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Title: Life History and Ecology of the Five-lined Skink, Eumeces fasciatus
Author: Fitch, Henry S., 1909-2009
Language: English
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Transcriber's Note - Text Emphasis

  _Text_  -  Italic



  UNIVERSITY OF KANSAS PUBLICATIONS

  MUSEUM OF NATURAL HISTORY

  Volume 8, No. 1, pp. 1-156, 2 pls., 26 figs. in text, 17 tables
  September 1, 1954

  Life History and Ecology
  of the Five-lined Skink, Eumeces fasciatus

  BY

  HENRY S. FITCH

  UNIVERSITY OF KANSAS
  LAWRENCE
  1954



  UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY

  Editors: E. Raymond Hall, Chairman, A. Byron Leonard,
  Robert W. Wilson

  Volume 8, No. 1, pp. 1-156, 2 pls., 26 figs. in text, 17 tables
  Published September 1, 1954

  UNIVERSITY OF KANSAS
  Lawrence, Kansas

  PRINTED BY
  FERD VOILAND, JR., STATE PRINTER
  TOPEKA, KANSAS
  1954

  25-3559



LIFE HISTORY AND ECOLOGY OF THE FIVE-LINED SKINK, EUMECES FASCIATUS

By

Henry S. Fitch



Introduction


The common five-lined skink (or common blue-tailed skink) is a small
woodland lizard, abundantly and widely distributed over the eastern
United States. Many authors have casually discussed this lizard or have
treated in detail some phase of its biology. Excellent brief summaries
of the known facts concerning its life history have been published by
Smith (1946:349-350 and 1950:187-188) and Pope (1947:153-157).
Nevertheless, no thoroughgoing study of its life history and ecology has
heretofore been made.

In 1932, taxonomic studies by Dr. Edward H. Taylor revealed that the
lizards previously referred to in the literature as _Eumeces fasciatus_,
actually were three closely related and similar, partly sympatric
species. Although Taylor's work was careful and detailed, and indicated
numerous minor differences by which the three species could be
distinguished, many herpetologists were reluctant to accept his findings
for nearly a decade thereafter. Consequently a large amount of
literature concerning five-lined skinks is either obviously composite in
the sense that it is based upon two or three species, or is not
definitely assignable to any one species. In the study here reported
upon, all pertinent literature available to me has been examined, and
evaluated, and important findings of other authors have been
incorporated in the discussion. However, mine was primarily a field
study, and in one small part of the geographic range of the one species.

The University of Kansas Natural History Reservation is a tract of 590
acres preserved as a natural area, available for the pursuit of
ecological studies. The studies undertaken include intensive
investigations of selected species of vertebrate animals. The main
criteria used in selecting these species have been whether or not they
were sufficiently abundant and generally enough distributed to play an
important role in the over-all ecology of the area, and whether a
species was sufficiently accessible for study with available techniques.
Among the 300 species of vertebrate animals recorded from the
Reservation, the five-lined skink is one of those most frequently
noticed in the field. In actual numbers it is probably exceeded only by
the cricket frog (_Acris gryllus_), the leopard frog (_Rana pipiens_),
the ring-necked snake (_Diadophis punctatus_), the prairie vole
(_Microtus ochrogaster_) and perhaps the white-footed mouse (_Peromyscus
leucopus_). Although numerous, the skink is not easy to study because it
is secretive in its behavior, and is inactive in inaccessible shelters
during the greater part of the year.

The five-lined skink generally occurs along with a characteristic set of
community associates in a particular type of situation. It is a predator
on various small animals, mostly invertebrates. For some of the many
prey species the effect is certainly negligible, but for others its
predation may be a major ecological factor. In areas where optimum
habitat conditions exist its biomass may exceed that of any other
insectivorous animal, and in such situations it assumes a major role as
a predator and as a competitor with other insectivorous types. In turn
it provides part of the food source of various larger predators,
including reptiles, birds and mammals. It is a host and carrier of
various parasites, including at least one species that regularly attacks
humans--the common chigger. It is not evident on the basis of the
present findings that the skink is either harmful or beneficial to any
perceptible degree, in its over-all effect on human affairs and economy.
Nevertheless, there probably are various unsuspected relationships.

In the course of my field study many workers on the University of Kansas
Natural History Reservation helped by capturing skinks; especially
Sydney Anderson, Richard Freiburg, John Hawken, Dennis G. Rainey and
Lewis L. Sandidge. Mr. Robert Gordon very kindly furnished information
on specimens in the Tulane University collection, which served as a
basis for comparing the breeding schedule of the southern population
with that of _E. fasciatus_ in northeastern Kansas. Dr. W. J.
Breckenridge kindly permitted examination of material in the University
of Minnesota Museum of Natural History. Dr. Edward H. Taylor has made
helpful suggestions from time to time. Mr. Richard B. Loomis helped me
in various ways with the field work, and made available his personal
field notes with records of predation on _Eumeces_ by various snakes.
Dr. E. Raymond Hall, Director of the Museum of Natural History, has
critically examined the manuscript, and has been helpful in various
ways. The line drawings and graphs, with the exception of Figures 8 and
9, were made or completed by Mrs. Louise Brunk, artist for the Museum.

The study here reported on was initiated in May 1949, and was continued
through 1950, 1951 and 1952. A few observations made in 1948 have been
included. Various separate items of information obtained in 1953 have
likewise been incorporated especially where histories of individual
skinks are presented, but the manuscript was completed in essentially
its present form in the fall of 1952.



Methods


Skinks were obtained by active search; rocks and boulders were lifted up
and the skinks thus exposed were seized by hand before they had time to
escape. This method was effective when the skinks were using rocks for
shelter and when temperatures were low enough so that they were slow and
sluggish, but in hot weather the skinks were so quick and active that
those exposed usually escaped. Usually skinks could be obtained much
more easily by trapping. At the pond rock pile (Fig. 26), for instance,
shelter was so readily available that the skinks could seldom be caught
by hand. Gallon cans buried with the tops open flush with the surface of
the ground served as pitfalls and were effective when they were
carefully placed, at the bases of rock ledges or logs or stumps, where
the skinks were most likely to fall into them. Most of the skinks
recorded at the rock pile were caught by this method, and sometimes
several were caught together in the same pitfall. Ordinarily each
pitfall was covered with a large flat rock, propped against a nearby
object to leave ample space for the skink to enter beneath it. The rocks
provided protection from direct sunlight, from rain, and from predators.
Still another method of catching skinks was with wire screen funnel
traps (Fitch 1951:77). These funnel traps were of different sizes, and
were made of different kinds of wire mesh. They were set for reptiles
that were mostly larger than five-lined skinks, and those having
quarter-inch wire mesh permitted many of the immature skinks to escape.
Most of these funnel traps were from about one foot long and five inches
in diameter, to about twice these dimensions, with funnel openings about
1.5 inches in diameter. Some made of 1/8 inch wire mesh, six or seven
inches long, and three or four inches in diameter, with funnel openings
only a little larger than the body diameter of an adult skink, were
found to be suitable for skinks of all sizes, and were used successfully
at the pond rock pile. Most of the skinks trapped were adult males, and
they were taken chiefly in May. The funnel traps were generally placed
at the edges of rock outcrops, boulders or logs, where skinks were
likely to be intercepted in their usual travel routes. Each method of
collecting skinks resulted in occasional mortality to them but most
losses were in those caught in funnel traps. In these traps they
sustained rapid loss of moisture, and were usually somewhat desiccated.
Two or more adult males were often caught together, and in most of these
instances the first one caught probably served as bait attracting
another and arousing his pugnacious interest. Injuries were frequent,
and some deaths occurred because in the close confines of a trap the
loser in a fight was unable to escape further attacks.

Most of the skinks caught were examined, and released within a few
minutes. Snout-vent length was measured by holding the skink against a
rigid transparent plastic millimeter ruler and exerting a slight pull on
each end of the lizard until it tired and relaxed its muscles,
eliminating bends and kinks. Even with such precaution, precise
measurements could not be obtained and the readings often varied a
millimeter or more for the same skink measured two or more times on the
same day. Tail length was similarly recorded with separate readings for
the original and regenerated portions. Also recorded were sex (when
discernible), color and pattern, breeding data, injuries, general
condition, and sometimes temperature. Many of the skinks were brought to
the laboratory, and were weighed to the nearest tenth of a gram.

Occasional trips were made to localities away from the Reservation to
collect skinks. Some of those obtained were kept under observation in
terraria where their behavior was studied. Most were preserved and were
used for data on habitat preferences, seasonal changes in the gonads,
size group, stomach contents, and various other items of information.



Description


The scutellation and osteology have been described in detail by Taylor
(1936:39-48 and 199-206) and others, and need not be repeated. The
five-lined skink is slender and elongate, somewhat snake-like (though
much less so than many other skinks) as the head, neck, body, and tail
are not well set off from each other, and the sleek, streamlined
contours are broken only by the small limbs protruding from the sides of
the body. The body is slightly flattened laterally, tending toward
quadrangular shape in cross section. The head is wedge-shaped, with a
short, rounded snout. The nostrils are laterally placed, well back from
the tip of the snout. The eyes are small and deep set; the iris is dark.
The neck is thick and strong, nearly as long as the head. The torso is
3-1/2 to 4 times as long as it is wide. The tail is almost square in
cross section at its base, but is circular in cross section for most of
its length. The limbs are moderately developed; when adpressed along the
sides of the body, the forelimb and hind limb overlap by a length about
equal to the longest toes of the forelimb. The limbs are pentadactyl and
all the toes are well developed and have claws (Figures 1 and 2). The
claws are short, and are curved in such a manner that their tips are
directed downward, each approximately at right angles to the axis of the
toe (Figure 2b). The limbs are moderately thick and muscular. The upper
arm and forearm segments are of approximately equal length, as are the
femoral and tibio-fibular segments of the hind limb.

    [Illustration: FIG. 1. Antipalmar view of right front foot, × 9.]

    [Illustration: FIG. 2. A. Antiplantar view of right hind foot, × 9.

       B. Terminal part of second toe of left hind foot, and its claw, in
          lateral view, × 9.]

The five-lined pattern is characteristic of the hatchling, but gradual
ontogenetic change results in its dulling, suppression, and eventual
loss. In the hatchling the ground color of the head and body is black or
dark brown, with five milky white longitudinal stripes extending the
length of the head and body, and on the basal one-fourth of the tail.
The five light lines are of approximately equal width, and are separated
by dark interspaces 1-1/2 to 2 times as wide. The mid-dorsal stripe
includes most of the two mid-dorsal scale rows. Posteriorly it extends
onto the base of the tail, where it becomes increasingly suffused with
the blue color of the tail, widens, and loses its identity. In the
nuchal region, this dorsal stripe narrows and splits into left and right
branches, which diverge anteriorly to form a lyrate pattern on the head.
On either side of the dorsal stripe are the dark interspaces, nearly
twice as wide as the stripe itself and tapering to a point posteriorly
on the tail, likewise tapering anteriorly to a point immediately above
and in front of the eye. Lateral to these dark areas are the
dorsolateral stripes; they extend from the basal one-fourth of the tail
anteriorly onto the head along the superciliary region, tapering to a
point on the anterior superciliary. Below these stripes are the dark
lateral areas which extend from the basal part of the tail anteriorly
along the sides of body and neck region (including the upper half of the
aperture of the ear), eye region, and loreal region. Below this dark
area on each side is the lateral stripe. It extends along the sides just
above the level of the limb insertions (broken or pinched to a fraction
of its average width above the hind limb insertion), broken by the ear
opening, and extending anteriorly to include all the supralabial scales
(with the exception of their upper edges) and the rostral. Here the left
and right lateral stripes may be said to join; however in the facial
region these stripes are not well defined, partly because the dark areas
that border their lower edges do not extend so far forward. This
lowermost dark area is about equal in width to the lateral stripe. It
extends from the posterior infralabials posteriorly, to include the
fore- and hind-limbs, and onto the basal part of the tail. The ventral
surface of the head and body is dull white or pearly gray.

Thus, there are 12 longitudinal bands of color on the body: the five
narrow, subequal, pale lines separated by the six dark areas, of which
the dorsal and dorsolateral are broad and of approximately equal width,
while the ventrolateral is narrower; and lastly the broad, pale ventral
area.

    [Illustration: FIG. 3. A. Osteoderm of an old adult male,
       from near the midline of the back, × 25.

    B. Another osteoderm from same male, from belly near midline, × 25.

    C. Another osteoderm from side of same male, at a point
       approximately halfway between foreleg and hind leg, × 25.

    D. Osteoderm of a juvenile obtained in April, from near midline of
       back, × 25.

    E. Tongue from dorsal view, shown in its normal position in the
       lower jaw, × 2-1/2.]

The tail in young individuals is bright blue. In _Eumeces_ the tail
characteristically has a color different from that of the body, and is
usually more conspicuous; in many species it is blue, but in others it
may be purple, greenish-blue, red, pink, or orange. Hatchlings have the
most brightly colored tails, and as growth proceeds the colors gradually
become duller. In _E. fasciatus_ the bright colors of the tail are
mostly or entirely lost in old adults, especially in males, and in
individuals of either sex that have lost their original tails and
regenerated new tails. Young which lose their tails and regenerate them
at an early age have the regenerated portions colored almost as brightly
as the originals at first.

The skin is tight fitting and relatively thick, stiffened by a bony
armor. A small bony plate or osteoderm underlies each scale. Oliver
(1951:127) has called attention to the pattern of ornamentation on the
osteoderms, which becomes more complex with advancing age. He has
suggested the possibility that age might be accurately determined on the
basis of extent of osteodermal ornamentation. I have compared
osteodermal ornamentation in marked individuals of known age, but have
found it to be of limited applicability as a method of age
determination; size and pattern are probably more satisfactory bases for
estimating age, even though they do not permit definite aging of old
adults and are not infallible for skinks short of adult size. In adult
_E. fasciatus_ the pattern of ornamentation is closely similar to that
figured for _E. laticeps_ by Oliver (op. cit.) and also resembles the
pattern shown for an Old World skink, _Mabuya multifasciata_, as figured
by Smith (1935: 2). The pattern differs somewhat in osteoderms on
different parts of the body, and is most nearly symmetrical in those
near the midline on either dorsal or ventral surface (Figure 3).



Relationships


_Eumeces_ is a widespread genus occurring in the New World in southern
Canada and southward into Costa Rica. The greatest number of forms is in
Mexico. In the Old World numerous species occur in southeastern Asia and
on adjacent islands, and other species occur westward across southern
Asia, and across North Africa to Morocco, with a major break in the
continuity of distribution in the Himalayan region. Taylor in his
revision recognized 57 forms with fifty full species, belonging to 15
major groups within the genus. Since then only relatively minor changes
in classification have been proposed. Several new species and subspecies
have been named, and several species have been relegated to the status
of subspecies.

Within the genus there are several groups that have representatives in
both the New World and the Old World. Smith and Etheridge (1953:159)
point out that the most primitive line of _Eumeces_ is best represented
in the Old World, where there are two groups and nine species, while in
the New World this line has only three tropical relict forms. For this
reason, Smith and Etheridge concur with Taylor (1936:67) in considering
the genus to be of Old World origin; but the two main lines of the
genus (the four-lined and five-lined stocks) are both regarded as being
of New World origin. According to this idea, the Asiatic members of
these two groups migrated from the New World. In the early Tertiary,
warm temperate climates extended north to the Arctic Circle, and
_Eumeces_, or at least some of its species, may have had a distribution
straddling migration routes to both North America and Asia.

Of the 15 groups within the genus, the _fasciatus_ group, with a dozen
species, has more representatives than any other. The _fasciatus_ group
is characterized by having the tail bright blue with dorsal body pattern
of five light lines on a darker ground color; mid-dorsal line
bifurcating on head to form lyrate markings (this striped pattern and
bright color of the tail becoming dull or obsolete in the adults);
medial preanal scales overlapped by those lateral to them; two pairs of
nuchals; no postfemoral pocket; four supraoculars; scales on sides of
body in parallel rows. The characters that separate members of the
_fasciatus_ group from each other are minor. The width and position of
the light lines differ somewhat among them. The mid-dorsal light line
bifurcates either on the nuchals or on the parietals. The complex of
scales in the temporal region differ in shape and relative size.

The following table, compiled mostly from information set forth by
Taylor (1936:186-283), indicates some of the main differences and
similarities between species in the chief characters upon which the
classification is based.

The close resemblance between _E. fasciatus_ and its Asiatic relatives
is remarkable considering the great distance separating them and the
long time that must have elapsed since their isolation began. Some of
the Asiatic forms differ from each other almost as much as they differ
from _fasciatus_. Of the Asiatic species, _elegans_, _tamdaoensis_,
_oshimensis_, and _marginatus_ differ from _fasciatus_ in markedly
larger size; _elegans_, _marginatus_, _oshimensis_, and _stimsonii_
differ in lacking a postnasal; all but _tamdaoensis tunganus_ and
_xanthi_ differ in having only a single postmental; all but _tunganus_,
_E. latiscutatus okadae_ (and sometimes _oshimensis_ and _elegans_)
differ in reduced number of scale rows; all but _tunganus_ differ in
having a lateral postanal scale differentiated, and usually keeled;
_tunganus_, _xanthi_ and _elegans_ differ in having a patch of enlarged
scales on the posterior side of the thigh; and in all, the primary
temporals and upper and lower secondary temporals differ in size and
proportions. Although some of the Asiatic forms seem to be directly
derived from others, _fasciatus_ is somewhat intermediate between the
more divergent forms, and fulfills most of the conditions to be looked
for in an ancestral type.

    Table 1. Distribution, Pattern, Size, and Lepidosis of the
       "Five-lined" Skinks (Fasciatus Group of the Genus Eumeces)

  ==================================================================================================================================
                  |_fasciatus_
                  |         |_laticeps_
                  |         |         |_inexpectatus_
                  |         |         |         |_tunganus_
                  |         |         |         |          |_xanthi_
                  |         |         |         |          |        |_elegans_
                  |         |         |         |          |        |         |_tamadoensis_
                  |         |         |         |          |        |         |       |_oshimensis_
                  |         |         |         |          |        |         |       |        |_stimsonii_
                  |         |         |         |          |        |         |       |        |         |_barbouri_
                  |         |         |         |          |        |         |       |        |         |       |_marginatus_
                  |         |         |         |          |        |         |       |        |         |       |       |_latiscutatus_
  ----------------+---------+---------+---------+----------+--------+---------+-------+--------+---------+-------+-------+--------------
  Distribution    |E U. S., |Most of  |SE U. S. |W Szechwan|SE      |SW       |Indo-  |Amami-  |Ishigaki-|Amami- |Okinawa|Japan,
                  |except   |E U. S., |         |(in       |China   |China,   |China  |gunto I.|jima, Riu|shima  |       |(main I.)
                  |Fla. and |except   |         |N China)  |        |Formosa, |       |        |  Kiu I. |       |       |
                  |N New    |N tier   |         |          |        |Pesca-   |       |        |         |       |       |
                  |England  |of states|         |          |        |dores I. |       |        |         |       |       |
                  |         |         |         |          |        |         |       |        |         |       |       |
  Juvenal Pattern |  5      | 5 or 7  | 5 or 7  |  5       |  5     |  5      |  5    |  5     |  7      | ..... |  5    |  5
                  | lined   | lined   | lined   |lined     |lined   | lined   | lined | lined  | lined   |       | lined | lined
                  |         |         |         |          |        |         |       |        |         |       |       |
  Max. snout-vent |         |         |         |          |        |         |       |        |         |       |       |
    length in mm  | 80      | 130     |  89     | 81       | 76     | 96      | ..... | 99     | 63      | 66    | 93    | 80
                  |         |         |         |          |        |         |       |        |         |       |       |
  Postnasal       |present  |present  |present  |present   |present |absent   |present|absent  |absent   |present|absent |present
                  |         |         |         |          |        |         |       |        |         |       |       |
  Postmental      |  2      |  2      |  2      |  2       |  2     |  1      |  2    |  1     |  1      |  1    |  1    |  1
                  |         |         |         |          |        |         |       |        |         |       |       |
  No. scale rows  |28-30    |30-32    |30-32    | 28       |22-24   |26-28    | ..... |26-28   | 26      | 22    | 26    |26 (or 24)
                  |         |         |         |          |        |         |       |        |         |       |       |
  Lateral postanal|undiffer-|undiffer-|undiffer-|undiffer- |differ- |         |       |        |         |       |       |
    scales        |entiated |entiated |entiated |entiated  |entiated|keeled   | ..... |keeled  |keeled   | ..... |keeled |keeled
                  |         |         |         |          |        |         |       |        |         |       |       |
  Large scales on |         |         |         |          |        |present  |       |        |enlarged;|       |       |
    back of thigh |absent   |absent   |absent   |present   |present |irregular| ..... |absent  |regular  |absent |absent |absent
                  |         |         |         |          |        |         |       |        |         |       |       |
  Median          |         |         |not      |          |        |         |       |        |  not    |       |       |
    subcaudals    |widened  |widened  |widened  |widened   |widened |widened  | ..... |widened |widened  |widened|widened|widened
  ----------------+---------+---------+---------+----------+--------+---------+-------+--------+---------+-------+-------+--------------

The American _Eumeces laticeps_ and _E. inexpectatus_ seem to be more
specialized than _E. fasciatus_ and might have been derived from it or
from a common ancestor differing but little from the modern _fasciatus_.
Both differ from _fasciatus_ in having more scale rows. _E. laticeps_
also differs in having eight instead of seven supralabials and in having
the median subcaudal scales greatly widened, in having intercalated
plates on the outer side of the fourth toe nearly to the ultimate
phalanx, posterior supralabial low and elongate, young sometimes
seven-lined instead of five-lined, and especially in much larger size,
stocky build, and in early loss of striped pattern. _E. inexpectatus_
differs in having the median subcaudals not at all enlarged, and in
having the dorsolateral stripes a little more widely separated from the
midline.

_Eumeces fasciatus_ and its relatives present a curious exception to
Jordan's Rule, which states that the nearest relatives of any given
species are to be found neither in the same area nor in a remote one,
but in an adjacent region separated by a barrier. _E. fasciatus_ is
absent from almost all of Florida; otherwise its range overlaps most of
the ranges of both _laticeps_ and _inexpectatus_, the former including
the southeastern United States south of about latitude 40°, and the
latter being mainly in the Atlantic and Gulf states from Chesapeake Bay
into eastern Louisiana. Presumably both of these species began their
differentiation as southern populations of an ancestral _fasciatus_ and
later became isolated from it and continued their differentiation until
they overlapped it again as distinct species. The differentiation of
_laticeps_, being much greater, presumably took place at an earlier time
than did that of _inexpectatus_, and at present it overlaps _fasciatus_
more extensively. _E. laticeps_ probably diverged to such an extent that
competition with _fasciatus_ is greatly reduced where the two species
occur together.

