense or for escape outside their homes, and when
gathering their food must not loiter much to eat as they go, but must
pick up what they can carry and hasten to the safety of their doorways.
This is the reason why surviving species of such animals have acquired
cheek pouches, in which they can transport a fair meal of their food to
be eaten at home at leisure.
During the larger part of the year food is scant, and these rodents
get into the way of picking up every bit they can find, and seem so
restless and energetic that some of them, such as the viscachas and
pack rats, accumulate about their burrows or nests quantities of
inedible things, moved, apparently, by mere objectless acquisitiveness.
The search for food, the foremost occupation and anxiety of these small
wood-folk, would be increasingly stimulated as the ripening season of
the seeds and nuts on which they depend advanced, and the impulse to
incessant industry, so necessary in the poorer parts of the year, would
now be overworked, and each animal, in his haste to be up and doing,
would constantly bring home more food than would be consumed, so that
it would pile up in the accustomed "dining room." The gradual failure
of outdoor supplies, as winter came on, would lead to the eating, with
increasing frequency, of those fragments casually saved in and about
the burrow or house, which, from their nature, would not have decayed.
The animal which had been most busy and clever in food gathering would
own the largest amount of the leavings of these autumnal feasts. Having
the most food he would be among those of the colony or neighborhood
strongest and most likely to survive, and to give to his offspring the
tendency to strength and industry which had been his salvation. This
would be continued and shaped by the process of natural selection into
a valuable, instinctive habit of gathering nonperishable food in large
quantities every autumn, and thus providing themselves with stores
to last through the coming winter; but it does not follow that the
squirrels and mice are conscious of this wise forethought.
The striped, chattering, ever-busy chipmunks, of which America
possesses several delightful species, although able to ascend into
trees, and frequently doing so, are groundlings, and fond of rocky
places into whose crevices they can quickly rush when an enemy is seen
or heard; hence their fondness for the stone walls that in the East
divide farm fields, and in general they are more inclined to associate
with man and his works than are the tree squirrels, although the grays
lend themselves readily to the semidomestication of residence in
village streets and city parks, as the red never does. The chipmunks
dig long underground tunnels, enlarged here and there into chambers
serving as bedrooms, storerooms for food, and refuse bins; and the
northwestern species are so numerous that between what they eat and
waste in gardens and grainfields and the bad runways for water their
galleries make, they are justly regarded as a pest.
These pretty but troublesome chipmunks are called "gophers" in some
parts of the West, but that name is more generally given to the gray or
brownish ground squirrels of the plains, classified as spermophiles by
naturalists; and they are so varied, numerous and destructive wherever
grain is grown, from the prairies of Kansas and Nebraska to the
California valleys, and northward to the Saskatchewan, that extensive
and costly poisoning operations are necessary to suppress them. Similar
to them, but larger, are the prairie dogs, whose communities, or
towns, of burrows and tunnels render useless large tracts of land in
the southern half of the plains. Very similar animals to these abound
in Russia and eastward throughout the open country of central Asia.
They have undoubtedly increased much within late years through the
killing off of the natural enemies that in the old days held their
multiplication in check.
The prairie dogs used to be called "marmots," a term that applies
more properly to some larger European burrowing rodents and to our
woodchucks, which are so common all over the eastern half of the
country, and, in another species, on the summits of the northern
Rockies, where they are known as "whistlers." The most remarkable
thing about them is the length and intensity of their dormancy in
hibernation. There remains only the beaver, the largest of the rodents
except the capybara, and altogether the most important one, measured
by the value of its fur, and by the service its race has done through
thousands of years in preparing, by its clearings and dams, valleys for
man's cultivation.
Every beaver settlement is a true colony, the offspring of some
previous settlement, which may be hundreds of years old. When such a
settlement becomes too populous for the food supply, young males and
their mates travel to some fresh spot by a small woodland stream, and
begin life by digging a burrow in the bank with an underwater entrance,
and at once dam up the stream by piling sticks, sod and mud across
its current at some favorable spot below their home, the effect, if
not the conscious purpose, of which is to maintain a depth of water
in the stream at all seasons sufficient to cover the entrance to the
burrow, and also to permit the storage of green wood under water (and
ice) near the home for food (they eat the bark) during the next winter.
The young beavers born that season will remain through the winter
with the parents, and a domelike house is usually built in which the
family lives. Next season the young set up a home for themselves near
by, and so the colony grows. Beavers get most of their food by cutting
down trees other than evergreens, and gnawing the bark. As the trees
disappear near the bank, and the colony increases, the dam is enlarged
so as to spread the set-back water over a wider territory; and later
canals are cut deep into the woods, permitting far-away trees to be
felled, and their pieces floated to the houses, especially in gathering
the supply for winter. Old dams are sometimes 100 or more yards long,
and are built with astonishing intelligence with reference to holding
back a great breadth of water. These are diligently and skillfully
repaired; and the houses become, in the course of years, big enough to
accommodate three generations of beavers at once, and are so massive,
especially when frozen in winter, which is the time of most danger from
their enemies, that they are practically safe from attack. From such a
mature colony others are continually formed, until in a level, swampy
region the whole district is well occupied by beavers. This is possible
now, of course, only in the remote Northwest; but a few beavers survive
in the Rocky Mountain region of the United States, under protective
laws, and they are still numerous in the more thinly settled parts of
Canada, and furnish a large return to trappers.
CHAPTER XXIX
MAMMALS OF THE SEA
Whale is a general name for the extensive and varied order of marine
mammals termed in science Cetacea. Their origin is obscure, but it is
certain that their very ancient ancestors were land animals, evidence
of which is afforded by their anatomy, especially in embryonic and very
young specimens. Here are classified not only the great true whales
but their smaller relatives, the sportive dolphins and porpoises, the
grampuses or blackfish, the white whales often seen in the lower St.
Lawrence River, the killers, and such out-of-the-way forms as the
narwhal, from whose snout projects a long twisted "tusk," which is a
strangely overgrown incisor tooth. In all these animals the shape is
fishlike, as is required by the fishlike habits; the skin is smooth
and usually blackish, or black with white markings; the forelimbs have
become paddles and the tail a pair of horizontal flukes. As they are
mammals with lungs and breathe air, whales must come to the surface
frequently for that purpose. At the instant they emerge the pent-up
air is expelled from the lungs through the nostrils at the top of the
nose. In the case of the larger species this big discharge of moist
breath condenses in the cold air into a visible vapor, often mixed with
sea spray, which is called a "blowing"; but no water is expelled from
the mouth, with which the "blowholes" have no connection. The smaller
kinds of cetaceans, of which the variety is immense, are in the main
fish-eaters, but the killer seizes and devours porpoises and seals
also, and a band of them may unite to worry a big cachalot to death.
Most species go about in small bands, or "schools."
The great whales are of two distinct families: (1) baleen whales, and
(2) toothed whales. The first take their name from the blade-shaped
plates of horny material (whalebone) hanging, to the number of two or
three hundred, from the roof of the mouth, each central blade eight or
ten feet long in ordinary cases. These "right" (i. e., proper) whales,
as they are called by the men who hunt for and harpoon them, are huge
creatures often fifty to seventy-five feet long, ranging all northern
oceans, even amid arctic ice; yet, despite their bulk, they feed
exclusively on the small crustaceans and other minute creatures of the
plankton swept into the mouth by the million as the whale rushes along
the surface, the water scooped up escaping from the sides of the mouth,
and the food being caught by the fringes of baleen and swallowed like
a continuous meal. In addition to the whalebone obtained from these
whales the hunters cut away and save the thick layer of fat (blubber)
under the skin for the sake of the oil it yields. The beeflike flesh of
the muscles is good meat. This kind of whale is becoming very scarce.
The toothed whales consist of the single species called sperm whale,
or "cachalot," which is of gigantic size, a lesser cousin ("kogia"),
and an inferior genus, the beaked whales of the Antarctic. All are
more common in the tropics and South Pacific than elsewhere. The great
sperm whale differs in form from a "right" one mainly in having
a huge, flattopped, almost square-fronted head, beneath which is
hinged a somewhat shorter underjaw. The cavernous mouth is armed with
strong, pointed teeth, and these whales prey on fish and especially on
cuttlefish. They can swallow whole nothing larger than a salmon, but
can bite larger prey into manageable pieces, and have more than once
seized and crushed a boat in their jaws. The cachalot attacks the giant
squid whenever it meets one and the marks of the squid's winding arms
and cruel suckers are often seen on the hides of whales as scars of
some struggle between these Titans of the deep. The value to mankind
of the sperm whale lies in the liquid fat and the valuable substance,
spermaceti, that fill a vast cavity in the top of its skull, a single
whale yielding several barrels of it, from which the commercial
"spermaceti" and a fine oil are extracted. In their intestines are
frequently found lumps of the secretion known as "ambergris," used as
a base for perfumes, the price of which is so high in the market that
a few pounds will cover the expenses of a ship's voyage. Ambergris is
also found floating in the open sea or cast up on shore, and for a long
time its origin was unknown.
CHAPTER XXX
THE WORLD'S HERDS AND FLOCKS
The great tribe of animals called Ungulata ("hoofed") or Herbivora
(eaters of herbage--herbivores), combines two types of structure into
which they have diverged since their origin at the dawn of the Tertiary
era, namely:
I. Odd-toed, or solid-hoofed, ungulates (Perissodactyla), typified by
horses; and
II. Even-toed, or split-hoofed, ungulates (Artiodactyla), typified by
the cattle.
They exist in every part of the habitable globe except Australasia,
have furnished sustenance to the larger Carnivora, and have supplied
the need of man for assistance in his labor, and with materials for
food, shelter, and clothing. Without them modern civilization would
have been impossible.
Both divisions have lost the plantigrade (flat-soled) walk of their
early ancestors, and now step on the tips of their toes. This has been
gradually gained as an adaptation to the increase of dry land and the
formation of grassy plains, which we know went on steadily, especially
through the last third of the Tertiary era. The short, massive legs
and spreading, five-toed feet, useful in sustaining an animal's weight
in marshes, were slowly changed to longer, more slender limbs and a
digitigrade walk as greater speed and nimbleness were required in
making their way over wide pastures to and from watering places or in
escaping the beasts of prey, which were themselves becoming swifter
and more active in jumping by a coordinate evolution of abilities.
But before proceeding to the typical hoofed tribes, mention must be
made of the elephants, which belong in this order. Elephants appear to
stand apart from all other mammals, and from the earliest times have
attracted attention by their huge bulk and strength, and by traditions
of their intelligent performances. They seem a necessary part of
our ideas of Oriental life and grandeur, and a circus without trick
elephants would be a poor show in the eyes of the American youngster.
[Illustration: THE SOUTHERN MAMMOTH
Drawn by Christman. (American Museum of Natural History)]
The naturalist classifies them (order Proboscidea) in this place
because they are plainly, although remotely, related in structure to
the solid-hoofed browsers; but only recently has he been able to trace
their ancestry back to a small, tapirlike forefather of Miocene days,
with no trunk and no tusks. The trunk, of course, is the animal's
lengthened nose, become an organ useful for many purposes other than
breathing; and the tusks are overgrown upper incisor teeth. The
elephants of the present time are few compared with those of warmer
past ages, when many species, as well as various cousins, such as
long-haired mammoths and towering mastodons, wandered over Europe,
Asia, and our own country. Now only two kinds remain: one in Africa,
the other Asiatic. They differ in many ways, most noticeably in the
size of the ears, which in the African elephant are very much larger
than those of the Asiatic species. Both are forest animals, feeding
on leaves and twigs. African elephants were formerly to be found all
over the wooded parts of that continent, traveling about in herds that
sometimes numbered a hundred or more individuals; and were varied in
appearance, some being taller than any Oriental one, while others (in
the Congo region) are so small as to be called dwarfs. The natives have
never captured and made use of them, and few have been tamed by anyone
within recent years, but in the time of the Carthaginians and Romans
they were held captive, ridden, and employed in war, and in sports of
the arena. They have been greatly reduced in numbers by ivory hunters,
and would be nearly or quite extinct now had they not been protected in
recent years by wise laws.
The Asiatic, or "Indian" elephant, which is confined to India,
Ceylon, Burma, and the Malay countries, still roams the jungles as a
wild animal, but every herd is known to and protected by the local
governments, and from time to time these are rounded up, and young ones
are captured and trained to man's service. Only in this way can the
domestic supply be maintained, since these elephants rarely produce
young when in captivity. They are utilized as riding and burden-bearing
beasts, for hauling heavy loads, especially in the army service, and in
handling large timber and other industrial operations. Some ivory is
obtained from this species, but the tusks are far smaller than those
of the African elephants, and the females bear none at all, while both
sexes are armed in Africa, where an old "bull's" tusks have been known
to exceed a weight of 300 pounds each.
[Illustration: PREHISTORIC STRAIGHT-TUSKED ELEPHANT
Drawn by Christman. (American Museum of Natural History)]
Although there is no reason to suppose the African elephant is less
intelligent by nature than the Oriental one, nearly all the evidence of
thoughtfulness in these animals comes from Indian examples--a species
that has been studied and educated for hundreds of years. That they may
be taught to do almost anything of which their bodies are capable is
plain; but undoubtedly they comprehend very largely the purposes of the
man directing them, and use "brains" in assisting him to carry them
out. They have retentive memories, appreciate kindness, and constantly
show skill and discretion in accomplishing what they are asked to do.
In regard to no other sort of animal has so much been written as of
elephants; and the sum of the testimony is that they are not only very
teachable and faithful in performing their tasks, when not disabled by
fear, but often use surprisingly good judgment in their work.
Distantly related to the elephants, yet so remote in relationship
to anything else as to be set apart in an order (Hyracoidea) by
themselves, and with no visible geological ancestry, are the queer
little "conies" of the Scriptures, called rock rabbits, and dassies
in South Africa. They have a singular resemblance to rabbits, apart
from their little round ears, and are more like enlarged copies of
our western pikas, but their anatomy and teeth show they are far from
being rodents; and they are classified here mainly by reason of their
rhinoceroslike teeth, and the hooflets on their toes, so that they
form a quaint intermediary between the elephants and the solid-hoofed
section of the ungulates; they are, indeed, relics of an exceedingly
primitive and ancestral type of ungulates.
