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Title: Mammals of Mount McKinley National Park
Author: Murie, Adolph
Language: English
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*** Start of this LibraryBlog Digital Book "Mammals of Mount McKinley National Park" ***
MAMMALS OF MOUNT McKINLEY
NATIONAL PARK
ALASKA
by
Adolph Murie
Sketches by Olaus Murie
Photographs by Charles J. Ott
[Illustration: Mount McKinley Natural History Association]
Published by the
Mount McKinley Natural History Association
[Illustration: NATIONAL PARK SERVICE]
Published in cooperation with the
National Park Service
Copyright August, 1962 by
Mount McKinley Natural History Association
Printed in U.S.A.
Pisani Printing Company, San Francisco
CONTENTS
Denali Wilderness 1
Introduction 3
Grizzly Bear 7
Black Bear 11
Caribou 11
Moose 15
Dall Sheep 17
Mountain goat 20
Wolf 21
Coyote 22
Red fox 24
Lynx 26
Wolverine 27
Marten 29
Mink 30
River Otter 31
Short-tailed weasel 31
Least weasel 33
Snowshoe rabbit 33
Collared Pika 35
Hoary marmot 37
Arctic ground squirrel 39
Red squirrel 40
Northern flying squirrel 43
Porcupine 43
Beaver 47
Muskrat 49
Shrews 50
Bat 52
The Mouse World 52-54
Hay mouse
Brown lemming
Bog lemming
Chestnut-cheeked vole
Tundra vole
Meadow vole
Red-backed mouse
Checklist of Mammals of Mount McKinley National Park 56
[Illustration: Caribou migrating from summer range.]
Denali Wilderness
The national park idea represents a far-reaching cultural achievement,
for here we raise our thoughts above the average, and enter a sphere in
which the intangible values of the human heart and spirit take
precedence. Mingled with the landscape of McKinley Park is the spirit of
the primeval. The region is dedicated to the preservation of wilderness.
Here we try to refrain from the coarser uses of nature legitimate
elsewhere.
All the plants and animals enjoy a natural and normal life without human
restrictions. Freedom prevails—the foxes are free to dig burrows where
they will; to hunt ptarmigan, ground squirrels and mice as the spirit
moves; and they share in the ownership of the blueberry and crowberry
patches. The grizzlies wander over their ancestral home unmolested; dig
roots and ground squirrels, graze grass, and harvest berries according
to whatever menu appeals to them. The “bad” wolf seeks an honest living
as of yore; he is a respected citizen, morally on a par with everyone
else. His hunting of mice, ground squirrels, caribou and Dall sheep is
his way of life and he has the freedom to follow it. No species of plant
is favored above the rest, and they grow together, quietly competing, or
living in adjusted composure. Our task is to perpetuate this freedom and
purity of nature, this ebb and flow of life—first, by insuring ample
park boundaries so that the region is large enough to maintain the
natural relationships, and secondly, to hold man’s intrusions to the
minimum.
Most of us feel with Thoreau that “The wilderness is near as well as
dear to every man.” We come to McKinley to watch; to catch a glimpse of
the primeval. We come close to the tundra flowers, the lichens, and the
animal life. Each of us will take some inspiration home; a touch of the
tundra will enter our lives—and, deep inside, make of us all poets and
kindred spirits.
Our national parks, here in the north, are set aside, not only for
Alaskans, or for Americans, but for all humanity. To preserve the
delicate charm and the wildness of the region our thoughts must be
guided by a morality encompassing the spiritual welfare of the universe.
[Illustration: Tundra in the foreground and on the far side of
Thorofare Bar. Muldrow Glacier shows at the foot of Mount McKinley.]
Introduction
[Illustration: Bear and cub.]
The Mount McKinley region was set aside as a National Park in 1917. The
foresighted conservationists who advocated National Park status for this
country were activated chiefly by their desire to preserve the flora and
fauna in its pristine condition. An effort was made to give the park
ample boundaries, but desirable extensions were later made, and it is
possible that in the future additional adjustments will be desirable
from the standpoint of assuring a self-sustaining ecological unit.
A drive from the Nenana River, the eastern boundary, to Wonder Lake,
some 90 miles to the west and directly north of Mount McKinley, is
always a fresh adventure. No two days are the same. One day we may see
more grizzlies than usual; on another trip we may be especially
fortunate and catch sight of a wolf or a wolverine. It is desirable to
drive slowly and to stop occasionally to examine the landscape for
animal life—the mountains for Dall sheep, the river bars and passes for
grizzlies and caribou, and the water, for birds, beaver, or moose.
Some of the birds to be seen along the way are the ptarmigan—willow
ptarmigan in the low country, rock ptarmigan on the high passes (the
white-tailed are confined to higher elevations and probably will not be
seen)—the long-tailed jaegers, the whimbrel (Hudsonian curlew), golden
plovers, short-billed gulls, golden eagles, and several kinds of ducks.
Ornithologists will be especially interested in seeing such asiatic
birds as the wheatear and the willow warbler.
Much of the park is treeless tundra, but strips of woods follow the
rivers far into the park, and patches grow here and there on the
adjacent mountain slopes. Timberline varies according to soil and
exposure; in places it reaches elevations of over 3,500 feet.
White spruce is the common conifer. Black spruce is confined to poorly
drained and boggy areas. Along the north boundary I have seen a few
patches of tamarack. Cottonwood and aspen are widely distributed and a
few tree birches grow at lower elevations. Along the McKinley River an
extensive strip of cottonwoods may be seen from the highway.
The tundra supports a growth of willow and dwarf birch. Over twenty
kinds of willow occur in the park. They range in size from small forms
only 2 or 3 inches in height, to brushy growths 20 feet tall. In places
the small willows may grow dense enough to form a sod. These shrubs are
highly important for wildlife. Alder brush is widely distributed and
plentiful on canyon slopes; near Wonder Lake there are many clumps of
alder in the rolling tundra.
The low ground cover over the park consists of mosses, lichens, sedges,
grasses, horsetails, and herbaceous plants—many species of each. Early
flowers may begin blooming in late April and early May, and at the
higher elevations some blooms may be seen in late summer.
The annual berry crop is bounteous and is an important source of food
for a host of birds and mammals. Even the mountain sheep have been found
enjoying the blueberries. Blueberry, crowberry, cranberry, buffaloberry,
and alpine bearberry are all widely distributed. The berries begin to
ripen in late July.
With the melting of the snow in the spring, the white landscape of
winter is transformed into a brown countryside—brown grasses, sedges,
and leafless shrubbery. Snow fields still persist on the mountain
slopes, and the spruces are dark green, but brown hues seem to dominate
one’s impression of the tundra at this time. In June—the time varies a
little with the year—the landscape is magically transformed from a dull
brown to the brightest green. Early in August spots of red and yellow
colors begin to show. By late August and early September the country is
again transformed and we have a world of crimson and other shades of
red, trimmed with yellow and gold of willow, aspen, and cottonwood. The
alders add contrast for they remain summer-green throughout the autumn
color season.
Over much of the country the ground remains frozen below a depth of a
few feet. In some shaded areas where the ground is deeply carpeted with
moss the soil remains frozen within less than 2 feet of the surface. The
continuous thawing of the soil in summer keeps the surface moist until
autumn. The thawed surface soil tends in places to creep imperceptibly
down slopes as it becomes water-soaked, even though plant life has a
strong stabilizing influence. Occasionally the soil becomes saturated
with moisture to considerable depths and we have rather large land
slides such as the one that recently formed Slide Lake on Stony Creek;
the one that shows prominently on the south slope of Sable Mountain; and
one to the south of the road at about 3-Mile that caused spruces to lean
in various directions. Thawed, water-logged surface soil rests uneasily
on the frozen sub-stratum.
[Illustration: Typical glacial stream. Grizzlies and caribou may
often be seen in the streambed and Dall sheep on the mountain
slopes.]
A number of parallel, northward-flowing streams head in glaciers lying
along the north slope of the Alaska Range. The streams are not
large—most of them can be waded without getting too wet—so it is
surprising to find them bordered by wide gravel bars. This is due to
lack of stream stabilization. In summer the streams carry a load of silt
which may be dropped along the way. Channels are continually being
gouged out here and filled in somewhere else so that the stream keeps
breaking over its sides and forming additional channels. High water, due
to a warm day and much glacier melting, or to heavy rains, may cause the
streams to flow into entirely new channels. When the main stream reaches
the side of the gravel bar it will erode the bank and thus broaden the
river bar. This type of erosion is noticeable just below the Teklanika
bridge. Gravel bars that have not been invaded for a long period may
become covered with vegetation, and it is on some of these old bars that
we often see grizzlies digging roots in the spring of the year. But even
these bars are temporary. One such bar on the Toklat River was invaded
by part of the river a few years ago and much of the sod is being washed
away today. Physiographic processes are all very active in the region.
On many slopes we see the turf breaking away, and here and there a small
land slip.
[Illustration: Typical ice blister.]
Those who come to the park the early part of the summer may see
extensive fields of ice on the river bars. These are the result of what
is called overflow. During cold weather the ice on the streams freezes
so thick that there is not room for all of the water to pass under the
ice, and since it must run somewhere it develops pressure and breaks out
on the surface where it spreads widely underneath the snow. Here it
freezes. This process continues throughout the winter and often forms
ice patches many feet thick. When one is dog-mushing on rivers the
overflow water under the snow is a hazard before it freezes, and the
driver of a dogteam must watch to avoid such spots. Conditions are worst
during the coldest weather, at a time when a wetting is most serious.
Out in the park there are no trails except for one down Savage Canyon.
The country is so open that trails are not needed. The river bars
furnish excellent hiking, and even walking across the upland tundra is
easy. A number of campgrounds are located along the road between the
Nenana River and Wonder Lake.
This booklet is made available as a quick reference pertaining to the
mammals in the park. The comments on each species are brief but perhaps
sufficient to suggest their status. Distances are deceiving so field
glasses should be used in searching the landscape for the larger animals
such as sheep, caribou, and bears.
Grizzly Bear
_Ursus horribilis_
The grizzly’s domain in the park extends from the glaciers at the heads
of the rivers, northward to the north boundary. The grizzly may be
discovered on an old river bar, on one of the low passes between the
rivers, or traveling high on a mountain slope. One of the favorite
haunts along the road is Sable Pass, where each summer one to four
females with cubs, along with a few lone or mated bears, take residence.
Any bear seen out in the park is almost certain to be a grizzly because
the black bear is confined to the wooded low country along the east and
north boundaries. The hump on the shoulder and the dishfaced profile
(rather than almost straight, as in the black bear) are good field
characters. The general coloration varies from cream color (rare) to
straw color, brown, chocolate, and black. The legs are always blackish.
The fur fades considerably during the spring and summer. Hence, the new
coat, fully developed by autumn, is always darker, and gives the bear a
new, fresh look. One old male grizzly, not very fat, weighed 650 pounds.
The females are considerably smaller. Because of the long claws on the
forepaws, the track of the grizzly can be readily distinguished from
that of the black bear, whose forepaw claws are shorter and more curved.
In the spring when grizzlies first come forth from their dens they seem
to do much wandering over the higher slopes. At this season I have noted
their tracks leading to the remains of sheep, caribou, and moose that
had succumbed during the winter. Usually the wolves, foxes, and
wolverines have long since feasted on the fleshy parts, but the bears
are happy to crush the bones that remain on the premises and thus obtain
a taste of the succulent marrow.