Since _Eumeces laticeps_ was recognized by Taylor as a species distinct
from _fasciatus_, numerous authors have accumulated field observations
that demonstrate ecological divergence between the two. Conant (1951:33)
wrote that in Ohio _laticeps_ prefers a dry habitat of bare rocks,
cliffs, dry hillsides, and trees. He summed up the habitat difference as
follows: "_Fasciatus_ appears to be essentially terrestrial, to prefer a
moist environment and to be at home in ravines in southern Ohio.
_Laticeps_ on the other hand, is largely arboreal (particularly adults),
prefers dry cliffs, sunny hillsides and hilltops and lives in general
above the habitat of _fasciatus_." Netting (1939:127) likewise states
that in Pennsylvania _E. laticeps_ inhabits drier places than does
_fasciatus_, and is largely arboreal. Other authors with few exceptions
agree that _laticeps_ is largely arboreal, but most describe it as at
home in forest swamps and bottomlands. My own field experience with it
is limited. In the Pigeon Lake area of Miami County, Kansas, the
northwesternmost known locality of occurrence for _laticeps_, the
habitat relations described by Conant for Ohio were almost reversed.
_Eumeces laticeps_ was relatively scarce, and confined to the vicinity
of the swamp chiefly in areas that are flooded in time of high water.
All those seen were on or near massive snags of dead trees still
standing, but decayed and honeycombed with cavities. Slabs of bark
clinging loosely to the tree trunks, with spaces beneath, provided
shelter for the skinks and for the abundant arthropod fauna which
probably constituted their chief food source. This is one of the few
places in Kansas where a remnant of the original bottomland forest
remains. In central Louisiana, in 1947 and 1948, persons living on the
Kisatchie National Forest told me of large, red-headed skinks living in
hollow trees, which must have been _E. laticeps_. In the literature _E.
laticeps_ is frequently referred to as red-headed, although the reddish
suffusion on the head of the adult male is ephemeral in this species as
it is in _E. fasciatus_ and others. The heightened activity of the adult
males in the breeding season seems to have drawn attention to this
conspicuous temporary coloration while its absence at other seasons has
scarcely been mentioned.

Mansueti (1948:213) describing the habits of _laticeps_ in Maryland,
Louisiana and elsewhere in the southern states, emphasizes its arboreal
habits, referring to it as "'scorpion' of the treetops." He describes it
as dashing up and down tree trunks, along fences, and in abandoned
buildings. However, he states that it also spends much time on the
ground, and may take refuge in holes and cracks near ground level, and
gravid females are less arboreal, making their nests in decayed logs of
chestnut or oak. He mentions individuals having been found living far
above ground in tall trees, in nests of birds of prey. One old male that
was frequently seen by him always retreated far up a dead chestnut tree
that towered above the surrounding forest of scrub pine. Mansueti also
mentions arboreal combats between males and implies that they are
territorial. Taylor (1936:59) described _laticeps_ as typically an
arboreal form, almost invariably found in trees, and he indicated that
it has claws more curved than in other species--an obvious arboreal
adaptation. Parker (1948:25), however, stated that "_E. laticeps_ is
reputed to be rather arboreal, but field work in western Tennessee has
not borne out this belief. A few of the specimens have been found in
tall, dead trees, as has _E. fasciatus_." This statement evidently was
based on a small number of observations.

Cook (1943:15) mentions a female _laticeps_ found in a nest with a
clutch of 27 eggs (hence certainly a communal nest of two or more
females) in a burrow under a log, on July 8, 1941, in Lee County,
Mississippi. This account is under the name _Eumeces fasciatus_ but the
large size of the female precludes the possibility of it being either
_fasciatus_ or _inexpectatus_. The remainder of Cook's account is
evidently based on a composite of observations on all three species.

Goin and Goin (1951:29-33) have given an excellent brief account of
behavior and seasonal schedule in a small colony of _E. laticeps_ near
Gainesville, Florida, based on almost daily observations over a period
of years. In view of the greatly different climatic conditions, the
seasonal schedule is remarkably similar to that of _E. fasciatus_ in
Kansas, and it seems that the minimum threshold temperatures required
for activity are much higher in _laticeps_. Temperatures of 80° F. or
above for several consecutive days seemed to be a necessary stimulus for
emergence from hibernation; emergence was in the last week in March or
the first week in April in Florida. Hatching was found to take place in
late June or early July. Adults were last seen before retiring into
dormancy in the latter half of September and young of the year remained
active into October some two or three weeks later. The skinks observed
all lived in hollow water-oaks. When the population was at an especially
high level, in the late summer of 1949, each hollow oak was inhabited by
one young and one adult. Territoriality and mutual exclusiveness of
adults and even of young seems to be implied. The skinks were seen
eating spiders, ants, and cockroaches.

Neill (1950:115) mentions one sizable colony of _E. laticeps_ living in
a treeless urban area, in Georgia and depending for shelter on piles of
metal drums and other industrial equipment. Evidently, however, this was
an exceptional situation. In another paper, Neill (1948b:109) described
the specialized hibernation site requirements of _laticeps_ in Georgia;
the skink retires inside large, rotting pine stumps, especially those
that are leaning. He states (1948a:157) that in Georgia, _laticeps_ is
most common in the Coastal Plain and is much less numerous above the
Fall Line (the line between the Coastal Plain and the Piedmont). Deckert
(1918:31) wrote of "_Plestiodon fasciatus_" in the vicinity of
Jacksonville, Florida, where only _E. laticeps_ and _E. inexpectatus_
occur: "Inhabits hollow trees, always near water. Blue-tailed ones often
live around human habitations."

With regard to the ecological traits of _E. inexpectatus_ that
distinguish it from _fasciatus_, authors are much less definite, and
evidence is somewhat conflicting as the differences are relatively
minor. Engels (1949:269) noted the occurrence of _E. inexpectatus_ on
two low islands of submarine origin, off the North Carolina Coast,
Harkers Island and Shackelford Banks, and he surmised that the absence
from them of _E. fasciatus_ and _E. laticeps_ must have some ecological
significance, since all three species occur on the adjacent mainland.
Most of the island _inexpectatus_ were taken from beneath loose bark of
standing trees, while mainland _fasciatus_ was taken from beneath loose
bark of fallen trees.

Barbour and Carr (1940:129) wrote of _inexpectatus_ in the vicinity of
Miami, Florida: "... it seems to be the only one [of the five-lined
skinks] which has adapted itself to life under the rather specialized
environmental conditions existing in its rocky and decidedly tropical
habitat. It is one of the very few forms which have established
themselves on some of the waterless and poorly vegetated islands on both
coasts of the peninsula. _E. inexpectatus_ is much less arboreal than
either _laticeps_ or _fasciatus_. Although it climbs trees when pressed,
it is usually found on the ground among leaves or about fallen logs, and
particularly about stone walls or old buildings made of cut rock."

On the other hand, Neill (1948a:157) states that in Georgia,
_inexpectatus_ is often observed basking on tree trunks, and though
adults often forage on the ground, they dash for the nearest tree when
disturbed, usually climbing to a considerable height before halting. The
juveniles, however, are said to climb only rarely; they hide beneath
objects on the ground when they are pursued. Neill stated that _E.
inexpectatus_ occurs in dry pine forests where _laticeps_ and
_fasciatus_ are lacking, as well as in moist or even swampy woods. _E.
inexpectatus_ often forages on the sides of old buildings.

Hoffman (1953:172), in discussing means of differentiating between
_inexpectatus_ and _fasciatus_ in Virginia, states that there are ample
differences in color and behavior as well as in scalation. He describes
the color difference (blue color of tail of juveniles extending
anteriorly beyond pelvis; light stripes reddish-orange on head,
sublateral line present, in _inexpectatus_) but he does not describe the
differences in behavior. He states that _inexpectatus_ is the most
abundant lizard in southeastern Virginia. Carr (1940:76) also states
that _inexpectatus_ is less arboreal than _laticeps_ and is often found
under logs and boards in dry sand.

_E. inexpectatus_ thus seems to be adapted to a somewhat drier, more
open, habitat than that typical of _fasciatus_, but it is not clear
whether either species is more arboreal in habits. It is to be hoped
that the present inconclusive summary will draw attention to the problem
and will lead to more critical comparisons of the habitats and behavior
of the two species by herpetologists in the southeastern states. The
differences, both ecological and morphological, that distinguish
_inexpectatus_ from _fasciatus_ are of a degree usually found between
subspecies of the same species. The extensive geographic overlap between
them is indeed remarkable in view of the slight degree of
differentiation, morphologically and ecologically. They are, however,
complementary in part in their ranges, while _laticeps_ shares all parts
of its range with either one or the other, or both of them (see Figures
4 and 5).

    [Illustration: Fig. 4. Geographic distribution of _Eumeces
       inexpectatus_, as indicated by published records; only marginal
       and near-marginal records are shown, excluding those of doubtful
       validity.]

Under present conditions, with these three species so similar in habits
and so extensively overlapping in geographic range, it is difficult to
visualize a barrier such as would have been required for allopatric
speciation of the type, usual in vertebrates, to have occurred. One
might be tempted to postulate sympatric speciation, with the parent
form, presumably _fasciatus_, giving rise to the other two by abrupt
mutations. However, the demonstrable antiquity of the five-lined skinks
would allow ample time for divergence, allopatric speciation, and
subsequent disappearance of the barrier and intermingling of
populations. The displacement of floras and faunas that occurred in the
Pleistocene, with the successive advances and retreats of the
continental ice sheets might have had some part in bringing about the
present overlapping distribution, after the disappearance of the
original barrier. Such a barrier might have been an eastward extension
of the central grasslands to the Atlantic Coast at a time when the
climate of the continent was warmer and drier.

    [Illustration: Fig. 5. Geographic distribution of _Eumeces
       laticeps_, as indicated by published records; only marginal and
       near-marginal records are shown, excluding those of doubtful
       validity.]



Habitat and Limiting Factors


TEMPERATURE AND MOISTURE RELATIONS

For approximately half the year, at the latitude of northeastern Kansas,
five-lined skinks are dormant. In early fall, even before the advent of
cold weather, they are hard to find apparently having begun their
retirement into the sheltered situations where they spend the winter,
even though they may not be fully dormant at that time.

Remarkably little is known of the hibernation habits of this species or
of reptiles in general for that matter. The limit of tolerance to low
temperatures, the type of insulating medium, the moisture relationships,
the specific stimuli which cause the animal to retire to its hibernation
site or to emerge from it have not been determined. On only a few
occasions have natural hibernating sites or the dormant skinks in them
been observed by zoologists. Linsdale (1927:78) recorded one found in a
sawdust pile late in the winter of 1924 in Doniphan County, Kansas.
Hamilton (1948:211) found skinks of this species hibernating in Grant
Parish, Louisiana, in hollow logs 18-20 inches in diameter, five in one
log and three in another, on January 23, 1943. Frost in the damp wood
almost reached the lizards, which were in a torpid condition. These
observations were made when the temperature was 36°F. after the weather
had begun to moderate following an unprecedented four-day cold wave when
temperatures dropped to within a few degrees of 0°F. In both logs the
skinks were accompanied by hibernating anoles (_Anolis carolinensis_).
Neill (1948b:109) in Richmond County, Georgia, found _E. fasciatus_
hibernating in old stumps, fallen timber, piles of debris, or beneath
rocks and ground litter. Beneath scraps of rotting wood he often found
dead, frost-rimmed specimens which apparently had frozen to death.
Hibernating skinks of this species were found singly or in pairs. Some
were not fully dormant when found but could only gape and twist when
uncovered.

Of hibernating _E. laticeps_, Neill wrote, "Many examples are covered
with a waxy exudation, which I believe to be a secretion of the lizard
itself, rather than of the surrounding medium. This exudation has been
noted in other species also." Scott and Sheldahl (1937:192) described a
hibernating aggregation of _Eumeces septentrionalis_ found in Palo Alto
County, Iowa, on February 15, 1937, as follows: "The skinks were found
beneath a ledge of yellow clay about four and one-half feet below the
surface. The lizards, 52 in number, were assembled in a compact group
about the size and shape of a football. A soft, web-like material
surrounded the mass and adhered to the bodies of the animals. Upon being
uncovered some of them exhibited signs of life; others were dead."
Breckenridge (1943:595) reported that a gravel digging crew found
hibernating _E. septentrionalis_ in late October and in January at
depths of two feet (one), and three feet (groups of three and eight).
Tihen (1937:405) recorded that two five-lined skinks found on January
13, 1948, were hibernating eight feet underground at Ranson, Ness
County, Kansas. This locality is far to the west of the main range of
_fasciatus_. Conant (1951:30) mentions the finding in Ohio of a young
blue-tailed skink under a log where it seemed to be hibernating, on
January 22. The spot where it was resting was soggy, and surrounding
areas were covered with several inches of water.

In the course of the present study, no five-lined skinks were found
hibernating under natural conditions, but on numerous occasions in early
spring, two or three or four skinks were found together under massive
flat rocks in semi-torpid condition, beside deep holes or crevices which
presumably led to their hibernation sites in better insulated cavities.
In the winter none could be found in such situations under large rocks,
nor in the superficial types of hibernation sites described by Neill and
Hamilton in the southern states. In the more severe winter climate of
Kansas better protected hibernation sites are required. In the rock
ledge situations where skinks were studied, excavation for the purpose
of finding hibernating individuals was not practical.

On several occasions when skinks were put in the freezing compartment of
a refrigerator and frozen solid, at temperatures several degrees below
freezing, they failed to revive when warmed. However, they can survive
temperatures a little below freezing. On April 1, 1953, one was placed
in the freezing compartment with a thermometer inserted rectally. After
2-1/2 hours when the compartment was opened, this thermometer showed a
temperature of -2.5°C, after a delay of several seconds in obtaining a
reading because of condensed moisture on the thermometer obscuring the
mercury column. Another thermometer that rested beside the skink in the
compartment showed 27°F. The skink was limp and immobile. It was placed
on a table top at normal room temperature, and it warmed rapidly. When
it had reached 1.5°C, it contracted its muscles in response to a light
pinch. At 9.5°C it raised its head and had its eyes partly open. Twenty
minutes after its removal from the freezing compartment, it was still
lying in the same position, its temperature having reached 13.5°C. When
handled it seemed dazed for several seconds as if just awaking. Then it
crawled away briskly.

On March 28, 1953, a skink was placed in the freezing compartment for
about 10 minutes, and upon removal its temperature was recorded as
-0.5°C. It was not frozen, but was limp and unresponsive to such stimuli
as pinching or pricking. At 1.5°C feeble movements of the legs were
noticed. The eyes were still closed. At 3.4°C the legs moved as if in
walking. At 6.0°C the skink raised its head and took several steps
forward. At 7.5°C it protruded its tongue and dragged itself about for
several steps. At 9.0°C movements of the sides indicated an inspiration
approximately every three seconds. At 12.2°C it opened its eyes.

On March 25, 1953, a skink that I had caught the day before and left
overnight in an unheated room, was found to have burrowed into loose
earth in its container. When exposed, its temperature was 1.8°C and it
was unable to crawl normally, but took only one step at a time, and
progressed with slow lateral squirming motions. Placed on the ground
outside the building, in the shade where there was still a little frost,
it moved forward persistently for several inches trying to burrow into
the surface litter. After a few minutes, its eyes were shut and it
seemed incapable of further locomotion. Its temperature was 1.4°C. When
placed on its back it was able to turn over slowly after several
seconds. A few minutes later its temperature was 0°C, and it was totally
helpless, although still capable of feeble movement. When stimulated by
touch, it flexed its body a little, or moved each limb slowly in an arc
as if walking, the movement taking several seconds. Placed on its back
or side it was unable to right itself.

Less than three hours later I saw a skink that was active in the field.
Slight movement at the edge of a rock that was exposed to sunshine
attracted my attention and turning the rock I found the skink
underneath, lively enough to scramble for shelter but slow and stiff
compared to those that are fully active. Its temperature was 13.5°C and
air temperature was 7.5°C. In damp soil beneath the rock where the
lizard was found, temperature was only 5.7°C. It seemed that the skink
had been sufficiently warmed by contact with the undersurface of the
rock to move into the open, and was just emerging when I approached.
After capturing the skink, I set it on a rock in the sunshine, and in
five minutes its temperature had risen to 26°C.

As compared with its reptilian associates in northeastern Kansas,
_Eumeces fasciatus_ is outstanding in its ability to become active and
carry on normal activities at relatively low air temperatures. In spring
it is usually seen in the open before any other kind of reptile, because
it has the capacity to move about sluggishly at temperatures so low that
some other reptiles are numbed and completely immobilized, and because
it has small size enabling it to make rapid adjustment upward by
insolation, or contact with sunshine-warmed surfaces. By virtue of this
ability it has been able to extend its range farther northward than most
other reptiles, and it has gained the advantage of a longer growing
season. This advantage was especially apparent in the spring of 1953. A
mid-March warm spell with seven out of eight successive days having
maximum temperatures in the sixties culminated on March 20, with a
maximum air temperature of 82°F. This warmth was sufficient to activate
most of the five-lined skinks, and a few reptiles of other kinds. After
the unseasonably high temperature of March 20, there was rapid return to
cooler weather with temperatures frequently below normal throughout
April. As a result there was little activity of other kinds of reptiles
that month, but five-lined skinks were active on most days. On only a
few days, those with temperatures in the low forties or those on which
the sky remained overcast, did the skinks remain inactive. On most days
maximum temperatures were in the fifties and sky was clear. Under these
conditions the skinks were able to emerge and bask, rapidly raising
their body temperatures far above those of the air and substrate.

By the end of April some kinds of deciduous trees have not yet begun to
leaf out, and in most other kinds the leaves are still in an early stage
of development. Absence of a leaf canopy during April permits the skinks
to utilize the spring sunshine to maintain their body temperatures at
almost the same high level that they maintain in the same situations in
hot summer weather.

    Table 2. Temperatures (in Degrees Centigrade) of Skinks Found Under
       Flat Rocks Exposed to Sunshine, Contrasted With Air Temperatures;
       Spring of 1953.

  ==========+==========+============+===========+
            |   Age    |   Skink    |   Air     |
    Date    | and sex  |temperature |temperature|
  ----------+----------+------------+-----------+
  March 23  | Ad. [F]  |     20.8   |  12.4     |
  March 23  |   young  |     24.7   |  12.4     |
  March 25  | Ad. [M]  |     22.8   |  12.5     |
  March 25  |   young  |     21.0   |  12.5     |
  March 25  |   young  |     25.7   |  14.5     |
  March 25  |   young  |     22.5   |  14.5     |
  March 27  | Ad. [M]  |     26.6   |  16.5     |
  March 27  |   young  |     22.0   |  16.5     |
  March 27  | Ad. [F]  |     22.5   |  16.5     |
  March 27  | Ad. [F]  |     20.5   |  16.2     |
  March 27  | Ad. [F]  |     26.5   |  19.3     |
  March 27  | Ad. [F]  |     30.7   |  19.3     |
  April 4   |   young  |     22.0   |  18.1     |
  April 5   | Ad. [F]  |     26.0   |  13.0     |
  April 6   | Ad. [M]  |     31.5   |  13.5     |
  April 6   | Ad. [M]  |     23.7   |  16.0     |
  April 6   | Ad. [F]  |     22.2   |  16.0     |
  April 6   | Ad. [M]  |     20.0   |  16.0     |
  April 6   | Ad. [F]  |     20.0   |  16.0     |
  April 6   | Ad. [F]  |     26.5   |  20.3     |
  April 20  | Ad. [F]  |     29.7   |  17.2     |
  April 20  | Ad. [F]  |     25.8   |  17.2     |
  ----------+----------+------------+-----------+

Recent studies by Cowles and Bogert (1944:288-289) and Bogert (1949:198)
have brought out the fact that terrestrial poikilotherms, and especially
lizards, maintain fairly high and constant body temperatures through
behavioral thermoregulation, during their periods of activity. For
genera and species of lizards, there are optimum body temperatures,
which the individual tends to maintain, fluctuating within a range of
only a few degrees while it is active. Forms that are not closely
related may differ notably in their optimum temperatures, although
within any one genus the range is slight. For example in the iguanid
genus, _Sceloporus_, Bogert found that different species from such
distant regions as Arizona and Florida agreed in having body
temperatures approximating 35° or 36°C., while different members of the
teiid genus _Cnemidophorus_ in the same two regions were found to
approximate 41°C. in mean temperatures. In commenting on the
distribution of North American lizards as affected by opportunity for
behavioral thermoregulation by direct insolation, Bogert (_op.
cit._:205) wrote: "Such secretive lizards as skinks (principally
_Eumeces_ in North America) with low body temperature preferences
approximating 30°C. are dominant in Florida and the Gulf Coast, in
contrast to the Teiidae and Iguanidae (several genera in the United
States), which are far more abundant in the arid regions of the
Southwest." Bogert and Cowles (1947:19) record that in a large
individual of _Eumeces inexpectatus_ taken near the Archbold Biological
Station in Florida, the body temperature was 33.2°C.

In the 1952 season, a small thermometer of the type described by Bogert
(_op. cit._:197) was frequently carried on collecting trips, and cloacal
temperatures were recorded for the lizards collected. For those found in
traps the opportunity for behavioral thermoregulation was limited, and
temperatures usually approximated those of the air. The circumstances of
capture, and the air temperatures were recorded for most of the skinks
taken. For those found under rocks or in other shelter, the temperature
usually approximated that of the immediate surroundings, and averaged
much lower than for those taken in the open, but some found in such
shelters had temperatures many degrees higher than their surroundings,
and were fully active, having evidently just taken to cover to escape
notice as the collector approached. As soon as a lizard was secured it
was held in a leather glove or heavy cloth to prevent conduction of heat
from the collector's hand, and a reading was taken within a few seconds.
Most of the skinks found in the open could not be caught immediately but
were secured only after minutes of maneuvering on the part of both
collector and lizard. In most instances this maneuvering probably
entailed some loss of heat by the lizard, as it interrupted its
thermoregulatory behavior to run to a place of concealment, usually in
shadow on a tree trunk, or in or beneath ground litter. Excluding all
those not found active in the open, the mean temperature, in a sample of
41, was 31.5°C. ± .60. This figure is thought to be slightly too low
because of heat loss by many of the skinks in the time required to
capture them.