[Illustration: WART HOG, ONE OF THE UGLIEST ANIMALS TO SEE
Photo, Elwin R. Sanborn, N. Y. Zoological Society]
[Illustration: THE MALAY TAPIR, RELATED TO THE PIG AND THE RHINOCEROS
Photo, Elwin R. Sanborn, N. Y. Zoological Society]
RHINOCEROSES, TAPIRS AND HORSES
Included by their general anatomy among the perissodactyls, although
they have several toes on each foot, all reaching the ground, and, like
those of elephants, connected by webs and clothed with thick, hooflike
nails, are the rhinoceroses and tapirs. The rhinoceroses are relics
of a long and interesting geological history. Two belong to Africa,
one of which, the common "black," browsing rhinoceros, is still
abundant south of the equator in all the more open and less occupied
parts, of the continent; while the other, the larger, square-lipped,
grass-eating, or "white" rhinoceros, has become very rare save in
certain remote and upland plains. Both have thick, hairless skins of a
pale lead-gray, which lie smoothly over the whole body, and both have,
on the nose, two horns, composed of matted, whalebonelike hairs, not
a part of the skeleton but springing from the skin. The front horn is
always much the longer, in some cases reaching a length of more than
fifty inches. Asia has three species of rhinoceros, all of which differ
from the African in having functional incisor teeth, and in their
hides. The best known is the "Indian" rhinoceros, now confined to the
hot jungles of the extreme northeast of India. It has only one horn,
and its dark hide is thrown into heavy folds looking like artificial
armor. It became known to Europe early in the sixteenth century, and
became the subject for some of the most curious speculations and
superstitions of that credulous age. The "Sondaic" or hairy rhinoceros
still is to be found in jungles from Bengal around to the end of
the Malayan Peninsula. It is smaller than the Indian one, and its
folded and tesselated hide supports a coat of short hair; its horns
are only two little protuberances on its nose. Finally Sumatra and
Borneo have a rhinoceros whose coat is still more hairy, and among
whose peculiarities is the possession of two formidable horns. These
creatures are perhaps the best examples remaining of what Merck's
rhinoceros (fossil) and other big quadrupeds of the Pleistocene era
looked like.
[Illustration: MARKHOR, AN ASIATIC WILD GOAT]
[Illustration: MOUNTAIN SHEEP OR BIGHORN OF THE ROCKY MOUNTAINS
Photos, Elwin R. Sanborn, N. Y. Zoological Society]
[Illustration: BROAD-NOSED RHINOCEROS
Merck's Rhinoceros--prehistoric. Drawn by Christman. (American Museum
of Natural History)]
The tapirs are even more widely separated in habitat than the
rhinoceroses, for four species dwell in the New World between Guatemala
and southern Brazil and Guiana, while the fifth belongs to Malaysia.
They are forest animals, and mainly browsers, the long, almost
trunklike nose and lips enabling them to seize and tear off leaves and
twigs easily. They choose low districts, as a rule, and rush into the
safety of water when in danger from the jaguar or other beasts. They
are shaped somewhat like a very fat pony, but with a big, pointed head,
and are clothed with short hair of plain dark tints, but the young are
spotted at first. They are timid, secretive and nocturnal in their
habits. Their flesh is excellent meat.
This brings us to the horses, whose geological history is one of the
romances of natural history, as it is traced from the little five-toed
eohippus of the Eocene up to the herds that roamed our western
prairies, and disappeared so completely, and so unaccountably, in the
era just preceding the present. Our domestic horses, consequently,
are all of Old World origin. As far back as man can be traced in his
supposed birthplace in central Asia herds of small horses fed upon
those high plains; and about fifty years ago bands of ponies were
discovered ranging the dreary deserts of Dzungaria, or northwestern
Chinese Turkestan, and specimens are now living and breeding in the
Zoölogical Park in New York and in European collections. This truly
wild horse stands about ten hands high, and is covered with thick hair
of a dull brown color, unstriped.
Such horses were undoubtedly hunted and killed as food by Paleolithic
men; and when, many, many thousands of years ago, they had in some
degree domesticated them, and began to migrate southward and westward,
they took these horses with them. Those people that gradually occupied
Persia, Mesopotamia, and the plains of Arabia and North Africa,
developed them into riding animals that became perfected in what we
know as the Arabian horse. Those tribes that migrated across Russia
and along to the northern shore of the Mediterranean, found in Europe
a similar, but more robust horse, now designated the "forest" horse,
which the savages regarded as game. The two interbred in the course
of time; but the southern breeds have remained smaller, lighter, and
more agile, while the northern or forest stock has been the foundation
of the heavy draft horses of northern Europe. After the Crusades Arab
blood was introduced to effect a still further refinement of the horses
of southern Europe, and it was from this Arab-improved stock, prevalent
in Spain, that the horses sent to the Spanish colonies in the Americas
were derived. Our plains, and the pampas of South America, soon became
populated with these horses run wild--"mustangs," showing even yet
traces of their aristocratic lineage.
So near to the horses that they belong to the same genus (Equus) are
the zebras, which differ mainly in their brighter coloring, less bushy
tail, "roached" manes, and lack of those callosities called "chestnuts"
on the hind legs. The zebras are exclusively African, and include two
types, a southern and a northern. The true zebra, now extinct, except
where kept and bred in captivity, belonged to the mountains near the
Cape of Good Hope, was only about twelve hands high, and had black
stripes on a white ground.
In the more open parts of Africa, north to Lake Rudolph, roamed
Burchell's variety of this zebra, the one now commonly seen in
menageries, in which the coat is creamy or golden yellow, and the black
stripes are far broader. Its northern variety, Grevy's zebra, has the
black stripes narrower, but so much more numerous that the white shows
as mere lines between them. To these must be added an extinct species,
killed off many years ago by Boer farmers and other sportsmen, which
was known as the "quaha" (quagga) from its barking neigh; it was a dark
brown, with stripings only on the head and neck.
The zebras seem incapable of becoming useful in harness or under the
saddle, but their very near relatives, the asses--in spite of the sober
gray of their dress, and their ungainly ears--have given us the patient
and enduring donkey, which has been a servant of mankind, at least in
Egypt, ever since the date of the earliest monuments; and wild asses
still flourish on the deserts of Africa from Algiers to Somaliland.
Another somewhat larger and more variable species roams the upland
plains of Persia and northern India, while a variety, the "kiang,"
lives on the arctic tableland of Tibet, and is as untamable a creature
as can be imagined.
[Illustration: BURCHELL'S ZEBRA OF NORTHERN CENTRAL AFRICA]
HIPPOS, PIGS AND CAMELS
With the hippopotamus we begin the long list of artiodactyls, or
cloven-footed animals, in which the weight of the body rests equally
on the two central digits (third and fourth) which are alike in
development, while the second and fifth digits, when present, do
little or no work, except in the hippopotamus, whose outside toes are
as long as the central ones, because needed by an animal treading
on muddy soil, and accustomed to swimming. Although this huge marsh
denizen is now confined to Africa, it ranged into southern Europe and
eastward to India within quite recent times, but was destroyed by the
human settlement of these countries; and civilization will in due
time exterminate it from the Congo and Nile basins where it now is so
numerous, and so incompatible with commerce and industry.
The swine are the first artiodactyls to show the typical cloven feet,
and in them the two hind toes reach almost to the ground, so as to
help the footing in the soft ground that they frequent. The foremost
member of the family (Suidæ) is the wild boar of the Old World, known
from the North Sea to the Bay of Bengal; and it is hard to realize that
the fat hogs of our stockyards are modifications of this bristling
forest boar with his muscular form, swift gait, and terrible tusks. Far
more ugly in appearance, however, is the wart hog of Africa and the
hairless "babiroussa" of Celebes, whose upcurved tusks far outmeasure
those of the Indian boar. America has a family of native swine named
peccaries--small, thin-legged, grizzled-black pigs, with very thick,
bristly necks and large, angular heads. They have wicked little eyes,
razor-sharp tusks in both jaws, and no visible tails, and the young
are not striped as in the typical Suidæ. These pigs go in companies,
wandering mainly at night in search of food, and taking almost anything
edible. They are irascible, attack with fierce energy in concert, and
are formidable foes to anything afoot, driving even the jaguar up a
tree when the band turns on him. One kind of peccary is common in
southwestern Texas, and its roving bands do much damage by night to
crops and gardens; it is called a "javelin."
[Illustration: PREHISTORIC HIPPOPOTAMUS
Drawn by Christman. (American Museum of Natural History)]
The swine occupy a somewhat intermediate place between the solid-hoofed
and the split-hoofed sections of the Herbivora; and the stomach is
simple except in the peccaries, where it takes a complicated form that
approaches that of the ruminants. This simplicity, with the correlated
fact that swine do not chew the cud, enabled the leaders of the ancient
Hebrews to set pigs apart, as unclean, by a more general definition
than a mere name could give, thus leaving no way of escape for those
who might be inclined to dodge the prohibition by quibbling. All other
Herbivora are ruminants, that is, chewers of the "cud"--those that
gather and swallow their food in haste, and then at leisure recover it
and thoroughly rechew it in small quantities (cuds).
This strange operation, like the carrying away of food by pocket mice,
monkeys, etc., enabled these comparatively defenseless animals to
gather nutriment in a short time and then retreat to a safe place to
prepare it for digestion. Associated with this practice is a large,
complicated stomach, normally consisting of four chambers, into the
first and largest of which the hastily swallowed forage is first
received. Then, when swallowed a second time, it passes on into the
second or true stomach, where real digestion begins.
[Illustration: THE KUDU, OR STRIPED ANTELOPE OF AFRICA; AT THE RIGHT,
HEAD OF THE GREATER SABLE ANTELOPE
Photos, Elwin R. Sanborn, N. Y. Zoological Society]
[Illustration: HEAD OF AN ALASKAN MOOSE
Photo, American Museum of Natural History]
[Illustration: AXIS, OR SPOTTED DEER OF THE EAST INDIES
Photo, Elwin R. Sanborn, N. Y. Zoological Society]
[Illustration: AMERICAN DEER WITH HORNS IN "VELVET" STAGE
Photo, Elwin R. Sanborn, N. Y. Zoological Society]
CHAPTER XXXI
THE WORLD'S HERDS AND FLOCKS--_Continued_
CAMELS, DEER, GIRAFFES AND PRONGHORNS
This is a rather miscellaneous group introducing the typical Herbivora.
The most ancient of them in the style of their structure are certain
little spotted creatures, like miniature deer in appearance, that
inhabit the forests of western Africa and the Orient, and are known as
chevrotains. The fact that in their metapodial bones they resemble the
structure of camels causes these apparently so distant animals to be
placed next to camels in classification.
The history of the camels (Camelidæ) is very similar to that of the
horse. The family originated in North America, where it developed
from little creatures, by changes and adaptations to a life on dry
uplands, as did the horses, into a species which in the Pleistocene was
a third larger than any now living. Meanwhile camels had made their
way over the land which in the later Tertiary connected Alaska with
Siberia, into the high plains of Asia, where the camels found favorable
circumstances and developed into the two species we know. Others
migrated, earlier in the family history, into South America, where they
ceased to grow tall after the camel model, but became the huanacos
of Patagonia, of which the llamas (yah-mas) are prehistorically
domesticated descendants, and into the woolly vicuñas of the Andean
mountains.
[Illustration: LLAMA
(_Lama peruviana_)
A domesticated animal of South America]
Modern camels are of two kinds--the single-humped and the
double-humped. The latter, or "Bactrian," is confined to Asia, and is
able to endure the cold and snows of the tablelands of that continent,
where its burdens are carried in winter as well as summer. What was
the extent to which the single-humped, or ordinary camel, ranged
before its prehistoric enslavement by men, we do not know--if it
roamed the deserts of Arabia and northern Africa as well as those of
Turkestan, no evidence of it remains. A few small-sized, gaunt, wary,
and swift-footed camels still run wild among the almost inaccessible
sand dunes of the Gobi Desert, but it is not certain that they are
relics of the original wild stock. At any rate the camels have always
been creatures of the world's waste places, and all their quaint
peculiarities such as their sole pads and the water-storing sacs in
their stomachs (rumens) are adaptations to their desert home.
[Illustration: BACTRIAN CAMEL
(_Camelus bactrianus_)
The two-humped camel of Asia]
The deer family (Cervidæ) is of great extent, and world-wide in its
distribution, except that it is entirely absent from Africa and
Australia. In none are more than two toes of use in walking, the
second and fifth toes hanging at some distance behind and above the
functional hoofs, which are narrow and pointed. All have slender, long
legs, giving swiftness and great leaping power; and very short tails,
with the exception of the rare and peculiar David's deer of China,
whose tail is almost like that of a cow. The coat of hair is short and
brittle, reddish brown or foxy in summer, grayer in winter, in some
species plain, or spotted only when fawns, in others variegated with
small, whitish spots. The distinctive badge of the family, however,
is the pair of horns borne on the heads of the males (also by females
in the reindeer and caribou), collectively and more properly called
"antlers," since they are not composed of horn, but of true bony
material. They are poised on two protuberances on the top of the skull,
where in spring arises a growth of fleshy material, covered with
velvety hair, that rapidly takes the shape of the antler characteristic
of the species (and age) of the deer, and as it grows is filled with
lime salts that gradually replace all the tissues. Then the "velvet"
dries and scales off and the ivorylike antler emerges. This remains as
a serviceable weapon and ornament of the buck until the beginning of
winter, when its attachment to the skull loosens, and the antler drops
off. This happens annually in the case of all deer--one of the common
and universal facts in zoölogy that many find it hard to believe. The
"horns" of the various deer vary in size from short and simple "spikes"
to the wide-branching antlers of the moose and wapiti; but these last
are acquired only when the buck is fully matured, the yearling showing
only a spike, and acquiring branches ("tines") one by one annually as
he grows until his proper complement is reached; but in a few small
species no branching ever occurs.
The family contains many genera and species, but only the most
noticeable can be mentioned. The most familiar one, probably, is the
small, spotted fallow deer of southern Europe, bands of which ornament
the parks of grand estates in Great Britain and on the continent;
its antlers broaden at the end into the form known as "palmated," on
account of its resemblance to an open hand with fingers. Even more
celebrated in song and story is the red deer, the males of which are
"stags" and the females "hinds." These are large, dark, reddish brown
animals, with grandly symmetrical antlers, every tine or "point"
on which--seven on each side in a "full head"--has its name in the
language of hunting. This deer, still wild in the highlands of Scotland
and in the mountainous forests of eastern Europe, is also to be found
right across Asia, where local varieties go by the names of "maral" in
northern Persia, "hangul" in Kashmir, and so on to eastern Siberia,
where far taller species live than are known to Europe; and all vary in
minor particulars only from our wapiti--which it is fair to regard as
of the same stock.