The spring and early-summer food is chiefly the root of the peavine
(_Hedysarum alpinum americanum_) that flourishes on old vegetated river
bars and on many mountain slopes. Using both paws, with their long
claws, and straining backward with his body weight, chunks of sod are
turned over to expose the thick peavine roots. With delicate strokes,
his paws further expose the roots, which taste much like the garden
variety of pea. So extensive is the root-digging at times that an area
may look like a plowed field when the bear has finished. At this season,
because of these food habits, bears can often be seen on the open river
bars and on the ridge slopes. Cranberries and crowberries that have
wintered under the snow are often eaten in spring.
In June, green vegetation becomes available and a drastic change of diet
results. The root digging is terminated for something better. A grass,
(_Arctagrostis latifolia_), with a stiff and juicy stalk, and growing in
swales and wettish areas, is a favorite. The bears also graze
extensively on horsetail (_Equisetum arvense_), mountain-sorrel (_Oxyria
digyna_), and the tall showy white saxifrage (_Boykinia richardsonii_).
A pea (_Oxytropis viscida_), growing abundantly far up the streams on
old river bars is extensively grazed.
The grizzly is quite fastidious in his feeding on dock (_Rumex
fenestratus_). He severs the thick juicy stem with a bite and as he
chews, the large reddish seed head drops from his lips, neatly
discarded.
The grizzlies continue grazing and chomping green grasses and herbs
until berry time when another major change of food habits takes place.
Some grazing still persists but now the bears turn wholeheartedly to
blueberries, crowberries, and the bitter scarlet buffaloberries, the
three species of berries most abundant and available. The lush berry of
alpine bearberry (_Arctous alpinus_), that ground-hugging woody plant
that colors patches of the landscape a brilliant scarlet in autumn, are
sometimes eaten, but not with any efficiency. The berry diet continues
through the autumn but at this season a few roots may again be sought.
The bear belongs to the order _Carnivora_ and yet little mention has
been made of meat in the diet. He is perhaps, so to speak, a victim of
evolution and has had to adjust. As his mature size became ever larger
through eons of time, he became too slow to catch large herbivores such
as the caribou, and his large body required more sustenance than could
be secured by digging for mice and ground squirrels under usual
circumstances. Therefore he had to turn more and more to vegetation
which could be secured in quantity. This is not as drastic a change as
we might offhand suppose. It is one chiefly of degree, because we find
carnivores such as the fox and the marten turning to a berry diet for a
period, from choice.
But it appears that the grizzly would like more meat than is generally
available. This I infer from the quantity he eats when he finds a
carcass and from the avidity with which bears of all kinds seek spawning
fish when available. The only animal that the grizzly consistently hunts
in the park is the ground squirrel, but a squirrel contributes only a
mouthful and its capture usually requires excessive time and energy.
Sometimes a squirrel is surprised and captured before it can disappear
in a burrow. But generally a squirrel is secured only after extensive
excavating which may involve as much as half an hour, and not
infrequently the bear, after much digging, fails to unearth his intended
victim. In years when meadow mice and lemmings are especially abundant,
bears may make their capture a project which contributes at least a
tasty diversion. Caribou and moose calves may occasionally be captured
when very young, but the season for this food is short. Occasionally
tidings come to a bear’s keen nose that carrion lies upwind, and the
lucky bear keeps gorging until only a few bones and patches of hide
remain.
After feeding on a carcass the bear often covers it with sod and
vegetation. One fall at Stony Creek I watched a bear at a cache which
showed up as a dark mound surrounded by a dark circular area from which
the sod had been torn loose. For an hour the bear kept methodically
raking the surrounding area beyond.
[Illustration: Grizzly bears digging for ground squirrels.]
He was scraping the loose vegetation toward the cache, working leisurely
with one paw at a time. The loosened material was pushed toward the
cache as the work progressed. When I examined the area later, I noted a
circular patch, extending out 20 feet from all sides of the carcass,
that had been combed clean of loose vegetation. The bear finally lay
down on the cache to wait for digestion to create more space for this
rich fare.
North of Wonder Lake a grizzly had similarly covered a caribou that a
hunter had left lying in the field. The bear was not at the cache, but
since most of the carcass was still intact, he probably was not far
away. I found some carcasses that were not covered with sod. A mother
and two yearlings at Polychrome Pass left a caribou carcass without
covering it and retired to some steep cliffs overlooking the area. The
following day they rested near the carcass, but still no effort was made
to cover it.
Mating takes place in May, June and early July, and a pair remains
together for two or three weeks. I suspect that a male might look for a
second marriage following the termination of the first. One large
crippled male was successfully consorting with two females at the same
time, neither female objecting to the presence of the other—in fact,
both probably preferred it that way.
The cubs are born in the hibernating den in midwinter, are 8 or 9 inches
long, and weigh less than 2 pounds at birth. The number of cubs in a
litter ordinarily varies from one to three, two being the most frequent.
The cubs not only nurse throughout the first summer but to about the
same extent during their second summer abroad, when they are robust
yearlings. I had been surprised to find yearlings regularly nursing, but
it was a greater surprise to observe mother grizzlies nursing cubs over
2 years old, in their third summer abroad. The protracted nursing period
indicates a breeding interval of females with cubs, of three or more
years, since females followed by nursing yearlings have not been seen
consorting with a male.
The dens used for hibernation are excavated by the grizzly if natural
caves are not available. A den is usually dug on a rather steep slope.
The entrance to one I examined was about 2 feet wide and a little less
than 2½ feet high. A tunnel 6 feet long led to the chamber which was
roughly 4 feet in diameter. Cinquefoil brush and grass had been used for
the bed. This den was still usable six years after it was dug. But
another den dug in October caved in the following summer. It lacked the
firm protective sod roof of the more durable den.
Bears, like humans, enjoy a good back-scratching. Trees along a trail or
on some strategic point are much used, as shown by the rubbing signs and
the adhering hairs. If trees are not available, willow brush, a boulder
or a sod bank may be used. The corner of a log cabin is considered an
excellent surface. A pole lying on the ground is a fair substitute, and
where no structure is available and a bear feels itchy he may lie on the
ground with all four feet in the air, wriggling ludicrously with
excessive energy to do the job.
Generally the grizzlies wander freely over the tundra. But they are not
averse to taking advantage of a convenient trail when they have a
definite destination. Trails that are much used by bears, such as we
sometimes find along the bank of a river or through a woods, show a
series of worn depressions. These depressions are due to the grizzlies’
tendency to step in the same tracks. They no doubt have been formed by
the passage of many bears over a long period. Pieces of such bear trails
may be seen a half mile above Teklanika bridge and a short distance
below the bridge, on the west side of the river bar.
The grizzly has survived in only a few states, more by accident than by
our planning for his future. In Alaska we have a great opportunity for
giving the grizzly and the rest of the fauna ample room for carrying on
their living in a natural, free manner. The grizzly needs extensive
wilderness country for his way of life, and wild country is also vital
for the highest development of human culture. If we provide for the
future of the grizzly, we at the same time provide wilderness for our
own needs.
Black Bear
_Euarctos americanus_
The black bear is widely distributed in Alaska. In the park it is
confined to the forested areas along the north and east boundaries. I
have occasionally seen one near the Nenana River and in the Wonder Lake
area I have seen them 3 or 4 miles north of the park feeding on
blueberries.
Black bears may be black or brown, but those I have seen at McKinley
have all been of the black color phase. The black bear lacks the
pronounced shoulder hump of the grizzly. The tan muzzle is also
distinctive. Equipped with strong, curved claws, the black bear climbs
trees with surprising agility, a talent the grizzly seems to lack.
The food habits of the black bear are similar to those of the grizzly,
but in general they spend more time turning over rocks and tearing apart
logs in search of insect life. They feed on herbs and grass, are fond of
berries, hunt mice and dig out ground squirrels, and are ever on the
alert for carrion. In the Rocky Mountains and on the West Coast, they
occasionally strip the bark from trunks of spruces, pines, and firs in
order to feed on the inner cambium layer. Along the coast of Alaska they
sometimes congregate to feed on spawning salmon.
Where we have bears we have potential bear problems. Roadside feeding of
bears creates beggar bears—always dangerous. Allowing bears to obtain
food in cabins or camps demoralizes them, encourages them in a life of
plunder and general anti-human depredations—the usual outcome is damage
to humans and the death of the bears. A point of view generally
disregarded by all is the effect of garbage on the bears. No garbage
should be made available to bears anywhere for the simple reason that
such artificial food interferes with the natural feeding habits of bears
and their natural distribution, tending to congregate large numbers of
them in a limited area. Administrators and public alike must ever be
heedful of the problem. Clean campsites and proper garbage disposal are
desirable in this regard.
Caribou
_Rangifer arcticus stonei_
The caribou is a circumpolar deer adapted to life in the Arctic. Both
sexes carry antlers and even the calves grow a spike 6 or 8 inches long.
The cow’s antlers are small and branching; those of the old bull are
towering and picturesque, with a well-developed brow tine extending over
the nose from one or both antlers. As you see the caribou in his easy,
swinging trot, you will perhaps notice his big feet. The hoofs, rounded
and spreading, and the dew claws well developed, serve him as snowshoes
in winter, and as a broad support in the soft tundra.
[Illustration: Caribou.]
Each spring the caribou appear in faded, dun coats, their color pattern
gone, the long hair worn and frayed. Winter hardships are behind and the
sprouting, nutritious, vitamin-packed green forage is available—nature’s
restorative. On the hummocks the caribou are already finding the new
growth of sedge hidden by the old, leached, brown blades. As the winter
coat is shed, and the new black pelage shows in patches, the animals
have a moth-eaten look.
In May and early June, the caribou that have wintered along the north
boundary of the park and northward to Lake Minchumina, move into the
park, continue eastward to the Teklanika and Sanctuary rivers, and cross
to the south side of the Alaska Range over the glaciers at the heads of
these rivers. At this time the bands are small, numbering from a few
individuals to one or two hundred. After feeding on the south side of
the range for 2 or 3 weeks, the caribou return en masse, usually in late
June or early July, but in 1960 about the middle of June. Herds
numbering one or two thousand are not unusual, and I have seen an
assemblage of four or five thousand. The herds cross Sable Pass and
travel parallel with the road to Muldrow Glacier. From there they may
strike northward or continue on westward. In August and September at
least a few caribou may be found especially in the Wonder Lake area.
Caribou are inordinately fond of lichens which they eagerly feed upon at
all seasons. In summer they take advantage of the variety of foods
available and feed extensively on grasses, many herbaceous species,
willows, and lichens. Lichens are much sought in fall and winter, and in
these seasons grasses and sedges continue to be major foods.
Caribou are plagued by warble flies and nostril flies throughout the
summer. These beelike insects cause the caribou great annoyance. The
warble fly lays eggs on the hair of the legs and underparts of the body.
The eggs soon hatch, the larvae penetrate the hide, and move to the back
region where they emerge as swollen larvae in the spring. The nostril
flies deposit living larvae in the nostrils. The larvae become lodged
back in the throat in a mass and the following spring are coughed out;
they pupate on the ground, and soon emerge as terrorizing flies. A
caribou may dash away in panic to escape a fly, then stop in a wet sedgy
depression and hold its nose close to the ground. Thus it may stand for
long periods if not attacked. On sunny days when the flies are very
active, the movement of the herds is drastically influenced. The large
herds may seek a high, breezy ridge, or a snowfield, to minimize the
attack. Commonly, one or two thousand on such days assemble in a compact
group on a broad gravel bar where they may stand all day. Should clouds
cover the sun, the herd disperses to feed, but again converges if the
sun reappears.