In order to test the range of tolerance and verify the preferred optimum
temperature of the five-lined skink, an experimental terrarium was set
up providing extremes of temperature at each end. A false floor of 1/8
inch wire screen was provided, with a seven-inch strip of galvanized
sheet metal beneath it at each end. Beneath the screen and sheet metal
at one end the space was filled with chopped ice, and "dry ice."
Observations were made on hot, clear summer days, with the terrarium
arranged so that the half of it containing ice, was in shadow, and the
other half was in sunshine. The strip of metal, warmed by direct
sunlight, became uncomfortably hot to the touch while at the other end
the sheet metal and overlying screen were cooled by the ice. A narrow
zone across the middle of the terrarium had screen but no underlying
sheet metal and was the only part within which the lizard could maintain
normal temperature, one end being uncomfortably hot and the other end
too cool. A large dead skink left on the metal strip in direct sunlight
for five minutes had a cloacal temperature of 45.3°C., and after five
minutes on the screen at the cool end, its temperature had dropped to
25.5°C. On several occasions a number of skinks were put in the
terrarium and their temperatures taken at brief intervals. Temperatures
ranged from 21.6°C. to 37.7°C. but were mostly within a much narrower
range, from 28° to 36°C. One skink that seemed to be sick was sluggish
in behavior, not responding to the extremes of temperatures as readily
as the other individuals and his temperature fluctuated widely and
irregularly. Eliminating this individual, 66 temperature readings taken,
from five other skinks, gave a mean of 32.6°C. ± .235. While nearly all
the temperature readings were within a range of ten degrees, two of the
readings were outstandingly low and perhaps should be discarded. If this
is done, a mean of 33.8°C. ± .19 is obtained for the remaining 64. There
is distinct bimodality in this series however, with a mean of 34.2° for
the 49 higher readings, and a mean of 28.8°C. for the 15 lower
temperatures. A similar bimodality is evident in the readings obtained
from skinks caught in the open under natural conditions. It seems that
the lower readings result from lags in the skinks' response when body
temperature drops slightly below the optimum. The skink is quick to make
adjustment whenever its temperature appreciably exceeds this optimum
level, and is in extreme discomfort at only a few degrees higher
temperature. At slightly lower temperatures, however, the skink
experiences no discomfort, and only slightly decreased efficiency in its
various functions, and its thermoregulatory behavior in making
readjustment toward the optimum is likely to be leisurely and
interrupted unless its temperature drops below 28°C.

Catching the skinks in the experimental terrarium at frequent intervals
to take their temperatures involved some disturbance to them,
interrupting their thermoregulatory behavior. The experimenter's first
attempt to grasp a skink sometimes failed, and it then dashed about the
terrarium for several seconds, probably altering its temperature
somewhat. Nevertheless most of the lizards' movements were motivated by
thermoregulation. This was especially evident when they were left
undisturbed, and is illustrated by the following notes on behavior of an
adult female and half-grown young of _fasciatus_ and a young _E.
obsoletus_ on the afternoon of July 21, 1952.

  2:58 All resting over cooled metal.

  3:01 Female runs to line of sunshine and shadow, coming to rest with
       approximately half her body in sunshine, the other half in shadow
       over the cooled metal.

  3:03 Female reverses position so that hindquarters previously in shadow
       are now in sunshine, and forequarters are in shadow.

  3:03-1/2 Young runs to middle coming to rest in sunshine on screen.

  3:04 Female moves back to the cool end.

  3:05 Young moves to edge of cooled metal but not over it, in a narrow
       middle strip that has sunshine.

  3:05-1/2 _E. obsoletus_ moves from cool end to middle, partly in
           sunshine.

  3:07 _E. obsoletus_ adjusts its position in narrow middle strip of shadow
       just off the cold end.

  3:08 Boards used for shading adjusted back slightly so that
       _E. obsoletus_ is in sunshine.

  3:08-1/2 _E. obsoletus_ moves back to cold end.

  3:10 Young still at middle, but resting mainly over cooled metal with
       tail partly in sunshine.

  3:10-1/2 Young moves out into sunshine at middle.

  3:11 Female moves out into sunshine at middle. _E. obsoletus_ moves over
       cooled metal to its edge, coming to rest partly in sunshine.

  3:12 Female moves back over cooled metal.

  3:13-1/2 Air temperature 33.3°C. _E. obsoletus_ shifts a short distance
       so that it is resting entirely over the cooled metal, with only part
       of its tail receiving sunshine.

  3:17 Young moves about in sunshine, then comes to rest in shadow with half
       its body over cooled metal.

  3:19 Young shifts so that more than half its body is in sunlight in middle
       section.

  3:20 Young shifts away from sunlight, coming to rest with most of its body
       over the cooled metal.

  3:21-1/2 Female moves from cooled metal to sunshine in middle strip.

  3:23 Female moves out of sunshine, partly over edge of cooled metal.

  3:30 Young moves off cooled metal, coming to rest over edge of warmed metal
       in narrow middle strip that is in shadow.

  3:30-1/2 Young moves back away from warmed metal, pauses briefly, and then
       moves over cooled metal coming to rest there.

  3:31 Female shifts so that about half her body is in sunshine in the middle.

  3:32 Female shifts back into shadow, partly over cooled metal.

  3:33 Boards providing shade readjusted so that female is in sunshine.

  3:33-1/2 Female moves back into shadow over cooled metal.

  3:38 Female moves to edge of cooled metal, resting partly in sunshine;
       sky is becoming slightly overcast.

  3:40 Temperature of female 33.4°C.

  3:41 Temperature of young 32.8°C.

  3:43 Temperature of _E. obsoletus_ 32.4°C.

  3:45 Young moves to shaded edge of warmed metal. Finds a dead spider
       dropped there and eats it.

  3:47 Temperature of female 32.3°C.

  3:48 Temperature of young 36.4°C.

  3:50 Temperature of _E. obsoletus_ 33.8°C.

  3:52 Sky partly overcast with thin layer of clouds;
       observations concluded.

Having once emerged from its hiding place a skink becomes more or less
independent of the temperature of the air and substrate, as it is
capable of thermoregulation through insolation. However, after a period
of cooling and inactivity in dormancy, or merely resting for the night
in temporary shelter, the skink is dependent on warmth from the air or
substrate or both to become sufficiently activated so that it can emerge
and take advantage of direct sunlight. About 10:00 a. m. on April 13,
1951, when the air temperature was a little less than 10°C., a large
adult male rustling among dry leaves attracted my attention. Obviously
recently emerged from hibernation, he was caked with dried mud and his
eyelids were nearly sealed shut. He had been sunning, however, and was
active enough to elude my attempts to catch him, as he scurried into a
deep crevice under the ledge. On the morning of March 24, 1951, while
the temperature was still between 10° and 15°C., a subadult skink, the
first one of the season, was seen sunning itself at the entrance of a
deep crevice under the ledge. This skink was still not fully active, and
its movements were stiff, yet it was alert and wary, and it quickly
retreated back into the crevice. During the first week of May, 1952,
skinks were active in abundance and numbers were caught daily in funnel
traps and pitfalls. On May 9, however, the maximum air temperature was
16.5°C. with cloudy sky and occasional showers. Under these conditions
skinks stayed under cover; none was seen in the open nor caught in a
trap, and several found under rocks were slow and sluggish. On May 10 a
terrarium with several adults was placed in dilute sunshine beside a
window in an unheated room. After a period of basking the skinks were
stimulated to activity, but were unable to attain normally high
temperatures, and as a result their movements were like slow motion
caricatures of the normal behavior. Males approached each other with
menacing demeanor, with heads turned, snouts depressed, and forequarters
standing high. Frequently one would edge up to another and bite hard at
its flanks. The several males were sexually aroused by the presence of
the two females, but were capable of only the preliminary phases of
courtship, in delayed and protracted form. The temperature of one was
18.2°C. when the sun had nearly set and activity was tapering off, at an
air temperature of 16.2°C. At 16°C. skinks in a terrarium with no access
to sunshine for the most part showed no interest in food and kept out of
sight under cover. When exposed their activity was directed almost
entirely toward burrowing into the substrate or searching for objects
beneath which to hide. One adult female was partly exposed by scraping
away loose soil into which she had burrowed. A mealworm was then dropped
just in front of her head. She tested it several times with her tongue
and then ate it without emerging, her movements being much less brisk
than they normally are in feeding. Probably this approximates the
threshhold temperature for feeding behavior. At 19.5°C. the several
skinks in this terrarium were moving about in the open although they
were not exposed to sunshine, and they accepted food avidly when it was
offered, but were much slower than at optimum temperatures. On May 16,
1951, when a pair of skinks were put together in a terrarium in the
laboratory at 21°C., copulation ensued but it was of longer duration
than in other observed instances, seemingly because of the relatively
low temperature.

Relatively few temperature readings on gravid or brooding females under
natural conditions were obtained as they were easily disturbed and
tended to desert their nests at slight provocation. To avoid desertions
handling was kept to a minimum. Occasionally gravid females were caught
in the open, but most of them were in nest burrows under flat rocks.
These females found in nests were mostly cold to the touch, and the
temperature readings taken on some of them usually approximated the air
temperature, being either higher or lower (depending on whether the air
was cooling or warming and whether the lizards were warmed by contact
with rock or soil receiving sunshine). On May 23, 1952, 22 skinks were
seen, four adult males, seven adult gravid females, and 11 young. Of
these the adult females all were in nest burrows, and were cold and
slow; consequently all of them were caught without difficulty. The males
and young, however, were either fully warmed or warm enough to escape
rapidly, so that only three of the young and no adult males were caught.
Temperatures of the females tested were 25.6°, 23.6°, 23.5°, 22.3°, and
19.4°, and for the three young, 32.8°, 28.4°, and 28.4°. Air temperature
varied from 20.5° to 24.8°. For the total of 30 females in nest burrows
whose temperatures were taken in 1952, the average was 26.3°C, ranging
from 16° to 34°. Gravid females, and those with nests and eggs were
rarely seen in the open.

The five-lined skink is confined to a region where summer rains are
frequent. It is evident that a regular supply of drinking water is one
of the most critical ecological requirements. Bogert and Cowles
(1947:19) found that an _E. inexpectatus_ experimentally kept at high
temperature lost moisture at a more rapid rate than any other reptile
tested (including two other kinds of lizards, four kinds of turtles, an
alligator, and three kinds of snakes). They remarked that this rapid
moisture loss presumably accounts for the inability of skinks to survive
in containers when no moisture is readily available, and also accounts
for their absence in truly arid habitats. The Natural History
Reservation is situated near the western edge of the species' range in a
climate that may be near the limit of its range of tolerance. However,
on most summer mornings low woodland vegetation is copiously laden with
dew, and this evidently fulfills the need for drinking water. Diminution
of surface activity and retirement to underground retreats seem to be
closely correlated with cessation of rains in late summer. After
rainless periods in August and September, when morning dew is no longer
available these skinks, especially the adults, are no longer regularly
seen in the open. They have retreated to underground shelters where they
spend nearly all their time. The time of disappearance varies from year
to year and the correlation with varying weather conditions seems
obvious. While no actual experiments were performed to determine the
moisture requirements, it is evident that the need for moisture rises
sharply with increased temperature. Skinks that are dormant in
hibernation survive for periods of months without drinking, with but
little loss of weight. In their underground shelters temperature is low
and presumably relative humidity is high. At temperatures above their
optimum of approximately 34°C. the skinks are especially subject to
rapid moisture loss, since evaporation of body moisture is resorted to
as a device to keep the temperature below the lethal level. The skinks
subjected to extremes of temperature in an experimental terrarium were
seen to lap up condensed moisture on the cooled metal plate at intervals
of a few minutes. After an hour or more in the experimental terrarium
they seemed somewhat debilitated. Skinks brought from the study areas to
the laboratory for weighing and other records, were ordinarily returned
on the following day. When circumstances prevented adherence to this
schedule in hot summer weather, mortality could be expected in the
skinks kept in cloth bags or glass containers, unless water was
provided. Dramatic weight loss of up to more than 30 per cent was
recorded in some individuals, kept at the high temperatures which
usually prevailed in the laboratory, over periods of days in the summer.
Skinks having access to drinking water often ingest amounts far beyond
their immediate requirements, which may be stored in the bladder and
drawn upon over periods of days as it is needed, or may be utilized to
dampen the soil of the underground shelter and raise the humidity, as
incubating females seem to do.


GEOGRAPHIC RANGE AND THE DECIDUOUS FOREST HABITAT

EUMECES FASCIATUS corresponds in its distribution with the original
hardwood forests of eastern North America, as mapped by Braun
(1950:cover folder) and the "Oak-Wild Turkey Biome" of Shelford
(1945:240). Few species of vertebrate animals have ranges that coincide
more closely with this extensive area (exclusive of the northern edge,
that part characterized by Braun as the Hemlock-White Pine-Northern
Hardwoods). This latter is a mixed forest which actually is transitional
between the more typical deciduous forest farther south and the Taiga
Biome (or Formation) to the north, which is dominated entirely by
conifers. At the northern edge of its range _Eumeces fasciatus_ is much
less generally distributed than it is farther south. Although it is well
established and even may be locally numerous in South Dakota, Minnesota,
Wisconsin, northern Michigan, Ontario, northern New York, and
Connecticut, the locality records from these states are few, and
seemingly represent isolated and widely separated colonies that are able
to persist because of favorable combinations of environmental factors
not of general occurrence in the surrounding regions. Figure 6 shows the
extent of the hardwood forests as mapped by Braun (excluding the
transitional Hemlock-White Pine-Northern Hardwoods Association) with
specific locality records of _E. fasciatus_ included in all outlying
portions of the range. The locality records are those published by
Taylor (1936:206-212) supplemented by other marginal records, more
recently published, by Hamilton (1947:64) for New York, Breckenridge
(1944:97) for Minnesota, Hudson (1942:42) for Nebraska, Smith (1950:185)
for Kansas, Brown (1950:116) for Texas, Neill (1948:156) for Georgia,
and Neill and Allen (1950:156) for Florida. Along the northern edge of
its range, the skink invades the Hemlock-White Pine-Northern Hardwoods
Association, in Massachusetts, New York, Pennsylvania, Ontario,
Michigan, and Wisconsin, but does not penetrate far into it anywhere.
Correspondence of its northern limits with those of the Oak-Chestnut,
Maple-Basswood, Beech-Maple and Oak-Hickory associations is remarkably
close, considering the fact that the boundaries of these climax
associations are not sharply defined; rather they merge by gradual
stages into the northern coniferous forests, with outlying peninsulas
and islands where conditions are favorable.

The outlying northern localities where _E. fasciatus_ occurs within the
Hemlock-White Pine-Northern Hardwoods Association are all within the
region of Pleistocene glaciation, which 20,000 years ago, or even more
recently, were covered with the continental ice mass during Wisconsinan
time. Yet the localized northern populations of skinks evidently are
relicts from a time when favorable conditions were more widespread in
the general region. Braun (_op. cit._:464-465) indicates five successive
postglacial stages in the trends of climate up to the present, as
revealed by bog pollen profiles: (1) Cool and moist; (2) warm and dry;
(3) warm and humid; (4) warm and dry; (5) cool and moist. Stages 2 and 4
would have been most favorable for encroachment of the skink into
glaciated regions, whereas stages 3 and 5 might have caused retrenchment
of its populations. In view of the localized habits of individuals, and
the lack of any mechanism for rapid dispersal, the time available seems
no more than adequate for the distance of 200 miles or more northward
that the skinks must have moved since the final retreat of the ice
sheet. This northward movement involved crossing of formidable barriers
such as the Great Lakes. Even minor barriers such us small rivers and
creeks, might be expected to halt population movements for long periods.

[Illustration: FIG. 6. Geographic distribution of _Eumeces fasciatus_ as
indicated by published records (marginal and near-marginal records
shown, excluding those of doubtful validity). (1) Distribution of the
Deciduous Forest Formation of eastern North America, as mapped by Braun
(1950), but excluding the Hemlock-White Pine-Northern Hardwoods
Association that is transitional to the more northern coniferous
forests. (2) The shaded area in Kansas that is outside the Deciduous
Forest Formation comprises the Kaw River District, Cherokee Prairie
District, and southern Osage Savannah Biotic District (Cockrum, 1952).]

The over-all geographic range is approximately square, roughly a
thousand miles across, from north to south and from east to west. On the
east and south it is limited by the Atlantic Ocean and the Gulf of
Mexico. On the north and west its limits correspond with those of the
hardwood forests. On the northwest, it reaches southwestern Minnesota
and the southeastern corner of South Dakota, extending far out into
peninsular extensions of the Oak-Hickory Association which penetrate
westward into the prairies along the main river valleys.

In Kansas it occurs over the eastern one-fourth, west to the Flint
Hills, and a little farther west in peninsular extensions of the forest
along some of the main river valleys. In Braun's map the Deciduous
Forest Biome is shown to reach only the eastern edge of Kansas along the
Kaw River and Missouri River at and near their junction, the Osage (or
Marais des Cygnes) River valley near the Missouri border, and the
southeastern corner of Kansas. However, for almost 100 miles farther
west from the Missouri border, the country has the aspect of a savannah
with scattered groves of trees on hillsides and along streams, providing
suitable habitat. The distribution of the five-lined skink in eastern
Kansas corresponds well with certain "Biotic Districts" as mapped by
Cockrum (1952:12), namely the Kaw River, Osage Savannah (southern part),
and Cherokee Prairie. Conversely the skink is excluded from the Short
Grass Plains and Mixed Grass Plains Biotic Districts which occupy nearly
all of the western three-fourths of the state. There are two specimens
in the University of Kansas Natural History Museum, labelled Ranson,
Ness County. This locality, in the western third of the state, more than
150 miles from any other recorded station, may represent an isolated
colony; however Smith (1950:185) states that the record needs
verification, and it is not included in the map, Figure 6.

In Oklahoma the distribution records fit fairly well the portion of the
state mapped by Braun as the Oak-Hickory Association of the Deciduous
Forest, but extends a little farther west in the northeastern part of
the state. A game type map published by the Oklahoma Game and Fish
Department, Division of Wildlife Restoration, in 1943 shows in more
detail distribution of the main vegetation types within the state. The
locality records for the skink fall almost entirely within three of the
fifteen vegetation types mapped, namely, the oak-pine, and oak-hickory
forest of the state's eastern edge and the post oak-blackjack oak type
of the eastern and central parts. The locality records extend almost
throughout the area occupied by these three types but not in attenuate
westward extensions of the post oak-blackjack type that occur along
several of the main stream courses. In Texas likewise the recorded
localities fall mainly within the area mapped as deciduous forest, but
with several slightly beyond its boundaries. In a detailed map of the
"game regions" of Texas (Anonymous, 1945:1), some of these outlying
localities fall into the coastal prairie area, and the remainder into
the post oak and blackland prairie belts, which grade into each other
and the oak-hickory forest.

The former distribution of the five-lined skink may be postulated on the
basis of the fossil record of its community associates since it is a
primitive and conservative type. Taylor (1936:56) explained the present
discontinuous distribution of the genus on opposite sides of the world
on the basis of a former northern connection of the continents. He
wrote: "I regard migration from North America to Asia as having taken
place via land bridges joining the Alaskan peninsula with Asia either at
Bering Straits or via the Aleutian Island arc to Kamchatka, or both. One
would need postulate but slight climatic changes since the present
climate of this coastal region is probably no more rigorous than that of
southern Canada which has three species of the genus." However, such
former northward distribution, while entirely probable, would have been
possible only in a climate much milder than that which prevails at
present. In Asia, _tunganus_ on the mainland and _latiscutatus_ on the
island of Hokkaido extend north to about latitude 43°, and in North
America, _fasciatus_ extends slightly farther north. In order to have
crossed between Alaska and Asia on presumed land bridges these skinks
would have had to extend their ranges about 20 degrees north of their
present limits, into what is now a cool climate. The winter climate of
the Bering Sea is perhaps not much beyond the range of tolerance of the
more cold-adapted forms of _Eumeces_, but the cold, cloudy, wet, and
changeable summer climate is far beyond the range of tolerance of
_Eumeces_ or any other lizard.

It is highly improbable that the fossil record will yield direct
evidence for the existence of a northern ancestral _Eumeces_ of the
_fasciatus_ group. The characters by which the various forms are
recognized are to be found mainly in details of pattern and scalation;
the skeleton is so conservative that specific characters are ill defined
or lacking even in well preserved fossil material. This hypothetical
ancestor probably was a member of a deciduous forest community having
components in common with the modern forests where the American and
Asiatic species occur, along with types now extinct, and others which,
though existing at the present time, have become separated from their
original associates and occur in other regions.

Hollick (1936:11) has described a rich early Tertiary Alaskan flora
strikingly different from that of the same region at the present time.
Composed of genera now characteristic of warm-temperate to subtropical
climates, it was remarkable in having many types of plants that are now
most characteristic of the North American hardwood forests in the
southeastern part of the continent. Besides such widespread genera as
_Fagus_, _Betula_, _Ulmus_, _Platanus_, _Castanea_, _Corylus_,
_Carpinus_, _Crataegus_, _Spiraea_, _Myrica_, _Smilax_, _Pinus_,
_Picea_, and _Abies_, this flora included others now characteristic of
both warm-temperate southeastern North America and Eastern Asia, as
_Magnolia_, _Nyssa_, _Sassafras_, _Persea_, _Benzoin_, _Hamamelis_,
_Liquidambar_, _Celastrus_, _Nelumbo_, and _Onoclea_. It included genera
_Carya_, _Taxodium_ and _Comptonia_ that now are limited to SE North
America, _Sequoia_, now limited to western North America, and also
included several genera which at present are limited to southeastern
Asia: _Ginkgo_, _Glyptostrobus_, _Cinnamomum_, _Hausmannia_,
_Artocarpus_, _Dillenia_ and _Koelreuteria_. This fossil flora provides
strong evidence that in the early Tertiary climatic and habitat
conditions as far north as Alaska were favorable for the existence of an
ancestral _Eumeces_ similar to the modern _E. fasciatus_, which might
have given rise to both North American and Asiatic members of the
_fasciatus_ group.

There is abundant evidence for the existence of an Eocene land
connection between Alaska and northeastern Siberia, permitting free
interchange of faunas between the two continents, as shown by the almost
simultaneous appearance of various mammalian groups in the fossil
records of Asia and North America. Simpson (1947:627) has summarized the
evidence that such intermigrations were occurring throughout most of the
Tertiary, with occasional interruptions as in middle Eocene, and in
middle and late Oligocene, and with increasing selectivity, chiefly a
progressive tendency toward screening out of the groups less tolerant of
cold (judged on the basis of their modern representatives). In the late
Tertiary, and especially in the Pleistocene, animals known to have made
migrations between North America and Asia were types now characteristic
of boreal climates (_e. g._ pika, hare, vole, lemmings, marmot, jumping
mouse, fox, wolverine, bear, moose, caribou, sheep, bison, camels,
mammoth). Simpson believes that there was fairly strong climatic
selectivity even in the Miocene interchanges, and he indicates several
important groups that were non-migrants in the Miocene, most of them
remaining so through the Pliocene and Pleistocene--the primates,
Rhizomyidae, Gliridae, Viverridae, Hyaenidae, Dicerorhininae, Suidae,
late Anthracotheriidae, Hippopotamidae, Tragulidae, Muntiacinae,
Lagomerycidae, Giraffidae, and Bovidae. He states that there is good
evidence that these are all mainly warm-climate animals which are not
likely to have ranged in any force into a cold-temperate or boreal
environment. In view of these conclusions it seems doubtful whether
_Eumeces_ or other reptiles could have crossed the Alaskan-Siberian land
connection so late as the Miocene.