None of all these stags is more stately than the American wapiti--the
"elk" of all western men--which once abounded from the Adirondacks
and southern Alleghenies to California and the borders of Alaska.
Everywhere of old it was plentiful and easy to kill, and the pioneers
swiftly destroyed it as civilization was pushed westward, until its
mighty herds have vanished almost as completely as those of the bison.
It thrived anywhere and everywhere, climbing the wooded heights of
the Appalachians (where the very last one was killed near Ridgway,
Pennsylvania, in 1869), loafing in the warm, well-watered valleys of
the Mississippi basin, herding in the sun-baked plains, or scrambling
up and down the roughest of western sierras. Equally broad in its
appetite, those that browsed or ate mast and fruits in the eastern
woods did no better than those which grazed on the bunch-grass plateaus
from the Rio Grande to Peace River; and in winter it would keep fat
where other deer or cattle might starve, because able to paw through
the snow to the dried grass.
The other round-horned deer of the United States are the familiar
Virginian, white-tailed, or willow deer, which is to be found all over
the country, and in similar species in Mexico and Central America; the
larger black-tailed, long-eared "mule deer," or "jumping deer," of the
plains and the foothills of the Rocky Mountain region, and the small,
forest-keeping, black-tail, or Columbian deer of Oregon and northward.
Canada, Alaska, and the northern parts of Maine and Minnesota, are
the refuge of that biggest of all the deer, which we call by the
Indian name "moose," but which is known to Europeans as "elk," for it
is a circumpolar species that once roamed in great numbers through
the woods of all Europe, and in this country far southward along the
Appalachians. Until the World War the elk was preserved in certain
large forests of Lithuania and central Russia, but it is doubtful if
any survived the desolation of that region during and after the war.
The moose is everywhere a forest-ranging animal, especially fond of
regions where rivers and lakes abound, in which it finds desirable
food in summer and takes much pleasure; yet in the mountainous West it
often climbs to high and dry heights. Its principal diet is leaves and
twigs, pulled off by the long, flexible lips that are so characteristic
a feature. The moose is a huge, immensely strong and ungainly animal,
blackish brown with pale legs and belly, and with a neck so short that
it can graze only by kneeling. A very large bull may stand six and
a half to seven feet high at the withers, which, with the neck, are
clothed in a thick mantle of long, coarse, stiff hair; and from the
throat hangs a long hairy strip of dew-lap skin (the "bell"), which
in old age draws up into a sort of pouch. The long and narrow head
ends in an overhanging, flexible muzzle, that may be curled around a
twig like a proboscis. On this massive head and neck the bulls carry
a wonderful pair of flattened antlers, always surprisingly wide in
spread, but varying greatly in weight, and that irrespective of the
relative bigness of the animal. The moose of the Kenai Peninsula,
Alaska, are famous for the immensity and complication of their horns;
one pair preserved in the Field Columbian Museum, Chicago, have a
spread of seventy-eight and a half inches, show thirty-four points,
measure fifteen inches around the burr, and with the dry skull weigh
ninety-three pounds; but very few reach such dimensions.
[Illustration: REINDEER CROSSING A STREAM
From a prehistoric engraving on an antler found in southern France]
Another flat-horned deer is the famous reindeer of the boreal regions
of both hemispheres, for our arctic caribou are the same animals
under another name. No truly wild reindeer now exist in the Old World,
but they are scattered over all the Barren Grounds, or treeless coast
areas and islands, from Greenland to Alaska; and the Eskimos depend
on them not only for food to some extent, but even more for clothing
and tentage. Every autumn enormous herds of these caribou, gathered in
migration, sweep southward to less frigid and snowy feeding grounds in
the region between Hudson Bay and Great Slave Lake, and there enable
the Indians to provide themselves with meat and skins for the winter.
These arctic caribou feed mainly on the lichen called "reindeer moss."
Another kind, the "woodland" caribou, inhabits the uncivilized forest
borders south of the Barren Grounds, and the mountain region from
British Columbia to the arctic shore of Alaska and Yukon; and in the
east occurs in Ungava, Labrador, Newfoundland, and New Brunswick. They
are not regularly migratory, but wander in small herds, prefer swampy
woods, and their habits approach those of the moose. There is no great
difference otherwise between them and the arctic caribou; but they vary
a good deal, so that several species have been named among those of the
west, one of which, in Alaska, is quite white.
Southeastern Asia has many kinds of deer, such as the large staglike
sambar of India and eastward; the spotted axis, or chital; the sika of
Japan; and a variety of small Oriental species exist.
[Illustration: OKAPI
(_Okapia johnstoni_)
A relative of the giraffe, found in the forests of Africa]
The giraffes of equatorial Africa (family Giraffidæ) are closely
related to the deer. They are hornless, but from the top of the skull
project two protuberances, several inches in length, which answer to
the horn-cores of the deer, but carry no antlers, and are permanently
covered with hairy skin; between them is a third shorter protuberance
of the skull. A few years ago it was discovered that there existed in
the dense forests of the lower Congo valley an animal of this family,
but smaller and more antelopelike in body, and without the towering
characteristics of the giraffe, called by the Pygmies of that district
"okapi" or "o'api." It is chestnut in color, with yellowish cheeks and
the legs marked with wavy, whitish stripes. It is perhaps not rare, but
is exceedingly difficult to obtain in the dense jungle it inhabits.
Two singular animals remain to be mentioned here, as standing
intermediate between the deer and the cattle family, next to be
considered. One of these is the musk deer of the Himalayas, from
which is taken the "pod," or ventral gland, that contains the odorous
substance "musk." This is a strange, old-fashioned, solitary little
creature, the size of a half-grown kid, and having very large ears,
almost no tail, and no horns, but wearing a pair of keen weapons in the
long upper canines which hang well down below the lower jaw. The four
toes of the feet are almost equal, and the hoofs so free that they can
fairly grasp any projection, so that the animal is a marvel of agility
and surefootedness.
Our American pronghorn "antelope" is the second of these intermediate
animals, and is not far removed in its structure from our white
mountain goat. It foreshadows the sheathed-horned ruminants, but
differs from all of them in the fact that its horns bear a prong, and
also in that they are periodically shed and renewed. This beautiful
and graceful little animal, truly antelopelike in form and habit,
stands about three feet high at the shoulder, has slender legs and
feet, with no false hoofs, and is exceedingly swift in its bounding
gait. It is now almost gone from the wide plains where only a few
years ago it was to be seen in summer from the Saskatchewan to the Rio
Grande and southward. In the autumn it would gather in the North into
ever-increasing herds that swept southward to pass the winter in Texas
and New Mexico, and then would return northward with the advance of
spring. The extension of fenced ranching, but most of all the spanning
of the plains by railroads, rapidly put an end to these migrations, and
the wasteful killing of the pronghorns in sport, or as food, completed
the virtual extermination of one of the most interesting and desirable
animals of the New World.
CHAPTER XXXII
SOME SUPREMELY USEFUL ANIMALS
The fact that likeness of structure, which compels naturalists to group
certain animals into a family in spite of possible unlikeness in size
or form, is accompanied by resemblance in quality, is well illustrated
by the family Bovidæ (Latin _boves_, "cattle") which includes goats,
sheep, antelopes, and oxen; for all of these in flesh, products
and disposition, are alike suited to the requirements of men, and
especially of mankind in a social civilization. This family of animals
furnishes us with nearly all of our milk, butter, and cheese; with
flesh food, woolen clothing, leather goods, horn, gelatin, etc.: and
gives us such servants as the ox and goat; while sportsmen find in it
the most fascinating of their larger game.
The distinctive feature of this most useful of animal tribes is the
possession of hollow horns, properly so called. Horn is a chitinous
material developed from the skin, and not dissimilar to hair; indeed
it would be no great stretch of facts to say that a cow's horn was
composed of agglutinated hairs. These horns are sheaths that grow over
cores of bone--outgrowths of the skull--increase in size until their
wearers are mature, grow at the base as fast as worn at the tips, and
are never shed. They may be borne by the males alone, or by both sexes;
or the males may have horns far larger than those of the female, as
in the sheep; and in a few cases both sexes are hornless. No family
is more difficult to subdivide, for the various forms intergrade
inextricably.
Our mountain goat, or "mazama," which dwells on the snowy heights of
the Pacific Coast ranges, from southern British Columbia to farthest
Alaska, is one of these intermediate ones, suggesting both goat and
antelope in its make-up. It is about the size of an ordinary domestic
goat, has small, sharp, black horns, and is clothed in long white hair
with an undercoat of wool fitting it for the wintry cold in which its
life is spent, for except in midwinter it never comes below timber
line, and even then avoids the wooded places. In the rough mountains
of Japan lives a similar goat antelope, woolly, but not white; and the
lofty heights of western China is the home of a smaller one, the goral,
and the Himalayas have the big serow. All these have short, sharp horns
rising from the top of the skull. Their nearest western neighbor is the
famous chamois of the Alps and Carpathians of Europe. The extraordinary
agility of these mountaineers is possible because of the pads beneath
their hoofs that give them the clinging surefootedness which is so
remarkable.
Most closely allied to them, probably, are the goats, also denizens of
mountain regions, the typical species being confined to the highlands
between the Caucasus and northwestern India. This is the true goat from
which the domestic goat is descended; but the long-haired "Angora"
goat is derived from the markhor, a sheeplike animal of the Himalayas
with tall, much twisted horns. One of the special characteristics of
the goats (genus Capra) is the beard of the rams; and this feature
belongs also to the ibexes, several similar species of which are
found from the Pyrenees eastward along the mountain tops to northern
China, each occupying a limited section of country, and one inhabiting
the mountains about the head of the Red Sea. That of Spain is called
"bouquetin," and that of the Alps "steinbok." All the rams possess
great horns, sometimes fifty inches long, that rise from the occiput,
curve backward, and show on their fronts a series of prominent cross
ridges. One passes from these goats to their near relatives, the sheep,
by way of the "bharal" (or "burrel") which combines the characteristics
of the two sections so thoroughly that the proverbial "separating
the sheep from the goats," easy enough on the farm, is practically
impossible among wild flocks. In this crag-loving wanderer the horns
of the rams are as long as those of an ibex, but roundish and wide
spreading, instead of upright and cross-ridged. The "aoudad," whose
home is in the mountains of Morocco and Algiers, and which is familiar
in menageries, has such horns, but approaches nearer in other respects
to the typical sheep, whose rams carry the great spiral horns at the
side of the head, that are still the pride of our domestic merinos, and
were the badge of the Theban god of gods, Ra Ammon. No better example
of these magnificent mountaineers, which under one or another of
several specific and local names, such as argali, oorial, etc., are, or
were, to be found on rough highlands all the way from the Mediterranean
to Bering Sea, can be shown than our own "bighorn" sheep of the Rocky
Mountains, and of the mountains of Canada and Alaska.
Now we come to the great and beautiful section of the antelopes,
in which naturalists recognize thirty-five genera and perhaps a
hundred species. Antelopes were scattered in Pleistocene days all over
continental Europe and Asia, but never were present in America, for
our so-called "antelope" is a pronghorn, as has been explained. Two or
three species now inhabit the plains of central Asia--among them the
swiftest mammal known, the Mongolian "orongo." The ungainly "nilgai"
and the little "black buck" are familiar in India, and the pretty
dorcas gazelle races across the sands of Syria and Arabia; but the
vast majority of antelopes belong to Africa. They range in size from
the duikerboks, not much bigger than fox terriers, to the eland, which
has almost the bulk of an ox, and should be domesticated, like beef
cattle, for its excellent flesh. No handsomer mammals than antelopes
exist, judged by either form or coloring. They inhabit all sorts of
country, too, as in other lands do the deer, of which Africa has none.
Deserts, such as the Sahara and the Kalahari, and the stony steppes
of Somaliland, support not only the swift and agile gazelles, but
several large kinds. The grassy plains of South Africa were formerly,
and to some extent still are, the pastures of great herds of such
antelopes, large and small, as blesboks, wildebeests (or "gnus"),
hartebeests, steinboks, springboks, and many others. Springboks used to
assemble at certain seasons, and migrate across the veldt in countless
thousands, allowing nothing to stop the headlong rush of the host. The
thick jungle is the refuge of the harnessed antelopes, and of several
diminutive kinds rarely seen in the open; and along the watercourses,
and in marshes, live the big red waterbucks, the shy sitatungas, whose
feet are curiously modified to fit them to walk on boggy ground; while
rocky hills are the chosen home of the klipspringers and duikerboks,
agile pygmies that creep about among the brush like big rabbits, or
leap from rock to rock like miniature goats. A score or more of the
species of these beautiful creatures have been carelessly or wantonly
exterminated, and many others have become rare, but protective laws are
now in force in all the parts of Africa controlled by the Government of
South Africa, or organized as British, French, or Belgian dependencies.
The quaint and complex musk ox, a lone relic of a past era now exiled
to the remotest north, is a connecting link between the sheep and
the cattle, the last and best of the ruminants. Here, as elsewhere,
the style of the horns is characteristic of the group--slender,
backward curved or twisted, and somewhat compressed or keeled, in most
antelopes; heavy, cross-ridged, triangular in section and often spiral
in the sheep and goats; rough and helmetlike in the musk ox and some
buffaloes; and in the oxen round, smooth and always springing from
the side of the skull. The cattle fall into three groups: buffaloes,
bisons, and oxen.
The buffaloes are tropical cattle, usually heavily built, with massive,
flattened, wrinkled horns, and the hair so thin that in old animals the
bluish black skin is left almost naked. The typical buffalo is that
native to India and Ceylon, where it formerly roved in herds, which,
quickly forming into a compact bunch, heads and horns out, defied
attack from even the lion or tiger. Bulls often exceed five feet in
height, are extremely strong and quick, and carry rough horns, sweeping
back circularly, which may measure twelve feet around the curve. Such
a veteran herdmaster spends his days wallowing in marshy jungles, his
broad, splayed hoofs sustaining him in the muddy soil, and his hairless
back, coated with clay, proof against insects; but evenings and
mornings he leads his band out to feed in lush prairies where the grass
is tall enough to hide them. This is the race that has supplied the
working cattle of hot, swampy regions, especially where rice is grown,
and that has been the farmer's servant in the Far East, in Egypt, and
in parts of Spain and Italy from time immemorial. Several breeds have
been developed, of which the best known to Americans is the carabao of
the Philippines. Africa has native buffaloes in two species, neither of
which has been domesticated. The African buffalo is regarded as perhaps
the most dangerous brute a sportsman can meet in that land of irritable
beasts. Only rarely will even the lion attack one single-handed, and
then seldom succeeds.