[Illustration: A caribou bull.]
By midsummer the old hair has been shed and the caribou are in a short
blackish coat that continues to grow. Not until September is this new
pelage fully developed. By then it has become a rich chocolate brown,
trimmed with white. The pattern is most striking in the old bulls. A
silvery cape covers the neck and part of the shoulders and forms a mane
on the throat. A white line extends back along the sides of the body,
and the belly is white. The blunt nose is tipped with white and an oval
white patch surrounds the tail. A white patch shows the location of the
upper gland on the hind legs. White anklets border each shiny black
hoof. The pattern is similar, but much more subdued in the cows and
younger bulls.
The magnificent antlers of the old bulls have hardened by late August.
The velvet covering them during their growth is now rubbed off with a
vigor suggesting the oncoming rut. At first the white antlers are often
stained pinkish by the blood in the velvet. Continued rubbing on the
brush removes the pinkish color and the antlers develop to a rich brown.
The bulls begin to spar soon after rubbing off the velvet. Even before
serious fighting occurs, a bull may show his superiority to some of his
companions. At this time two strange bulls do not hesitate to approach
each other and, with no preliminaries, join antlers and try to drive
each other back. These early fights are brief and on a more or less
friendly basis. A sharp prong may cause a bull to pull away and be
unwilling to resume sparring. But later, when a bull has acquired cows,
up to a dozen or two, he herds them constantly, and fights all
challengers.
The single reddish calf is generally born in May. His strength and speed
develop rapidly so that he is soon able to follow the herds in their
hurried travels. By autumn he has acquired a coat similar to that of the
adults.
A close relationship exists between the caribou and the wolf, one that
has prevailed for thousands of years. Although the wolf largely subsists
on caribou over much of the north, natural adjustments have prevailed so
that caribou have prospered in the presence of wolf populations. Wolves
prey extensively on caribou calves in spring. When a wolf takes after a
herd of caribou containing calves, both old and young hold their own for
a time. But soon a calf may begin to fall behind the racing herd, its
endurance not quite up to that of the others. It is overtaken and
eliminated. Natural selection has operated, a culling operation that
over eons of time would seem to have evolutionary significance.
Grizzly bears capture a few very young calves. Encouraged by their
early-season success they continue chasing calves long after the calves
have gained strength and speed enough to readily escape. After a few
failures, I suspect that a grizzly learns that the calf-catching season
has passed and is no longer tempted to gallop ponderously and
fruitlessly with excess power but not sufficient fleetness to capture
fleeing calves.
Moose
_Alces alces gigas_
The northern conifer forest, stretching across the continent, is the
home of the moose. In Alaska he has reached his greatest size. A mature
bull weighs 12 to 15 hundred pounds, and his huge, palmate antlers have
reached a record spread of about 80 inches.
At a distance the moose appears to be black except for his long,
light-colored stockings. The large head is supported on a short neck, a
shoulder hump is prominent, the nose is loose and bulbous. A special
feature is the bell that hangs from the throat. The legs are
inordinately long and the hoofs sharp.
Moose may be discovered anywhere along the park road. They are
frequently to be seen between Savage and Sanctuary rivers, and along
Igloo Creek. In the Igloo Creek area three or four old bulls may
generally be found spending the summer together, their daily movements
usually covering about a half-mile or less. We speak of the moose as a
forest animal, but it is often found the year round in willow brush
beyond timber. It is not uncommon to see moose in the willows on the
treeless passes such as Sable and Polychrome.
The principal food of the moose is browse. In summer the leaves are
stripped from the branches; at other seasons the twigs are eaten.
Willows and dwarf birch are the chief browse species in the park. Aspens
and cottonwoods are relished but are not plentiful enough to be very
important. Alder is generally eaten only sparingly in winter. Farther
south over the moose’s range, firs and hemlock are highly palatable in
winter. The long legs enable the moose to reach high in his browsing. It
is not unusual to find winter browsing sign 12 feet or more from the
ground where the moose have stood on snow to feed. Tall willow brush and
aspen saplings are often broken over in order to get at the twigs out of
reach. The muzzle may be used for this, or the limb may be grasped in
the mouth and pulled down. Many broken willows are evident on the bars
along Igloo Creek.
The long legs and short neck make grazing difficult. In Wyoming I once
saw a cow and calf feeding on mushrooms, a delicacy. Reaching the ground
was not easy—the calf dropped to his knees, and the cow was for part of
the time down on one knee.
In summer moose may be seen in lakes and ponds feeding on submerged
vegetation. Where the water is deep the moose may disappear below the
surface in his feeding.
[Illustration: Bull moose in a snowstorm.]
[Illustration: Yearling moose.]
Rutting activities begin by the first of September and continue into
October. The antlers of the bulls have reached full size and hardened by
the end of August, at which time the bulls begin to rub off the velvet,
the skin that has covered the growing antlers. Saplings and brush are
thrashed with great vigor, and this activity continues long after the
antlers have been cleaned. Apparently it serves as one of the outlets
for the strong rutting emotions. The bulls soon begin to spar and to
determine who is boss over whom. And they begin to seek the cows. A
successful bull usually has but a single cow, and he follows her closely
as she moves about in her feeding. During the rut he utters at intervals
a deep grunt. The cow, apparently when in an emotional state, utters a
drawn-out wailing call.
The one or two calves are generally born in late May or early June. They
are reddish without spots. The mother must sometimes protect her calf
from prowling grizzlies and this she generally seems fully capable of
doing, judging from incidents in which the bear is chased away by an
infuriated mother. A large male grizzly, however, is apparently not
easily discouraged. By autumn the calves have made a surprising growth
and have a new coat that resembles that of the adults. They remain with
the mother until near the time for a new calf, when she no longer
tolerates their presence.
The moose is a wilderness animal, requiring for his haunts big country.
The picturesque bull, silhouetted on a hill or on a lake shore, adds
repose and serenity to the wilderness.
Dall Sheep
_Ovis dalli_
The Dall or white sheep is one of the outstanding wildlife features of
the park. The north side of the greater part of the Alaska Range is
excellent sheep habitat. Within the park the most extensive sheep
country extends from the Nenana River to the Muldrow glacier, a distance
of about 70 miles by road.
Most of the sheep spend the winter north of the road. This is favorable
winter range because the snowfall is relatively light and strong winds
keep the exposed ridges free of snow.
Many sheep remain on the winter range all year, but more of them migrate
toward the heads of the rivers in May and June. In making the migration,
the sheep must in places cross 2 or 3 miles of low country. They are
fully aware of their vulnerability to grizzlies and wolves in these
crossings. Before venturing away from a safe take-off ridge, they may
scrutinize the low country for a day or two, until they feel that no
danger lurks along the way. A band of 60 or 70 sheep may move across
slowly in a rather compact group; at other times urgency replaces
caution and they frequently break into a hurried gallop. Having reached
the safety of rough country again, the sheep may gambol about as though
the weight of tension has suddenly been lifted. The return migration is
made in August and September.
The large amber-colored horns of the rams with transverse ridges and
sweeping outward curl have a rugged, graceful beauty. They may spread
widely at the tips or curl rather close to the head. The ewes are less
imposing. Their horns are slender spikes that extend upward in a slight
curve, resembling those of the mountain goat but they lack the shiny jet
black color and are not as sharp. The horns are never shed and continue
to grow throughout the sheep’s life span of 11 to 14 years. The growth
is slight during the later years. Growth takes place during the summer
when food is highly nutritious. In winter only a groove or ridge
encircling the horn is formed. By counting these annual rings the age of
a sheep can be determined.
For detecting danger the sheep depend on their sharp eyes. They appear
to disregard scent which for many animals is the final decisive word on
any situation. But this seems quite logical, because the sheep generally
have a strategic view, and in the varying air currents no dependence can
be placed on getting scent messages. Noises are considered rather
unimportant unless the sheep have already caught a glimpse of movement
nearby.
To approach sheep for photography it is usually best to move slowly
toward them from below with no attempt to hide. They at once become
suspicious if they glimpse someone stalking. However, I have at times
stalked sheep where the opportunity for undetected close observation was
obvious. On one occasion, from a ragged rocky ridge top, I spent most of
an afternoon watching a band of rams some 50 yards away without being
discovered. Some bands are wilder than others and the same band does not
always behave uniformly. A band that has rested and is ready to move may
take your approach as an excuse for a romp.
The food of sheep consists of grasses, herbaceous species and browse,
chiefly willow. Scattered over the range are a number of salt licks
which the sheep seek for minerals.
The most active mating period extends from about the middle of November
to the middle of December. The rams who have been fraternizing on
friendly terms for many months, now and then showing mating behavior
such as gentle joustings, begin to take greater notice of the ewes. The
old rams continue to associate, but now serious battling takes place.
The fighting follows rather uniform conventional rules. The two matched
battlers move apart several yards, then, as though by a signal, they
turn and face each other and at the same time rise up on their hind
legs, then charge full speed at each other, their horns crashing
together with a loud thud. If the joust is even, they may repeat the
performance until the superiority of one of the combatants is evident.
But there is some tolerance among the rams, for two or more may breed
with ewes in a band indiscriminately.
The numbers of sheep on a range under natural conditions may vary
considerably. In the park, a very high population, possibly as high as
5,000 or more, suffered severe losses during 1929 and again in 1932, due
to extremely deep snow conditions, and an icy crust in the latter year.
In 1945 the population was down to about 500. Since 1945 there has been
a steady increase. The numbers in 1959 were up to about 2,000.
[Illustration: Dall sheep; rams on the Alaska Range in summer.]
Sheep are subject to wolf predation, especially when the numbers are so
high that part of the population must graze on hills too gentle for
safety. Sheep legs are strong and sturdy but for their effective
functioning steep country is needed. The steep terrain is, so to speak,
part of their legs. In my studies in the park, the losses showed that it
was the very old, the ailing, and the lambs in their first winter that
were most vulnerable to predation. The lynx (when rabbit numbers have
crashed and these animals have become scarce), wolverine, and grizzly
may capture an occasional sheep but their effect is unimportant. The
golden eagle may capture an occasional young lamb, but all my
observations and food-habit studies indicate that any eagle predation
that takes place is insignificant. If the park is large enough to
support the sheep and their predators (natural conditions), we have a
situation ideal for the future of the sheep.
Mountain sheep have a high esthetic appeal. In part this may be due to
their setting, for we associate them with their beautiful haunts, the
precipitous cliffs and ledges intermingled with green slopes spangled
with flowers. This is idyllic country in which to hike and climb. Here
we encounter the golden eagle who shares the ridge tops with the sheep;
the wheatear, who comes all the way from Asia to nest; the gray-crowned
rosy finches; the flashing black and white snowbirds nesting in rock
crevices; and the surfbird that has left the ocean beaches to nest in
these remote mountains. And up high, the saxifrages, delicate yellow
poppies, forget-me-nots and spring beauties add color to it all.
Mountain Goat
_Oreamnos kennedyi_
On May 27, 1955, a goat was discovered on Igloo Mountain on the slope
directly above the cabin I was occupying. It remained on the mountain
for 3 weeks before wandering away. It has not been seen since. This is
the only verified record for the park. But two road men reported seeing
a goat cross the road at Mile 3, on August 8, 1950. I believe this to be
a good record because both men are reliable observers. In the fall of
1950 a goat was shot at Cantwell, not far from the park boundary.