On the contrary, the climate and habitat conditions with which _Eumeces_
might have been associated, although present as far north as Alaska in
the Eocene, evidently had shifted far to the south by mid-Tertiary time.
Axelrod (1950:230) has described a Miocene forest of the Columbia
Plateau and northern Great Basin indicative of a uniform temperate
climate and an average rainfall of thirty-five to sixty inches. This
forest included: (_a_) various genera now characteristic of the
southeastern hardwood forest or confined to it--_Carya_, _Castanea_,
_Comptonia_, _Fagus_, _Liquidambar_, _Nyssa_, _Taxodium_; (_b_) other
genera at present more characteristic of the western United
States--_Sequoia_, _Lithocarpus_, _Pseudotsuga_, _Mahonia_, _Thuja_,
_Gaultheria_, _Amelanchier_; (_c_) wide-ranging genera including
_Alnus_, _Acer_, _Betula_, _Populus_, _Quercus_, _Picea_, _Pinus_,
_Tsuga_, _Cornus_, _Ribes_, _Rosa_, _Hydrangea_; (_d_) modern east Asian
genera, including _Ginkgo_, _Ailanthus_, _Glyptostrobus_, _Keteleria_,
_Koelreuteria_, _Metasequoia_, _Pseudolarix_, _Pterocarya_, _Zelkova_,
which were eliminated from the North American flora in the latter part
of the Tertiary. In short, this western Miocene forest was remarkably
similar in many respects both to the presumably ancestral early Tertiary
Alaskan forest and the modern southeastern hardwood forest. The extent
of this Miocene forest is unknown but judging from the sites where it
has been recorded, it had progressed about halfway, both in latitude and
in actual distance, from Alaska to the area occupied by the modern
southeastern deciduous forests. Several other reptilian genera have
distributions similar to that of the _fasciatus_ group, with
representatives in southeastern Asia and southeastern North America that
probably have parallel histories of distributional divergence from early
Tertiary northern ancestors similar to contemporary species (Schmidt,
1946:148-150). _Alligator_, _Natrix_, _Ancistrodon_, _Scincella_,
_Elaphe_, _Opheodrys_, and within the genus _Eumeces_, the _obsoletus_
group, all provide excellent examples.


EFFECT OF CLIMATIC FACTORS

Accounts of the habits and habitat, by various authors, indicate
versatility in behavior, and adaptation to a variety of habitat
conditions in different climates and plant associations. Some of the
differences evidently result from the skink's tendency to maintain
itself in surroundings of favorable temperature and humidity, which
obviously are to be found in different types of situations at different
extremes of the range. Hence even though the skink itself may remain
unchanged, it tends to behave somewhat differently under diverse
environmental conditions. Such environmentally enforced differences in
habits would be difficult to distinguish from those having a genetic
basis. Although no subspecies of _Eumeces fasciatus_ have been
recognized, local populations undoubtedly differ somewhat in size and
other characters that have a genetic basis.

At the northern edge of its geographic range, _fasciatus_ occurs in
isolated colonies and seems to be restricted to open, rocky situations
which receive the maximum amount of sunlight. Breckenridge (1944:96)
wrote that at the two Minnesota localities representing the northwestern
corner of the known range, the skinks were found at granite outcrops,
and he mentions one found in western Wisconsin, at Taylor Falls, under
an 18-inch slab of a basalt outcrop in sparse oak woods. Patch (1934:51)
described a habitat at Arden, Ontario, among massive granite-gneiss
domes, with sparse vegetation. At Point Pelee, Ontario, the species is
common in the drier, more sparsely wooded situations, hiding beneath
loose bark of stumps and logs.

Ruthven (1911:264) found _E. fasciatus_ in the vicinity of sandy beaches
in the Saginaw Bay region of Michigan. Elsewhere in its range it is more
characteristically an inhabitant of hardwood forests, preferring the
better drained and more rocky situations, according to the testimony of
numerous authors. In eastern Illinois, Smith (1947:33) found it confined
to the area south of the Shelbyville moraine, and not ranging into a
prairie habitat. Near Elkville, Illinois, Cagle found the species
abundant in higher and drier areas within sparse stands of oak in second
growth woods, but it was absent from the low swampy areas adjacent to
streams. Conant (1951:30, 210), describing the habitat in Ohio, stated
that the species does not occur in swamps and areas that are subject to
spring floods nor on dry hillsides, but is abundant in some areas where
there are rotting stumps and logs remaining from former patches of swamp
forest, and usually is found in low, moist situations, in wooded valleys
or even at the edges of swamps and bogs. Lynn (1936:49) wrote that in
Virginia, it is most often seen on steep, boulder-strewn hillsides and
old sawdust piles. In the central Ozarks of Missouri, Owen (1949:49)
found it abundant and saw it almost daily on rocky ledges, fallen
timber, and fence rails, while _E. laticeps_ was seen only once. Taylor
(1936:59) wrote that _E. fasciatus_ occurs where there is timber and is
often found about fallen trees and rotting stumps, or about old
sawmills where wood refuse has accumulated. Smith (1950:187) wrote that
in Kansas the species is commonly found in wooded areas in moist
situations about stones, leaves and rotten logs. Gloyd (1928:120) wrote
that in Franklin County, Kansas, _E. fasciatus_ occurred in upland
situations and was the most abundant lizard where there were rocks,
brush, or decaying wood. Gloyd (1932:401) also recorded it as abundant
in the Pigeon Lake area, Miami County, Kansas, in wooded areas of
sufficient elevation to be out of the river flood-plain.


HABITAT IN NORTHEASTERN KANSAS

In northeastern Kansas I have collected or observed this skink in
several dozen localities, and searched unsuccessfully in numerous other
localities. Absence of this skink, in some situations and its presence
and relative abundance in others, provided a basis for appraising the
environmental factors that are of critical importance. River valleys, of
the Kaw and Wakarusa and their tributaries, with deep alluvial soil,
alternate with flat or rolling upland some two hundred feet higher in
elevation, and having shallow, rocky soil. Where the uplands slope to
the valley floors, there are steep hillsides, usually with extensive
limestone outcrops along their upper slopes. The alluvial plains
formerly supported hardwood forests, while the hill slopes and uplands
were largely prairie. At the present time the bottomland forest has been
almost completely destroyed, as it grew on the most fertile and
potentially productive soil, and has been replaced by cultivated crops.
There are still trees along streambanks, and in occasional woodlots, but
I have failed to find any skinks in such situations. I doubt that they
ever have been numerous in the bottomland woods; lack of rocks for
shelter, and periodic flooding are unfavorable factors. In the Kaw flood
of June and July, 1951, for instance, the entire valley was inundated,
and in smaller tributary valleys such as that of the Wakarusa, flooding
is frequent at the season when skinks are incubating their eggs. The
uplands, formerly prairie, now are used partly for cultivated crops and
partly for pasture. The soil is poor and rocky, and now heavily eroded.
The pastures mostly have a weedy type of vegetation indicative of
overgrazing. Five-lined skinks are absent from most of this upland.

The steep slopes from the upland to the valley floor are now mostly
wooded, and the population of skinks is chiefly in this band of
woodland. Some of the hillsides that have relatively gentle slopes are
treeless and are used for pasture, or are even under cultivation. Where
second growth forest is present its aspect differs depending upon slope,
exposure, and past treatment. Osage orange and honey locust are
aggressive invaders on some dry hillside pastures, and in this type of
woods the skinks are scarce or absent. Some hillside areas, especially
on moist north slopes have thick second-growth woods, in which elm is
usually the principal tree, with several oaks and hickories, walnut,
hackberry, coffee tree, locust and osage orange, and with a dense
understory vegetation of dogwood, gooseberry and coralberry, with vine
tangles of grape, poison oak, and greenbrier. Such woodlands provide
little food for livestock, and are often fenced off from adjacent
pastures. The shading creates conditions unfavorable for skinks and they
are relatively scarce in the denser woods. They are much more numerous
in woodlands that are fenced in with pastures heavily grazed by cattle
or horses, with understory vegetation kept cropped back, and with more
open ground and patches of sunlight. However, they are absent or scarce
in woods that have been subjected over periods of years to browsing, by
sheep or goats, so heavily that hardly any herbaceous vegetation remains
and so heavily that the soil is packed from trampling. Along the upper
slopes, especially about heads of gullies, in areas strewn with flat
rocks, in fairly open mixed woods, with some decaying wood on the
ground, habitat conditions are most nearly optimum for the skinks.
Artificial habitat features, such as rock piles, stone walls, wood
piles, rail fences, or old deserted buildings and sheds, with loose
boards lying about on the ground may support unusually high
concentrations of skinks when the surrounding habitat is favorable.


STUDY AREAS

The University of Kansas Natural History Reservation where most of the
field work for this study was done, has been described in a recent
publication (Fitch 1952:8). While records were obtained from scattered
points throughout the 590-acre Reservation and elsewhere in northeastern
Kansas, field study of this skink was concentrated on four relatively
small areas totalling only about ten acres in extent (Figure 26). These
areas were selected on the basis of abundance and availability of the
skinks, and of variety of habitat conditions represented.

One of these sites was a deserted quarry on a southward projecting spur
of the plateau-like cuesta top, where the upper layers of the Oread
limestone are prominently exposed. In the course of operations, begun
about 1937, the area was denuded of trees and shrubs, and the upper
layers of limestone were removed from a strip about 50 feet wide and
more than 100 yards long. The exposed outcrop presented a vertical rock
face five to ten feet high, with south and southeast exposure. Numerous
jagged seams and fissures in the rock hastened its disintegration.
Quarrying had been discontinued several years before the present study
was begun in 1948. At that time there were talus-like accumulations of
rock and soil several feet wide along the base of the rock face,
supporting a luxuriant pioneer vegetation especially, sweet clover,
stickleaf, ragweed and elm seedlings.

The habitat conditions provided by the exposed rock outcrop at the
border of woods and open land, proved unusually favorable for reptiles
in general, and it was one of the most productive sites on the
Reservation for Sonoran skinks, collared lizards, racerunners,
ring-necked snakes, blue-racers, bull snakes, pilot blacksnakes, scarlet
king snakes, slender tantillas, copperheads, and timber rattlesnakes.
For the five-lined skink, however, this disturbed area was marginal, and
supported only a sparse population. Several decaying two-inch boards
were preferred hiding places where the skinks were found most
frequently, and remains of collapsed rock walls, one in the center of
the area and one at the edge of the woods, were also occupied. Skinks
may have tended to wander away to more favorable situations or may have
been more subject to predation than those elsewhere, since the incidence
of recaptures was relatively low. Most of the records from this general
area were from a ledge in adjacent woods rather than from the quarry
itself. Another site was a rock fill in a ravine below a pond made in
1937. This rock fill was 70 feet long, up to 30 feet wide, and three
feet deep. East and north of the rock pile was a grassy dike, and beyond
it the pond. On the west open grassland extended approximately 200 feet
to the edge of the woods, with a diversion ditch at its border. On the
south end, the rock pile was adjacent to woodland at the base of a steep
slope with north exposure. On this slope the dense stand of second
growth oak and hickory with an almost continuous leaf canopy was a poor
habitat. The rock pile was thus partly isolated and surrounded by areas
that were either uninhabitable to the skinks or supported only sparse
populations of them. By 1948 the rock pile was partly covered by grape
vines. Dead leaves and other debris had accumulated in the deeper
interstices between the rocks. Spiders, beetles, snails and other small
animals were extremely numerous in the vicinity of the rock pile and
provided an abundant food supply. A large sycamore on the west side of
the rocks provided some afternoon shade. This rock pile provided shelter
for reptiles other than the five-lined skink--especially the garter
snake, water snake, copperhead, and brown skink. Another area of about
two and a fourth acres ("Skink Woods," Figure 21) was the one most
productive of skinks. It is a wooded upper slope adjacent to a hilltop
pasture. Along the hilltop rim the upper stratum of the Oread limestone
presents a rock face as much as four feet high at the north end, but
less exposed at the south end where it was partly covered by deposited
soil. Approximately 100 feet down the slope a second outcropping is
present, with many loose rocks and boulders throughout the whole area.
Soil is light and loamy. The slope has a west exposure. The stand of
trees is fairly open, with several large elms, walnuts, and yellow oaks,
and occasional hackberries, ailanthus and red haws. This area was
included in a narrow strip of woodland fenced about 1940 as a runway
connecting a hilltop pasture with a valley pasture where water was
available at a time when both pastures were heavily grazed by horses and
cattle. As a result of trampling, browsing and grazing by livestock,
understory vegetation of this area presented a different aspect from
that in most other parts of the woodland. Saplings of the dominant tree
species and shrubs, notably dogwood, gooseberry and crabapple, were
relatively scarce. Herbaceous vegetation, especially muhly grass, was
conspicuous. By 1953 in the fifth growing season after livestock were
removed, the area still contrasted with other parts of the woodland in
sparseness of shrubby vegetation. Old stock trails were still
discernible, and some sheet erosion and gullying had occurred. The
effect of livestock in holding back woody undergrowth seemed to be an
important factor in improving the habitat as the skinks were much
scarcer in adjacent woodlands on either side that were similar in
species composition, size, and numbers of the larger trees, but
different in having much thicker underbrush. These adjacent woodlands
were not entirely comparable, however, because they had more
north-facing exposures. Reptile associates in the Skink Woods area
include the brown skink, Sonoran skink, glass-snake, worm snake,
ring-necked snake, blue-racer, garter snake, pilot blacksnake,
copperhead and timber rattlesnake, but only the worm snake and
ring-necked snake were abundant.

Rat Woods, an area of approximately four acres, was like Skink Woods,
formerly the upper part of a connecting strip between hilltop and valley
pastures and was altered by the effect of concentrated trampling and
browsing by livestock. It is V-shaped, with the apex at the north end,
and the slope exposures southwest and southeast. The area is bisected
from north to south by a small gully, and remains of an old rock wall.
To the east of this gully the lower outcrop is prominent but west of the
gully, it is but little developed. As compared with other wooded areas,
this one was relatively dry. Trees, and other vegetation in general, are
somewhat more xeric in aspect than are those in Skink Woods. Along the
upper ledge are elms and hackberries, with many thick clumps of fragrant
sumac. The trees are mainly elm, walnut, honey locust, and osage orange
with hardly any oaks or hickories and, with shrubby undergrowth of
dogwood, gooseberry, and coralberry sparser than in adjacent woodlands.
Herbaceous vegetation consists largely of muhly grass, geum, and avens.
On the hilltop edge above the ledge are many flat rocks of varying
sizes, and the slope is thickly strewn with rocks, some of the larger
ones deeply embedded in the soil. The population of five-lined skinks
was relatively sparser than in Skink Woods. Other reptiles including the
Sonoran skink, racerunner, glass-snake, worm snake, ring-necked snake,
blue-racer, bull snake, pilot blacksnake, garter snake, scarlet king
snake, slender tantilla, and copperhead, were more numerous in this area
than in most other parts of the Reservation. The comparatively scarce
prairie skink was found only in this area, and the scarlet king snake
and slender tantilla were found only here and at the quarry.



The Annual Cycle of Reproduction and Growth


SEASONAL OCCURRENCE

Collectors and other observers have often noted that reptiles, in
general, are not found in equal abundance throughout the entire season
of their activity. Many kinds are most in evidence within a period of
weeks after emergence from hibernation, which corresponds with the time
of breeding and later they become much scarcer. In skinks of the genus
_Eumeces_ this tendency is perhaps even more pronounced than in most
other kinds of reptiles. By midsummer or considerably earlier their
period of greatest activity is passed, and in some kinds, adults, or
individuals of any size can rarely be found in the latter half of the
growing season, even by a skilled collector familiar with their habitats
and habits. Thus, Taylor (1936:5) in the preface of his revision of
_Eumeces_, describing the difficulties involved in assembling needed
series of the many Mexican species by collecting on summer field trips,
wrote: "In 1934 in western Mexico ... I met with most disheartening
results ... (although more than 1500 specimens were collected) only a
single specimen of _Eumeces_ was taken. Hobart Smith, in 1934,
accompanied by David Dunkle, made a journey into northwestern Mexico ...
and while generally successful, likewise obtained only a single specimen
of _Eumeces_."

    [Illustration: FIG. 7. Seasonal occurrence of five-lined skinks,
       based on data collected in 1949, 1950, 1951, and 1952; adult males
       and adult females are taken in greatest numbers in May, and in
       progressively smaller numbers through the summer and autumn;
       yearlings are found in increasing numbers through March, April, May,
       and June, then in decreasing numbers through the summer and autumn.]

In the present study the tendency of _E. fasciatus_ to concentrate its
surface activity in early spring was clearly shown. In unseasonably warm
weather in early spring, even in February in one instance, individual
skinks have been found active on the surface or beneath flat rocks
warmed by the sun; but general emergence ordinarily does not occur until
sometime in April, depending on the weather. Unless the weather is much
warmer than the seasonal norm, the skinks spend much of April in a
torpid condition, either not becoming fully active until late in the
month, or lapsing into torpidity with the return of cool weather after
their first emergence from hibernation. During warm periods in April,
however, activity is at or near its annual maximum for all individuals
regardless of sex or age.

In May, with the advent of much warmer weather, daytime temperatures are
usually high enough for the skinks to be active. Adult males travel
about more actively and persistently than females or young, and as a
result they are found so much more frequently that the numbers taken
approximate those for adult females and young combined. Many of the
adult males recorded in May were taken in funnel traps or pitfalls.
Active males in the open were difficult to catch, and a high percentage
of them escaped. To the casual collector or observer, these skinks are
much more in evidence in May than at any other time of year, and most of
those seen are adult males. By June, the numbers of skinks seen in the
open decline abruptly. The adult males become relatively scarce, with
reduction from more than half to about one-sixth of the total, and the
young, about half-grown at that season, make up approximately half of
the total. The adult females make up approximately one-third of the
total June sample, but few of them were found active on the ground
surface. Most were found in nest burrows beneath flat rocks. Under such
conditions they tended to be sluggish in behavior, and were caught much
more easily than were males and young. July was characterized by
progressive decrease in the numbers of adult males, adult females, and
second year young, whereby the numbers of each group were little more
than half of those for June; and by appearance of a new crop of
hatchlings which made up about one-third of the month's sample.
Hatchlings first appeared from early July to late July in different
years; few were recorded in July in some years. Females were much less
commonly found in nests in July than in June because many nesting
attempts were terminated before the beginning of July or early in the
month, and probably because those that remained were often more deeply
buried and better concealed. By August the adult males, and the second
year young (by then approaching adult size) were found in still smaller
numbers, but the number of hatchlings and of adult females approximated
those recorded in July. In the females there is evidently some
resumption of activity after the incubation period is terminated. The
females are then hungry and sometimes emaciated, weighing less, on the
average, than the year-old young of shorter snout-vent length. The
numbers of hatchlings are augmented through early August in some years,
as late broods continue to hatch. By early September few skinks except
hatchlings are to be found, and activity continues to wane throughout
the month. In October skinks of any age or sex group are a rarity, even
though temperature is about the optimum for their activity. Little is
known concerning where and how they spend the fall months. Probably they
are not actually dormant, but retreat underground where temperature is
moderate and humidity is high. Individuals kept in captivity at this
season were listless showing but little inclination to feed. The only
five-lined skink taken on the Reservation in November was found in a
funnel trap after a rain at the end of a long drought. It may have been
attracted to the surface by moisture.

The following table shows the dates on which various events of the
annual cycle were observed in each of five different years. Owing, to
the secretive habits of the skinks, these events generally were not
observed until somewhat after their earliest occurrence in any one
season. The lag was greater in some instances than in others.

    Table 3. Phenology of the Annual Cycle in Five Different Years.

  =====================+=========+=========+=========+=========+=========
                       | _1949_  | _1950_  | _1951_  | _1952_  | _1953_
  ---------------------+---------+---------+---------+---------+---------
  Earliest emergence   |         |         |         |         |
    from hibernation   | Mar. 30 | ....... | Mar. 24 | Mar. 29 | Mar. 20
  General emergence    |         |         |         |         |
    from hibernation   | ....... | Apr. 7  | Apr. 14 | Apr. 17 | Mar. 27
  Breeding coloration  |         |         |         |         |
    appearing in males | ....... | Apr. 15 | Apr. 25 | Apr. 28 | Apr. 16
  Peak of breeding     |         |         |         |         |
    season             | May 3   | May 12  | May 16  | May 10  | May 7
  Females starting     |         |         |         |         |
    nest burrows       | May 26  | May 24  | May 19  | May 19  | May 24
  Last appearance of   |         |         |         |         |
    gravid females     | June 10 | June 17 | June 29 | June 9  | .......
  Earliest appearance  |         |         |         |         |
    of eggs            | June 10 | June 13 | June 24 | June 22 | June 16
  Earliest appearance  |         |         |         |         |
    of hatchlings      | July 5  | July 15 | July 23 | July 3  | July 13
  Latest hatching      |         |         |         |         |
    date               | July 15 | Aug. 8  | Aug. 8  | July 14 | .......
  Latest fall record   | Oct. 15 | Sept. 19| Sept. 26| Nov. 9  | Oct. 12
  ---------------------+---------+---------+---------+---------+---------


SEXUAL CYCLES AND BEHAVIOR

Reynolds (1943:370 and 1947:191) studied the histological and gross
seasonal changes in the reproductive organs of the adult male _Eumeces
fasciatus_. There is a well defined annual cycle. "Early seasonal
increase in seminiferous epithelial heights and in diameter of lumina
and tubules reached a maximum in April followed by regression reaching
complete involution by August. Late seasonal revival of activity
results, by November, in size of testicular elements comparable to those
seen in January. Primary spermatocytes predominate in the germinal
epithelium in January, secondary spermatocytes and spermatids in
February, with spermatids and metamorphosing sperm dominating from March
until late June when the germinal material of the current season is
exhausted." Fifty-three adult males were used as a basis for his study.
These were of diverse origins from Arkansas, Florida, Missouri,
Tennessee, and Indiana. Since sexual cycles in such widely ranging
species tend to be synchronized with local phenology, and change
somewhat from one region to another, the seasonal cycle may have been
somewhat obscured by the diverse origins of the material. The Florida
specimens may have been of the species _E. inexpectatus_. Apparently
Reynolds' experimental skinks were kept in captivity for varying lengths
of time before their reproductive organs were examined. The normal cycle
would almost certainly be altered in captivity, especially in skinks
kept at high temperatures during the time that they would normally be
hibernating.