The bisons, although regarded by systemists as of two species, the
North American "buffalo" and the European "wissent," are as nearly
alike as well can be. The latter originally ranged over all Europe, and
was necessarily a forest animal, and hence never could assemble into
herds as did its American cousins. It has been protected on the Czar's
and other great estates in Lithuania and Russia, to the number of about
700; but these preserves were ravaged during and after the World War.
The wanton waste that swept away the millions of our American bison
in a few short years would long ago have exterminated this species
also had it not been preserved in bands here and there in the West
and in various animal collections. The peculiarity of the bison is
the massive, humplike strength of the fore quarters, the great mop of
hair upon them and about the head, and the short, stout horns growing
straight out of the side of the head.
The animal called "bison" by sportsmen in India is the gaur, one of
four species of true oxen inhabiting southeastern Asia--heavy animals
with massive, upcurved horns, a long, ridgelike spine, short tail, and
fine, glossy, dark-colored hair. A big bull of the gaur or "sladang,"
as Malays call it, will stand six feet tall at the shoulders, and is
one of the greatest game animals of the world in every sense of the
word. Celebes has a curious dwarf ox, the "anoa," which is hardly
bigger than a goat. Contrasted with this is the great ungainly yak of
Tibet and the high Himalayas, where it still wanders in a wild state,
although large herds are kept by the Tibetans as beasts of burden
in a region where hardly any other large grazer can exist. Finally,
the Orient is the home of an extraordinary race of ancient domestic
animals, the white, humped cattle of India, of which many breeds exist,
modified by local conditions and purposes, and prehistorically used in
Egypt and probably southward. No wild animals of its kind exist, and we
know nothing of the origin of the race.
We now come to the most interesting species of the family, now extinct
as a wild animal, but perfectly traceable--the primitive wild ox of
Europe, the original of our farm cattle. It was much larger than any
modern breed, and bore immense, wide-spreading horns, as still do
certain coarse breeds in southern Europe, and especially in Spain,
whence the herds of long-horned cattle of America were derived.
Old bulls were black, but there is reason to suspect that the cows
and calves may have been red. This great animal roamed throughout
Europe and western Asia, and was counted among the fiercest of
game in Cæsar's time, who found it called "ur," or "aurochs"; the
former word was Latinized as _urus_, and the latter, when this ox had
disappeared, became transferred to the bison. Even in Roman times the
wild ox was growing scarce, and it died out early in the seventeenth
century. Meanwhile, from prehistoric days, calves have been tamed by
the peasantry, and such cattle as Europe and the Mediterranean basin
generally possessed were until quite recently little better than rough
descendants of this captured stock.
The so-called "wild white cattle" preserved in various British parks
are, according to Lydekker, albino descendants of the tamed native
black aurochs stock, of unknown antiquity, and are kept white (with
blackish or reddish ears and muzzles) by weeding out the dark-colored
calves which occasionally appear; but do not represent the original
aurochs as well as do the Welsh breed preserved in Pembroke since
prehistoric days. These park cattle are all of moderate size, elegantly
shaped, with soft hair, white, black-tipped horns of moderate length,
and many wild traits.
CHAPTER XXXIII
BEASTS OF PREY--THE CARNIVORA
"One of the most striking and significant results of the study of the
later Mesozoic and earliest Tertiary mammalian faunas," remarks Prof.
W. B. Scott, "is that the higher or placental mammals are seen to be
converging back to a common ancestral group of clawed and carnivorous
or omnivorous animals, now entirely extinct, to which the name of
Creodonta was given by Cope. The creodonts are assuredly the ancestors
of the modern flesh-eaters, and, very probably, of the great series of
hoofed animals also, as well as of other orders. From this central,
ancestral group the other orders proceed, diverging more and more with
the progress of time, each larger branch dividing and subdividing into
smaller and smaller branches, until the modern condition is attained."
The story of the creodonts--savage marauders large and small--includes
the rise of the powerful order Carnivora--the beasts of prey, whose
food is the flesh of other animals. There always has been, and always
will be in every department and rank of animal life, some or many
species that live by preying on their neighbors; and every living
thing, from monad to man, has to fear such enemies.
The essential characteristic of the Carnivores is the dentition, which
is adapted to seizing, holding, biting, and cutting. The canines,
rarely prominent in other groups, here become of prime importance--a
dagger and hook in one--a tearing instrument. Naturally this tooth is
most developed in the dogs and the bears, which have little other means
of seizing and holding an animal, whereas the cat has efficient aid
in its claws. The cheek teeth in this order are (typically) not flat
"grinders" but angular and knife-edged, especially the foremost molars
that shut past one another like scissor blades; and it is evident that
such teeth are necessary to animals that must cut their food into
pieces small enough to swallow, and are not concerned about chewing it.
The order contains two distinct divisions, namely:
_Marine Carnivores_--Seals, sea lions, walruses.
_Land Carnivores_--Cats, dogs, weasels, bears, etc.
The marine carnivores (suborder Pinnipedia, "fin-footed") have their
whole organization adapted to an aquatic life, and appear to have
acquired it almost from the beginning of the diverse specialization
that sprang from the generalized creodonts, for nothing is known of
their ancestry that connects them with the known lineage of their kin
on land. The body approaches a fishlike form, and the four limbs are
turned into more or less perfect paddles, or "flippers." The teeth are
of the carnivorous type; the eyes are always large and prominent; and
external ears are lacking except in one family.
The least modified of the three families of marine carnivora is that
of the eared seals--the sea lions and fur seals of the North Pacific
ocean, and southward to Cape Horn. They have kept much independence of
action in the hind limbs, and are able to climb readily about the rocks
of the islands and shores to which they resort in midsummer for the
birth of the young. They have an obvious neck, small external ears,
nostrils at the tip of the snout, and in general more characteristics
like those of land carnivores, especially the bears, than have any
other pinnipeds. They live wholly on fish. Several species termed "sea
lions" were formerly numerous from Oregon southward to Patagonia, and
on certain South Sea islands, but they have been all but exterminated
except in California. These southern species, dwelling in warmer
latitudes, are known as "hair" seals, because their coat lacks the warm
undercoat of the northern species (_Otaria ursina_) which is the "fur"
seal of commerce, and which would long ago have disappeared had it not
been placed under international protection in its breeding places on
islands in Bering Sea. Thither, as summer opens the ice, gather the
herds that have been wandering in the ocean during the winter. The
females are much the more numerous of the two sexes, and having spread
all over the islands, formerly in hundreds of thousands, are collected
into "harems." The "bulls" are three times the size of any of the
females, and there are incessant combats between rival bulls. The young
born here are strong enough to swim away with their mothers in the
early autumn.
Similar in general organization, and in the freedom and usefulness
of the hinder limbs for creeping on land or ice, are the walruses
(Trichechidæ), of which there are two arctic species, one in the North
Atlantic, and one in the seas of Alaska and Kamchatka. In old times
they came as far south in winter as Nova Scotia and the coasts of
Britain. A full-grown male walrus is a very bulky animal, ten to twelve
feet long, and his skin is covered with a short coat of hair that in
old age almost disappears, while his bulldoglike muzzle bristles with
quill-like whiskers. The especial feature of the walrus, however, is
the pair of great ivory tusks, often two feet or more long, which are
the canines of the upper jaw. They are the tools with which the animal
digs from the mud of the bottom the clams and other shellfish on which
it feeds, and are formidable weapons enabling it to protect itself and
its family and mates, for which the walrus shows remarkable affection
and loyalty, from the attacks of the polar bear, the only enemy besides
man that it has to fear.
The true seals (Phocidæ) have become still further specialized toward
a completely aquatic life. Their hind limbs are extended straight
behind the body, and take no part in progression, the fore flippers
alone enabling them to swim and dive with ease and speed. Their strong,
clawlike nails enable them to climb onto ice floes or the shore, to
which they resort for rest and sunshine and to bear their young. These
are usually only one, or at most two, at a birth, and in some species
they have to be carefully taught how to swim, fearing the water.
All of the many kinds of seals of this family are confined to the
northern hemisphere, and mostly to the arctic region; but the great sea
elephant, now almost extinct, lived in the antarctic, with one colony
on the coast of southern California. Most seals are gregarious, and
some congregate in immense herds on ice floes far from land, but the
majority of species stay near shore. Seals feed chiefly on fish, of
which they consume enormous quantities; some, however, subsist largely
on crustaceans, especially prawns that swarm in the northern seas; also
on mollusks, echinoderms, and even occasionally on sea birds.
We are now ready to turn to the land carnivores, which, by the larger
opportunity, better food, and varied conditions the land affords, have
advanced far beyond their marine cousins. In these more favorable
circumstances, and by their struggle for a living against the powers
of defense or escape of their intended prey, and the competition of
one another, they have become widely diversified in organization and
habits, and in some of their representatives have developed the highest
intellectual and physical ability in the animal kingdom.
BEARS, DOGS, WOLVES, FOXES AND JACKALS
The bears (Ursidæ) stand lowest in the scale of rank among the
Carnivora because they retain more than the others archaic
characteristics in their anatomy. The family is singularly
uniform--that is, all bears are much alike in their heavy bodies, broad
heads, powerful limbs with "plantigrade" feet, resting the whole sole
on the ground (whereas most other quadrupeds are "digitigrade," i. e.,
standing on their toes), and an extremely short tail, almost invisible
in the coat of long hair that clothes their bodies. Distinction into
species has been found difficult. An English naturalist once exclaimed
that he knew but two in the whole world--the polar bear for one and all
the rest for the other. At the other extreme the American systemist,
Dr. C. Hart Merriam, announced in 1918 that the American brown and
grizzly bears alone were divisible into eighty-eight species and
subspecies, based on variations in their skulls! For ordinary readers
all the big brown bears of Japan, Asia, Europe, and Canada, inclusive
of the grizzlies (of which few now remain) may be regarded as one
species; the polar bear, with its elongated head and body, and
pure, white fur, as another; the small gray "glacier" bear of the St.
Elias Alps in Alaska as another; the "blue" one of Tibet, the shaggy,
long-lipped, sloth bear of India, and the miniature sun bear of Borneo,
as three more; and finally the common yellowish-nosed American black
bears, the Andean "spectacled" bear, and the very similar black bears
of the Himalayas, as together constituting a seventh species.
[Illustration: WOLVES IN WESTERN NORTH AMERICA
Copyright, Underwood & Underwood]
[Illustration: BEAR IN A ROCKY MOUNTAIN FOREST
Copyright, Underwood & Underwood]
All these are as alike in habits, allowing for different surroundings
and food supply, as in appearance. Eating everything from nuts,
berries, and insects, to fish, ground squirrels, and big game, their
dentition comprises not only powerful canines, but molars capable of
smashing bones. Bears are too slow and clumsy, however, to do much as
big game hunters, save, perhaps, the polar giant in seizing seals, and
it is therefore necessity rather than choice that reduces these really
formidable beasts to the petty business of nibbling berry bushes,
digging up bulbs or the nests of wasps and gophers, and tearing rotten
logs to pieces in hope of finding ants and beetle grubs. The most
inveterate insect hunter of the tribe is the Indian sloth, or honey
bear. Sir Samuel Baker remarks that its favorite delicacy is termites,
for which it will scratch a large hole in the hardest soil to the
depth of two or three feet. "The claws of the forepaws are three or
four inches in length, and are useful implements for digging. It is
astonishing to see the result upon soil that would require a pickax to
excavate a hole." Having reached the large combs at the bottom of the
cavity the bear blows the dust away with a strong puff, and then draws
the honey and larvæ out of the comb into its mouth by sucking in its
breath.
Nevertheless bears eat a good many young and small animals, and in
the neighborhood of farms steal many calves, colts, and pigs. It is
an animal to be feared by men when met, although as a rule bears are
inclined to run away rather than resist, except when a she-bear feels
that her young are in danger. Bears are rather solitary, the males
wandering about alone, the females accompanied by cubs often as big
as themselves. The young, two as a rule, are born in midwinter in the
family den, which may be a rocky cave or the hollow of an old tree,
the center of a dense thicket or simply a bed beneath the snow. The
cubs at birth are surprisingly small--not larger than rabbits--and are
naked, blind, and very slow to develop; hence the mother is extremely
solicitous about them, and heedlessly brave in their defense. Bears
hibernate only in the coldest regions.
Allied to the bears is the large black and white "coon bear"
(Æluropus), a rare, vegetable-feeding brute of eastern Tibet, which is
a relic of the Pleistocene. Near it in structure is the queer Ælurus of
the same region, which connects the bears with our raccoons and those
other "little brothers of the bear," the kinkajous and coatis of the
American tropics.
THE DOG FAMILY--WOLVES, FOXES AND JACKALS
Some of my readers may have asked themselves how the order of the
families or other groups of mammals is determined--why the edentates
follow the marsupials, the Rodentia come next, and so on. The reason is
that their ancestors, so far as we know them as fossils, seem to have
been related in a way that indicates such a succession of development
in time. It is scarcely more than an indication, however, for although
in describing them, or making a list, we must set the animals in a
row, naturalists long ago ceased attempting to show that any linear
arrangement of that kind represented the reality. The present variety
among mammals (as in other classes) is the result of development along
different lines from one or more points of beginning.
Throughout a long period in the early part of the Tertiary era there
prevailed a class of beasts of prey, some as big as tigers, which,
however, were by no means Carnivora, as we now know them, for their
teeth in most cases were still of the insectivore type. These were the
creodonts, of which I spoke a few pages back. They combined in their
structure the features of all the different families of Carnivora, and
it was not until there had developed from their stock a single family,
Miacidæ, and the rest had died out, that the canine, or carnassial,
teeth became prominent in their jaws, and nature found in this the
right road to progress. To this anciently extinct family we may trace
all the varieties of existing Carnivora. The oldest and most central
stock appears to be that of the dog family (Canidæ).
The least of these are the jackals of Africa and Asia, small, active,
noisy, reddish and variously marked animals like miniature wolves,
which dwell in deserts and open districts, where they hide in dens
during the day, and come out at night in search of mice and anything
else they can get. They haunt the suburbs of towns, and do great
service as scavengers, but also raid farms and villages, killing great
numbers of poultry, lambs, and weakly sheep and goats by methods much
like those of our American coyotes.