The nearest known goat range is about 60 miles from the park in the
Talkeetna Mountains. The goats that reached the park may have been
sporadic wanderers for it is not unusual for goats to occasionally
wander 25 or 30 miles from their known ranges. On the other hand, it is
possible that the goats are expanding their range toward the park. In
1959, I was told that a band of a dozen goats had been reported at the
head of Jack River where they had not been reported before. Jack River
lies between the goat range and the park.
Identification is not difficult. The goat’s horns are short, slightly
curved spikes, similar to the horns of the female sheep, but shiny black
and smooth rather than grayish and rugose. The goat’s chin whiskers are
identifying, as is the shoulder hump, and the knee length pantaloons of
long hair. Also the goat’s face is noticeably longer than that of sheep.
The goat sexes are similar.
It is not unlikely that goats will continue to be occasionally seen in
the park. Any lone “sheep” might turn out to be a goat.
[Illustration: Alaska wolf.
_From a color sketch by William J. Berry._]
Wolf
_Canis lupus pambasileus_
Wolves vary considerably in size and color. The average male weighs
about 100 pounds and the female somewhat less, about 85 pounds. Their
color may be almost white, black, gray, or brown. Most wolves in
interior Alaska are either black or brownish like a coyote. The facial
markings show some variation and there may occasionally be noticeable
patterns over the rest of the body. A few wolves have a blackish saddle;
one that I knew had a black robber-mask across the eyes. Individual
disposition and behavior also varies. A handsome male had an extra touch
of spirit in his gallop; a male parent had a dour expression and seemed,
to my imagination, weighted with care. Wolves raised in captivity from
puppyhood are extremely friendly.
For a den, the wolf considers an enlarged fox burrow both convenient and
suitable. Dens have been found in a variety of situations. One was
located on a wooded rock bluff, another was beyond timber near the top
of a bluff bordering a river, and one was on a wooded island between old
river channels. The four to six young, probably the average size of
litter, are born the early part of May. The mother remains at home with
the pups and the male provides the victuals.
At one den that I observed closely there were two extra males and an
extra female with the pair. These wolves all fraternized in the most
friendly manner. Before departing for the night hunt, the five would
sometimes assemble in a close group, wag tails and frisk about, and
sitting on haunches sing in chorus. Later in the season this group of
five adults was joined by two additional males.
The following year the same pair returned to the den. They were
accompanied by one of the extra males that had been at the den the
previous year. The extra female and one of the bachelors set up their
own housekeeping farther down the river. But when their pups were large
enough to travel, they all came up the river and joined the original
pair. Young and old combined added up to 15 wolves. This wolf pack was
composed of two pairs, an extra adult, and 10 pups. Some of the extra
wolves of the previous year were not seen—they may have been trapped or
poisoned beyond the park boundaries during the winter months.
The wolf’s food varies with the seasons and the prey species available.
When voles and lemmings are plentiful, the wolves may spend hours in the
grass and sedge areas pouncing on them. During the summer months the
ground squirrel has at times been one of the more important food items.
Occasionally an unfortunate marmot is surprised and in years when
rabbits are plentiful, the snowshoe rabbit becomes a food source. I have
found remains of several porcupines eaten by wolves, the spine-covered
hide neatly inverted.
But the wolf also, and primarily, feeds on the ungulates—the mountain
sheep, caribou, and moose. Under natural conditions the relationship
between the wolf and these prey species is old and tried. There is the
aphorism, “nothing in nature offends nature.” In the hunting of these
animals the wolf appears to be an evolutionary force in that there is a
tendency for the weaker individuals to succumb.
In spring the wolf hunts the caribou calves, which early develop
surprising speed, so that when a wolf chases a group of caribou, the
calves race along with the adults. But after a time a weak calf, one not
up to the others in endurance, may begin to drop behind, and it is this
weak individual that is overtaken, an example of the elimination of the
weak, the survival of the fittest. In the winter hunting, the old and
weak animals are the most susceptible. It is a struggle, a testing for
all, but through the ages, the sheep, moose, and caribou have survived
and come down to us adapted to their particular way of life, with the
wolf as one of the environmental factors.
At McKinley we have an opportunity to preserve a northern flora and
fauna. But the future of the wolf is precarious because the home range
of the park wolves extends beyond park boundaries into territory where
the wolf has no protection, where there is a bounty on his head. The
silencing of the longdrawn call of the wolf would be a tragic loss to
the human spirit.
Coyote
_Canis latrans incolatus_
So far as known, the coyote has always been rare out in the park. Along
the Nenana River, however, I frequently have heard his song. Here he
seems to find conditions more favorable for his way of life. Perhaps it
is the presence of the snowshoe rabbit in this low brushy country that
attracts him.
[Illustration: Coyote.]
[Illustration: Red fox.]
The coyote weights about 25 pounds on the average. His color is brownish
with black-tipped hairs intermingled. Color variation in coyotes is so
slight it is not noticeable in the field; he does not have the black,
whitish and various color patterns that are present in the wolf. The
muzzle is long and pointed, ears well developed, eyes sharp.
As a field biologist I have had an opportunity to observe coyotes in
many regions. In Yellowstone I made a 2-year study of its relationships
with other animals because it had been feared by some that he would
destroy the antelope, bighorn, and deer, if not controlled. The study
showed that the coyote there lived chiefly on meadow mice and pocket
gophers in summer, and carrion in winter, and that he had no harmful
effect on the large ungulates.
On the San Carlos Indian Reservation in Arizona the coyote was blamed
for cattle losses. Here a study showed that the basic cause of losses
was over-use of the range and that where grazing was good all losses
were insignificant. Cattlemen are finding this true and are beginning to
appreciate the usefulness of the coyote as a curbing influence on rodent
depredations. In addition to a meat diet, which includes great
quantities of grasshoppers in season, the coyote feeds extensively on
fruit. On Isle Royale, in Lake Superior, I found it feeding on
sarsaparilla berries; in Jackson Hole, Wyoming, on silverberry and
quantities of haw; in Arizona, on manzanita and juniper berries, the
latter being the winter staff of life.
The coyote is best known for his song, which in all its variations,
symbolizes the spirit of wildness and remote country. J. Frank Dobie in
his _The Voice of the Coyote_ expresses the sentiment of many when he
writes: “I confess to a sympathy for the coyote that has grown until it
lives in the deepest part of my nature.”
Red Fox
_Vulpes fulva alascensis_
The fabled red fox is abundant, widely distributed over the park and
frequently seen. Silver, cross, and red color phases, along with some
intermediate variants, are well represented, and two or three of these
types frequently show up in a single litter. The prominent white tip on
the tail distinguishes the fox from the coyote and wolf.
Hundreds of dens are scattered over the countryside, many more than are
used in any one season. They are located indiscriminately in spruce
woods and out on the open tundra miles from the nearest tree. Each pair
has a selection of old dens to choose from, but often they occupy
favorite sites year after year. During a season, a family sometimes
moves from their first choice to a den nearby. The connecting burrows of
a den usually have 5 or 6 entrances and one I examined had 19.
The young are born the early part of May. By June the blackish,
blue-eyed, chubby pups may be seen walking about clumsily. At this age
they are nursed in the open. One mother that I often watched almost
always nursed her five pups from a standing position. Only twice did I
see her lying on her side to nurse. As the pups grow they become slimmer
and the eyes turn brown and the coat color changes so that the different
color types can be identified. Although nursing seems to cease toward
the end of June, the cubs remain at the den into September.
While the male travels far to hunt, the vixen remains at home to watch
over the pups. Most of the time she is curled up at the den or perhaps a
hundred yards away on a prominence. When she wishes to nurse the pups or
give them food, she puts her head in the mouth of a burrow and calls
softly “mmmmm,” “mmmmm.” If they do not come forth, she may go to
another entrance and call. But usually they respond at once. A sharp,
guttural “klung” has the opposite meaning; when the pups hear this
warning they scurry into a burrow. This command is often given after the
pups have nursed and the mother wants to go off a short distance to lie
down.
The female exhibits extreme friendliness toward her mate. When he
returns to the den after an absence she greets him with tail-wagging,
face-licking and much wriggling of her body. He is less demonstrative
and acts tired, which he probably is after several hours of hunting. She
picks up his offerings—usually mice or ground squirrels—eats her fill
or, if not hungry, carries the booty to the burrows and calls to the
young. He moves off to one side to rest. She sometimes watches for his
return from various points. One evening a vixen impatiently moved from
one lookout to another for over 2 hours before the male arrived and
received her warm welcome.
Mice and lemmings are the staple all-year food, but in summer the ground
squirrel may make up about half the diet. When snowshoe hares and
ptarmigan are plentiful, they become prominent in the diet. Carrion is
especially attractive in winter, and the fox attends carcasses and curls
up on the snow to wait until the wolves and wolverine have eaten. He
robs wolf and wolverine caches, and he sometimes has his own caches
robbed.
In the latter part of July the foxes go berrying, for they are fond of
fruit. Blueberries and crowberries are everywhere available for the
picking. The berries are also eaten in winter sometimes, it is said,
quite extensively when mice are scarce.
Foxes appear to be well able to take care of themselves. They can outrun
the grizzly, wolf, and wolverine. When the golden eagle swoops at him he
stands on watch with his bushy tail erect and straight as a ramrod. The
eagle dares not strike.
Lynx
_Lynx canadensis_
The lynx manner is one of independence, confidence and complacency. He
walks through the woods with dignity, looking neither right nor left. Of
course, he is not as oblivious as he appears to be. He may even stop to
watch you, but only briefly, and then he continues sedately on his way.
His long legs are thicker than seem necessary to support the lean body,
but they are no doubt valuable for long jumps and pouncing. The large,
widespreading feet serve him well as snowshoes, and strong, curved claws
enable him to scramble readily up a tree. The eyes are startlingly big
and yellow and the throat ruff gives to the face a squarish look. Long,
glistening black tassels adorn the ears. The stub tail, about 4 inches
long and tipped with black, serves to register emotions. The winter fur
is soft and grayish, with few markings except for the facial pattern;
the summer coat is more tawny.
Nature has bestowed on the lynx a snowshoe fixation so that he spends
his nights and days thinking and dreaming of rabbit dinners. So
dependent has he become on the rabbit for his main course that his
numbers flourish and wane in the wake of rabbit statistics.
During the period between 1954 and 1956, when lynx were abundant in the
park, I made a study of their food habits by analyzing several hundred
lynx scats. In addition to rabbits, the lynx had fed considerably on
ptarmigan and in summer on ground squirrels. This part of the diet
increased as the rabbits decreased. But with the decline of the rabbits,
the supplemental foods did not suffice to maintain the population, and
the lynx became scarce.
[Illustration: Lynx.]
In the winter of 1907-08, Charles Sheldon noted two instances of lynx
preying on sheep. The rabbit population had crashed and the lynx had
turned to other sources for survival. One lynx that made its attack on a
sheep from ambush found the prey rather large, for in the ensuing
struggle he received some severe bruises. He apparently was driven to
hunting animals out of his class. About 2 years after rabbits
disappeared in the Kuskokwim River region a number of years ago, lynx
did some preying on reindeer in winter by leaping on their backs and
biting the neck. The lynx were said to have attacked the reindeer only
that one winter. During periods of food scarcity, lynx have also been
observed to prey on each other.
The young are born in May in a cave, or perhaps more often, under a
windfall. The gestation period is about 60 days.