The seasonal change in gross appearance of the testes is not great. In
the breeding season the testes are slightly enlarged and are firm and
engorged, with pinkish or orange tinge. In immature males, and adults
that are not in breeding condition, the testes are smaller, attenuate,
paler colored, and flaccid. Sizes of testes in some males killed in the
breeding season are recorded in Table 4.

    Table 4. Sizes of Testes in Spring and Early Summer in Sexually
       Mature and Juvenal Males.

  ==============+===============+===============+===============
                |  Snout-vent   |   Sizes of    |     Age
       Date     | length in mm. | testes in mm. |    class
  --------------+---------------+---------------+---------------
  May 6,   1951 |      76       |   7.0 × 4.0   |  old adult
  May 20,  1951 |      77       |   5.0 × 2.8   |  old adult
  May 20,  1951 |      74       |   6.2 × 3.2   |  old adult
  May 20,  1951 |      74       |   5.5 × 3.0   |  old adult
  May 20,  1951 |      66       |   5.0 × 2.8   |  young adult
  May 20,  1951 |      65       |   4.2 × 3.2   |  young adult
  May 20,  1951 |      64       |   5.3 × 3.1   |  young adult
  May 20,  1951 |      45       |   2.5 × 1.0   |  juvenile
  May 20,  1951 |      40       |   1.5 ×  .3   |  juvenile
  June 3,  1951 |      65       |   5.0 × 2.5   |  young adult
  June 10, 1951 |      67       |   4.0 × 1.8   |  young adult
  June 25, 1951 |      75       |   4.0 × 2.0   |  old adult
  June 25, 1951 |      70       |   3.5 × 1.8   |  young adult
  June 25, 1951 |      51       |   2.0 ×  .5   |  juvenile
  --------------+---------------+---------------+---------------

From the time of emergence in spring, males show some tendency to seek
out females, and frequently a pair may be found together under the same
rock, weeks before the onset of the breeding season. There is no
satisfactory evidence that such associations have any permanence. At
the time of emergence from hibernation the males rarely have even a
trace of reddish coloration on their heads, and more than a month
normally elapses before attainment of breeding coloration. Each year
that observations were made activity of the skinks was interrupted by
cold weather in April, so that the lizards were fully active for only
part of the time between their earliest emergence and their attainment
of breeding condition five to eight weeks later. The reddish suffusion
of the breeding season, hardly showing in the first few weeks after
emergence, appears suddenly within a few days in all adult males of the
population. The best indication of the time necessary to attain breeding
condition was provided by an adult male whose hibernation was
interrupted on December 15 by bringing him into a warm room where he was
kept at 80° F. or more in the daytime, and approximately 70° F. at
night. Thirteen days later, on December 28, the male had developed a
noticeable reddish suffusion. On January 3, nineteen days after
hibernation terminated, the suffusion was near its maximum. When an
adult female was placed with the male on this date, he showed sexual
interest but the courtship was not consummated. On January 6, the 22nd
day, the male's colors had reached their maximum, and when the female
was placed with him, pursuit and copulation occurred promptly.

In the spring of 1952, the first skink of the season was found on March
29, still only partly activated, and under a large flat rock. Skinks
were not caught or seen in any numbers until April 17, however, and
general emergence probably occurred only a day or two earlier than this.
On May 10, 1952, breeding activity was estimated to be at its peak. By
May 28, the reddish suffusion was conspicuously faded in several males
taken. By June 10 it was no longer discernible.

In the immature female the oviducts are small and threadlike, and the
ovaries have grapelike clusters of pale whitish eggs, which are minute,
often less than .5 mm. in diameter (Figure 8A). In sexually mature
females ova enlarge rapidly after emergence from hibernation in the
spring. While eggs are still in the ovary, they are approximately
spherical. In late April and early May the developing ova enlarge
rapidly. Approximate average sizes (dimensions in mm.) of developing
ovarian ova in each of 22 mature females on different dates were as
follows: April 17, 1949: 2.6, 2.3, 2.2, 2.2, 1.9, 1.9; April 18, 1949:
2.2, 1.9, 1.8, 1.1, 1.1; April 24, 1949: 4.6, 3.2, 2.5, 2.3; May 6,
1951: 2.5, 2.3; May 20, 1951: 7.0, 6.2; May 25, 1951: 8.0; June 3, 1951:
6.0, 5.5.

The two females containing ovarian eggs on June 3, 1951, were retarded
individuals, taken along with several others that had already ovulated.
Copulation takes place in early May before the ova have grown to their
full size. In the following weeks both the ova and the oviducts enlarge
rapidly. Upon passing into the oviducts, the ova assume an oval shape
and are approximately 9 by 6 mm. before the albumen and shell are added.
Deposition of a clutch of eggs probably extends over only a day or two
at most, as clutches appear abruptly in the nest cavities. On only a few
occasions were the females found in nest cavities with their clutches
partly laid.

    [Illustration: FIG. 8. Adult female skinks with ventral body walls
       removed to show reproductive organs. A. Condition in April shortly
       before the breeding season; the ovary (O) is still small and
       elongate, with the small ova forming a grapelike cluster; right
       ovary removed to expose the small bandlike oviduct (OD) beneath it.
       B. Condition in late May shortly before ovulation; the greatly
       enlarged ovaries are removed to expose the oviducts (OD) now
       enlarged and convoluted for reception of the ova. C. Same stage
       as B, with mature ova (O) filling most of the body cavity and
       concealing other internal organs, I--intestine; L--liver;
       approximately natural size.]

Sexual behavior is for the most part limited to a short period of weeks
in spring. In an average year in the area of the study the first two
weeks of May would include the peak and the greater part of the
breeding season. The "courtship," such as it is, and mating have been
described by many observers. However none of the published accounts
seems to include all the essential features in their usual sequence as
observed in the present study. It has been brought out by the studies of
Noble and Bradley (1933:94), Noble and Teale (1930:54) and Schmidt
(1933:71-76) that the sexual behavior of lizards has phylogenetic
significance. Certain basic patterns in mating behavior are
characteristic of saurian families, other traits are characteristic of
genera, while certain details may be characteristic of species, or
perhaps even of subspecies.

In the breeding season the adult male directs the greater part of his
activities to a search for females, and finds them by both sight and
scent. Observations on searching males suggest that they trail females
by scent to some extent, or at least detect their presence in the
general vicinity by this means. Upon discovering a female, the male
pursues her with vigor and determination unless the temperature is too
low, or unless he is not at the height of breeding condition. The female
makes no positive response but reacts to the male's presence by fleeing,
either frantically or perfunctorily, but if she is physiologically ready
to breed the reaction is usually somewhat intermediate between these
extremes. The first reaction of the male as he approaches the female is
to touch her with his tongue, apparently receiving olfactory stimuli
which are essential to the mating pattern. Rushing in pursuit of the
female, he then attempts to seize her in his jaws. Most often a
preliminary grasp is secured on the female's tail. The female may resist
vigorously, wriggling and clawing, turning upon the male to bite or to
threaten with her gaping jaws. At the first opportunity the male deftly
shifts his grip from the female's tail or hindquarters to a more
anterior position, which may be as far forward as the forelimbs or may
be as much as an inch behind them, a little to one side of the
mid-dorsal line. The male secures his hold by pinching loose skin into a
small fold. Having gained this position the male is more or less out of
reach of the female's jaws, and after a brief struggle both rest quietly
except for their rapid breathing, usually for a minute or more, the
ventral surface of the male resting on the female's dorsal surface. The
male suddenly thrusts his tail beneath that of the female. His hind leg
then rests over the base of her tail and the right angle formed by the
laterally projecting hind leg and the tail in each lizard aids to guide
their hindquarters into position so that cloacal contact is established.
Copulation then begins immediately. The male's body may be bent in a
semicircle, to one side of the female, or may be in an S-shaped loop,
depending on whether or not the hemipenis employed is on the side
opposite to that on which the female is grasped. Only one hemipenis is
inserted, but occasionally the other may be everted also. As copulation
begins the male's hind leg, flexed over the female's tail base quivers,
but otherwise there is hardly any movement during approximately the
first one-third of the copulatory period, and this phase may last for
from one to three minutes. Then, abruptly, the male begins rhythmic,
jerky flexions of the proximal portion of the tail, at the rate of
approximately one per second. These tail movements are in a dorsoventral
plane, and there is no perceptible movement of the body. Shortly after
these movements cease, contact is broken usually at the initiative of
the female, as she suddenly struggles to escape and is released either
immediately or after a few seconds by the male. She then moves away,
pressing her cloacal region against the ground. Her movements have
become unhurried, with little or no attempt to avoid the male's
attention. The male usually follows, either close behind, or straddling
the female's tail or body. He may nip at her tail or body repeatedly,
but without securing a grip. When the female pauses, he may come to rest
with his chin or forequarters resting on her. Usually the association
does not last more than a few minutes.

PLATE 1

    [Illustration: FIG. 1. Habitat of _Eumeces fasciatus_ near the
       center of the "Skink Woods" study area on the University of Kansas
       Natural History Reservation, a glade with loose rocks that were
       used as nesting sites and shelter by many five-lined skinks.]

    [Illustration: FIG. 2. A log on rocky slope in open woods with
       sparse undergrowth, fifty feet from center of glade shown in Fig. 1.
       The trees are mostly oaks (_Quercus Muehlenbergii_). The decaying
       log in middle foreground is much frequented by the skinks as a
       shelter and source of insect food.]

PLATE 2

    [Illustration: FIG. 1. Old adult male, year-old young and hatchling
       in July, showing differences in size and pattern.]

    [Illustration: FIG. 2. Adult female skink in a natural nest, with
       her clutch of eggs late in incubation. The nest cavity is excavated
       in loose soil beneath a flat rock, which was raised momentarily to
       expose the nest to view.]

    [Illustration: FIG. 3. The same female and nest, with eggs in
       process of hatching.]

Noble and Bradley (1933:77) mention frequent homosexual matings between
captive males. However, I observed no homosexual matings, either under
natural conditions or in confinement. The pugnacious behavior of males
that are in breeding condition ordinarily would prevent homosexual
mating. Males in such weakened condition as to be unable to defend
themselves effectively might evoke sexual attack, instead of the usual
fighting response in other males. Although no actual experiments were
performed in the present study in connection with the courtship and
mating behavior, accounts of some workers seem misleading. My own
observations indicate that the capacity for sex discrimination in this
particular kind of lizard, and probably in others, has been underrated.
For example, it has been stated that the male rushes with open mouth at
the neck of any other skink that happens to be around, and he identifies
it as a male if it fights back, or as a female if it does not. On the
contrary my observations indicate that sex recognition occurs almost as
soon as the male is aware of another skink's presence. The red head of
the breeding male is an excellent example of a social releaser in the
sense that this term was used by Tinbergen (1948:8). Like the red belly
of the breeding male stickleback, it facilitates sex recognition and
evokes hostile behavior on the part of other males. Courtship, mating,
and fighting reactions however, seem to be evoked by the interaction of
a complex of social releasers. Whereas males and females are strikingly
different in appearance in the breeding season, visual sex recognition
is complicated by ontogenetic changes. The body stripes characteristic
of the female pattern, become dull or even disappear in some old
females, which then approximate the typical male pattern. On the other
hand newly matured males in their first breeding season retain distinct
body stripes of the female pattern. Their sex is evidenced mainly by
their reddish facial suffusion, which is not quite so extensively
developed as it is in older individuals. Also, in these newly matured
males the temporal region is not so swollen as it is in old males.

The male whose dormancy was terminated in early winter by bringing him
into a warm room causing him to assume breeding coloration and to breed
some four months earlier than those under natural conditions has already
been mentioned. By the time the regular breeding season arrived, this
male had long since undergone sexual regression and retained no trace of
the red suffusion. In this condition, placed in a terrarium with a mixed
group of breeding adults, his social status was of unusual interest. He
exhibited no interest in the females and was less pugnacious toward
other males than were the individuals in breeding condition. Although he
seemed somewhat more nervous and timid, his hostile behavior was not
entirely suppressed, as from time to time he moved up to other males and
bit them viciously. His color pattern resembled those of certain old
adult females in which the body stripes have been suppressed, but the
breeding males evidenced no uncertainty as to his sex and were uniformly
hostile. Their reactions were not noticeably different toward him than
they were toward breeding males. The importance of an olfactory stimulus
as a social releaser in sexual behavior of lizards has not been
appreciated, although Noble and Mason (1933:10) did demonstrate its
importance in the behavior of the female toward her eggs.

It is evident from published accounts, and from my own limited
experience with _fasciatus_ in parts of its range other than
northeastern Kansas, that the phenology of the breeding cycle is subject
to geographic variation, synchronizing with the somewhat different
climatic conditions under which the species occurs. However, the
difference is less than might be expected, in view of the species'
extensive range. As a result of the early spring, and the warm summer
climate in the southern states, dates of laying and hatching may be
several weeks advanced. On April 12, 1952, Dr. Wilfred T. Neill showed
me several live _E. fasciatus_, collected a few days before along the
Trinity River in southeastern Texas, which appeared to be at the height
of breeding condition. In northeastern Kansas on that date, general
emergence had not yet occurred, and it was not until about May 10 that
the population attained the peak of breeding condition. On May 8, 1948,
near Burr Ferry, Vernon Parish, Louisiana, I caught an adult female in
her nest burrow, and she contained eggs ready to be laid. Data with
which Mr. Robert Gordon kindly provided me for specimens from southern
Louisiana and southeastern Texas, in the Tulane University collection,
indicate gravid females on June 4, 1952, and June 17, 1948 (3), and
females with their egg clutches on June 16, 1948, June 17, 1948, June
23, 1950; and hatching dates in captivity of July 19, 1949, July 19,
1950, July 25-26, 1949. These dates correspond well with those for
specimens obtained in northeastern Kansas in the same years. In the
northern part of the range, Ruthven (1911:264) recorded that in the
Saginaw Bay region, females taken on June 19 had eggs nearly ready to be
laid, and after July 2 clutches were found frequently; young of the year
were first observed on July 31. A juvenal specimen in the University of
Minnesota Natural History Museum, collected on August 11, 1938, at
Dresser Junction, Wisconsin, is 30-1/2 mm. in snout-vent
length--approximately the size of juveniles in northeastern Kansas at
the same season. Evans and Roecker (1951:6) record hatching as occurring
in the first week of September at Arden, Ontario, indicating that at the
northern edge of the range hatching may be delayed as much as two
months. With such delayed hatching, but little time remains for the
young to grow before they are forced into retirement for hibernation.


FIGHTING

Territoriality in the usual sense is lacking in the five-lined skink,
and could scarcely exist in an animal of its habits. To defend a
definite area (territory) against intruders of its own species, the
animal would have to detect such intruders promptly. The skink, however,
is so secretive in habits that at any given time the individual is
likely to be hiding and inactive, even when conditions are favorable for
it to be in the open, and other individuals therefore can then wander
onto its home range unopposed. Even when an individual is active, it
lacks the ability to detect others, except within a radius which would
encompass only a small fraction of the entire home range. The senses
are inadequate to inform one lizard of the presence of another until the
two are only a few yards, or even a few inches apart. Usually the lizard
is on the ground, where even small objects obstruct its view, and vision
is probably effective for only a few yards. Hearing is probably
effective for about the same radius in detecting animals of
approximately its own size. Scent is effective in detecting prey near at
hand or on contact, but probably does not serve for detection of other
lizards that are not in the immediate vicinity. Therefore, the area
covered by one in the course of its normal activities may harbor many
others, and individuals most of the time are unaware of the others on
their home ranges.

Under most circumstances these skinks behave toward each other with
tolerance or indifference, but during the breeding season adult males
become hostile, and fight on sight. Their reddish facial suffusion
serves as a social releaser which elicits hostile behavior and
facilitates sex recognition. As the breeding season wanes, the reddish
suffusion fades rapidly and male hostility, probably controlled by the
same hormonal complex, is likewise suppressed. Hostile behavior is rare
in adult females or young at any time.

Combats and pursuits have been observed most frequently the last week of
April and especially in the first two weeks of May. At this season
funnel traps set along rock ledges often caught two adult male skinks
together. In almost every instance one of the two confined males was
mutilated, with pieces of skin and flesh bitten from the tail and with
chin, snout, and neck scarred; most serious wounds were usually in the
sacral region or base of the tail or both. Often the wounds were so
severe that the skink died in a short time in captivity and presumably
others that were released died also.

On April 28, 1949, a large adult male skink, chased by another, ran out
in the middle of a trail and stopped. The pursuer stopped a few inches
from it, then after a long pause, retreated in the direction from which
it had come. For the five minutes that the pursued skink was watched, it
lay motionless, partly hidden by dry leaves, evidently seeking to avoid
further pursuit by concealment. I caught it without difficulty, and it
seemed weak and dazed, as if injured in the fight. Its reddish suffusion
was conspicuous, but not fully developed.

On May 3, 1949, an adult male having bright red facial suffusion was
observed searching persistently in ground litter; he was seen to find
and pursue a female, and to copulate. A few minutes after mating was
completed and the pair separated, a second male also searching in the
vicinity came within sight of the first one. The two noticed each other
at a distance of about 18 inches, indicating their awareness by their
more alert, jerky movements, and spasmodic vibrating of their tails. The
newcomer darted at the other, and for a moment they dodged and sparred.
As one broke away to run, the other seized it by the tail. They were on
an exposed tree root about an inch in diameter. The skink that was
caught twisted its body around underneath the root and seized its
adversary by the tail likewise, so that their linked bodies encircled
the root, each squirming to disengage itself from the other's jaws.
After a few seconds they did break apart, and then maneuvered briefly
menacing each other at close quarters, but they gradually moved away and
lost contact.

On May 10, 1949, two adult males were seen to approach each other
slowly, pausing for perhaps a minute when they were a little more than
one foot apart. Then one edged up to the other, and with a sudden lunge
seized it by the head. The one seized broke away with a vigorous jerk,
and promptly retaliated by biting the first one's head. After a few
seconds of rapid sparring and thrashing, they broke apart, and one
chased the other for several feet until it eluded further pursuit by
dodging and hiding.

    [Illustration: FIG. 9. Adult male skinks fighting. A. Menacing
       approach. B. One has lunged and secured a grip on the other's side,
       holding it at right angle. The one caught is unable to flex its
       body and neck enough to secure a retaliatory grip on the attacker,
       and must break away by violent thrashing.]

On May 12, 1950, my attention was attracted by a rustling in dry leaves.
Within a few inches of my foot two adult males were struggling fiercely
with jaws interlocked. Sudden violent twisting and thrashing alternated
with quiet periods of a few seconds duration, in which the lizards
scarcely moved except for heavy panting and twitching of their tails.
After perhaps two minutes of fighting, one broke away and ran. For a
distance of several feet it was closely pursued by the other, which,
however, soon lost contact with it in the rough terrain and surface
litter.

On May 12, 1951, rustling in dry leaves attracted my attention to two
large adult males fighting. For about fifteen minutes that they were
observed, they struggled, with neither yielding ground, though they
thrashed and rolled about over an area of several square feet. Sometimes
they were disengaged for short intervals. Then facing in opposite
directions, with their heads side by side, they would snap at each
other's necks and shoulders (Figure 9). Part of the time both males had
grips and were biting each other simultaneously, but more frequently one
or the other had a temporary advantage. When one secured a grip it would
strain to the utmost, biting as hard as it could and lunging forward
with frequent short jerks, meanwhile striving to keep out of reach of
the other's jaws. The one caught in the attacker's grip was usually
unable to flex its body sharply enough to reach its opponent at all, or
could barely reach it at such an oblique angle that its jaws slipped off
the smooth body. Sometimes the one held did succeed in catching the
other's front foot. The one caught in the other's jaws always succeeded
in tearing loose after a short time. In the interval while the attacker
rested with jaws partly relaxed, the victim had an opportunity to break
away. Even when both were free, they did not obtain grips easily, but
often made several unsuccessful lunges and bites, the jaws of each
slipping off the firm, smooth sides of its opponent. Sometimes the
attacker seized a fold of skin, or sometimes obtained a wide grip on its
body. One which had obtained a grip sometimes rolled rapidly, spinning
the other around and dashing it against the ground. As these rotations
stopped, the victim might come to rest on its back in such a position
that it was temporarily helpless, but always broke loose after further
struggles. Neither showed any inclination to retreat until finally, when
they were interlocked, rolling about almost at my feet, I attempted to
catch them. Then they instantly disengaged and rushed away, and one
escaped. The one caught had suffered but little injury in the fight.
Numerous tooth marks were discernible as minute abrasions on the surface
of the scales, but the bony dermal armor had not been perceptibly
penetrated during the prolonged and violent struggle.


EGGS

The eggs of _Eumeces fasciatus_ are like diminutive chicken eggs in
appearance. They are white when first laid, slightly translucent when
held to the light. Within a day or two after they are laid, these eggs
are soiled to a dull tan color, somewhat mottled, as a result of being
rolled and dragged about in contact with the floor and wall of the nest
burrow. Like the eggs of most other reptiles, those of _Eumeces
fasciatus_ have parchmentlike shells. These shells are thin and easily
punctured. As incubation proceeds, the egg enlarges by gradual
absorption of moisture and the somewhat elastic shell is stretched. An
egg left in water for as much as a day does not gain in weight
appreciably. Except for occasional abnormal ones, the eggs of any one
clutch are notably uniform in size and shape at the time they are laid.
As incubation proceeds, some eggs enlarge more rapidly than others, and
attain larger ultimate size. Differences in shape also appear, some eggs
becoming relatively elongate and thin, while others are thick and blunt.
Some become distorted to asymmetrical shapes. In nests that have been
deserted by the females, eggs of irregular shape are especially
noticeable. It seems probable that the frequent shifting of the eggs by
the female prevents unequal drying or stretching in different areas of
the shell. Normal young were observed to hatch from grossly misshapen
eggs. Under conditions of drought, the eggs may not enlarge normally
during the latter part of incubation, and may become indented or partly
collapsed, and yet apparently normal young hatch from them. Both in the
field, and in laboratory experiments, eggs were found to have remarkable
tolerance for excess moisture. After heavy rains of summer
thunderstorms, nests were sometimes found to have water trickling
through them, and on occasion eggs were found to be partly submerged in
water in the nest cavity. Exposed rocks at the heads of small gullies
often were chosen by the female skinks as the shelter for their nests.
In these situations the nests were exposed to run-off water. In July,
1951, especially, unusually heavy precipitation resulted in the flooding
of many nests. In some instances desertion by the females and
destruction of the eggs seemed to have been caused by this flooding,
even in the well-drained hillside situations where this study was made.