The coyote is a true wolf; and the wolves are connected with the
jackals by a small intermediate species in India. Formerly the coyote
ranged eastwardly throughout the prairie east of the Mississippi,
but farmers gradually killed it off. On the sparsely settled plains,
however, it survives from the Arctic Circle to the tropics in several
species, and continues to maintain itself because its natural enemies
have been killed off, and because it is extremely clever in dodging
new perils. It is far more destructive to the ranchman's chickens,
pigs, and lambs than even the big timber wolf, but, on the other hand,
benefits the industry by aiding him in exterminating troublesome
gophers, prairie dogs and rabbits.
The big gray wolf--the wolf _par excellence_--which our Western men
usually call "timber" wolf, to distinguish it from the coyote (the
wolf of the plains) is the most widely distributed of all beasts of
prey, for despite the various names given it this fierce and capable
animal is to be found throughout the northern zones of the globe,
from Kamchatka, Japan, and northern India right around to Alaska.
Where civilization prevails it has been killed off, yet lingers where
mountains give it hiding places even in the oldest settled parts of
Europe. In North America wolves abound in all the wilder parts of
the West and North, contesting with skill and courage the effort of
advancing civilization to get rid of them. This wolf, in its largest
examples, such as the often pure white specimens of the Arctic coasts
and islands (where it travels as far north as do the caribou and other
game), may measure three and a half feet in length, exclusive of the
bushy tail, and may weigh 150 pounds. Its color is typically rusty or
yellowish gray above, more or less grizzled, while the underparts are
whitish, and the tail is often tipped with black. These hues are paler
in northern than in southern specimens, and in warm regions totally
black races are known, one of which exists in Florida.
The wolf's mode of life is virtually that of the whole canine family,
making allowances for differences in climate and circumstances.
Choosing a convenient little cave among the rocks of a mountainside,
or, when this is not handy, digging a burrow for themselves, a pair
will establish a "den" in early summer, where presently six or eight
whelps may be born; but usually only two or three survive babyhood. At
this season small game is abundant, and the animals wandering around
alone by day as well as by night, pick up a good living, grow fat and
lazy, and are little to be feared save by the mothers of fawns or
lambs. As the onset of winter fills the forests with snow, cold gales
moan through the trees, and the long, dark nights enshroud an almost
dead world, this peaceable disposition changes into a hungry ferocity
and a force of craft and caution born of the direst need, which at last
make the animal formidable to man himself. Yet actual attacks on men
are much more rare than stories and traditions would lead one to think.
It is at this season, when the rabbits and other small creatures are
gone or hidden in hibernation, and large game must be depended on for
food, that the wolves form themselves into small companies, or "packs,"
and assist one another. To this class of animals hunting is truly "the
chase," for their method is, having found their quarry (in which the
good nose for a trail and a keen hearing assist them), to keep it in
sight and run it down. Having overtaken the quarry, a sideways leap
enables them to thrust in the long canine, and drag on it--and the
result is death unless the hunted creature is able to turn and fight
off its foe with hoofs and horn.
The forests of southern Brazil harbor a long-legged, reddish species
called "maned," which is a true wolf; and South America generally has
several kinds of "fox dogs" (genus Lycalopex) that sufficiently make
up for the absence of true wolves, as do jackals the lack of wolves in
Africa and Arabia.
Foxes have long been regarded as constituting a separate genus under
their Latin name Vulpes, but conservative naturalists now think they
belong with the wolves in the genus Canis ("a dog"). The type is that
of a smaller, more agile and delicate animal than a wolf or jackal,
with a broader skull and sharper muzzle, larger ears, a longer, more
bushy tail, and usually longer fur. Weaker than its wolfish relatives,
though endowed with great swiftness, and used to playing the double
rôle of hunter and hunted, its brain has been developed to a high
degree to make up for its bodily deficiencies, and shows capacity
for further development. Nevertheless the fox is not quite such a
marvel of shrewdness as he is reputed to be, and fox hunters in Great
Britain--under whose combination of care and chase his education has
been more advanced than anywhere else--note much diversity in brain
work among them.
Although the North American red fox has a different name from the
typical European one it is virtually the same, and shows its skill and
adaptability by continuing to live and flourish in the midst of our
civilization, where it practices quite as much sly craft and success
in chicken stealing as does "Reynard" on the other side of the ocean.
The red fox is to be found all over the continent as far south as
Georgia, and where the winters are cold his long and silky fur becomes
of marketable value, especially in its darker varieties. The animal has
touches of black on the tail and the legs, and this seems liable to
affect the whole pelage in the North. Thus some are all black; others
are black with every hair tipped with white, and are called "silvers";
others have a blackish band along the spine and across the shoulders.
To these the name "cross-foxes" is given. The skins so marked bring
high prices, and an extensive industry has arisen in Canada by breeding
black and marked foxes in captivity, where pure color strains have been
developed, whereas in nature one or more of these melanistic varieties
may occur in any litter of normally red parents.
North America has three or more other species of fox, one of which,
the gray fox, is common throughout the country east and south of
the Appalachian heights, as far north as the lower valley of the
Hudson River. It is smaller and grayer than the red fox, is more of
a forest-keeping animal, and does not burrow, but makes its nest
in the bottom of a decayed tree or stump, or within a hollow log.
Living in a climate where small game is abundant the year round, and
chicken-stealing comparatively easy, he has not been driven to the
straits of getting food in winter to which the northern foxes are
driven, and hence has developed less of the ingenuity and cleverness
they show. On the high plains of the West dwells a small, active fox,
known as the kit fox, or "swift," which feeds on the ground squirrels
and mice of that region, and makes its home in a burrow (often one dug
by a prairie dog), where it hibernates in winter. It is now rare and
very wary.
Throughout the polar regions right around the globe is found the
arctic fox in great numbers, and wandering in summer, at least, to
the farthest islands, where its prey consists of lemmings, rabbits,
ptarmigan and fish. This is a shy little beast, with blunt nose, short,
rounded ears, a very long, bushy tail, and the soles of the feet well
shod with hair, giving them a firm and warm grip on the snow and ice
over which they leave tiny tracks from Labrador to Siberia. In summer
its dress is brown with whitish or drab underparts; but in autumn this
is replaced by a coat of long, pure white hair beneath which is an
undercoat of fine wool. A small proportion, however, are never either
white or dark brown, but are slate gray all the year round. In some
rather southerly places the "blues" prevail, forming a local race. Such
is the case in Greenland, Iceland, and the Aleutian Islands, where blue
foxes are now carefully preserved and cared for in a semi-domestic
condition for the sake of their valuable fur. Several small kinds of
foxes occur in Asia, and in India one affords some sport with hounds.
The prettiest of all are the little sand-colored, big-eared "fennecs"
of the deserts of northern Africa and Arabia. No foxes tame well, nor
do any of them cross with dogs as wolves and jackals constantly do,
and apparently no fox blood has entered into the composition of the
domestic dog.
There remain in this ancient and cosmopolitan family a considerable
number of animals which from their general appearance we call "dogs."
Among these is the long-bodied, short-legged, primitive "bush dog" of
Guiana; the "bakoor" of South Africa; several Oriental species; and
the hated "hunting dog" of Africa. The last named is a terror even to
a lion. It ranges the country in swift-footed packs, dreaded by every
creature of both forest and veldt, and every writer increases its
reputation for both strategy and ferocity. This has led to its being
killed off, until now it is common only in the remote wilderness.
Formerly it was known even in Egypt, and it is the party-colored,
prick-eared dog represented on the ancient mural paintings at Beni
Hasan and elsewhere.
Of the Asiatic wild dogs the most familiar is that one of India called
in the north "buansuah" and in the south "dhole." Like the others it
is normally rusty red in color, and makes its lair in rocky jungles,
whence, more often by day than by night, it makes its forays usually
in packs from which even the leopard and tiger flee--just as in this
country half a dozen curs will send a cougar or jaguar up a tree in
fright. But it avoids settlements, and does little damage to domestic
animals.
This brings us to the consideration of the origin of our domestic
dogs, a matter which seems to me more simple than some authors have
regarded it. This was doubtless among the very first animals to become
attached to the camp or family of primitive man, and in every case,
at first, at least, it would be of some local species of wolf, for
anatomists agree that no admixture of any blood outside the genus Canis
is traceable in the dog; and probably would be cherished or tolerated
as a reserve supply of food rather than as an aid in hunting. But it
is not unreasonable to suppose that when famine came and the stone
ax was raised against the poor animals, those that had proved good
watchers, or were the special pets of the women and children, would
be the last to be sacrificed and sometimes would be saved altogether.
Thus an improving and alterative selection would have begun almost
from the start. Moreover, these early camp dogs would become modified
by interbreeding and by the influences of captivity; and as their
vagabondish owners wandered about would be crossed not only with
diverse sorts of tamed dogs, but with the wild stocks of new countries;
and this complication would increase as civilization extended.
Nevertheless this appears not quite to complete the story. There is a
quality which we recognize as "doggy," and as something distinctive.
Whence came it? I am of the opinion that it is derived from one or more
kinds of canine animals, exterminated by primitive man, which were
more "doggy" than wolfish, and which formed in large part the stock
of the first domesticated dogs. This supposition is supported by the
fact that there have been found remains of a distinct canine species,
allied to the Australian dingo, which was domesticated by Neolithic
men, and perhaps contributed to existing varieties of the dog. The
earliest Egyptian monuments show pictures of large dogs with "lop"
ears--denoting one of the most striking differences between dogs and
wild wolves or jackals, whose ears are invariably "pricked."
THE SOURCE OF COSTLY FURS
A descendant of the Creodonta called Cynodictis, which lived in the
Eocene, or earliest of the Tertiary periods, is regarded as the
forefather of the dog family, but its character is such that it might
as well be said to be the progenitor of the weasel family (Mustelidæ),
which may thus be suitably considered the nearest relatives of the
Canidæ. These are the small, but alert, muscular and wide-awake animals
whose coats, adapted to the cold regions in which most of them live,
furnish us with warm and beautiful furs; hence the Mustelidæ may be
called the family of "fur bearers." They resemble the dog tribe in the
breadth of the skull, and in the dentition, which serves well for the
wide variety in their fare; but instead of the long, high-stepping
legs of the galloping dogs they have short, strong limbs adapted
to creeping, digging, climbing, or swimming. The swimmers are the
otters--one marine, the other a denizen of rivers and lakes. The sea
otter is peculiar to our northwestern coast, where it used to be
very abundant from California to Bering Sea, but is now so rare, on
account of the great demand for its unequaled fur, that its pelt is
worth several hundred dollars to the fortunate hunter. It is truly
pelagic, rarely landing anywhere but on some outer reef or isolated
rock, and eating fish, sea urchins, and crabs; and is much larger than
the land otter, and with a short, flattened tail instead of the long,
tapering one that characterizes the latter. Of the river otters about
ten species are recognized, scattered all over the cooler parts of the
world, and much alike in their four webbed feet and fish-eating habits.
They are lively, playful creatures, and by their wariness, nocturnal
habits, and skill in hiding their burrows, made in the bank with an
underwater entrance, they are able to persist here and there in the
midst of civilization.
Allied to the otters in structure are the badgers and skunks. Of
the former, our badger has been killed off everywhere except in
the northwest, where it still digs its deep holes in the ground for
its daylight rest and partial hibernation, and finds plentiful food
among the gophers, doing the ranchmen more good by destroying these
pests than it does harm by its digging. The European badger differs
in various ways; and there is an Oriental one, the "stinking" teledu,
which illustrates the fetid odor that belongs to all of this family.
This disagreeable quality is developed in the skunks into an effective
weapon of defense. The food of skunks consists mainly of insects and
field mice, and is everywhere so abundant that they find civilization
favorable to them rather than otherwise, and remain numerous all over
the country in several species, of which the familiar large northern
skunk, and the small southern striped one, are best known. The skunks
are confined to America, but South Africa has a very similar creature
in the zorilla.
We now come to a large number of vigorous, bloodthirsty and cunning
little carnivores, the terror of small game, as are the cats of
larger animals, which are grouped by their similarity of structure
in the "weasel" section of the family (Mustelinæ). Some are mainly
terrestrial, others arboreal in habit of life. All have rather long
bodies, short legs armed with strong, sharp claws, pointed heads,
catlike teeth, and brains equal, if not superior, to any other
carnivore. Among the terrestrial species the glutton of Europe and its
analogue in Canada, the wolverine, are prominent. The wolverine is a
large, shaggy, somewhat clumsy animal that seeks its prey mainly on
the ground, but occasionally climbs to a low branch or an overhanging
rock whence it may leap upon the backs of a deer or sheep. It displays
the greatest sagacity and persistence in getting a living where life
is precarious; and is so clever in robbing the trappers' lures and
penetrating his "caches" that the forest people consider it hardly
anything else than a devil on four legs, and charge it with deliberate
malice. The voracity of its European cousin long ago became the subject
of ridiculous traditions, and has given the word "glutton" to the
language. Two similar, but smaller, mustelines, the tayra and the
grison, inhabit Central and South America. The latter defends itself in
the same manner as the skunk.
The weasels, stoats, polecats, minks, and the like form a group
distinctly northern, except that one species ranges southward into
the Andes. They do their work on the ground, although some are able
to climb trees. Slender, lithe, sharp-clawed, secretively colored,
and endowed with strength, speed and cleverness, the weasels are the
scourge and terror of the ground-keeping animals, and do more than any
other class of agents to restrain mice, gophers and similar nuisances.
Europe and Siberia have the stoat, the ermine-weasel and the polecat,
a domestic form of which is the ferret; and we have in North America
several distinct weasels, as the short-tailed and the long-tailed of
the East, the bridled weasel of the Pacific Coast, the black-footed
ferret of the plains, and the little six-inch "mouse hunter" of the
Northwest, which is the smallest carnivore known. All the northern
weasels become pure white in winter when they live in a region where
the snow lies continuously and the cold is steady; but south of that
line they do not change color. The change from the summer brown to the
winter white--when they become "ermines"--is produced by an actual
loss of color in the hair; but the spring change back to brown is
effected by shedding the old white hair and getting a new brown coat.
In the Middle Ages ermine fur was permitted to be worn only by royalty,
and later by judges on the bench. A somewhat different, and strictly
American, species is the mink. It is somewhat less slender than the
weasels, and is semiaquatic in habits, dwelling always near streams,
where it feeds on earthworms, frogs, and fishes. Having this kind of
food, and being keen-witted and secretive, it has been able to continue
to exist in the midst of civilization, and the vast number of its dark
pelts that come to the fur market are nearly all got by farmers' boys
in traps set near home.