In early June, 1955, I saw a lynx in the spruce woods near Savage River.
As I stood watching I heard crying sounds up in the woods. The lynx
disappeared in the direction of the crying. I followed and saw the
parent under a windfall as it was departing with a baby in its mouth,
the last of a litter it was moving. Snow and rain had fallen and the
mother was carrying her family, one by one, from under an inadequate
windfall to another about 250 yards away. The new home was under a
brushy spruce that provided a dry shelter in any kind of weather. So
well hidden and secure did the mother feel that she barely opened her
sleepy eyes even when approached within 20 feet.
How empty the woods and willow patches become with the decline of the
rabbits and the departure of the lynx. It is like an empty stage after
the actors have finished their play and departed. Scattered through the
quiet woods are their signs of life and activity, but the action has
stopped. On the tall willows, 6 feet from the ground, is the gnawed
white rabbit-line, where rabbits had sat on the snow and gnawed the bark
within reach. In places the ground is littered with severed twigs, many
of them partially gnawed. And everywhere one encounters tufts of rabbit
fur and hind legs, left on the green moss, signifying rabbit tragedies
and lynx banquets. But the rabbits will return again to dance in the
moonlight, and the lynx will be back in his rich domain walking with
stately and regal step.
Wolverine
_Gulo hylaeus_
The fabulous wolverine is a powerful and picturesque member of the
weasel tribe weighing up to 35 pounds or more. Because of his stocky
build and long hair, he resembles a small bear. Frequently the large
hoary marmot is mistaken for him—there is considerable similarity. But
the broad yellowish-tan stripe on the sides of the body is distinctive.
A whitish collar, not always visible, extends across the throat. The
tail is short and bushy; the sharp, well-developed claws are whitish.
His range is circumpolar and extends southward in the mountains to
Colorado and California, but he is now scarce south of Canada.
The wolverine in late years seems to have become more plentiful in the
park; nevertheless, it is always considered something special to see
one. They range from river bottom to ridge top, are found in the woods
or in open country miles beyond timber. Perhaps because of the open
view, he is frequently seen on the low passes, especially on Sable Pass.
In winter the track of the far-wandering wolverine is frequently seen.
In his usual gait he bounces along with back arched. Each jump usually
leaves a set of three imprints; the one in front is made by a hind foot;
the middle imprint is made by a hind foot falling in the track of a
front foot; the rear imprint is made by the other front foot. As in the
tracks of a hopping rabbit, the hind feet tend to be brought up ahead of
the front feet.
The wolverine readily climbs trees. One winter, near a moose carcass,
tracks in the snow showed that a wolf had chased a wolverine up a tree
on two or three occasions. If the two had met in the open the
threatening posture of the wolverine would, no doubt, be sufficient to
discourage attack. When attacked by a dog, a wolverine has been seen to
lie on its back in a defensive attitude, a position that was effective.
Powerful ripping claws and jaws face the attack.
Not much quantitative information has been gathered on his food habits.
I have watched him pouncing on mice and suspect that mice (voles) and
lemmings are the most important items in his diet. In summer he captures
ground squirrels, sometimes by doing some digging. Once I noted that he
had dug out a wasp nest hidden in the ground. The calves of caribou and
moose, when very young, are no doubt potential victims. But observations
indicate that even a caribou can ward off an attack on the young calves.
Such items would, of course, be unimportant in the wolverine’s total
economy. His wide wanderings in winter would seem to be helpful in
finding carrion. In rich wild country, considerable carrion probably
comes his way. I have found the wolverine attending a frozen moose
carcass for a number of days. When a carcass is not frozen, he carries
away what he can to cache for later use.
The gestation period is said to be about 9 months. The breeding
apparently takes place in summer. The fertilized eggs, after brief
development, lie unattached and dormant in the uterus for several
months. Some time in midwinter the eggs become attached to the wall of
the uterus and the more usual development takes place. (The marten and
short-tailed weasel have a similar breeding history.) Females have been
found in a nursing condition in early April. Along Igloo Creek, Mr. and
Mrs. Edwin C. Park watched a mother nurse two young at least two-thirds
grown.
[Illustration: Wolverine.]
According to Peter Krott, in his fascinating book about the wolverine in
Europe, this fierce animal makes a friendly pet. The author, in the
beginning, made a business of acquiring young wolverines for sale to
zoos. Because the animal was rare and intriguing, the demand was great
and the prices remunerative. But Mr. Krott and his wife became fond of
the wolverines and found it ever harder to dispose of them. Soon they
ceased selling them, and, instead, kept them as pets and allowed them to
roam freely over wild country. Studies were made of their habits. Their
wolverines might wander far and stay away for several days, but they
would return at intervals.
The wolverine is at home in the McKinley wilderness. Here we have the
rare opportunity of seeing him in his natural environment.
Marten
_Martes americana actuosa_
The marten is long and lithe, and its graceful activity is conspicuous.
The usual color is a rich brown, shading to blackish on the feet and
tail. The face is grayish with a short, dark line extending upward from
the inner corner of each eye. A large orange throat and breast patch is
very striking in most individuals. The fur is soft and long, the tail is
long and well-furred, and serves to register various emotions. The
marten is alert to sounds and this is indicated by its well-developed,
broad ears.
The body is 16 to 17 inches long, and the tail, including hair at tips,
8 or 9 inches. A large male may weigh up to 2½ pounds. The female is
somewhat smaller than the male.
The marten is found in the forested parts of the park along the northern
and eastern boundary. In winter, I have noted a few tracks in the big
spruce woods south of Wonder Lake. In Wyoming, I have found martens in
rock slides beyond timber, the rock crevasses furnishing the desired
protection.
[Illustration: Marten.]
At one time the marten was thought to depend on the red squirrel for his
daily fare, but recent studies indicate that ordinarily relatively few
red squirrels are eaten. A food-habits study made at Castle Rocks near
the northwest corner of the park showed that the martens there were
living primarily on meadow voles and the red-backed mouse. Blueberries
were eaten in winter as well as in summer. In Wyoming, I have found
martens feeding extensively on blueberry, rhamnus, haw, and mountain
ashberries by choice at a time when voles and other foods were
plentiful. Like the fox and coyote, they have a strong predilection for
berries. In slide rock, they manage to capture an occasional pika.
The marten breeds in July and August, but the young are not born until 9
months later. The long gestation period for such a small animal is due
to the delayed attachment of the fertilized egg to the uterus. Except
for the period when the female is followed by young, and during the
breeding period, martens travel alone.
In Grand Teton Park, Wyoming, where I had much opportunity to observe
martens, I found that, although they seldom captured a red squirrel, in
their vagabond life over their home area, they did use red squirrel
homes for sleeping. The marten might spend a few days resting in a
squirrel’s spare nest, then move on to another squirrel domicile for a
few days. The squirrels suffered only the inconvenience of an unwanted
guest, and perhaps the temporary loss of a favorite bed.
Mink
_Mustela vison ingens_
The mink is the amphibious member of the weasel family. He lives along
rivers and lakes and probably forages more in the water than on land.
Fish, frogs, insects, snails, crayfish, rabbits, muskrats, and mice all
appear on his bill of fare. In the country between the mouth of the
Yukon and the Kuskokwim River, the mink is said to subsist largely on
Alaska blackfish (_Dallia pectoralis_). So abundant were the mink in the
area that the Eskimo were called “mink people.” The muddy waters in this
watery region apparently supported enough blackfish for both the mink
and the natives. This fish is said to have been the chief food of the
natives. It is very tenacious of life. Kegs of live fish, packed
densely, were kept for food in the dwellings. A steady slow rotary
movement of the mass of fish brought each fish to the surface at
intervals for a gulp of air. When a frozen blackfish is thawed, it is
said to become as lively as ever.
Mink tracks have been noted along the Nenana River, but over most of the
eastern half of the park the mink is rare.
River Otter
_Lutra canadensis yukonensis_
The otter is rare in the park. It was reported present in Wonder Lake
some years ago and tracks in the snow were reported at Savage River. It
probably occurs in the Nenana River, along the eastern park boundary.
The otter, a member of the weasel family, has become adapted to life in
the water. His body is about 3 feet long, and his long muscular tail is
over a foot long. His cousin, the sea otter, plentiful in the Aleutian
Islands, is much larger and more specialized for an aquatic life.
I have watched a family of otters in Grand Teton Park fishing for an
hour or longer. They kept diving steadily, and occasionally one would
come up with a small fish which he would proceed to eat, beginning at
the head. Larger fish are taken ashore. Trout, chubs, and suckers were
available but numerous droppings showed that the otter were feeding
chiefly on the chubs and suckers. The fish taken were no doubt those
most easily captured. A few crayfish were also eaten. This particular
family was living in a large beaver house also occupied by beavers. They
entered their chamber by land and apparently lived upstairs above the
beaver’s part of the house with its underwater entrance.
In winter the otter frequently travels over the snow from one piece of
water to another. In these travels he slides on his belly down all
slopes and sometimes even on the level. In play, a family may repeatedly
climb a mudbank or a snowbank to course down a slide leading into water.
Short-Tailed Weasel
_Mustela erminea arctica_
Two species of weasel occur in the park. The larger one with a
black-tipped tail is called the short-tailed weasel, and the smaller one
with an extremely short and all-white tail is the least weasel.
Both weasels are brown in summer and white in winter, a protective
coloration no doubt useful in escaping detection. In some southern parts
of their ranges these weasels remain brown all year, and in intermediate
areas part of the population turns white in winter and part of it
remains brown. It is apparent that climate has an effect on coat color,
the specific factor being the presence or absence of snow on the ground.
It has been pointed out that the short-tailed weasel is much larger in
the north than in the southern part of the range. In Wyoming and
Colorado, where the tiny least weasel is absent, the short-tailed weasel
approaches the least weasel in size and probably fills that weasel’s
niche in the environment.
The food of the short-tailed weasel probably consists chiefly of various
species of meadow mice and lemmings. Observations indicate that ground
squirrels and rabbits may occasionally be captured. Shrews no doubt are
also on the menu.
In winter, weasel tracks form an odd pattern. Their jumps are
alternately long and short, and often they make an erratic trail.
Frequently the tracks show that the weasel disappears and travels
beneath the surface for a stretch before reappearing.
Even though weasels are not very palatable because of their
well-developed musk glands, they nevertheless are often preyed upon. It
is a case of coyote or fox capturing any small animal that moves and
examining the victim afterwards. Weasels are often left uneaten.
[Illustration: Short-tailed weasel.]
Least Weasel
_Mustela rixosa eskimo_
The range of the least weasel is circumpolar. In North America it is
found over most of Alaska and Canada, and southward to Montana, Kansas,
North Carolina. It is widely dispersed but apparently nowhere abundant.
This tiny weasel is only 6 to 6½ inches long with a maximum tail length
of 1½ inches. It is the smallest living member of the carnivores and
weighs no more than a meadow mouse. The tail is pure white, lacking the
black tip present in other weasels.
I have a record of four specimens from the park. One captured in a
mousetrap was 5½ inches long, the tail measuring less than 1 inch. I
found a dead one at an eagle perch on a ridge top, and remains of two
others on gravel bars, apparently discarded after being captured.
A sourdough on the Koyokuk River with whom my brother and I stayed one
night, had a least weasel spending the winter with him. It had the run
of the cabin and was very tame.
Apparently the chief food of the least weasel is mice, some of them
about as large as himself.