    Table 5.--Measurements in Millimeters and Weights in Grams of Eggs
       in the Same Clutch at Different Stages During Their Incubation,
       Showing Gradual Increase in Size.

  ===============+=========+========+========+========+========+========+========+===========
                 | June 17 |  June  |  June  |  June  |  July  |  July  |  July  |  July 30
                 | (laid)  |   18   |   24   |   28   |   17   |   20   |   28   | (hatched)
  ---------------+---------+--------+--------+--------+--------+--------+--------+-----------
  Average length |         |        |        |        |        |        |        |
  (for 7)        |  .....  |  ....  |  ....  |  ....  |  13.7  |  14.3  |  14.7  |  .......
  Average width  |         |        |        |        |        |        |        |
  (for 7)        |  .....  |  ....  |  ....  |  ....  |  10.5  |  10.9  |  11.1  |  .......
  Typical length |  .....  |  11.1  |  ....  |  12.5  |  14.0  |  14.3  |  14.8  |  .......
  Typical width  |  .....  |   7.5  |  ....  |   9.9  |  11.0  |  11.2  |  11.0  |  .......
  Maximum length |  .....  |  11.5  |  ....  |  ....  |  14.5  |  15.0  |  15.5  |  .......
  Maximum width  |  .....  |   7.5  |  ....  |  ....  |  10.9  |  11.1  |  11.4  |  .......
  Minimum length |  .....  |  10.5  |  ....  |  ....  |  12.5  |  12.8  |  13.5  |  .......
  Minimum width  |  .....  |   7.0  |  ....  |  ....  |   9.9  |  10.0  |  10.5  |  .......
  Average weight |  .....  | .38^10 |  .58^5 |  .63^9 |  .82^8 |  .90^7 |  1.0^7 |  .......
  Typical weight |  .....  |    .4  |  ....  |  ....  |  ....  |    .9  |   1.0  |  .......
  Maximum weight |  .....  |  ....  |  ....  |  ....  |  ....  |   1.0  |   1.1  |  .......
  Minimum weight |  .....  |  ....  |  ....  |  ....  |  ....  |    .7  |    .7  |  .......
  ---------------+---------+--------+--------+--------+--------+--------+--------+-----------

     Superior number indicates the number of individuals averaged.

The extent of tolerance to immersion in water probably depends on the
stage of development, the temperature, the oxygen content of the water
and other factors. One egg was fully immersed for ten minutes on July
20, 1951, then returned to a container with damp soil in the laboratory,
where it seemed to develop normally. On July 30 it was opened and found
to have a living fetus, which was a week short of hatching. On July 22
another egg of the same clutch was immersed and left in water for 23
hours. On July 30 it was ruptured in handling and found to contain a
living fetus. On July 31 two eggs were placed in a dish of water in a
refrigerator. On August 5 they were removed and opened. Fetuses were
dead and were not appreciably larger than the one of the same clutch in
the egg opened on July 31. On August 5 two of the remaining eggs of this
clutch were placed in a Petri dish, partly immersed in water, with
approximately one-fourth of the surface of each protruding and exposed
to the air. Forty-eight hours later it was found that both eggs had
hatched. Evaporation had reduced the water in the dish to an amount
sufficient to cover only about the lower one-third of each egg. One
hatchling was missing, evidently having climbed out of the shallow dish
and escaped to the floor. The other was found still standing in the
water with its head protruding, and it was lively and in good condition.
The remaining four eggs in this clutch, which had been kept in a
container of damp earth, were also hatching on this date. On July 10,
1952, an egg in a late stage of incubation was immersed in water in the
laboratory. On July 14 when removed, it had fungus growing on it, and
was found to have a dead fetus, nearly full-sized.

The range of temperature tolerance of the embryo is wide, probably
comparable to that of the adult. Time required for incubation is
dependent on temperature. Persistently wet and cloudy weather in the
summer of 1951, keeping temperatures relatively low in nests, was a
contributing cause to late hatching that summer. As compared with 1952,
hatching was about one month delayed in 1951, but later emergence and
breeding accounts for part of the difference. The extent to which low
temperature may delay incubation was indicated by the effect of
refrigeration on several experimental eggs, as recorded below.

  1. July 8, 1952  Egg transferred from natural nest to jar of damp soil
                   in refrigerator at 13.8°C.

     July 14, 1952 Seems to be in good condition.

     July 19, 1952 Partly collapsed. Weight and measurements same as on
                   July 8; opened and found to contain a dead fetus.
                   Snout-vent length 23 mm., forehead bulging, skin
                   delicate and membranous. Colors somewhat dull,
                   indicating that it was not quite fully developed,
                   although it had attained the minimum hatching size.

  2. July 10, 1952 Egg from natural nest (15.0 × 10.5 mm., .95 gm.) put
                   in refrigerator at 11.6°C. Control (14.5 × 10.6 mm.,
                   .8 gm.) from the same clutch kept in hatching medium
                   in laboratory.

     July 13, 1952 Control egg hatching; refrigerated egg shows no
                   indication of hatching.

     July 14, 1952 Experimental egg 15.8 × 10.8 mm., 1.0 gm., seems to be
                   in good condition. Nest from which it was taken found to
                   have all remaining eggs hatching today.

     July 19, 1952 Experimental egg 15.0 × 10.0 mm., 1.0 gm., removed from
                   refrigerator and transferred to container in damp rotten
                   wood in laboratory. Seems to be in good condition.

     July 23, 1952 Experimental egg found to be hatched this morning, and
                   hatching must have occurred either in the night or late
                   yesterday. Eggshell still damp and pliable.

  3. July 10, 1952 Egg from natural nest (14.0 × 10.5 mm., .8 gm.) put in
                   refrigerator at 11.2°C., in container with damp decayed
                   wood. Control egg (14.2 × 10.1 mm., .8 gm.) from the
                   same clutch kept in the same hatching medium in the
                   laboratory.

     July 12, 1952 Nest from which experimental and control eggs were
                   taken has started to hatch, and two hatchlings were
                   seen there.

     July 13, 1952 Control egg hatched.

     July 14, 1952 Experimental egg 14.2 × 10.1 mm., .8 gm., seems to be in
                   good condition. Nest in field examined and all eggs were
                   hatched, with only three of the hatchlings remaining,
                   the others having dispersed.

     July 19, 1952 Experimental egg 14.0 × 10.0 mm., .95 gm., still appears
                   to be in good condition; removed from refrigerator and
                   kept in laboratory.

     July 23, 1952 Experimental egg found to be hatched, and hatchling
                   active although still in hiding beneath rotten wood.
                   Probably it hatched early in the day of July 22; the
                   empty shell is still moist.

These experiments seem to show that, in the later stages of incubation
at least, lowering of temperature to 11° or 12°C. almost halts
development of the fetus. Harm does not necessarily result, however, and
when again warmed to normal incubation temperatures, the eggs eventually
hatch, the incubation period being lengthened by a time approximately
equivalent to the interval of refrigeration.

Under natural conditions the time required for incubation probably
varies within wide limits, controlled mainly by temperature. No two
clutches receive the same amount of heat, as sites differ greatly in
extent of insulation, and exposure to sunlight. Each year, earliest
appearance of hatchlings is in a warm, sunny situation, and in cooler,
well shaded places hatchlings appear somewhat later. Their incubation is
evidently somewhat protracted, although later emergence from hibernation
and later breeding of adults in these situations might also contribute
to the delay.

Widely different incubation periods have been recorded in the literature
and the variation probably is not due to temperature alone. Noble and
Mason (1933:4) recorded incubation periods for six females from the same
locality, and evidently kept under the same laboratory conditions, as
47, 41, 36, 29, 29, and 27 days. Despite the wide difference in
incubation time, all six clutches hatched within a 12-day period from
July 5-17. It seems improbable that differences in temperature account
for the 20-day disparity between maximum and minimum incubation time, in
these females kept under similar conditions. Cagle (1940:229) recorded
an even shorter incubation period for one kept in the laboratory, which
laid eggs on June 30; hatching occurred on July 23 and 24. Retention of
eggs in the oviduct by females kept under unnatural conditions would
partly explain their late laying and the short incubation period of
their clutches. Such ability to retain eggs in the oviduct while their
development proceeds would not be especially surprising in _E.
fasciatus_ since its congener _E. lynxe_ of the highlands in southern
Mexico is normally ovoviviparous (Hartweg, 1931:61; Taylor, 1936:171).
Cagle did not determine incubation time for any of the natural nests
found, but evidently in all of them laying occurred earlier than in the
single female brought to the laboratory while still gravid. All the eggs
in natural nests found by him were brought to the laboratory and most of
them were hatched. Cagle remarked: "The fact that these 26 nests hatched
within a period of nine days seemingly indicates that the egg laying
period extends over not more than two weeks."

In the present study no incubation periods so short as those recorded by
Noble and Mason, and Cagle, were observed. Incubation times were
recorded for clutches both in the laboratory and in the field, but for
most of the clutches only approximate incubation periods were recorded.
Failure to record the exact date of laying or of hatching, or both
resulted from attempts to avoid frequent disturbance of females in their
nests, which might have caused them to desert.

One clutch of eggs laid in a terrarium probably on June 17,
1951--possibly a day or two earlier--hatched on July 30, after an
incubation of about 44 days. Another clutch, found in a terrarium on
July 17, 1951, was estimated to have been laid about a week earlier,
judging from the average length (11.8 mm.) and average weight (.55 gm.)
of the eggs. These eggs hatched on August 9, a little more than three
weeks after their discovery. A clutch found in the field on June 25,
1951, evidently recently laid (average length 12 mm., weight .45 gm.),
hatched 41 days later, on August 5. Another clutch found in a terrarium
on July 17, 1951, was estimated to have been laid ten days or two weeks
before, as the average length was 12.7 mm. The eggs hatched on August 7,
three weeks after their discovery. On June 25, 1951, an incomplete
clutch of three eggs was found with a female which still had an unlaid
egg. The three eggs probably had been laid the same day or the day
before. They were kept in the laboratory and weighed and measured at
intervals until July 28, 33 days after their discovery when both those
that remained were accidentally punctured and found to have nearly full
term fetuses. In the field a nest which contained only a gravid female
on June 24, 1951, had a clutch of eggs already mud stained and slightly
enlarged on June 29. The most probable date of laying was June 26. On
August 6 the eggs had all hatched but several young were still in the
nest. Probably most hatched on August 5. The incubation time was hence
approximately 40 days.

On June 21, 1951, a natural nest was found with eggs already somewhat
enlarged (12.5 × 8 mm.) and mud stained. This nest was checked from time
to time in the next few weeks, and after 39 days, on July 30, it was
found that all the eggs had recently hatched, but six young were still
in the nest cavity.

Another nest was found on June 24, 1951, with the eggs already markedly
enlarged (14 × 8 mm.) indicating that laying must have been several days
earlier--probably well over a week. Hatching occurred approximately 34
days later, probably on July 28, since on July 26 there was no sign that
hatching was imminent, and on July 30 only the empty dried eggshells
remained in the nest.

The incubation time approximated six weeks for those nests with most
complete records. Under wet and stormy weather conditions such as
prevailed in 1951, this may have been the normal incubation period, but
in warmer and drier years incubation time is shortened.

In the five-lined skink each adult female normally produces one clutch
of eggs annually. The size of the clutch produced is subject to
individual variation, and is influenced by the age, size and condition
of the female. Geographic variation in clutch size might also be
expected. Data were obtained from breeding females killed and dissected,
from counts of eggs found in natural nests in the field, and from
clutches of eggs laid by females kept in captivity. For the total of 115
recorded clutches represented by the combined data from all these
sources, the average number of eggs per clutch was 9.5.

In many females dissected for the purpose of obtaining egg counts,
ovulation had not yet occurred. The ovarian eggs present in each of
these females included two main size groups, the larger ones in process
of maturing and evidently destined for deposition in the current season,
and minute, immature ones. A few of intermediate size were always
present, however, resulting in uncertainty as to the size of the clutch
being produced, especially when development had not proceeded far. Even
when the larger eggs formed a fairly distinct size group, some usually
were well below maximum size. Relatively high counts of clutches were
obtained from these examinations of enlarged ovarian eggs. Evidently
development frequently is arrested, and resorption may occur before
ovulation. As a result the numbers of ovarian eggs developing are a poor
indication of actual clutch size. A series of gravid females were
obtained and examined after ovulation; the numbers of eggs in their
oviducts probably indicates accurately the sizes of their clutches.
Gravid females taken from their nest burrows and kept in the laboratory
in containers with loose damp soil soon excavated new burrows and
deposited clutches. Many natural nests were found in the field, and the
egg counts obtained from them provided further data concerning clutch
size. Although most of these clutches probably had their full
complements of eggs, others certainly had sustained losses to predators,
or to the females themselves, which may eat some of the eggs. Therefore
the average number found is erroneously low. Some of the natural nests
found may have contained two or more clutches or parts of them, and the
higher counts obtained from natural nests therefore are also
questionable.

For different sets of data on clutch size, numbers were as follows:

    Table 6. Size of Clutch.

  =================+===========+============+===========+=========+=========
                   | Number of |            | Standard  |         |
   SOURCE OF SAMPLE| clutches  |    Mean    | deviation | Maximum | Minimum
  -----------------+-----------+------------+-----------+---------+---------
  Early ovarian    |       25  | 11.4 ± .46 |    2.28   |     20  |      5
                   |           |            |           |         |
  Late ovarian,    |           |            |           |         |
  uterine, or laid |           |            |           |         |
  in captivity     |       56  | 9.16 ± .21 |    1.85   |     15  |      4
                   |           |            |           |         |
  In natural nests |       34  | 8.82 ± .32 |    1.85   |     16  |      4
  -----------------+-----------+------------+-----------+---------+---------

On the average, larger females produce more eggs per clutch than do
smaller females. Of 49 females for which measurements were recorded, and
which had uterine or large ovarian eggs, 31 were 70 mm. or more in
snout-vent length. These 31, mostly or entirely old adults, averaged 9.9
eggs per clutch, whereas 18 others that were 69 mm. or less in
snout-vent length, and that must have been mainly or entirely newly
matured adults in their first breeding season, averaged only 7.8 eggs
per clutch.

Smith (1946:350) states that in the northern part of the range of this
skink there is some indication of decrease in size of clutches. This is
not well shown by published records. For the southern states, most of
the published records of clutch size are by authors who did not clearly
distinguish between the three kinds of five-lined skinks, and there is
some doubt as to which species is involved in each record. For 56
clutches reported upon from north of approximately latitude 37°, I
obtain a slightly higher figure than for 11 clutches from south of this
line. Geographic trends are, of course, obscured by individual
variation, and perhaps by abnormal clutches produced by individuals kept
in captivity.

In Table 7, the figures marked with asterisks pertain to clutches that
might have belonged to skinks of the species _E. laticeps_ or _E.
inexpectatus_ since they were recorded in regions where _laticeps_ and
in some cases, _inexpectatus_ also, occurs along with _fasciatus_. If
these questionable clutches are excluded the remaining 55, definitely of
_fasciatus_, average 8.48 eggs per clutch, whereas the 12 questionable
clutches average 8.42. Both figures are close to the average of 8.82 ±
.32 eggs for the 34 natural nests recorded in the present study. For the
total of 1661 eggs of 182 clutches, from the combined sample of all
available records for clutches found in the present study or reported
upon in the literature, the average egg number is 9.13.

    [Illustration: FIG. 10. Correlation between size of female and
       number of eggs in clutch; females in their first breeding season,
       mostly less than 72 mm. in snout-vent length, produce smaller
       clutches, on the average, than do larger and older females, but
       there is extensive overlap.]

To sum up the available information on clutch size, the number of eggs
is most typically 9, 10, or 11 and is more in large old females, than in
small, newly matured females. In natural nests, even in those that are
successful, there is often some loss of eggs, which are eaten by
predators, or by the female herself, with the result that the egg
counts made by various observers average somewhat lower than the numbers
actually produced. The loss during incubation cannot be measured readily
since it is almost certainly sharply increased by the disturbance
entailed in observing nests. Exposing nests, even momentarily, for
observation, may result in compacting of the surrounding soil,
desiccation, temporary or permanent desertion by the female, and
exposure to predation. Some indication of the incidence of loss during
incubation might be obtained by counting and measuring the eggs in newly
found nests and correlating numbers with size (indicating the length of
time incubated).

    Table 7.--Numbers of Eggs Per Clutch, Time of Occurrence, Laying
       Dates and Hatching Dates, as Reported in the Literature by Various
       Authors.

  ==========+==============+===============+=========+=============+==========+=============
            |   Numbers    |               |         |             |          |
    AUTHOR  |   of eggs    | Date recorded | Natural | Laying date | Hatching |  Locality
            |  per clutch  |               |  nest   |             |   date   |
  ----------+--------------+---------------+---------+-------------+----------+-------------
  Allard    |          7*  |     ....      |   Yes   |    ....     |   ....   | Northern
            |              |               |         |             |          | Georgia
            |              |               |         |             |          |
  Bishop    |          8*  |     ....      |   Yes   |    ....     |   ....   | Breathitt
            |              |               |         |             |          | Co.,
            |              |               |         |             |          | Kentucky
            |              |               |         |             |          |
  Blanchard |          9*  |     ....      |  ....   |    ....     |   ....   | Tennessee
            |              |               |         |             |          |
  Burt      |       6; 11  | May, and      |   Yes   | June 12,    |   ....   | Douglas
            |              | June 18, 1926 |         | 1926        |          | Co.,
            |              |               |         |             |          | Kansas
            |              |               |         |             |          |
  Burt      |     9*, 9*,  | June 25 to    |   Yes   |    ....     |   ....   | Arkansas
            |     9*, 10*  | July 13, 1926 |         |             |          |
            |              |               |         |             |          |
            |              |               |         |             |          | Ashville,
  Burt      |          8*  | June 6, 1933  |   Yes   |    ....     |   ....   | North
            |              |               |         |             |          | Carolina
            |              |               |         |             |          |
  Burt      |          8*  | June 28, 1934 |   Yes   |    ....     |   ....   | Scott,
            |              |               |         |             |          | Mississippi
            |              |               |         |             |          |
  Burt      |          6*  | July 7, 1933  |   Yes   |    ....     |   ....   | Emma,
            |              |               |         |             |          | Georgia
            |              |               |         |             |          |
  Burt      |          6*  | July 8, 1933  |   Yes   |    ....     |   ....   | Elk River,
            |              |               |         |             |          | Alabama
            |              |               |         |             |          |
  Cagle     |   Average    |               |         |             |          |
            |  9.16 in 26  |               |         |             | July     | Elkville,
            | nests (6-15) | June-July     |   Yes   | June 30     | 23-24    | Illinois
            |              |               |         |             |          |
  Conant    |   7, 9, 10,  |               |         |             | July 27, |
            |      11, 13  |     ....      |  ....   |    ....     | July 27  | Ohio
            |              |               |         |             |          |
  Dunn      |         12*  |     ....      |  ....   |    ....     | Aug. 9   |
            |              |               |         |             |          |
  Evans and |              |               |         |             | First    | Arden,
  Roecker   |        6, 7  |     ....      |   Yes   |    ....     | week of  | Ontario
            |              |               |         |             | Sept.    |
            |              |               |         |             |          |
  Fitch     |           9  | July 22, 1947 |   Yes   |    ....     |   ....   | Vernon
  (field    |              |               |         |             |          | Parish,
  notes)    |              |               |         |             |          | Louisiana
            |              |               |         |             |          |
  McCauley  |  3; 20 in 3  |               |         |             |          |
            |  other nests |               |         | July 5      | August   |
            |   combined   |     ....      |   Yes   | and 6       | 30       | Maryland
            |              |               |         |             |          |
  Noble and |    2, 5, 5,  |               |         | May 23, 27, | July 5,  | Anderson
  Mason     |  6, 7, 8, 8  |     ....      |   No    | 31; June 6, | 5, 6, 7, | Co.,
            |              |               |         | 6, 13, 20   | 9, 17    | Kansas
            |              |               |         |             |          |
  Ruthven   | 6, 6, 8, 9,  |               |         |             |          |
            |  11, 13, 14  |     ....      |   Yes   |    ....     |   ....   | Michigan
            |              |               |         |             |          |
  Smith     |           9  |     ....      |   Yes   |    ....     |   ....   | Ohio
  ----------+--------------+---------------+---------+-------------+----------+-------------


BROODING

Lizards and snakes of several different families, are known to brood
their clutches of eggs, although the great majority of oviparous forms
do not do so. The brooding habit is perhaps best known in _Eumeces
fasciatus_, and has been described by many authors. By far the most
thorough account is that of Noble and Mason (1933) who observed and
experimented upon seven females that laid clutches of eggs in captivity.
These females, kept in separate terraria, excavated nest burrows for
reception of their clutches, and remained with them throughout the time
of incubation. There were three characteristic brooding postures; curved
in a semicircle around the clutch, in an S-shaped figure extending among
them, or lying straight, either over or among the eggs. The brooding
females, taken quietly from their nests without disturbing them, were
found to have temperatures averaging .4°C. higher than the nests.
Evidently normal room temperatures were maintained in the laboratory
where the terraria were kept. The females occasionally left their nests,
especially in late afternoon, to wander about the terraria, and to bask
in sunlight. While basking, their temperatures averaged 2.7°C. higher
than the nest temperatures. The authors suggested that an important
function of the brooding female was to transfer warmth from absorbed
sunlight to the eggs. They state: "In nature the importance of the
mother's body heat in the incubation of the eggs probably varies greatly
with the type of nesting site selected." They suggest that in clutches
deposited in logs or stumps beneath a thin layer of bark exposed to
direct sunlight the need for warming by the female would be less.

My own observations do not support the idea that brooding by the female
serves to hasten the development of the eggs. Both in the laboratory and
in natural nests, clutches deserted by disturbed females hatched and the
hatching was not unduly delayed. In the field, females were never
observed to bask in the sun beside their nest burrows, and seemingly
left them infrequently even to feed. When a female was caught in her
nest burrow, her temperature nearly always approximated that of the
surrounding earth with which she was in contact. The temperature in each
nest depends primarily upon its situation. When the immediate vicinity
of the nest receives direct sunlight, the eggs are warmed without the
aid of the female, but when there is no sunlight the temperature is much
lower. In order to maintain an appreciably higher nest temperature the
female would have to make frequent trips to spots perhaps several feet
or several yards away to find sunlight. Upon returning to the nest, her
body heat would be quickly dissipated into the eggs and the surrounding
damp soil. She would need to shuttle back and forth almost continually
between the nest and a spot exposed to sunshine. Cloudy weather often
preventing the warming of the eggs by absorption of solar heat prevails
during much of the incubation season, in the region of the present
study, and probably to an even greater extent throughout the range as a
whole.