The most valuable of the fur bearers, however, are those that belong
to the forests of the North and dwell in trees--the sables, martens,
and pekans. The sable is Siberian, the marten is North European, and
the pine marten and pekan are North American. The first three are
hardly distinguishable, each averaging about eighteen inches in length,
exclusive of the long, furry tail, and are brown, somewhat lighter on
the underparts, the breast-spot of the Canadian species being orange.
The body is long and supple, the legs short and the toes separate, with
sharp, long claws, as becomes so expert a tree-climber. The martens
exhibit great agility and grace in their movements, and live usually
in trees, furnishing with a bed of leaves a hollow in a lofty decaying
trunk or sometimes in a rocky crevice. Here the young are brought forth
in litters of six or eight early each spring. In winter, however, they
descend daily, and hunt rabbits and other prey over the snow. This
is particularly true of the big Canadian pekan, or "fisher" marten,
which is the least common of the tribe. These martens fade away as
civilization advances toward their forest retreats, and now are to
be obtained only in the wildest parts of the Canadian woods; and the
effort to tame and breed them in captivity has met with little success.
CIVETS, MONGOOSES AND HYENAS
This group of Old World animals represents the product of lines of
descent that had their origin very near that of the dogs, as is
particularly evident in the history of the hyenas (family Hyænidæ).
But between the noble courage and fidelity of the dog and the cowardly
brutishness of the hyena lies a great distance in character--as it
appears from the human point of view. Of course it will not do to
apply our highly elaborated standards to a moral estimate of wild
animal behavior, or to use seriously such terms as "cruel," "selfish,"
and the like, especially in the case of the predatory beasts that
work hard for their captures, must kill them the best way they can,
and must satisfy their own wants before yielding place to rivals or
inferiors; yet we cannot help admiring certain qualities in some of
them and disliking others, as if they were inspired by praiseworthy or
blameworthy motives. In the character of the hyenas, thus criticised,
there is nothing admirable except their extraordinary brute strength.
This is shown chiefly in their big heads, where their jaws are filled
with teeth of extraordinary size, and are worked by muscles that
enable them to crunch the leg bones of an ox, or indent and bend thick
iron, of which amazing examples are given by Selous, Neuman and other
African sportsmen. Otherwise they are the meanest of brutes, hated and
despised by every man and beast in the countries (Africa and southern
Asia) that they afflict.
Related to them, but very different in every way are the many species
of ichneumons and civets (family Viverridæ) of the same parts of the
world. The ichneumons, or mongooses, are small, dark-colored, unspotted
animals, varying in size from that of a weasel to the bigness of a
house cat, with compact bodies and pointed muzzles. They are active,
bold and predacious, living on small game of every sort, and making
their homes in holes in the ground. They are noted for their animosity
to reptiles, and in ancient Egypt were protected as "sacred" because
they killed asps and hunted for and ate crocodiles' eggs. The old term
"ichneumon" has disappeared, however, in favor of the term "mongoose,"
which is the name of the East Indian species famous for snake killing.
It is able, by its astonishing quickness, to spring upon and kill
a cobra, even when that deadly snake is prepared to strike at its
little foe. Mongooses were colonized in Jamaica and other West Indian
islands years ago to destroy the rats that were a plague in the sugar
plantations; but they presently turned their attention to the poultry
as easier game, and became a greater nuisance than the rats. These
fierce little snake killers constitute the "herpestine" section of the
family.
[Illustration: BAT WITH YOUNG BAT IN EACH POUCH, FOUND HANGING TO A
TELEGRAPH WIRE, NEAR LINCOLN, NEBRASKA
Photo, Keystone View Co.]
The "viverrine" section contains the civets, which have elongated
bodies, terrierlike heads, small, round, five-toed feet with
imperfectly sheathed claws, long, often bushy tails, and coats of rough
dark-colored hair marked with blackish stripes, bars, or squarish
blotches. The species are numerous, and varied, those of central
Africa, called "genets," resembling weasels. They include the
linsangs of the East Indies, with soft, fawn-colored fur; several East
Indian species inhabiting trees and going by the name of "tree cats"
and "toddy cats," one of which is domesticated as a mouser and pretty
pet by the natives; and the black binturong of the Orient, which is the
only animal of the Old World, not a marsupial, that has a prehensile
tail.
[Illustration: BLACK SPIDER MONKEY
Photo, Ewing Galloway]
[Illustration: RUFFED LEMUR, ATTRACTIVE BY ITS COLORING
Photo, Elwin R. Sanborn, New York Zoological Society]
The distinctive peculiarity of the true civet cats is the possession
of a pair of open pouches in the groin holding an oily substance
having an intense musky odor and known as "civet." This is present in
the five Oriental species, but is most copious in the civet cat of
northern Africa, which on this account is kept captive and occasionally
relieved, by the aid of a small spoon, of its civet for which perfumers
will pay a high price.
Madagascar possesses a remarkable animal in the foussa, or fossane,
which is nearly the size of our puma, has a weasellike head and a very
long tail, and is a fierce nocturnal marauder. It is classed with the
Viverridæ, but stands intermediate between them and the cats.
CHAPTER XXXIV
BEASTS OF PREY--_Continued_
In the cats (family Felidæ) we come to the most recent and advanced
development of the carnivorous type, by straight descent from the
Eocene Miacidæ. Their cardinal characteristics are found in their round
heads and short muzzles; their teeth fitted for cutting rather than
chewing, with sharp and slender canines very prominent; their sheathed
claws; and their powerful activity. Although the civets and the foussa
have retractile claws they do not show the perfection exhibited in
this feature in the cat family. Here the final bone of every toe (the
terminal phalange) is so hinged upon the one next behind it that
ordinarily it stands upright, held there by an elastic ligament, with
the sharp, curved claw hidden in a sheath of skin and thus kept from
touching the ground and so becoming blunted; for in the cat's method
of work sharp claws are needed to hold the prey on which it has leaped
until its teeth can come into play. When this seizing leap is made a
tendon running along the underside of the toe is retracted, pulling
down the claw and causing it to pierce and hold the body of the victim.
This is the explanation of Puss's familiar scratching ability, and
accounts for the fact that while dogs, developing long legs for their
style of attack, chase and finally seize their prey with their big,
strong canines, cats steal upon it or more often lie in ambush and
pounce on it, using their slender canines mainly as piercers. The cats
do their hunting mostly alone, and are therefore largely at the mercy
of wolves, etc., who go in packs; and herein lies the origin of the
fear and hate with which cats regard all dogs.
The cats are a very uniform group, all the many species belonging to
the single genus Felis, except the few lynxes and the cheetah. No
better example of the race can be found than our "fireside sphinx."
She is a direct descendant of the "Caffre," or "Libyan" cat, a native
of northeastern Africa, and especially of Egypt, where she still
runs wild. Reddish sandy in color, with faint, broken, darker bars
across the body, limbs, and tail, and narrow vertical lines on the
face, excellent copies of this original of all the domestic cats of
the western world, at least, may often be seen in our houses. This
likeness is supported by the evidence of history and archæology--the
skeletons of Egyptian cat mummies, and bones associated with the dawn
of history. In regard to the present, however, some deduction must be
made. In all parts of the world one or another of the smaller wildcats
of the country have been kept as pets in native houses; and wherever
the people have been far enough advanced to raise and store grain, they
have cultivated a cat or some other animal to free their granaries
from thieving mice. It was for this purpose, no doubt, that the cats
of Egypt were first tamed; and then, to make the people prudently
keep them and care for them, the priests invented a beneficent and
cheerful cat goddess, who, naturally, was said to walk abroad mostly by
moonlight. When the tamed Egyptian cats reached Europe with the early
Phoenician colonists and traders they would certainly soon meet and
interbreed with the native stock; and to such crossing is probably
due the banded or "tabby" cats. On the other hand, brindled cats were
formerly unknown in eastern Asia, whose spotted or foxy house cats were
derived from other and local sources. Since intercourse between Europe
and the Orient became frequent, more or less mixture has occurred;
although one very distinct Eastern breed persists--the long-furred
Persian or Angora cats, a race probably derived prehistorically from
the manul, of Turkestan.
The differences between members of this genus Felis, all of which seem
able to interbreed, when similar in size, are chiefly of size and coat.
Their prey and hunting methods are substantially alike everywhere,
and in domestication cats are slow to vary from the wild type in any
respect except in color--a result of their mixed ancestry. Puss remains
a savage in a civilized coat, and, accepting condescendingly the novel
comforts offered her, refuses to forsake her own forest gods for the
fireside shrines of her tempters.
The word "wildcat" is naturally used for any small feline, but strictly
belongs to the yellowish, tabby-marked, forest cat (_F. catus_) of
Europe and Siberia, now becoming rare. Closely allied to it is the
manul, of the central Asian steppes, where the long fur that envelopes
it (as preserved in our domestic Persian beauties) is required by the
awful cold of those lofty plains. Several other small cats inhabit
the desert parts of southern Asia, which abound in rodents; and the
long-legged, powerful, fawn-colored caracal ranges, nowhere numerously,
from India and Mesopotamia around to Arabia and South Africa. Africa
has several other cats of the open country, the best known of which is
the swift-running, handsome serval, which is an expert tree climber.
Southeastern Asia has three or four beautifully marked forest cats, and
four of great size--three leopards and the tiger.
The typical leopard is distributed from China and Borneo westward
to southern Arabia and all over Africa, except in deserts and cold
mountains; but the ounce, which may be regarded as a variety of it,
inhabits the Himalayas, staying near the borders of the snow line for
the most part, and another beautiful variety, the clouded leopard,
frequents the forests of the median slopes of that vast range. The
ground color of the leopard is yellowish brown, of varying intensity,
and is thickly covered with rosettes of black spots inclosing a clear
area, with the breast and belly white. The favorite haunts of leopards
are rocky, brushy hills with holes suitable for a den, where they may
watch the surrounding country, and at sunset descend with astonishing
celerity and stealth to cut off any straggling animal returning to the
village at nightfall. They prey boldly on the small Hindu cattle and
ponies, but more habitually on the sheep, goats, and dogs, and now and
then (but rarely) turn man-eaters.
The leopard cannot overcome, ordinarily, animals as large as the lion
and tiger slay, but everything of lesser size is acceptable, down
to robbing birds' nests and clawing grubs out of rotten wood. It is
somewhat smaller than our cougar, a male in good condition weighing
about 125 pounds.
[Illustration: TIGERS
(_Felis tigris_)]
The tiger--for there is only one, in spite of circus advertisements
of a "royal Bengal" as something different--is purely Asiatic, the
species ranging from the Caucasus and the mountains of Ararat to the
East Indies (Sumatra and Java), and northward to central Siberia and
Sakhalin. It is to be found throughout all India, but does not occur in
Ceylon.
Speaking of the tiger always brings to mind that other great cat, the
lion. These powerful marauders dispute the title of "king of beasts."
Their respective realms overlap but little. The lion, like the other
big cats, is a relic of a diminishing race and kingdom. In the early
Stone Age the "cave" lion (virtually the same as the present _Felis
leo_) roamed throughout the southern half of Europe, and its final
extermination north of the Mediterranean was doubtless accomplished
by prehistoric men. Afghanistan, Beluchistan and northern Persia were
rid of them long ago. A century ago lions were more or less prevalent
in northwestern India, but now none remain save a few in the Gheer,
a wooded hilly tract of Kattiawar. In Persia they survive only in
Farsistan, where marshes afford shelter, and the hosts of pigs feeding
on the acorns of the oak forests furnish subsistence. But they were
long ago exterminated from all Asia Minor, Arabia, Egypt, and Algeria.
From Abyssinia, and the southern Sahara southward to the Orange
River, lions still exist except in the most populous districts, and
in some places are very numerous. This range of territory shows that,
unlike the forest-loving tiger, the lion is an inhabitant of open,
bushy country, finding its game in the herds of antelopes, zebras,
and similar plains-running animals rather than in the jungle fauna to
which the tiger is confined; also that the tiger is inured to a far
colder climate. This difference in habitat and hunting requirements
accounts, in the minds of those who pay much attention to adaptive
(or "protective") coloration, for the difference in their dress, for
the tiger is said to become almost invisible in its yellow coat and
vertical black stripes amid the flickering shadows of the wood, or when
creeping through the long Indian grass, while the unmarked, grayish
yellow, or sand tint, of the lion is equally unnoticeable on the desert
or on the sere veldt of its East African hunting grounds. The great
mane of the male lion--but some never acquire this ornament, or only
scantily--and his greater height at the shoulder give him a majestic
mien.
A lion of large size measures about nine and a half feet from the nose
to the tip of the tail, which is about three feet long; stands three
and a half feet high at the shoulders; and weighs about five hundred
pounds. Most specimens, however, fall far short of these figures; and
the largest examples have come from South Africa. The dimensions and
weight of tigers average just about the same, the extreme examples
on record having no doubt been measured along the curves of the body
instead of in a straight line between the two terminal points, nose and
tip of tail, as is the proper method. The literature relating to these
two royal and puissant beasts is immense in its extent, and the best
of it is that written by the hunter-naturalists who during the past
century have studied and fought them in their native wilds.
[Illustration: LION
(_Felis leo_)]
The western hemisphere has a series of native cats which, although
not equal in size and strength to the lion and tiger, are hardly less
formidable in view of the game they hunt. The biggest is the jaguar,
which is found from western Texas to northern Argentina. It is about
the size of the leopard, but has a bulkier body, bigger head, shorter
and more massive limbs, and shorter tail; hence, while less active
and supple, it is perhaps more powerful than the leopard, and certainly
is stronger than the puma. The ground color varies from the yellowish
gray seen in arid Paraguay to almost red in the steaming equatorial
swamps, while in the lower Orinoco Valley deep brown and black ones are
common; but there is only one species. The coat is everywhere spotted
with black, not in the leopard's hollow rosettes, but forming larger,
irregular groups, each inclosing a black central spot.