Snowshoe Rabbit
_Lepus americanus macfarlani_
Like the ptarmigan and the northern weasel, the snowshoe rabbit, or
varying hare, each autumn changes from a dominantly brown summer coat to
a white winter ensemble. (In Washington where snow is scarce in its
habitat, the snowshoe rabbit remains brown the year round.) His coat
color blends at all seasons with his background, so all he need do to be
fairly sure of escaping visual detection is to have confidence in his
camouflage and sit motionless. The fur is so long, thick, and warm that
he can sit all day in fifty below zero weather without freezing. His
large hind legs are equipped with snowshoe feet, an obvious advantage in
snow country.
The most favorable rabbit habitat is the brushy country along the east
and north boundaries. Here a few may always be found. Out in the park
they are quite scarce except in those years when the population is at or
near a peak.
In winter, the rabbits feed on bark gnawed from various shrubs and
saplings. Willow, dwarf birch and alder, because of their high
palatability and abundance, are especially important winter foods. In
years of rabbit abundance, I have seen patches of willow and dwarf birch
trimmed to the snow line. At such times large willow brush may show a
white band 2 feet wide where the rabbits have gnawed the bark within
reach of the snow line. As the snow deepens, some foods are buried but
the change of level brings new food supplies within reach. A variety of
other shrubs are also eaten at this season. Spruce bark is relished.
Porcupines, and also red squirrels, feeding in a spruce tree
inadvertently add to the rabbit menu many dropped spruce twigs. In
summer, the rabbits turn to a variety of fresh green foods.
The young of the snowshoe rabbit are furred and active when born and
apparently there is no real nest provided. (In the cottontail branch of
the family the young are born hairless, helpless and in a warm nest.)
The litters may vary from one to six. The gestation period is about 36
days. The young are weaned (in captivity) when about 4 weeks old. The
females breed again soon after a litter is born. It seems likely that a
female may have as many as three or four litters during a summer. A male
is apparently with a female for only a short time.
A number of animals are subject to cycles of extreme abundance and
scarcity. The pendulum swings from one extreme to the other. A
population, in spite of enemies of all kinds, increases until the
numbers become so large that they threaten the food supply or, because
of congestion, are drastically reduced by diseases. The length of cycle
in a species depends upon annual losses and the rate of increase. Cycles
are relatively short in voles and lemmings which breed at an early age
(a few weeks), breed often, and have large litters. In these small
rodents the cycle may cover a span of about 4 years. In larger species,
the cycles are longer.
The snowshoe hare is one of the more obvious examples of a cyclic
species. From acute scarcity the population in about 10 years pyramids
until the country is full of rabbits. The woods are alive with a variety
of activity. Enterprise, lovemaking, and tragedy are at their peak. Not
only have the rabbits multiplied, but their enemies have flourished, and
the lynx, fox, wolverine and birds of prey have all prospered, and
certain enemies such as the lynx, become especially abundant.
During the high rabbit population peak, between 1953 and 1955, a few
dead rabbits began to appear in the summer of 1954. In early August a
group of tourists on a short walk noted three dead rabbits in the hotel
area. But the rabbits were still numerous in the spring of 1955 and I
anticipated the woods alive with young rabbits the following months.
Instead, they decreased. By July, along Igloo Creek, they had become
scarce. The so-called rabbit crash had taken place.
Nature steps into all situations, and one control or another
automatically appears. Food shortage, disease, predation or competition
enter the picture. Adjusting is a continuous process. Many people are
talking and writing about the human population explosion in our midst,
fearing that space for ourselves and nature is disappearing alarmingly.
Perhaps we should consider the snowshoe rabbit.
[Illustration: Snowshoe rabbit, or varying hare.]
Collared Pika
_Ochotona collaris_
The pika, cony, or rock rabbit, as he is variously called, makes his
home in rock slides. His way of life, and his physical attributes, are
such, that he would have difficulty surviving away from the labyrinth of
passages in his slide rock home.
The pika is in the same order (different family) as hares and rabbits.
Like rabbits, they have two pairs of upper incisors; back of the grooved
anterior incisors is a pair of very small incisors. The feet are furred;
the ears are not long but are rounded and prominent. Something has
happened to the external tail for there is none. The tail vertebrae lie
under the body skin. The plump body is about 6 or 7 inches long as the
cony sits on a rock; the color is gray.
[Illustration: Collared pika (cony, rock rabbit)]
The call is a single nasal “yank,” usually uttered while perched on a
rock where he can look around. He may be difficult to locate, but a
movement as he disappears in a crevice and reappears on the same rock or
one nearby will reveal him. Usually other calls from various parts of
the rock field will indicate the location of other pikas.
The pika is known for his hay making in preparation for the long winter.
During much of the summer he is busy carrying grass, herbs, and twigs to
his many caches located in cavities protected from the weather. The
vegetation is usually added slowly enough to the various caches so that
it all cures properly. Only occasionally is a cache moldy. I have noted
a few caches composed of the broad, heavy coltsfoot leaves that had
failed to dry properly; possibly these slow-drying leaves were harvested
in wet weather. Nearly all plants within range of his rocky habitat are
used. Willow, rose, grass, sedge, horsetail, various saxifrages,
fireweed, coltsfoot, fruiticose and even crustose lichens are some of
the many plants that have been found in the caches. Some books say that
the hay is spread over rocks to dry and then stored. The pika’s
technique is superior to such quick drying, and results in more
nutritious and greener hay.
The sheep, moose and caribou often seek mineral licks consisting of clay
which can be readily eaten. Ground squirrels and marmot feed on pebbles
or fine dust in their craving for minerals. On one occasion I watched a
pika gnawing a rock. A niche showed that a considerable amount of it had
been eaten. I carried the rock away as a sample of rock-eating but later
thought better of it and returned it to the pika. Perhaps in the future
I may be able to check the rock again.
Along the road, the first good place to look for pikas is in the jumble
of rocks above the Savage River bridge, an accumulation that has fallen
away from a rocky point, part of which is still in place. On Polychrome
Pass are several rock fields where many pikas are living. Another pika
place along the road is a mile or two beyond Camp Eilson. A pretty
picture is a pika carrying a bouquet of flowers, neatly arranged, as
though he were going a-courting.
Hoary Marmot
_Marmota caligata_
[Illustration: Hoary marmot mother and young.]
The hoary marmot is an amplified version of the eastern woodchuck. It is
roughly bicolor, being gray over the shoulder region and light brown
over the hips. The black patch across the nose enhances its facial
aspect somewhat, and the jet-black feet add a little contrast to its
appearance. He has a bushy tail that he jerks about a good deal,
especially when he travels. Occasionally, he is mistaken for a
wolverine. His soft color pattern is an excellent example of camouflage
and of this he apparently is aware as he flattens himself on a rock to
escape detection.
His voice is exceptional. One day, some years ago, I walked down Savage
Canyon with two companions. One of them, who stopped to photograph some
flowers, was left far behind. When he finally overtook us he said that
he had heard us whistling and had hurried as best he could. We said we
had not whistled, but he was still sure he had heard us. Then it dawned
on me that he had been hearing the loud piercing, prolonged warning
whistles of the marmots that make their homes in the canyon. This
whistle is one of the familiar sounds in marmot country. The approach of
a fox, grizzly bear or golden eagle is announced by loud whistling which
alerts everyone, including ground squirrels and mountain sheep, to be on
their guard.
One day three of us watched a youngish marmot high on a sheep ridge. He
was apprehensive and for a time whistled at intervals. When one of my
companions whistled in the same key, the marmot answered. But if the
imitation were off key there was no reply. The marmot responded as long
as our patience held. This instance may have been exceptional for I have
had no opportunity as yet to make additional observations.
The marmot has learned to seek a home in a rock fortress as a safeguard
against being excavated by a grizzly. Whenever possible the dens are dug
in rocky areas, or at rock outcrops. One den on a steep slope that I
observed for several years was enlarged and renovated each year. The
small rocks encountered in the digging were carried out in the mouth and
dropped on the edge of the mound. In late summer, mouthfuls of dry grass
are carried in for the winter hibernating nest. One look at the broad,
fat marmot suggests that he could sleep a long time without food. When
he retires, he may plug the entrance with rocks and mud.
The home life of the marmots has not been carefully studied but they
seem to live in colonies, all using a number of dens distributed as much
as 200 yards or more apart. I have seen several adults in a colony and
watched them move from one den to another. In traveling between some of
the dens the marmots are highly vulnerable if surprised by one of their
enemies. The attractive black-eyed young require two or more years to
gain the dimensions and weight of their elders.
Two excellent places to find marmots along the highway are the jumbled
boulders on the east end of the Savage River bridge and in Polychrome
Pass, especially on a gray, lichen-covered rock below the road and the
rocky ridge across the ravine from it. If not active, the marmots may
generally be seen flattened out on a rock, basking in the sunshine.
Some of the marmots in these places and also in remote areas are quite
tame. I walked practically alongside one big marmot as it fed in a patch
of mertensia. It gobbled up dozens of the big leaves and chewed them
down lustily and noisily, scarcely regarding my presence. Accustomed to
harmless mountain sheep and caribou, they sometimes apparently place
humans in the same category.
Arctic Ground Squirrel
_Citellus parryi ablusus_
[Illustration: Arctic ground squirrel at alert.]
The most neighborly animals in the park are the ground squirrels. They
quickly become tame at cabins and campgrounds and eagerly stuff their
cheek pouches with hotcakes until their gulps become ludicrous with
excessive efforts to make room for one more mouthful. Leave a cabin door
ajar and the bread supply is soon being appropriated.
Ground squirrels are always standing erect shouting worried warnings of
danger. Much of the time the cries seem to be only an outlet for
accumulated nervousness. But one learns to differentiate these cries
from those delivered in dead earnest. When extreme anxiety is
unmistakable, it pays to become alert. Their cries have often served to
call my attention to passing grizzlies, wolves, foxes, lynx and
low-flying eagles. And the whole wildlife community similarly benefits.
The message is relayed in all directions by ground squirrels in a sort
of chain reaction, but emphasis in delivery gradually decreases until
the message is lost. The cheery calls and sharp warnings of the ground
squirrels are for many of us, closely associated with the general flavor
and enchantment of the north country.
The winter months are spent hibernating in a burrow, curled up in a
grass nest. A few squirrels remain active until the middle of October or
even later. In the spring some come forth in April. Where deep
snowfields cover the dens and it seems unlikely that much temperature
change could penetrate to the squirrels, they nevertheless awaken as
though provided with alarm clocks and tunnel to the surface. Their muddy
tracks radiate from each den over the snow as the squirrels seek exposed
forage.
General observations indicate that the female has only one litter each
breeding season. The young do not reach adult size by the first autumn.
Year after year, the ground squirrel population in the park is high. Yet
no indication of cyclic behavior has been observed. Possibly their many
enemies prevent them from becoming superabundant and, therefore, subject
to epidemic disease.
Ground squirrels are an important factor in the park ecology. They
furnish about 90 percent of the golden eagle’s diet, and in some
localities they are the chief food of the gyrfalcon. The wolf at times
feeds extensively on them, and they contribute heavily, sometimes 50
percent, to the fox diet. The information available indicates that the
wolverine often captures them, and with the disappearance of the
rabbits, the lynx deigns to hunt them for a season. For the grizzly they
furnish his most dependable taste of meat. The bears spend many hours
excavating for ground squirrels.