Noble and Mason state (_op. cit._:9) that while in some non-brooding
kinds of lizards the eggs are actually damaged by turning, the female
_fasciatus_ frequently turns her eggs and moves the whole clutch about
in the nest cavity. On returning to their nests the experimental females
each invariably touched one or more eggs with their tongues as an
olfactory test. Eggs of other kinds of lizards not of the genus
_Eumeces_, and shellacked eggs of _fasciatus_, or paraffin models of
them, ordinarily were discarded immediately after a single touch of the
tongue. Eggs of other individuals of the species, and even the eggs of
_Eumeces laticeps_ were accepted as part of the brood. Any of the
experimental females would quickly retrieve one of her eggs moved a
short distance outside the nest cavity. Even if the whole clutch of eggs
were scattered about, the female would, over a period of hours, gather
the eggs and return them to the nest cavity. This movement of the eggs
is accomplished by rolling or pushing them in a loop of the body or
tail, or, less frequently, by grasping an egg in the jaws, lifting it,
and gently placing it in a new position. Even if the females were
blindfolded, they were still able to retrieve scattered eggs, but one in
which the tongue tip was experimentally removed showed no further
interest in its eggs, presumably having lost the capacity to recognize
them by olfactory test.

In the present study clutches unattended by females were observed to
sustain heavy losses, both in the laboratory and in the field, and no
doubt the attending female performs important functions other than that
of warming the eggs. In the damp or wet nest cavity, the eggs tend to
adhere to each other and to the earth walls and floor, and become sealed
to such surfaces as a result of partial drying, reducing the amount of
surface exposed to the air and probably hindering respiration. An
eggshell sealed in prolonged contact with the soil tends to rot with the
result that it is easily ruptured, and even if it is not broken there is
the likelihood of fungi or microorganisms gaining entry and killing the
embryo. In many of the eggs that were handled to obtain measurements
and weight, rupturing of shells occurred. The shells are tough and
elastic to the extent that even when eggs being handled were
accidentally dropped on the floor on several occasions, no damage to
them resulted. However, slight friction on the shell was sometimes
sufficient to puncture one. Particles of sharp rock from the nest cavity
may adhere to the shell, and result in rupturing, perhaps at weak spots
where prolonged contact with the soil has caused deterioration. The
female tends to keep her eggs in a compact cluster, shifting their
position frequently so that no part of an eggshell adheres to its
surroundings long enough for rotting to occur, and most of the surface
of each egg is exposed to the air.

Another important function of the brooding female seems to be that of
altering the nest burrow and shifting the eggs so that the effects of
unfavorable weather are minimized. The usual response to warm and dry
weather is deepening of the nest burrow. A cavity originally in loose
soil on the underside of a flat rock, having the eggs in contact with
the rock surface, may be displaced downward. The female excavates loose
soil from the floor of the burrow and packs it on the top and sides,
until the eggs are two or even three inches underground, in a cavity
different in position and shape from the original one, although derived
from it by gradual stages. In many instances, however, no such response
to drying was observed. Probably extensive alteration of the nest burrow
no longer is possible after drying of the soil has progressed beyond a
certain stage as these skinks are not strong diggers. In some nests that
were examined frequently, with resulting desertions by the attending
females, the outlines of the cavities became indistinct and the soil
around them became dry and packed. In heavy rains, when nest burrows are
partly flooded, the females move the eggs to avoid their being
submerged. The extent of the female's activity within the nest burrow is
suggested by the glazed condition of the earth walls and floor, and by
the mottled appearance which the eggshells soon acquire as a result of
being slid and dragged about in the nest cavity.

Still another important function of the female is to dampen the nest
burrow to prevent desiccation of the eggs. Even in dry weather, females
taken from nests almost invariably voided water in relatively large
quantities. They drink dew or other available water, and may void the
contents of the bladder to moisten the nest cavity, as on numerous
occasions, when nests were exposed by raising flat rocks covering them,
part of the chamber was seen to be recently watered, and distinctly
moister than the surrounding soil.

Noble and Mason (_op. cit._:16-19) found that brooding females, in the
laboratory, would vigorously defend their eggs against small enemies,
including mice and lizards and the smaller kinds of snakes that were
tested. The female watched alertly as the intruder approached, and
attempted to bite it if it came too near or touched an egg. The females
failed to defend their nests against persons and against a large
blacksnake; when confronted with such a threat, the female would run
from her nest cavity to hide. Cagle (1940:228) stated that the brooding
females found by him stayed in the nests even when the logs in which
they were situated were chopped open with an ax, and that the skinks
would attempt to bite when touched with the finger.

In the present study, females whose nests were exposed never made any
active attempt to defend them. Many darted away and hid as soon as they
were exposed. In other instances, especially when the nest cavity was
only partly exposed, from one side, the female cowered back against the
inner wall, opening her mouth in threat if closely approached. If
further molested she might then attempt to escape. In brooding females a
tendency to sluggishness, and an affinity for the eggs delayed the
usually speedy escape reactions. The temperature of the female was
ordinarily lower than it would have been in the open or on the underside
of a flat rock, and this also tended to slow her reactions. Gravid
females when exposed in nest cavities that still contain no eggs are
similarly sluggish and reluctant to leave differing little or none in
behavior from those that have laid their clutches. Usually the female
was found with her body encircling the eggs, holding them together in a
compact cluster in the center of the nest cavity. The eggs rest in
contact with the loose soil on the floor of the cavity, with each other,
and with the female's body in the case of the outer ones of the cluster.

Normal brooding habits proved to be difficult to follow because the
females were easily disturbed. In many instances those that had
excavated nest burrows, but had not yet laid, deserted the nests after
the disturbance involved in raising the sheltering rock. Females that
had already laid before discovery of their nests were somewhat less
inclined to desert, but many did so.

On numerous occasions, at the time of year when most females are gravid
and are staying in nest burrows, I have discovered well formed nest
burrows empty and seemingly deserted, with no female in evidence
nearby. In some instances the female may have been out foraging or
basking although she was not seen, and in other instances the female may
have been killed by a predator or eliminated by some other accident.
However, it seems that gravid females frequently do desert their
original nest burrows, for one cause or another, and excavate new ones.
Such desertions were noted many times in the females observed on the
study area, where the disturbance from my own activities in raising the
sheltering rocks may have caused shifts, but it was probably not the
sole motivation. One female shifted approximately 120 feet, to excavate
her second nest burrow in a site that was damper and more heavily shaded
than the first site. This was in the notably dry summer of 1952. Most of
the favorite sites under flat rocks in open situations, that were used
in 1950 and 1951, were not occupied in 1952 or 1953, although several
females did use them for original excavations, which were deserted
before laying, as drought conditions developed. In the summers of 1952
and 1953 nests were difficult to find, and those discovered were on the
average deeper and better protected than those found in other years.

As compared with other North American lizards in general, _Eumeces
fasciatus_ is notable for the relatively exposed and superficial
situations chosen as nesting sites. However, it occurs in a climate of
high humidity; in contrast, the great majority of our lizards live in
arid climates where the eggs are in much greater danger of desiccation,
and require better shelter to maintain the humidity at a sufficiently
high level. Accounts in the literature and observations in the present
study indicate that these skinks exercise a wide range of choice of
nesting sites. Ruthven (1911:264) stated that in northern Michigan nests
were usually in decaying logs; occasional nests were found in burrows in
sand, but invariably decaying wood was present in or around at least
part of the nest.

Blanchard (1922) mentions a nest in Tennessee that may have been made by
either this species or _E. laticeps_ "in a hollow in a dead willow tree
about fifteen feet from the ground buried in the loose, damp, rotted
wood." Noble and Mason (_op. cit._:16) quote Blanchard (_in litt._) that
in northern Michigan _fasciatus_ nests in logs that are exposed to
sunlight. Conant (1951:31) stated that several clutches of eggs found in
Ohio were an inch to six inches beneath the upper surface of the log or
stump which sheltered them. Evans and Roecker (1951:70) record finding
two incubating females inside rotten pine logs, in Ontario. Cagle,
studying this species near Elkville, Illinois, in oak-hickory woods,
found 25 natural nests of which three were in loose soil among the
roots of a fallen tree, another was under loose bark of a log, and the
remainder were all in cavities of partly decayed logs. Bishop (1926:119)
recorded finding a female with a clutch of eggs beneath damp boards at
Quicksand, Breathitt County, Kentucky.

In the present study, more than one hundred natural nests were found, of
which just one (containing two clutches of eggs) was in decaying wood
beneath the bark of an old log. All other nests were beneath rocks. On
the University of Kansas Natural History Reservation, where most of the
nests were found, the policy is not to tear apart decaying logs;
therefore the nests probably present in such situations were not
ordinarily found. On several occasions groups of hatchlings were seen on
logs within which they probably had hatched. In the area of the study,
however, decaying logs are scarce. The hardwood forests consist mostly
of young trees that are second growth on cutover areas or pioneer on
areas that were previously grassland. Because of frequent cutting there
are few old mature trees, and logs have not accumulated on the forest
floor. In northeastern Kansas, nesting in logs is comparatively rare. On
wooded slopes and the edges of level hilltops, the flat limestone rocks
that are often abundant provide preferred nesting sites. Even on
collecting trips off the Reservation, where stumps and logs could be
torn apart and searched, flat rocks were found to provide the main
source of nesting sites. These nest rocks varied from less than an inch
in thickness to nine inches or more, and from a few inches in diameter
to three feet or more. Some were resting loosely on the surface of the
soil and others were deeply sunken, on one side. Some were in situations
exposing them to nearly the maximum amount of sunshine whereas others
were in sites nearly always shaded. The varied character of the nesting
sites chosen demonstrated a wide range of tolerance for temperature,
moisture, and other factors, in the gravid and brooding female and in
the developing embryo.

As already mentioned, Noble and Mason (_op. cit._:9-10) noted that
females would accept and brood the eggs of other individuals just as
readily as their own, and several writers have reported gregarious
nesting habits, with two or more females occupying either the same nest
cavity, or separate cavities that were in close proximity. For instance,
Cagle wrote that among the small logs he found to contain nests, four
logs each contained one nest, five each contained two nests, and two
each contained three nests, while three other nests were found within an
eight inch square area in loose soil among tree roots. McCauley
(1939:93) in Maryland found three females brooding clutches of eggs,
which totaled 20, and which were so near together that there was
uncertainty as to which clutch certain eggs belonged in.

The gregarious nesting habit may be of benefit in permitting maximum
utilization of choice nesting sites, where such sites are in short
supply in an environment otherwise favorable. Also, the gregarious
tendencies make possible more continuous guarding of the eggs against
such natural enemies as can be repulsed by the female, since each female
occasionally interrupts her brooding to bask or forage.

Many of the nests that I found were in close proximity to others. Often
two nests, and sometimes even three, were found beneath the same rock,
and sometimes a distance of only two or three inches intervened between
the separate clutches. It seemed, however, that in almost every instance
each female had excavated a separate nest chamber originally. In some
instances adjacent nest chambers communicated with each other.

On July 13, 1948, a communal nest was discovered beneath loose bark of a
decaying elm log. There were 22 eggs in the combined clutch, and there
were two females in the vicinity. The bark was raised on several
different days to examine the eggs, and one or both females always were
found with the eggs.

On June 10, 1949, at the pond rock pile, a flat rock was turned and an
unusual nesting aggregation consisting of a minimum of eight females,
and probably more than ten, was found. The nests were somewhat disturbed
by movement of the rock. The ground beneath was honeycombed with tunnels
connecting the flask-shaped nest cavities, which were in part open to
the rock surface on their upper sides. Clutches of eggs numbered 13, 12,
11, 8, and 6 (the last attended by a female which appeared to be still
distended with several more unlaid eggs). Of five other females taken,
two had laid and three were still gravid. Of the five clutches, two had
eggs noticeably larger than those in the other three, and with their
shells mottled brown from adhering earth. These nest cavities were about
half an inch deep and two to three inches wide. The females were
released as soon as they had been examined. One female moved about over
the nest areas exposed, and evinced interest in a lone egg which had
become separated from the others. She moved up to it, standing high off
the ground, with her head turned at right angles to her body as if
preparing to push the egg forward in the angle thus formed, and tested
it with her tongue, but then she became alarmed and left the vicinity.
The flat rock was lowered over the nests again with a minimum of
disturbance.

On July 9, 1949, the flat rock covering the nests was raised again. Most
of the eggs had hatched. Two broods of hatchlings were still in their
respective nest cavities, and one entire clutch had not begun to hatch
although its incubation was nearly completed. Three eggs of _Scincella
laterale_ were found mixed with the _Eumeces_ eggs. One of these was
opened to verify their identity; the other two hatched a few days later
in the laboratory.

The following selected excerpts from my field notes, setting forth
histories of several nests, so far as they were known, give some idea of
the types of nesting sites chosen, the behavior of the females, and the
hazards to which the eggs are exposed.


       No. 1. At corner of pond rock pile.

  June 21, 1951. Female escaped when rock was turned. One egg measured
     12.5 × 8 mm., mud-stained.

  June 22, 1951. Nest not in evidence when rock was turned; digging into loose
     soil beneath to a depth of about an inch I exposed the eggs but did not disturb
     them further.

  July 23, 1951. When rock was turned, female did not attempt to escape, but
     withdrew to far corner of nest cavity; when caught she voided a large scat
     which seemed to consist mainly of _Ceuthophilus_ remains. Largest eggs in
     the clutch were 18 × 10 mm. but two were noticeably smaller, and all were
     heavily coated with dried mud.

  July 30, 1951. Six young in the nest cavity, still not fully active; all of them
     were heavily coated with dried mud.


       No. 2. At hilltop ledge, under flat rock 13 × 10 × 1 inches, with
       one edge sunken in soil; exposed to sunshine for most of day.

  June 24, 1951. Female, snout-vent length 70 mm., tail 27-51, weight 5 gms.
     Nine eggs, one of which measured 14 × 8 mm.

  July 18, 1951. Nine eggs still in their original nest cavity, attended by the
     female; she escaped into crevice behind the rock. The eggs were in slightly
     damp soil, and in contact with the undersurface of the rock on their upper
     sides; one egg was 17 × 10 mm.

  July 26, 1951. Eggs caked with dried mud; still attended by female.

  July 30, 1951. Dry and empty eggshells in nest cavity, evidently all the eggs
     had hatched; no other trace of female nor of young; July 28th seems most
     probable hatching date--if, on the 27th, some of eggs almost certainly
     would have shown signs of hatching on the 26th when they were examined,
     and if on the 29th some stragglers almost surely would have remained at
     the nest on July 30.


       No. 3. In small gully, on lower slope in hickory woods, beneath rock
       9 × 9 × 1 inches, shaded by trees on south side for much of the day,
       especially during latter part of morning.

  June 24, 1951. The gravid female was deep in nest burrow.

  June 29, 1951. When rock was lifted no trace of nest was visible except
     for slightly disturbed loose soil at the point where it had been. When
     some of this loose soil was cleared away, nest was revealed, with
     11 eggs, mud-stained, approximately 12.5 × 8 mm. The female was cold
     and sluggish, and did not attempt to escape, but cowered in the back
     of the nest burrow, with jaws gaping; she was caught and marked.

  July 20, 1951. Eight eggs remaining in the nest--two were accidentally
     destroyed in moving them. These two were fertile and contained live
     embryos, one of which measured 29 mm. in over-all length. One of the
     remaining eggs was 16.5 × 10 mm. Female was present with the eggs.

  July 25, 1951. Eggs still present in the nest cavity; female not in
     evidence, but might have been concealed in corner of nest chamber as
     it was not disturbed.

  July 28, 1951. Female was again found with the eggs. One or more of the
     seven remaining eggs were punctured in moving them during their
     examination. Eggs about 16 × 10 mm.

  August 3, 1951. Female was in nest with the eggs some of which are
     slightly indented from drying.

  August 6, 1951. When rock was turned, female darted out and ran to cover
     about ten feet away. The eggs had hatched but two young remained in
     the nest cavity, still rather slow and feeble in their movements and
     not yet fully active. When routed from cover a second time, the female
     ran back to the nest rock and took shelter beneath it.


       No. 4. On upper slope above ledge, under a rock 18 × 9 inches, in
       site shaded most of day; burrow nearly concealed beneath rock.

  June 24, 1951. Nest occupied by a gravid female, apparently ready to lay.

  June 30, 1951. Rock covering this nest has been undermined by a mole
     tunnel, and many nearby rocks are undermined also. The eggs were
     almost certainly destroyed by the mole's tunneling and may have been
     eaten by it, since no remains are in evidence.


       No. 5. At hilltop ledge beside old abandoned road, beneath flat
       rock nine inches in diameter and about 1-1/2 inches thick, shaded
       for first half of morning and most of afternoon, but exposed to
       mid-day sunshine.

  June 29, 1951. Standing water in bottom of nest chamber 1-1/2 inches
     below underside of the rock. Some of the eggs are more than half
     submerged. One egg is 14 × 8 mm.

  July 21, 1951. Entrance of abandoned nest burrow has been enlarged by
     running water channelled through in run-off during and after heavy
     rains; shrivelled remains of eggs present at the bottom of the burrow.


       No. 6. On grassy hilltop a few yards from ledge under flat rock,
       9 × 6 × 2 inches.

  July 23, 1951. Large female (snout-vent length 75 mm.) with three eggs,
     16 × 22 mm.

  July 27, 1951. Female escaped from nest cavity as rock was raised. Three
     eggs were still in the nest, and a young skink was partly emerged from
     one. A second egg not yet hatching was somewhat flaccid, 16 mm. long,
     heavily coated with dried mud. The third egg much shrivelled, was opened
     and found to have a dead fetus, perhaps a week short of hatching.

  July 28, 1951. The flat rock which formerly covered the nest cavity was
     found to have been raised and displaced, and no trace of the female,
     eggs or young remained. Of possible predators that might have moved
     the rock and destroyed the nest, skunk and opossum seemed the most
     likely, but there was no definite clue as to the predator's identity.


       No. 7. Two feet northeast of pond rock pile, under rock about one
       foot square on upper surface with maximum thickness of about eight
       inches, lying with upper side at 45-degree angle. The nest was under
       one edge, with approximately three inches of rock over it. The rock
       was exposed to sunshine throughout the day, except for grass shading
       its edges.

  July 23, 1951. When rock was turned, the female darted out of the nest
     cavity, but in her dash to escape she dropped into a nearby pitfall.
     When handled, she voided feces which contained the nearly intact shell
     of a skink egg. Six eggs present in the nest; one selected as typical
     was 11-1/2 × 8 mm. The eggs were slightly misshapen and might have been
     damaged from drying.

  July 26, 1951. When rock was raised, female darted out and escaped. The
     six eggs still remained in the nest.

  August 2, 1951. When rock was raised the female was not in evidence, and
     only three eggs could be found; they had fallen from the nest cavity
     to the bottom of the depression where the rock was imbedded and were
     somewhat dried and indented.

       No. 8. North slope, beneath rock approximately 18 × 15 × 4 inches,
       at edge of small gully, where shaded most of the time including
       mid-day hours.

  July 20, 1951. Female attempted to escape from the nest. Four eggs
     visible in nest, one 15-1/2 × 10 mm.

  July 25, 1951. When rock was raised the female ran from the nest.

  July 27, 1951. When rock was raised the female was in the nest with the
     eggs; she ran and hid beneath a boulder five feet away. After a few
     minutes she emerged and ran 15 feet to a hickory sapling and climbed
     it.

  July 28, 1951. Female was not in the nest but the four eggs were still
     present.

  July 30, 1951. Female found dead and partly eaten by ants beside rock
     one foot from nest; eggs still present in the nest.

  July 31, 1951. Eggs still present in the nest.

  August 3, 1951. Eggs still present, including some deep in the nest
     cavity which apparently were overlooked previously.

  August 6, 1951. One much indented egg found outside the nest cavity was
     opened and found to contain a live fetus, seemingly fully developed
     and normal. The opened egg was placed on damp soil in a shady place
     near the nest, but two hours later the hatchling had been killed and
     partly eaten by swarms of ants.

  August 9, 1951. The remaining eggs had disappeared, evidently taken by
     a predator as no empty shells remained to indicate that the young
     had hatched.


HATCHLINGS

Cagle (1940:229 and 232) has graphically described and illustrated the
hatching of the five-lined skink, and numerous observations in the
present study have served to corroborate his description. The first
indication that the time of hatching is at hand is a twitching or
jerking movement within the egg which continues until the shell is slit.
According to Noble and Mason (1933:5) the shell is slit with the
elongate premaxillary egg tooth which has its distal third bent forward
nearly at right angles to its base. Some young remain for an hour or
more with only the snout visible, however, once the head is extruded it
is not again withdrawn unless the lizard is badly startled. The eyes are
opened and blinked slowly, closed for a few minutes, and opened again.
After the eyes have become adjusted, the fore-body emerges and the front
legs are freed. In one clutch, observed by Cagle, hatching time for
individual eggs varied from 45 minutes to five and three-fourths hours.
If startled by visual or tactile stimuli, the little skink may lunge
forward through the slit shell, with a sudden straightening of its body,
and rush away for several inches. Its movements are slow, stiff and
clumsy as compared with those of a skink that is a few days old and
fully active. Hatching of a clutch ordinarily extends over 24 hours or
more. Some of the young may be fully hatched and active before others
from the same clutch have slit their eggshells.

Eggs ready to hatch ordinarily weigh somewhat more than one gram, up to
at least as much as 1.7 grams, but much of this weight is made up of
water absorbed during incubation. The hatchlings usually weigh from .2
to .45 grams. For each of two eggshells recently vacated, that were
washed and squeezed dry, weights were approximately .125 grams.
Hatchlings of the same brood differ perceptibly in size with several per
cent variation in total length, and weight. Some seem to be less fully
developed than others. On July 8, 1952, hatching of the last young in a
clutch was observed. Upon emergence, it differed in appearance from the
others of the brood hatched a few hours earlier. The top of its head
bulged slightly as in fetuses. The umbilicus was not yet closed, and the
protruding yolk mass hindered the hatchling's movements and made
crawling difficult. In order to progress it had to stand high off the
ground to prevent its ventral surface from dragging. Protrusion of the
yolk mass has been described in newly emerged hatchlings for the closely
related _E. anthracinus_ (Clausen, 1938:3-7) as well as in _fasciatus_.
Cagle (_loc. cit._) states that the mass of yolk is at first about 3 mm.
in diameter, but is completely used at the end of the third day. A group
of young retained by him, without food, died the sixth day after
hatching, seemingly from starvation. Three of five recently hatched
young were found by Cagle to have eaten ant pupae placed in a box with
them on the preceding day, even though the skinks still retained the
yolk masses. One hatchling of this group ate its own tail that had been
broken off in handling. Cagle described a color change taking place
during the first few hours after hatching; the ground color, dull
greenish at first, darkens to an iridescent black, the pale stripes are
altered from an original tan color to bronze, with a tinge of reddish on
the head, and the ventral surface which is partially transparent showing
the outlines of the internal organs at first, soon becomes opaque white.