This is the "tigre" of the American tropics, and indeed, is so called
wherever Spanish is spoken. It hunts the largest game of its country,
especially tapirs and deer; and wherever domestic animals are reared
it becomes a destructive pest. For the most part, however, these cats
subsist on capybaras and other rodents; and in Mexico on peccaries,
striking down stragglers and then hastening up a tree out of the way
of the furious herd of these sharp-toothed pigs brought together by
the squealing of the first victim. Rarely found away from water, which
seems as necessary to it as to the tiger, it is not surprising to find
that in such places as the reedy borders of the La Plata fish form
its main diet, snatched from the water by the paw. On the Amazon it
feeds largely on turtles and their eggs. It attacks the manatee in its
own element, and has been seen "dragging out of the water this bulky
animal, weighing as much as an ox." Even the crocodile and cayman are
regularly preyed upon. Its fondness for monkeys is also well known, and
it is hated and reviled by them with the same fury as leads the East
Indian apes to hurl sticks and bad language at the tiger.
The "cougar," as Buffon named it, the "puma" of the Peruvians,
"panther" and "mountain lion," as it is known in the United States,
is another big American cat familiar to woodsmen from New England,
Minnesota, and northern British Columbia southward to Patagonia; and
everywhere it is so precisely uniform that the most hair-splitting
systemists have been unable to subdivide its species (_Felis concolor_)
into local varieties. Its upper parts vary from foxy red to a dull
blue, this difference in color having no reference to age, season or
locality. The underparts are white; and there are no spots anywhere
except that the lips and outer rim of the ear are black, and a patch
of white marks each side of the muzzle. The panther was much dreaded
by the early settlers of the Eastern States and by the frontiersmen
settling the Mississippi Valley, who were more alarmed by its doleful
screams as it wandered about in the night, than by any history of harm,
for it avoided men with a greater fear than their own; nevertheless, it
became a nuisance by its raids on the farmer's live stock and he killed
it off, so that now pumas are to be met with only in the forested and
swampy fastnesses of some of the Gulf States and in the Far West.
There they still do great damage to the young animals on ranches,
especially where horses are plentiful on the range. This is equally
true of South America. Nowhere, however, is the puma feared by mankind
as is the jaguar; on the contrary, remarkable stories are recorded, and
constantly being verified by experience, not only of the cowardice of
the animal, but of its apparent desire to make friends with humanity,
following lonely persons without harming them, apparently merely in
satisfaction of an innocent curiosity. It is hunted usually with dogs,
to escape which it will climb into a tree, and once there remain to be
shot rather than come down to fight, even when the hunters are close up.
Tropical America is the home of several smaller cats, some of which
among the spotted ones are probably only varieties of the ocelot. This
highly variable but always beautiful creature is about two and a half
feet long in body, rather long in the legs, is an expert tree-climber,
and is abundant from Oklahoma southward into the Brazilian forest, but
has a different name in every country. It is grayish, thickly marked
with fawn-colored, black-edged, oval patches and stripes in endless
variety; and its fur is one of the most marketable in the country. On
the prairies and plains of the open country south of Brazil the pampas
cat, or "pajero," is common. It is of robust form, with long hair,
very plain in its grayish tint on the back, but beautifully spotted
and striped on the belly and legs. It is a ground-runner, preying on
rodents and birds. Brazil has in its forests a notable cat of medium
size called "jaguarundi," with a noticeably slender form, short legs
and a tail nearly as long as its body. It is dark gray in hue and
entirely unspotted. This may, on further study, turn out to be only a
variety of the "eyra," another cat of the tropics, sometimes met with
as far north as the Rio Grande Valley, which looks in its unspotted
chestnut coat more like a huge weasel than a cat. It is a graceful and
nimble climber, and lives on prey caught in trees.
Our common "bobcat," the wildcat best known to most readers, is a
lynx--one might say _the_ lynx, since in spite of the wide variety
that specimens show between those of Quebec and those of Texas, for
example, all seem to be one species, which is only locally different
from the lynx of the Old World. But Spain appears to possess a distinct
species in the pardine lynx. Lynxes differ from the typical cats
(_Felis_) in having only two instead of three pre-molar teeth, but most
notably in their heavy bodies, stout limbs, big and powerful feet,
very short, thick tails, and the tufts of hair on the tips of the
ears. The big Canadian lynxes are clothed in coats of long grizzled
hair, valuable in the fur market and suited to the freezing winters
of their home, where their fare during the cold months is restricted
almost entirely to hares; but in the United States, and especially
toward the south, these cats are much smaller, have thin coats and show
reddish and yellowish tints with much spottings. They have survived the
presence of civilization wherever rough hills or swampy forests give
them a refuge, and they prey on mice, rabbits, birds, and poultry.
A single cat remains to be mentioned, the curious cheetah, or hunting
leopard, which is known all over southern Asia, and Africa, and in
India and Persia is trained to hunt antelopes. It is somewhat less in
size of body than the leopard, but stands on long legs, and in color
is yellowish, with many obscure blackish spots. Its great peculiarity,
however, is the fact that its claws are not retractile, like those
of the true cats, or only partly so; and that it chases its prey
with great speed and in a doglike manner, although lacking the dog's
persistence and endurance. This mingling of characteristics makes it
hard to classify, and it perhaps should have led, instead of closed,
the chapter on the cat family.
CHAPTER XXXV
INSECTIVORA--HEDGEHOGS, MOLES AND SHREWS
Again we have to deal with the scattered and feeble relics of a once
important race; but that was long ago, even as geologists use the
word long, for the order of insectivores (Insectivora) may be traced
backward to the very earliest, hardly identifiable, fossil remains of
mammalian pioneers in a reptilian world. These are known mainly by
their dentition, which in this order is characterized by weak canines,
small sharp incisors, and all the back teeth small, with many points
and sharp edges designed for cutting through the shards of insects,
shells of eggs, snail shells and the like, rather than for chewing.
They had become, even in the Eocene period, a numerous and varied
group, including arboreal, terrestrial, and aquatic types, some of
considerable size, besides many minute forms comparable to the moles
and shrews of the present day, and very likely ancestral to them. At
the beginning of the Tertiary, they are indistinguishable from the
earlier of the creodonts, but these rapidly developed into powerful
beasts, while the insectivores retained more nearly their ancient ways,
and in the later Tertiary diminished rapidly in numbers and variety.
To-day only a few survivors are left, protected from their enemies by
armor, as in the case of the hedgehogs; by a subterranean mode of life,
as the moles; by their agility, minute size, and unpleasant odor and
taste, as are the shrews; or, finally, by their exile in some remote
corner of the world, where enemies are few. Thus we find remnants
of families so widely separated as Madagascar and Cuba--the same
disintegration that has overtaken many another ancient and decadent
tribe; and their organization is so generalized that systemists find it
difficult to place them in any serial arrangement with other orders;
the big Malayan kaguan, for instance, which lives in trees and looks
and behaves like a flying squirrel, was long classed with the lemurs.
Oldest of the existing insectivores, and nearest the original type, is
the hedgehog of Europe, which, when rolled up, presents to its enemy a
living chestnut bur of stiff spines hardly bigger than a baseball. All
day it lies curled up asleep in an underground nest (where in winter
it hibernates), and wanders about at night hunting for insects, worms,
snails, slugs and the like, and savagely attacking and killing every
viper it comes across--a valuable little animal, preserved by every
intelligent gardener. Next to it are the lively little "tupaias," or
tree shrews of the East, and the queer, long-nosed, kangaroo-shaped
jumping shrews of the deserts. A rarer oddity is the river shrew
of West Africa, looking and acting like a miniature muskrat. Then
there are the "almiquis" of Cuba and Haiti, which suggest small,
ground-traveling opossums, whose nearest relatives are the spiny
"tenrecs" of Madagascar.
More familiar to us are the moles and shrews of northern countries.
Moles are chiefly remarkable for the adaptation of their frames to the
requirements of an underground existence, in which they must travel and
seek their food, and not merely make their nightly home in burrows.
This has brought about an alteration of the forelimbs into digging
tools of really gigantic power when we consider the size of the animal,
and a strength of shoulders that enables them to bore their way through
loose soil without shoveling it out, save at long intervals. Everybody
knows the upheaved ridges that mark their paths on the lawn as they
move here and there beneath the grass roots in search of grubs and
earthworms. One of our common species, preferring wet meadows to the
uplands, is the star-nosed mole, whose muzzle is encircled by pink
tentacles, very sensitive, which give it its name.
Highest in rank among insectivores, though least in size, are the
shrews, one of which, our Cooper's shrew, is the smallest of all
mammals. They are mouselike in appearance, but with long, flexible,
much bewhiskered snouts, and are ceaselessly active, wandering about
underneath leaves, old grass, and logs, and boring their way into loose
loam or the punky wood of decayed stumps, in search of earthworms,
grubs, beetles, slugs, and similar prey, including young mice and the
fledglings of ground-nesting birds, and varying this fare by bites from
soft-shelled beechnuts, tuberous roots, etc. They are quick of hearing,
bold, pugnacious, and fierce, often killing and eating other shrews;
difficult to keep alive in captivity, utterly untamable, and easily
frightened to death.
[Illustration: MANDRILL, MOUTH OPEN TO SNARL
Photos, Elwin R. Sanborn, New York Zoological Society]
[Illustration: GORILLA, SOMEWHAT THOUGHTFUL]
[Illustration: CHIMPANZEES IMITATING SOME OF THE WAYS OF MAN
Photo, Elwin R. Sanborn, New York Zoological Society]
CHAPTER XXXVI
THE BATS--WING-HANDED MAMMALS
Next in advance of the Insectivora stands the order Chiroptera
("hand-wing"), which is the tribe of bats, divisible into two
suborders--the large, diurnal fruit bats, and the small, nocturnal
insect-catching bats and the vampires. No fossil remains bridging the
gap between these two orders has been discovered, nor can anyone yet
explain the steps in the acquirement of the bats' power of flight.
Bats are simply flying mammals, necessarily small, with the bones of
the forelimbs light, hollow, and greatly elongated, the middle finger
in some cases exceeding the total length of the body. These lengthened
digits support between themselves and the hinder limbs a membrane that
opens and closes much like an umbrella. This wing membrane consists of
a double layer of skin, one continuous with the hide of the back, the
other with that of the abdomen, fused together. The surface of the wing
is covered with microscopically minute hairs. To these hairs and the
bulbous underlying "end organs" are attributed the bat's exalted sense
of touch. The expanse of these leathery wings is far greater than that
of most birds relatively to the size of the body, but the muscles are
weaker; and the exterior thumb, with its strong claw, by means of which
bats scramble about rocks and buildings, recalls the similar organ in
archæopteryx. The hind limbs are small, while the knee bends backward
because of the outward twist of the limb. This makes the foot almost
useless for walking, but fits it, with its peculiarly strengthened
ankle, to be extended straight backward and serve as a means of hanging
the body head downwards--the bat's ordinary attitude in rest or sleep.
Bats usually produce two young at a birth, and the mother carries them
about with her, they clinging to her breast, where she keeps them warm
by folding them within her wings when they and she are hanging to the
branch of a tree. Nothing is made in the way of a nest.
The fruit-eating bats (division Megachiroptera) are distributed in some
seventy species from East Africa to the East Indies, Japan, Australia,
and Polynesia. They vary in size from an ounce in weight to some as
large as big squirrels, and in form from the grotesque "hammerhead" of
Africa to the many rust-red East Indian species that come naturally by
their name of "flying foxes," and approach foxes in size. These bats
feed on all sweet fruits, and in some regions, as Java, no delicate
fruit can be raised unless the tree is protected by nets. It is at
night that they make their forays, sleeping during the day in great
companies among the branches of some chosen tree.
Where a fig tree attracts a crowd of them, we are told by Eastern
writers, the roughest fighting begins over coveted plunder, each one
screaming, clawing, biting, and struggling to seize something and
get away to a secure retreat to enjoy it. No doubt these squabbles
are rendered more violent by the dissipated habits in which the bats
indulge during their nocturnal expeditions, for, according to Dr.
Francis Day and other observers, "they often pass the night drinking
the toddy from the chatties in the coconut trees, which results either
in their returning home in the early morning in a state of extreme and
riotous intoxication, or in being found the next day at the foot of the
trees, sleeping off the effects of their midnight debauch."
The second division (Microchiroptera) contains the carnivorous bats,
which include five families, two of which, the nose-leafed and the
desert bats, belong to the warmer parts of the Old World, and the
others are tropical (Emballonuridæ, and Phyllostomidæ), or have an
almost cosmopolitan range (Vespertilionidæ). In general the bats of
this division are night flyers, and retire during the day to caves,
hollow trees, and dark places in old buildings. Such haunts contain
great deposits of black guano, which in many places is gathered as a
most valuable fertilizer. The rock tombs and temples of Egypt and the
East are haunted by thousands of these tenants, and are occupied the
year through; but in cool countries the bats migrate or may go into a
partial hibernation. The food of most of them, and especially of the
Vespertilionidæ, to which all those of the United States and western
Europe belong, is exclusively insects, caught on the wing in the
twilight hours or in moonlight; and the service thus done to mankind
is of much importance. In the tropics, however, several species,
especially of the family Phyllostomidæ, feed largely on fruit, being
provided with long, brush-tipped tongues with which they scrape out
the soft interior of the banana and similar fruits. Two species of
this family are the famous "vampires" of the American tropics. The
name recalls the superstition rife in Europe in the Middle Ages as to
blood-exhausting fiends which were fabled to lull their victims into
unconsciousness by the slow flapping of their wings, and then deprive
them of life. The foremost of these vampires is a small reddish species
(_Desmodus rufus_), whose front teeth are like keen daggers, while the
cheek teeth have disappeared, having nothing to do, since the animal
subsists wholly on a liquid diet.
CHAPTER XXXVII
MAN'S HUMBLE COUSINS
We have now arrived at the highest division of the Mammalia, the order
Primates, a term here signifying "first" in rank of importance by
reason of the possession of a structure and faculties superior, as a
whole, to any other class. It includes the lemurs, the monkeys and
baboons, the anthropoid apes, and mankind. Man's undeniable superiority
to all the others is intellectual rather than physical (for in this
or that particular he may be inferior in ability to many of the lower
animals), and is much less apparent in primitive men than in those
highly civilized.
All primates have five fingers or toes, each covered at the tip by
a flat nail; and in most cases the thumb or great toe, or both, are
"opposable"--that is, may be bent around opposite the other digits so
as to form a grasping organ. The higher the primate in the scale of
organization the more perfectly are its forelimbs and hands adapted
to seizing and handling objects, and its hind limbs to supporting and
moving the body; and the whole sole of the foot rests upon the ground.
These and other characteristics fit the primates for life in trees,
where nearly all spend their time. The number of young, as a rule, is
no more than two annually, and they are born in a helpless condition,
hence they must for a period be nursed and be carried about by the
mother. The food consists almost wholly of fruit and other soft or
easily digested vegetable materials, insects and eggs, and the teeth
are of nearly even size.