Red Squirrel
_Tamiasciurus hudsonicus preblei_
The noisy red squirrel, with his churring, chattering, and
“sic-sic-ing,” lends a touch of the familiar to the northern woods. He
has followed the spruces along the rivers to timberline, and I saw one a
half-mile beyond timber, living perhaps temporarily, among the pikas in
tumbled rocks. They are generally plentiful, but in 1956 I found them
extremely scarce. A catastrophic die-off had apparently occurred in the
park, and that year the squirrels were also reported scarce in other
parts of Alaska.
These northern squirrels have a spruce cone economy. Even before the
middle of August they are frantically harvesting spruce cones (chiefly
white spruce in the park). One afternoon a squirrel worked steadily in a
group of spruces for almost 3 hours, cutting cones and giving them a
flip with his mouth or paws. Hundreds were scattered about under the
trees, and still they continued to rain and strike the ground with dull
thuds. Occasionally the squirrel seemed to get his wires crossed and,
instead of dropping a cone, would run all the way down the trunk with
it.
Sometimes twigs bearing a cluster of cones are nipped off. In two or
three sizeable caches all the cones were in clusters still attached to
twigs. Perhaps this rather efficient method of handling cones is at
times accentuated by certain individuals.
[Illustration: Red squirrel.]
In September I have seen many caches scattered about on the forest floor
as though piled hurriedly as a temporary expedient. One heap measured 5
feet long, 3 feet wide and about 7 inches deep. Possibly these heaps
were later stored more carefully in secluded spots with the tips of the
cones pointed downward. After the cones are stored, the squirrels
continue to give them solicitous care. One spring when melting snow
exposed a cache of cones, they were re-cached in various places, but
each cone was first bitten into, and if spoiled was discarded. About the
same time another cache of cones in a burrow was also removed and stored
elsewhere.
Another food item that is stored in quantity is the mushroom. Many are
placed on spruce branches where, if they do get wet, they will soon dry
out and remain edible, and I once found great quantities stored in a
cabin.
Aside from the cached foods, the red squirrels feed extensively, at
least through the winter and spring, on the buds of spruce twigs. Often
you may find many twigs on the ground with the tiny buds neatly removed.
In Wyoming, I have found squirrels in summer living for days on the
larvae in cottonwood galls, and I suspect such food may be eaten in
Alaska too, where galls are found.
[Illustration: Northern flying squirrel.]
Each squirrel commonly has two or more nests built of grasses, shredded
bark, ptarmigan feathers, and hair of rabbits, moose or whatever is
available. The squirrel piles this material on a branch until it is 2 or
3 feet high. One squirrel that I watched building a nest pushed himself
into the middle of the heap. Soon the whole nest shook vigorously at
intervals. Apparently he was forming a chamber.
The chatter of red squirrels, their piles of middens and their busy
harvesting activities, add cheer and life to the northern woods.
Northern Flying Squirrel
_Glaucomys sabrinus yukonensis_
When the gesticulating red squirrel has finished his daylight bustling
and retires to his nest, the flying squirrel comes forth to take over
the night, but in a gentle and quiet manner. Like the night-flying owl,
its coat is soft and its flight silent.
The furred “wing” membranes on each side of the body are attached to the
full length of the fore and hind legs and are supported and extended in
part by a cartilaginous process growing out from the wrist. Thus when
the legs are extended laterally, the squirrel becomes a glider with the
most delicate and reliable controls. His sailing carries him from the
top of one tree to the base of another where he checks his speed by an
upward swing and alights with a soft thud. Sharp claws and squirrel
agility give him the climbing ability to get quickly up a tree. Where
trees are widely spaced as they are in some stands of large cottonwoods,
he may in winter make a five-point landing in the snow, his broad
thickly-furred tail serving as rudder and gliding surface, and to a less
extent as a landing ski. I have seen tracks showing a touch and a raise
before the final landing with legs drawn under; then follow long jumps
over the snow to the nearest tree. The nest is usually built in a tree
cavity.
Perhaps the height of night esthetics is lying in a sleeping bag under
the open sky, the stars and moon lighting up the spaces between the
trees, and watching a family of flying squirrels gliding overhead in
their night play, their shadowy forms silhouetted against the moonlit
sky.
Porcupine
_Erethizon dorsatum myops_
The porcupine has been accused of being slow-witted, but we must admit
that he has not done badly for he is able to lead an unhurried life in
the country. His quill protection has, no doubt, decreased his need for
mental activity, and his eyesight does seem deficient. But his hearing
is quite keen, and judging by his nose activity it appears that his
sense of smell is on the acute side. His mental and physical attributes
are all based on the quill.
The upper surface of the porcupine, except for the vulnerable face, is
covered with several hundred ivory colored quills, touched with black or
brown, and reaching a length up to at least 2½ inches. They are
needle-sharp and just back from the tip are numerous minute barbs. When
the quill enters the flesh of an enemy, any muscular movement causes the
quill to move forward until it emerges on the opposite side or becomes
lodged against the bone or under the hide.
When the porcupine senses danger he raises the quills on his back and
has his muscular spine-studded tail in readiness to flip upward. He
tries to keep his rear toward the enemy and to push his head into
protective brush. The quills are loosely attached to the skin so pull
out readily when they stick into anything. The underside of the body, in
addition to the face, lacks quills but because of the short legs, the
belly region is close to the ground and not vulnerable unless the
porcupine is flipped over on his back. I knew a sled dog that sometimes
killed porcupines by weaving and maneuvering until he had an opportunity
to grasp the vulnerable nose and thus avoid the quills. Wolves, coyotes
and wolverines feed on porcupines; possibly they use a similar technique
in overcoming the quill armor.
In winter the porcupine feeds extensively on the inner bark and the
needles of conifers. The patches where the bark has been removed are a
common sight in porcupine woods. The spruces, in the last stand of
timber on the east side of the Toklat River along the road, were nearly
all killed by girdling, many of them back in the 1920’s when the
porcupine population was extremely high. This scraggly woods is a
favorite nesting area for pigeon hawks, sparrow hawks, magpies, and
shrikes so that porcupine activity that seemed generally harmful has
been highly beneficial to these species. Many porcupines spend the
winter in a willow patch beyond the spruce and subsist on willow. For
shelter in winter a windfall, hollow tree, or an old fox or wolf den may
be used. Several may take residence under a cabin.
In spring I have watched porcupines climbing clumsily in tall willow
brush feeding on the swollen buds. Swaying on a limb he reaches for a
slender branch, pulls it to him and passes the length of it past his
nose to discover the buds which he nips off. If the branch is
obstreperous and cannot readily be handled in this manner, he severs it
with his rodent incisors and then removes the buds as his paws
manipulate the twig past his jaws. The new shoots of fireweed and other
herbs are avidly sought in early summer. Willow leaves are included in
the varied summer diet.
The breeding season is in the fall and the young are born about 7 months
later. The usual single young one weighs about a pound, almost as much
as a new born grizzly. The eyes are open, the short spines are evident,
and protective reactions are soon functioning.
Their voice development is quite obvious when one or more porcupines
resides under a cabin. The night moanings, squeaks of irritability,
cluckings, and caressing sounds are enough to keep even the exhausted
hiker awake.
[Illustration: Porcupine.]
[Illustration: Beaver.]
Beaver
_Castor canadensis_
Beavers may be found at Horseshoe Lake, Riley Creek, various ponds near
the Nenana River, and in ponds and creeks along the road in the Wonder
Lake region. They are out chiefly at night, but many families emerge for
pond activity by 2 or 3 o’clock in the afternoon.
Beavers are large rodents, scaling 60 pounds or more. Their weight does
not make them good hikers but it is no handicap in water where they
paddle their way about as though they were skiffs. And when they sit up
to gnaw down an aspen or cottonwood, a favorite pastime, a good solid
fulcrum might be a comfortable advantage. The broad, flat, scaly tail
serves as a prop when sitting erect, as a rudder when swimming, and for
sounding an alarm (by slapping water) when an enemy is discovered.
The front feet are equipped with five strong toes which serve well as
hands for holding twigs as the animal feeds on bark. The claws function
well in all digging operations, and the arms suffice for holding gobs of
mud against the chest as he pushes the load onto the dam or house.
Occasionally, he carries mud in his arms as he walks up the house roof
on hind legs.
The hind feet are large and webbed for swimming. Even the nails on the
toes are flattened in keeping with the swimming needs. The nail of the
second hind claw is double and the nail of the first toe fits down on a
hard pad and is movable like a duck’s bill. These specialized claws are
used for combing the fur and possibly for removing some of the large
beetles that live in the fur. The prominent incisors, used for gnawing,
grow continuously, as they do in all rodents, in order to compensate for
wear. This is an especially fortunate adaptation for the beaver, who
does so much gnawing. Otherwise his teeth would soon be worn to the
gums. If an incisor for any reason is thrown out of line, so it has no
surface to bite against and wear, it will become excessively elongated
as it grows in a curve.
A flourishing beaver colony apparently consists of the parents, the
young of the year, and the previous year’s offspring. It is for this
reason that we often discover three sizes of beavers in a pond. Much of
beaver activity involves cooperative projects where there is latitude
for any amount of individual initiative. The dam or dams must be built,
or raised, or kept in repair. The house, located either out in the pond,
or partially or wholly on the shore, may require additional sticks, and
toward autumn is plastered on the outside with wet mud as a sort of
annual renovation. This “stucco” winterizes the lodge. Occasionally, it
is decided that a new house is needed and that gives young and old
plenty to do. Some beavers along Riley Creek live in bank burrows and
build no dams or houses.
[Illustration: The author inspecting a beaver house at low water.]
The most effective dam that has come to my attention was built at the
outlet of Wonder Lake in 1960; it raised the water level of the lake
over 2 feet. For many days the outlet stream was dry. The water held
back in the lake amounted to well over 100 million cubic feet or over 7
billion pounds of water.
The water depth beside the lodge must be deepened if too shallow, so
that the underwater entrance to the lodge is deep enough to keep from
freezing over, and imprisoning the occupants. Also a certain depth of
water is needed beside the lodge in which to store the brush pile that
is the winter food supply. Another activity practised extensively by
some colonies is the building of canals, some of which may have great
length. The mud from the digging is deposited along the canal forming a
raised border. These waterways are useful for general travel to food
areas and for transporting branches and poles.
The favorite foods of the beaver include willow, aspen, cottonwood, and
alder. Willow brush re-sprouts readily and grows rapidly, therefore
maintains itself better than some of the other foods. Also it flourishes
in the wet habitat created by the beaver ponds.
Where beavers create ponds with their dams, they produce a habitat for
fish, ducks, muskrats, shore birds, moose and many other forms of water
and shore life. In Wyoming, I have observed the dead trees, killed by
flooding, used by herons for nesting, and one of the heron nests was
later used by a pair of geese.
The rich, warm coat of the beaver has long been worn by both humans and
beavers, but the beaver wears it best.
Muskrat
_Ondatra zibethicus spatulatus_
In some parts of Alaska where extensive favorable pond habitat prevails,
muskrats are abundant and their sedge lodges are a part of the scenery.
In the park there are a few muskrats in Horseshoe Lake and other ponds
and creeks near the eastern border, and also in the Wonder Lake area.
These usually live in bank burrows with submerged entrances. It is not
uncommon to find a muskrat living in an occupied beaver house,
apparently utilizing an unoccupied cranny. They ply back and forth
across the pond, just as the beavers do, and submerge with a mouthful of
sedge which they are taking to the young. At Wonder Lake, I have seen
muskrats swimming under the little bridge across the stream inlet,
carrying sedges to young that were kept in a burrow in a nearby bank of
the lake.