LEMURS, GALAGOS AND AYE-AYES
The lemurs, or half-apes, are a large group of small tree-dwelling
animals that paleontology shows were in early Tertiary times much
more closely connected with monkeys than they are now; and it also
shows that in a former age their ancestors were scattered all over
the temperate parts of the globe; this assists us to account for the
strange distribution of the remnants that now live--a part of them in
the Malayan archipelago and a part in central Africa and Madagascar,
in which island, indeed, lemurs abound more than elsewhere, owing
largely, no doubt, to the scarcity of enemies. They differ from monkeys
in having elongated jaws, giving a foxlike aspect to the face, in the
woolliness of the coat (as a rule), and in their nocturnal habits and
weird cries that have been the source of many curious superstitions and
a reverence that no monkey ever inspired.
The most specialized of the group is a wan little Malayan creature
about the size of a small rat, with a long tail, long hind legs, and
toes ending in pads that enable the tarsier, or "malmag," as it is
called, to climb the smoothest bamboo. Its eyes are so big they seem
to leave no room for cheeks. Even more curious is the aye-aye of
Madagascar, which resembles a small squirrel with a terrier's face; its
hind feet are like a monkey's hand, and its forefeet are composed of
very long naked fingers armed with sharp claws useful in pulling bugs
and grubs out of crevices in bark, or the pulp out of fruits.
The typical lemurs have rounded heads, doglike muzzles, and a soft,
thick, woolly fur of various colors that is usually extended to form a
long, bushy tail; and the largest of them, the "babakoto" of eastern
Africa, is as big as a cat, and makes the woods ring at night with
doleful howls. They hide in holes in trees or in leafy nests during
the day, and at night wander about in trees, or on the rocks of the
mountains they frequent, in search of insects and sleeping birds and
their eggs, etc. All the lemurs proper, and their relatives, the
endrinas, belong to Madagascar. On the mainland a somewhat different
race, the galagos, abound throughout central Africa, and are renowned
for their leaping powers, general activity, and willingness to eat
anything they can catch or find ripe in the way of sweet fruit. They
are interesting as pets. The "slow lemurs" of the Malayan islands, on
the other hand, are noted for their sleepiness, moving about the trees
with such slothlike sluggishness and caution that it is a wonder they
ever capture enough food to keep alive. They are regarded with great
fear by the natives, not because they are more harmful than the other
lemurs, which are also dreaded, but because of strange supernatural
powers attributed to them. These ideas are older than our science, for
the name, _Lemures_, given them means "ghosts."
A remarkable thing about the Primates is that they show, even in
man himself, many structural traits recalling the anatomy of that
remote source of so many mammalian branches, the creodonts; and the
lemurs seem to stand between the Insectivora and the Primates, and
are certainly the most ancient part of the latter order, with many
affinities to the former. In a similar way they are connected with
the monkeys and apes by the marmosets. A very suggestive fact is that
the scattered distribution of modern lemurs much resembles that of the
comparatively few existing insectivores, especially as to Madagascar,
which was united with the continent of Africa during the earlier half
of the Tertiary era.
MARMOSETS, MONKEYS AND BABOONS
The marmosets, or "teetees" (titis), are a small family (Hapalidæ) of
little, arboreal, monkeylike creatures much enjoyed as pets in the
American tropics, but rarely able to endure our northern winters even
when protected most carefully from the cold. They look and act much
like pretty squirrels, have long, but not prehensile tails, and some of
them, as the "tamarins," have long silky manes. They possess several
lemurlike features, and, as has been said, are a connecting link
between the lemurs and the monkeys proper.
All the monkeys of the world are members of one or the other of two
families only--the Cebidæ, all American, and the Cercopithidæ, confined
to the Old World. They differ in several structural particulars, among
others in the number of teeth, and in the matter of bare spots of naked
skin on the buttocks (not seen in the Cebidæ), in the prehensility of
the tail, exclusively American, etc.; but the most striking difference
between the two groups is found in the nostrils. In the Old World
monkeys and apes (Catarrhines) the nostrils look downward and are close
together; in American monkeys (Platyrrhines) they are widely separated
and look outward. This absolute distinction between the Primates of the
two hemispheres has existed as far back as the race can be traced by
paleontologists, who have discovered no intermediate forms.
The American monkeys, or "sons of Cebidæ," as Dr. Cope once
expressed it, comprise the capuchins (Cebus), which may be taken
as the representative genus, the woolly monkeys (Lagothrix), the
spider monkeys (Ateles and Eriodes), the howlers (Mycetes), the
sakis (Pithecia and Brachyurus), the night monkeys or durukulis
(Nyctipithecus) and the squirrel monkeys or saimiris (Chrysothrix and
Callithrix). All are small, the largest having a body no more than
twenty inches in length, and are hairy or woolly, without any naked
callosities. Their headquarters are in the great forests of equatorial
South America, which is the exclusive home of many species, some of
which are restricted to narrow areas, the great rivers often acting as
impassable boundaries. No monkeys ascend high in the Andes, or reach
the West Coast; and none is found far south of the forests of Brazil or
north of south-central Mexico.
They are adapted to a life in trees, and most of them are aided in
security in hurrying about their precarious paths through the tree tops
by the fact that the tip of the tail, naked on the underside, will
almost automatically curl around a branch, gripping it so firmly that
the animal may hang by this grasp alone, leaving all four hands and
feet free for other service. Their agility, especially in the smaller
long-legged spider monkeys, is proverbial; but one must not believe the
old wonder tales of "living bridges" and the like. Best known are the
capuchins, which furnish most of the pets and organ grinders' slaves
seen in the United States; and their manner of life is substantially
that of the whole tribe, with such exceptions as that of the big-eyed
durukulis, which are strictly nocturnal in habit, and the big reddish
"howlers" that make the forest ring with lionlike roars at certain
times, giving the impression that a large company are howling in chorus
when it is only a solitary old male that makes all the noise. The
capuchins, like most other species, go about in small, orderly bands,
led by the oldest male, and remain most of the time in very tall trees.
Bates, in his "Naturalist on the Amazons," describes how, when the
foremost of a flock of monkeys reaches the outermost branch of a tall
tree, he springs forth into the air without a moment's hesitation, and
alights on the dome of yielding foliage belonging to the neighboring
tree, maybe fifty feet beneath, all the rest following his example.
The Old World monkeys are, as a family, of higher grade, larger size,
and greater historical interest than those of America. Fossil remains
show that the tribe is an old one, and was once able to range all
over Europe; now the few half-captive and altogether mischievous apes
on the rock of Gibraltar represent all that remain of a species once
numerous even in northern France, and so recently as the Pleistocene.
This ape is a macaque (Macacus), a genus that otherwise is purely
Asiatic and contains some of the most celebrated of the monkeys. Thus,
the suitably named pig-tailed macaque of the Far East is trained, in
Sumatra and Borneo, to climb the coconut palms and select and throw
down ripe nuts--the most really useful thing to the credit of monkeys;
the Japanese species is the one that is so much used in the decorative
designs of that artistic people; and the best known of all is the
common Bengal or rhesus monkey, which is revered by some sects of
Hindus, and is treated with tolerance or made a pet of, or an aid to
jugglers, throughout India. Several other macaques are common pets and
servants in the East. The macaques go about in flocks, and often come
to the ground. All have the habit of cramming food into their cheek
pouches for mastication at leisure. The majority of the species are
very docile when young.
Closely related to the macaques are the mangabeys, or white-eyelidded
monkeys of West Africa, and the central African genus Cercopithecus,
which includes many small-sized, handsome, tree-living kinds, of which
the most widely known is the diana monkey, whose long fringe of white
hair hanging from its neck and chest is in much demand in the fur
market. Even nearer relatives are those interesting but often repulsive
creatures, the baboons, between which and macaques stands the doglike,
stub-tailed, ground-keeping black ape of Celebes. This eastern instance
of an otherwise African group, like the single western macaque,
indicates, what fossil remains prove, that both genera were once far
more wide-ranging than at present.
The African baboons, of which there are about a dozen species, present
striking peculiarities in appearance, and all are much alike. In size
they vary from the bigness of a spaniel to that of a mastiff, and a
comparison with dogs is apt, for these apes go about habitually on
all fours, their limbs are stout and of about equal length, and their
heads and muzzles are canine; hence the ancient name _cynocephali_,
dog-headed. In some, as the mandrill, the naked nose is swollen at the
sides like a hog's snout, thrown into ridges and colored black, pale
pink, or blue and purple; while the great callosities on the stern are
of the same or contrasted colors. The fur is blackish, or yellowish or
greenish, grizzled by the fact that every hair is ringed with various
colors; or the coat may be party-colored. They go in bands, sometimes
exceeding one hundred individuals of all ages, and choose for their
lairs cliffs and rocky ridges full of crevices and thickets, such as
the extraordinary Black Rocks of Angola, where the yellow baboon dwells
in thousands, and subsists mainly on lichens. In such places they are
safe against any enemies except leopards (which the old males are said
to be able to vanquish) and the larger serpents or birds of prey;
and these can make away only with the young now and then. Dogs dare
not attack full-sized baboons, which have been seen again and again
going fearlessly to the aid of some little one that dogs have tried to
seize. Their sense of smell is amazingly keen, especially for hidden
water springs in the desert. It is recorded that the Bushmen of the
Kalahari plains used to train captives to help them search for water
when famine was impending; and undoubtedly the observation of what
roots, etc., these animals were accustomed to eat taught the earliest
human venturers into these regions what might be used there in the way
of food. Baboons also eat lizards and the like, and are fond of honey
and certain gums. With these habits it is not surprising that they are
everywhere exceedingly harmful to plantations, tearing up or trampling
down more than they can consume, and destroying a field in a night.
Some of these baboons are as tamable and teachable as other monkeys,
but they grow unruly and ferocious as they become old. They were tamed
and trained in ancient Egypt, where a religious sect held the shaggy
Arabian species (_Cynocephalus hamadryas_) to be sacred to Thoth, whose
statues are a human figure with a baboon's head.
GIBBON, CHIMPANZEE, GORILLA, ORANG-UTAN
This brings us to the anthropoid ("manlike") apes of the family
Simiidæ, which differ from the inferior apes that have been described
in fewer particulars than their size and appearance might suggest.
Thoroughly arboreal for the most part, when these apes come to the
ground they progress in a semi-erect fashion. Moreover when they put
their hands upon the ground to aid in walking, they do not rest their
weight, as do the lower apes, upon the flat of the hand, but upon the
back of the fingers. None of the anthropoids has a tail.
The gibbons are an Indo-Malayan group of monkeylike anthropoids with
small, long-nosed faces, and arms so long that when the gibbon stands
erect the fingers touch the ground. By means of these long arms they
swing themselves through the tree tops with astonishing speed, and are
adept at climbing and leaping about the mountain slopes that are their
favorite resorts. All the gibbons are noted for their far-carrying
voices, and often a band will utter weird howls in chorus answered by
another band, so that the forest is filled with indescribable noises.
The largest is the jet black, Sumatran "siamang," three feet tall.
In the same region, precisely eastern Sumatra and Borneo, lives a
larger relative, the orang-utan ("man of the woods"), or "mias," as it
is known to the Dyaks. Like the gibbons it feeds on leaves, buds and
soft fruits, especially the big, pulpy durian; and also like them is
shy and mild in disposition.
[Illustration: GORILLAS AND GIBBONS
The five upper figures are young gorillas in various postures; the
three lower are adult gibbons. (Lydekker.)]
This Malayan ape is smaller and weaker than its African cousins,
males standing not more than four feet six inches, and weighing 160
pounds, while the females are smaller. The body is bulky, the belly
protuberant, and the legs very short, while the arms are so long that
the fingers hang down to the ankle. The coat is a variable dark brick
red and long, forming a beard in old males. The head is short and high,
with the bony crest of the skull and the ridge over the eyes less
prominent than in the gorilla; while the nose is insignificant, and the
jaws are large and protrusive, with a long smooth upper lip. The eyes
have a pleading expression, the ears are small and closely appressed,
and many of the older males have the cheeks greatly and distinctively
broadened by flat callosities. Lastly, although its brain is most
like that of man, the orang-utan is inferior, in general, to both the
gorilla and the chimpanzee.
The chimpanzee and gorilla belong together, not only because both are
African, but because they are more closely related to one another
than to the Malayan anthropoids. The chimpanzee is to be found in the
equatorial forests north of the Congo, and also all along the upper
valley of the Nile and about the Great Lakes; but the gorilla seems
to be restricted to the rough coastal region between the Congo and
Kamerun. Both are black-haired apes, growing nearly to the height of
a man of medium size, but with short legs, very long arms, massive
chests and shoulders, and huge strength. The face and palms of the
chimpanzee are pale flesh color, those of the gorilla black. Both
make their homes in trees, feeding on succulent leaves, sprouts and
fruit, and like the orang-utans, making nightly platform like nests of
branches on which to sleep; but the old male gorilla is said to sleep
on the ground at the base of the tree in which its family reposes. Both
spend much time on the ground hunting for food, and they invade the
plantations of the Negroes, who are greatly afraid of them, and wreak
much damage there. Dr. Garner, whose investigations of their habits,
in his attempt to learn whether they and the monkeys of the region
had anything that might be called rudiments of a language, resulted
in adding much of importance in regard to them, reported that despite
its superior strength, the gorilla was in constant fear of the more
active chimpanzee, and fled whenever one approached. The best and most
recent observations indicate that the gorilla is not quarrelsome and
aggressive, but disposed to hide away from and avoid men whenever it
can, rather than to attack them. Nevertheless all these great apes are
debased, savage brutes of which nothing good may be said, despite the
fact that when caught young chimpanzees, at least, prove docile and
able to learn some simple imitations of human behavior; but in old age
even they become sullen and dangerous toward trainers who have treated
them with uniform kindness. They are base caricatures of men--side
lines of development that have proved failures in nature's experiments
toward making something out of simian material.
The successful line of human descent began far back of their earliest
specific history, and has developed quite independent of these brutal
offshoots from some parental stem of which we have no definite
knowledge.
* * * * * *
Transcriber's note:
Small capitals have been rendered in full capitals.
oe-ligatures have been converted to oe.
A number of minor spelling errors have been corrected without note.
*** End of this LibraryBlog Digital Book "Zoology: The Science of Animal Life - Popular Science Library, Volume XII (of 16), P. F. Collier & Son Company, 1922" ***
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