Because muskrats are associated with beavers they are sometimes mistaken
for young beavers. The longer scaly tail, that is flattened vertically
rather than horizontally, serves as a certain identification. The
muskrat is also much quicker in its actions, and is smaller than any
beaver old enough to be abroad.
The muskrats’ chief food consists of green vegetation (various
waterplants and sedges) and clams when available; it has even been
reported catching small fish in some regions. Some of the deeper
waterplants it secures by diving, and in the spring I have watched them
climb onto the ice to eat them. A muskrat looks very tiny sitting on the
ice beside a big beaver.
Muskrat have their winged and fourfooted enemies. Mink, living in the
same environment, prey on them, but not indiscriminately. Other
carnivores such as the fox, coyote, and wolf might encounter one on
land, but chiefly by accident.
Shrews
_Sorex sp. and Microsorex sp._
Shrews may be identified by their long, pointed, mobile nose, extremely
minute eyes, short velvety fur and blackish-tipped teeth. They are the
smallest mammals in the world, some kinds weighing less than 3 grams. It
would require over 100 of these to weigh one pound. Because of the
shrew’s small size and long nose, Alaskans frequently refer to them as
long-nosed mice.
Thousands of shrews (four species) are vigorously active in the park but
are rarely seen. Occasionally, one may be discovered crossing an open
area, like a mechanical toy, or one may flash from cover and as quickly
disappear. They share with the voles and lemmings the shade and darkness
of the hidden runways beneath the moss and grassy cover. Here they are
active predators, darting about in their search for prey. With nervous
activity they examine their microhabitat in search of insects and other
invertebrates. Spiders flee in haste when the presence of a shrew is
sensed. Their hunting technique appears to consist of random movements
until they collide with their victim. They no doubt depend chiefly upon
the sense of smell in recognizing their prey.
Shrews eat often and a great deal. In captivity, a shrew weighing 3.6
grams ate over three times its weight of food daily. Any kind of meat
attracts shrews, as many Alaskans have learned when discovering their
meat caches invaded by them. The energetic activity of shrews suggests
the need for rapid metabolism and plentiful supply of body fuel.
Although shrews are active throughout the winter, they nevertheless
appear to be delicately attuned to their environment. They seem to be
especially susceptible to chilling, perhaps because of their tiny body
and short fur. Winter temperatures in the north are severe, but ground
temperatures under the snow blanket are rather moderate. Shrews perhaps
require only a warm nest—their intense activity keeping them warm when
foraging.
Shrews are not rated high gastronomically by many mammals. This is
apparently due to the hip glands which have a strong, pungent odor. But
their lack of palatability does not give them much protection. If, for
instance, a fox locates a faint sound in the grass, he pounces and
learns later what he has caught. If the prey is a shrew, it may be left
where killed by the fox, carried a short way and dropped, or during
denning time even brought home to the den before discarded. I have often
found shrew carcasses lying uneaten about fox dens. Birds of prey feed
more extensively on them possibly because of their poorly developed
sense of smell, and sense of taste. Grayling, and also trout, have been
found with one or more shrews in their stomachs. At Moose Creek, several
grayling were taken which had eaten shrews, one having eaten three of
them. This indicates that the species captured, readily enter the water.
(One species, the water shrew, not found in the park, is specialized for
aquatic life).
[Illustration: Denali (Mount McKinley) in early winter.]
The shrew population is apparently cyclic for there are years when they
are very abundant, followed by years of extreme scarcity.
Four kinds of shrews are in the park. They differ from one another in
several respects, but may be fairly well identified by tail length
alone. The masked shrew (_Sorex cinereus_) has a tail averaging about 39
millimeters long; the tail of the vagrant shrew (_Sorex obscurus_)
averages about 48 mm.; and that of the rare pygmy shrew (_Microsorex
hoyi eximius_), 31 mm. The average length of tail of the Arctic shrew
(_Sorex arcticus tundrensis_) is about 36 mm., overlapping slightly in
this measurement that of the masked shrew, but the rich chocolate color
of the Arctic shrew will identify it.
Bat
_Vespertilioninae_
A bat was reported in flight at Wonder Lake in 1959 and again in 1960.
Since no specimen has been examined there is no definite identification,
but judging from the geographical distribution of bats it seems probable
that those seen in the park belong to the genus _Myotis_. Three or four
species of this genus are known to occur in southeastern Alaska. The
little brown bat (_Myotis lucifugus alascensis_) has been taken at
Illiamna Lake at the base of the Alaska Peninsula so it seems likely
that this is the bat seen at Wonder Lake.
The Mouse World
_Microtinae_
Are there any trails in the park? Yes, thousands of miles, but most of
them are under a canopy of grass and sphagnum moss and are only 1 or 2
inches wide, so of course they are not of much use to you. And even if
we could nibble on Alice’s mushroom and grow, in reverse, small enough
to use them, we would hardly dare, at least a lady wouldn’t, for she
would soon meet a mouse, inasmuch as these trails have been constructed
by, and belong to, mice. And I might add that the fierce little shrews
use them too. Where the trails cross green, mossy carpets and enter tiny
exquisite nooks I imagine one might also meet a few northern fairies.
Seven kinds of mice (voles and lemmings) are known to live in the park.
Some of these are quite outstanding for one thing or another, and
possibly all of them are, if we only knew more about them. However, we
do know that they are all important.
* * * * * * * *
I am best acquainted with the haymouse, or singing vole (_Microtus
miurus oreas_) because some of my field observations led me to him. Some
years ago I kept finding many caches of dried vegetation, some caches
large enough to fill a bushel basket. This hay was always kept either
off the ground or under cover. It was placed at the base of willows in
the basket formed by the many stems, or on a surface spruce root, in a
rock niche, or under a log. Pikas are known to make hay, but no such
activity has been reported for mice. Pikas were not involved for they
live in the talus rock, and these caches were mostly far from pika
habitat. After considerable effort, I learned that a yellowish-brown
field mouse was the interesting haymaker. The hay is put up for winter
use. The sign showed that sometimes a snowshoe hare found a cache and
helped himself.
In addition to hay, this mouse also stores roots in underground cellars
that he excavates, and the roots are not thrown in helter-skelter, at
least not in most of the caches I examined. The black, round nutlike
tubers of the horsetail were in one pile, coltsfoot underground stems in
another, and carrotlike roots of a pedicularis in still another. An
interesting feature was the structure of some of the tunnels which were
built in the form of a pearl necklace. Tiny passages, just large enough
for the body of the mouse to squeeze through, joined the cavities or, so
to speak, the “pearls.” In addition to all of these accomplishments,
these mice do much miniature warbling, enough so they have been called
singing voles.
[Illustration: Haymouse (singing vole)]
The tail is short, measuring slightly over 1 inch; the body length
averages about 5 inches. It is found from moist lowland habitats to
ridge tops.
* * * * * * * *
The large, plump, and richly-colored brown lemming (_Lemmus
trimucronatus alascensis_) is notorious for his overpopulation problem.
On some occasions they migrate in hordes, even into the ocean in some
parts of their circumpolar home. The lemming is cyclic in the park, but
usually only to about the same degree as the other mice. However, in the
low part of the cycle, they may become extremely scarce, more so than do
the voles. The brown lemming does not turn white in winter as does its
relative, the collared lemming (over most of its range). The body is
about 5½ inches long and the tail is just under 1 inch. The thumb claw
consists of a three-pronged flat nail. A large lemming weighs about
one-quarter pound. They are widely distributed in both open tundra and
woods where the habitat is not too dry.
[Illustration: Brown Lemming.]
* * * * * * * *
The northern bog lemming (_Synaptomys borealis dalli_) is usually not
thought of as a true lemming, but it does belong to the lemming tribe.
It has a short tail, less than 1 inch long; the body length is about 4
inches; the upper incisors have a vertical groove near the outer edge;
and the males have a white spot on each side marking the location of hip
glands. The thumb claw is a broad nail, in this respect resembling the
brown lemming. The distribution of this mouse is spotty. It was taken in
the Wonder Lake area in a wet grass and sedge habitat just inside a
spruce woods.
* * * * * * * *
The chestnut-cheeked vole (_Microtus xanthognathus_), the largest mouse
in the park, has a body length of 6 or 7 inches, tail length of about 2
inches, and weighs up to about 6 ounces. These mice live in isolated
colonies but where found may be abundant. Not recorded in the park since
1907 when it was abundant along the Toklat River.
* * * * * * * *
The tundra vole (_Microtus oeconomus macfarlani_) is a large vole widely
distributed, and is especially fond of dense grass or sedge habitats.
Its body length is 5 to 5½ inches, and tail length a little less than 2
inches. Its brownish-gray color is similar to the common meadow mouse.
* * * * * * * *
The meadow vole (_Microtus pennsylvanicus tananaensis_) is common in
interior Alaska, so far as known, but is rare in the park. With more
investigation, it may be found plentiful in places along the north
boundary. This is a common vole over much of Canada and the Rocky
Mountain, central and eastern states. It prefers moist habitats. The
body length is about 5 inches, tail about 2 inches, and the color is
dark brown.
* * * * * * * *
The northern red-backed mouse (_Clethrionomys rutilus dawsonii_) lives
in both the open tundra and the woods. Generally, it has a reddish back,
but in a dark color phase, the back is blackish. These mice are fond of
berries, their teeth being stained blue during the blueberry season.
They also feed on seeds, stems, and leaves.
[Illustration: Meadow vole.]
[Illustration: Red-backed mouse.]
[Illustration: Red-backed mouse.]
The several species of mice vary in abundance from year to year. In
places where some of them have been studied, a well-defined 3 or 4 year
cycle has been noted. The mouse populations have a tremendous influence
on our wildlife economy. Foxes, martens, weasels, owls, hawks and a host
of others feed extensively on this fauna and react to its abundance.
When the lemming increase in the north, the snowy owls (and others)
increase, and when the lemming become scarce, these owls come south in
search of food and we have the snowy owl invasions, especially in
north-central and eastern states. In 1955, when mice were abundant, the
hawk owls in the park reached a high point, but again became scarce when
the mouse population dropped.
Checklist of The Mammals of Mount McKinley National Park
[_] Arctic Shrew
[_] Masked Shrew
[_] Dusky Shrew
[_] Pygmy Shrew
[_] Bat (Species unknown)
[_] Black Bear
[_] Grizzly Bear
[_] Marten
[_] Short-tailed Weasel
[_] Least Weasel
[_] Mink
[_] Wolverine
[_] River Otter
[_] Red Fox
[_] Coyote
[_] Wolf
[_] Lynx
[_] Hoary Marmot
[_] Arctic Ground Squirrel
[_] Red Squirrel
[_] Northern Flying Squirrel
[_] Beaver
[_] Bog Lemming
[_] Brown Lemming
[_] Northern Red-backed Mouse
[_] Meadow Vole
[_] Singing Vole
[_] Tundra Vole
[_] Chestnut-cheeked Vole
[_] Muskrat
[_] Porcupine
[_] Collared Pika
[_] Snowshoe Rabbit
[_] Moose
[_] Caribou
[_] Mountain goat
[_] Dall Sheep
Transcriber’s Notes
—Silently corrected a few typos.
—Retained publication information from the printed edition: this eBook
is public-domain in the country of publication.
—In the text versions only, text in italics is delimited by
_underscores_.
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