Contrary to the statement by Noble and Mason (1933:5) that in captivity
the hatchlings seldom stayed together more than a few hours, litters of
young fully active, a day or two after hatching were found in the nests
with the females still looped around them on several occasions. On one
such occasion, although the brood scattered immediately into surrounding
vegetation where they hid, I succeeded in catching the female and six of
the young, and put them all together in a nylon bag to carry them back
to the laboratory. Several hours after the bag had been placed on a
table it was noticed that the family had again gathered into a compact
cluster in the bag with the female's body looped around the young in the
characteristic brooding position seen in those with young or eggs in
their nest cavities. When hatching is complete, the female may leave
before the young have dispersed. On August 5, 1950, a nest under
observation was found to have all of the young or most of them still
clustered in the cavity, but the female was not in evidence. The young
were active, and immediately took alarm as the rock was raised exposing
them. Almost instantly, they scattered and vanished. Subsequent search
revealed five of the young, each poorly concealed in tufts of grass or
under dry leaves or other ground litter at the edges of the depression
where the rock had lain. Once hidden, these young were reluctant to run
again and depended on concealment.

Having once left the nest, the young probably do not return to it, as
many nests examined within a few days after hatching were never found
occupied either by females or young after their original dispersal. As
soon as the dispersal occurs family ties are permanently severed. On
July 19, 1950, a group of active hatchlings was observed moving about
over a log, on what was probably the first day of activity away from the
nest. The log was in the bottom of a steep-walled gully, where it had
come to rest the night before. It had been an erect but dead and partly
undermined snag on the edge of the gully, and was blown down that night
in a violent thunderstorm. Most of the log was held clear of the rushing
water in the bottom of the gully by projecting limbs. The little skinks
were darting in and out of holes and crevices in the log, pausing
frequently to bask. As many as four were in sight simultaneously, but
probably the total included several more, as it was difficult to keep
track of individuals. An adult female, presumably the mother of the
litter was also present, but she took no interest in the young, and they
showed no evidence of dependence on her. On the contrary, several times
when one or another of the young happened to come near the female in the
course of its wandering, and noticed her, it was seen to shy away in
sudden alarm.

    [Illustration: FIG. 11. Sizes on specific dates of young hatched in
       1950 and 1952. Approximate size ranges at different times of year,
       and differences in trend between the two years are brought out.]

The young were much more active than the female. These and other young
observed in the open were almost constantly in motion. Pauses to bask at
any one spot were of only a few seconds duration. A certain log in Skink
Woods evidently was the site of one or more successful skink nests each
year that observations were made, although a nest was actually found in
it only in 1948. On July 26, 1950, recently hatched young were active on
this log. Temperature was about 22°C. and the young were alternating
frequently between shade and sunshine to maintain their body
temperature. Collectively they seemed to cover every square inch of the
log surface, poking and probing into niches, crevices and insect
borings. They had a tendency to seek out the highest points on the log
as resting places.

In moving about, foraging or sunning, the young often carry the tail
arched high, and keep it in motion with slow squirming undulations.
These undulations may be continued even when the lizard itself has come
to rest momentarily. The movements of the tail together with its vivid
blue color serve to attract attention to it. Such behavior has not been
observed in adults or partly grown young. Jopson (1938:90) observed an
instance in which two dogs cornered a young five-lined skink (either the
present species or _E. laticeps_) but were distracted by the wriggling
of its bright blue tail "either dropped by autotomy or knocked off" so
that the skink itself was allowed to escape. On another occasion these
same two dogs attacking an adult male skink, were not distracted by the
wriggling but dull colored broken tail, and they killed the lizard.


GROWTH

The subject of growth in _Eumeces_ was briefly discussed by Taylor
(1936:66) in his revision of the genus. Sorting fairly large series of
museum specimens into seeming age-size groups, Taylor concluded that
skinks require as much as 9 or 10 years to attain adult size. For
_fasciatus_, for instance, the snout-vent length of 65.7 mm. (small
adult size) was considered typical of individuals in their ninth year of
life, with yearly gain of only 6 or 7 mm. in length in the young. I have
seen the original data on which this conclusion was based, and the age
groupings, as assigned by Taylor, seemed plausible. However, in the
light of present knowledge, it is certain that the seeming intervals
between his assumed age groups would have disappeared with a still
larger series of specimens. The eight or nine size groups that Taylor
recognized as distinct annual age groups actually comprise only two age
groups, each having such wide dispersion of individuals (by retardation
of some and acceleration of others) that there is overlapping in size
between them.

Growth in reptiles is now much better understood. Many species have been
studied by a variety of methods, including observation of growth in
captives, recording of growth in marked individuals living under natural
conditions, and sorting of large series into age-size groups. Two
species of _Eumeces_ have been studied in some detail. Breckenridge
(1943:601-602) marked all the individuals of _septentrionalis_ that
could be found in a small colony in Minnesota and he concluded from the
growth recorded in several that were recaptured, that these skinks grow
to mature size (65 mm. and larger) at the end of their second year of
life and are ready to breed the following spring. Rodgers and Memmler
(1943:61) plotted the size distribution of a large year-round collection
of _skiltonianus_ from near Berkeley, California. They found that in
this species hatching occurs in July and August, hatchlings are about 25
mm. in snout-vent length, and grow to about 50 mm. by the time they are
one year old, and to about 65 mm. at two years of age, but most of them
breed at the end of their third year. Within the genus the species
_septentrionalis_ and _skiltonianus_ belong to groups separate from each
other and from that including _fasciatus_. While _septentrionalis_ and
_skiltonianus_ resemble each other in their growth pattern and in the
time required to reach sexual maturity, _fasciatus_ is notably different
in its more rapid growth and the shorter time it requires to reach
breeding maturity. This would scarcely be expected, as all three are of
similar size. Furthermore, _skiltonianus_ in the region of Rodgers' and
Memmler's study has a longer growing season than _fasciatus_ in
northeastern Kansas, while _septentrionalis_ in Minnesota has a growing
season markedly shorter than either. It is noteworthy that each of these
three skinks is the northernmost lizard in the section of the country
where it occurs.

In the present study growth was investigated by measuring and marking
large numbers of young, many of which were recaptured for subsequent
records, and by sorting into age-size groups all available measurements.
An understanding of the latter set of data was facilitated by
correlating it with the growth records of marked individuals. Changes in
the phenology of growth from year to year according to weather
conditions were noted.

As already indicated, hatching occurs from early July to mid-August in
northeastern Kansas. Unseasonably cool weather with frequent rains may
cause cumulative delay in breeding and incubation so that hatching may
average several weeks later than it does in years with relatively warm
and dry weather during the breeding season. Within any one year hatching
time is concentrated, so that the majority of the young hatch within a
period of two weeks, but microclimates in the situations where the nests
are made may differ enough to cause this much spread. Individuals living
on north slopes in thick woods, and receiving the minimum amount of
sunlight may have their emergence from hibernation and attainment of
breeding condition delayed. Later, nesting in the same situations, they
may have incubation of their clutches similarly delayed.

Newly hatched young average just under an inch in snout-vent length
(23-27 mm.) and weigh .2 to .45 grams. Most rapid growth occurs in the
period of weeks following hatching. The growth rate during this late
summer period cannot be well shown by comparing average size of series
taken on successive dates, because each series is likely to include some
newly hatched young.

In 1949, a series of recently hatched young averaged 26.7 mm. on July
10. By August 26, average length in a series collected was 42.9 mm.,
indicating an average gain of at least .35 mm. per day. One that may be
considered typical was marked on July 23, 1950, soon after hatching, and
it had a snout-vent length of 26.5 mm. and weighed .25 grams. It was
recaptured just a month later when it had grown to 36 mm. snout-vent
length, and weighed .8 grams. Potential growth rate under favorable
conditions is shown by the fact that some individuals have attained a
snout-vent length of 50 mm. by the third week of August, thus
approximately doubling their hatching length. A maximum growth rate of
about .5 mm. per day is indicated for these accelerated individuals, but
on the average, young are considerably less than 50 mm. in length even
when they enter hibernation. At the other extreme, representing retarded
growth, is an individual having a snout-vent length of only 34 mm. on
May 1. It must have been approximately nine months old on that date, but
of course had spent at least six months in hibernation. Even if it made
rapid growth subsequently, this yearling could scarcely have attained by
midsummer the pre-hibernation length of the most accelerated
individuals.

During the growing season following their first hibernation period, the
young grow to small adult size in most instances. After emerging from a
second hibernation they mature sexually and constitute an important part
of the breeding population.

Many of the skinks marked before their first hibernation, as hatchlings,
when they were a few days or a few weeks old, were subsequently
recaptured as well-grown yearlings or small adults, affording ample
information as to the usual growth rate and the extremes of acceleration
or retardation that occasionally occur. Records of selected individuals
in this group of skinks, marked early in life and recaptured after a
hibernation, are recorded below.

    Table 8. Records of Individual Skinks Marked as Hatchlings (Before
       the First Hibernation) and Recaptured the Following Year. Rapid
       Rate of Early Growth Is Shown.

  ========+=================+==========+=====================+======+=============================
          |                 |Snout-vent|                     |Weight|
          |    Date         | length   |   Tail length       |  in  |
          |                 |  in mm.  |     in mm.          |grams |    Remarks
  --------+-----------------+----------+---------------------+------+-----------------------------
  No. 1.  |August 8,    1951|    23-1/2| 30-1/2              |  .25 |Had just hatched when
          |April 28,    1952|    39    | 55 + 1/2            | 1.3  |first recorded; second
          |June 7,      1952|    48    | 69 + 1              | .... |capture was made soon
          |                 |          |                     |      |after emergence from
          |                 |          |                     |      |hibernation. All three
          |                 |          |                     |      |captures within a 50-foot
          |                 |          |                     |      |diameter.
          |                 |          |                     |      |
  No. 2.  |July 8,      1952|    25    | 25 (broken stub)    |  .3  |
          |April 23,    1953|    42    | 17 + 26             | .... |
          |June 23,     1953|    56    | 22 + 36             | .... |
          |                 |          |                     |      |
  No. 3.  |July 16,     1948|    26-1/2| 37                  | .... |Caught at the same place
          |July 5,      1949|    68    |101-1/2              | .... |on both occasions; in a
          |                 |          |                     |      |little less than a year
          |                 |          |                     |      |this female grew to
          |                 |          |                     |      |small adult size.
          |                 |          |                     |      |
  No. 4.  |August 23,   1950|    36    | 55                  |  .9  |The interval between
          |May 19,      1951|    46    | 69-1/2              | 1.7  |captures included about
          |                 |          |                     |      |two months of active
          |                 |          |                     |      |life, plus the hibernation
          |                 |          |                     |      |period; caught at the
          |                 |          |                     |      |same place on both
          |                 |          |                     |      |occasions.
          |                 |          |                     |      |
  No. 5.  |September 2, 1950|    34-1/2| 33 (broken stub)    | .... |Tail broken at first capture;
          |June 12,     1951|    45    | 48 + 3              | 2.0  |recaptured 40 feet
          |                 |          |                     |      |from original location.
          |                 |          |                     |      |
  No. 6.  |July 28,     1949|    36    | 56                  | .... |Recaptured 75 feet from
          |April 21,    1950|    49    | 83                  | 2.5  |original location.
          |                 |          |                     |      |
  No. 7.  |August 31,   1951|    38    | 58                  | .... |All three captures within
          |May 25,      1952|    48    | 82                  | .... |a 70-foot diameter.
          |June 30,     1952|    63-1/2| 57 + 26             | .... |
          |                 |          |                     |      |
  No. 8.  |August 23,   1950|    36    | 44 (broken stub)    |  .7  |Tail broken at first capture.
          |July 23,     1951|    69    | 37 + 49             | .... |Capture sites 150
          |                 |          |                     |      |feet apart.
          |                 |          |                     |      |
  No. 9.  |August 23,   1949|    39    | 53-1/2 (regenerated)| .... |This male was retarded
          |June 7,      1950|    46    | 70-1/2 (regenerated)| 2.1  |in growth, being still
          |July 23,     1950|    58    | 88 (regenerated)    | 3.7  |well short of small
          |September 3, 1950|    62    | 91 (regenerated)    | 4.9  |adult size as its second
          |                 |          |                     |      |hibernation period
          |                 |          |                     |      |approached; all four captures
          |                 |          |                     |      |recorded within
          |                 |          |                     |      |a few yards.
          |                 |          |                     |      |
  No. 10. |July 31,     1949|    38    | 23 (broken stub)    | .... |Capture sites
          |June 17,     1950|    58    | 43 + 36             | 3.6  |20 feet apart.
          |                 |          |                     |      |
  No. 11. |August 13,   1949|    40    | 66                  | .... |Approximately a year
          |August 8,    1950|    63    | 90 (regenerated)    | 5.0  |after its original record
          |                 |          |                     |      |this skink was recaptured
          |                 |          |                     |      |80 feet away, still
          |                 |          |                     |      |short of small adult
          |                 |          |                     |      |size.
          |                 |          |                     |      |
  No. 12. |August 19,   1949|    42    | 40 (broken stub)    | .... |All three captures within
          |June 13,     1950|    58-1/2| 58 + 28             | 4.1  |a 50-foot diameter.
          |July 5,      1950|    63    | 62 + 31             | 5.9  |
  --------+-----------------+----------+---------------------+------+-----------------------------

Many other young were not caught and marked until the growing season
following their first hibernation, and were recaptured within this
second growing season weeks or months after they were originally marked,
and after they had made substantial growth. Those recaptured near the
end of this second growing season, when they were a year old, or a
little more, usually had attained small adult size or were nearing it.
Selected records of these yearlings are presented below.

    Table 9. Selected Records of Individual Skinks Marked as Yearlings
       (After Emergence From the First Hibernation) and Recaptured One
       or More Times the Same Year. Rapid Growth Is Shown.

  =======+==================+==========+=================+======+=================
         |                  |Snout-vent|                 |Weight|
         |      Date        | length   |  Tail length    | in   |
         |                  |  in mm.  |    in mm.       | grams| Remarks
  -------+------------------+----------+-----------------+------+-----------------
  No. 1. |May 2,        1951| 38       | 53-1/2          | .... |Capture sites
         |September 25, 1951| 62       | 25 + 31         | .... |  30 feet apart.
         |                  |          |                 |      |
  No. 2. |May 8,        1951| 39       | 57              | .... |Capture sites
         |August 2,     1951| 60       | 67 + 25         | .... |  150 feet apart.
         |                  |          |                 |      |
  No. 3. |April 17,     1952| 39       | 55              |  1.1 |Capture sites
         |June 23,      1952| 57       | 73 (regenerated)| .... |  30 feet apart.
         |                  |          |                 |      |
  No. 4. |May 20,       1952| 45       | 67              | .... |Capture sites
         |May 28,       1952| 47       | 71              | .... |  15 feet apart.
         |June 9,       1952| 53       | 82              | .... |
         |                  |          |                 |      |
  No. 5. |May 22,       1952| 48-1/2   | 77-1/2          |  2.0 |Capture sites
         |July 20,      1952| 63       |106              |  5.3 |  10 feet apart.
         |                  |          |                 |      |
  No. 6. |June 11,      1950| 49       | 49 (broken stub)|  2.4 |Capture sites
         |September 2,  1950| 63       | 63 + 31         |  4.9 |  20 feet apart.
         |                  |          |                 |      |
  No. 7. |April 14,     1950| 47       | 72              |  1.9 |Capture sites
         |May 29,       1950| 50       | 82-1/2          |  2.5 |  50 feet apart.
         |                  |          |                 |      |
  No. 8. |May 12,       1952| 49       | 77              | .... |Capture sites
         |June 18,      1952| 61-1/2   | 98              | .... |  60 feet apart.
         |                  |          |                 |      |
  No. 9. |June 4,       1950| 54       | 89              |  2.8 |Both captures at
         |August 1,     1950| 64-1/2   |101 (broken stub)|  5.7 |  same site.
         |                  |          |                 |      |
  No. 10.|June 11,      1950| 49       | 49 (broken stub)|  2.4 |Capture sites
         |September 2,  1950| 63       | 63 + 31         |  4.9 |  20 feet apart.
         |                  |          |                 |      |
  No. 11.|June 13,      1949| 57       | 68 (regenerated)| .... |
         |August 8,     1949| 70       | 37 + 11         | .... |
  -------+------------------+----------+-----------------+------+-----------------

Adult skinks can be found in greatest numbers in the breeding season and
many of the young that were marked were recaptured as newly matured
breeding adults soon after their second hibernation, often still short
of average adult size. Selected records of such individuals are
presented below.

    Table 10. Records of Individual Skinks Marked as Young and
       Recaptured as Adults.

  =======+===============+======+=====================+======+=========================
         |               |Snout-|                     |      |                                |
         |               | vent |     Tail length     |Weight|      Remarks
         |     Date      |length|       in mm.        |  in  |
         |               |in mm.|                     |grams |
  -------+---------------+------+---------------------+------+-------------------------
  No. 1. |Male           |      |                     |      |Probably less than a
         |August 21, 1950|34    | 48                  |  .7  |  month old at first
         |May 30, 1952   |69    | 37 + 49             | .... |  capture; at second
         |               |      |                     |      |  capture 21 months
         |               |      |                     |      |  later and 185 feet
         |               |      |                     |      |  away, he had red
         |               |      |                     |      |  facial suffusion
         |               |      |                     |      |  already somewhat faded
         |               |      |                     |      |  as the breeding season
         |               |      |                     |      |  waned.
         |               |      |                     |      |
  No. 2. |Male           |      |                     |      |
         |July 31, 1949  |39    | 64                  | .... |All three captures
         |August 22, 1949|47    | 75                  | .... |  within a 70-foot
         |May 19, 1951   |73    | 69 (regenerated)    | .... |  diameter.
         |               |      |                     |      |
  No. 3. |Male           |      |                     |      |
         |August 5, 1949 |36    | 57                  | .... |Capture sites
         |May 3, 1951    |67    |103                  | 5.1  |  10 feet apart.
         |               |      |                     |      |
  No. 4. |Male           |      |                     |      |
         |June 16, 1951  |44    | 41 (broken stub)    | .... |Capture sites
         |May 28, 1952   |63    | 77 (regenerated)    | .... |  535 feet apart.
         |               |      |                     |      |
  No. 5. |Male           |      |                     |      |
         |April 12, 1950 |45    | 73                  | 1.9  |Capture sites
         |May 1, 1951    |67    | 17 + 48             | .... |  100 feet apart.
         |               |      |                     |      |
  No. 6. |Male           |      |                     |      |This individual had
         |April 12, 1950 |46    |  4 + 15             | 1.3  |  attained approximately
         |August 10, 1950|67    | 75 (regenerated)    | 5.3  |  average adult size by
         |May 12, 1951   |71    | 77 (regenerated)    | .... |  the 1951 breeding
         |               |      |                     |      |  season; all three
         |               |      |                     |      |  captures were within a
         |               |      |                     |      |  distance of 90 feet.
         |               |      |                     |      |
  No. 7. |Male           |      |                     |      |
         |April 30, 1950 |48-1/2| 78-1/2              | 2.4  |
         |June 15, 1950  |56    | 94                  | 2.9  |
         |May 19, 1951   |67    | 90 (broken stub)    | .... |
         |               |      |                     |      |
  No. 8. |Male           |      |                     |      |
         |May 3, 1950    |47    | 51 + 4              | 1.7  |Capture sites
         |May 29, 1951   |75    |115 (regenerated)    | .... |  450 feet apart.
         |               |      |                     |      |
  No. 9. |Male           |      |                     |      |
         |June 2, 1949   |51    | 46 (broken stub)    | .... |Capture sites
         |May 2, 1950    |66-1/2| 31-1/2 + 51         | 7.0  |  90 feet apart.
         |               |      |                     |      |
  No. 10.|Male           |      |                     |      |
         |May 20, 1950   |58    | 92-1/2              | 4.0  |Capture sites
         |June 21, 1950  |61    | 95                  | 4.7  |  within 40 feet.
         |August 21, 1950|70    |108 (broken stub)    | 7.2  |
         |               |      |                     |      |
  No. 11.|Male           |      |                     |      |
         |June 25, 1950  |62    |100                  | 5.1  |
         |May 1, 1951    |71    |113                  | 7.1  |
         |               |      |                     |      |
  No. 12.|Female         |      |                     |      |
         |April 15, 1950 |46-1/2| 73-1/2              | 1.5  |Capture sites
         |May 20, 1951   |72    |113                  | .... |  160 feet apart.
         |               |      |                     |      |
  No. 13.|Female         |      |                     |      |
         |June 11, 1950  |51    | 69                  | 2.5  |Capture sites
         |May 25, 1951   |66    | 40                  | .... |  20 feet apart.
         |               |      |                     |      |
  No. 14.|Female         |      |                     |      |
         |June 6, 1949   |52    | 47 (regenerated)    | .... |Capture sites
         |May 20, 1950   |68-1/2| 69 (regenerated)    | 7.5  |  20 feet apart.
         |June 9, 1950   |71    | 71 (regenerated)    | .... |
         |               |      |                     |      |
  No. 15.|Female         |      |                     |      |
         |July 2,  1950  |60    |100                  |  4.2 |Capture sites
         |May 21,  1951  |74    | 33 + 35             | .... |  20 feet apart.
         |               |      |                     |      |
  No. 16.|Female         |      |                     |      |
         |June 12, 1950  |57    | 83                  |  3.1 |Capture sites
         |May 1,   1951  |71-1/2| 53 (broken stub)    |  6.4 |  35 feet apart.
         |               |      |                     |      |
  No. 17.|Female         |      |                     |      |This female probably
         |June 22, 1949  |62    | 24 (broken stub)    | .... |  hatched in July 1948
         |May 22,  1950  |72    | 27 + 7              |  9.0 |  and was nearing adult
         |               |      |                     |      |  size when first caught
         |               |      |                     |      |  at an age of a little
         |               |      |                     |      |  less than a year. By the        |
         |               |      |                     |      |  next breeding season it
         |               |      |                     |      |  was an average sized
         |               |      |                     |      |  adult; both captures at
         |               |      |                     |      |  same site.
         |               |      |                     |      |
  No. 18.|Female         |      |                     |      |This female probably was
         |July 4,  1950  |64    | 30 + 55             |  4.3 |  Approximately a year
         |May 23,  1951  |73    | 31 + 62             | .... |  old when first caught,
         |               |      |                     |      |  and she grew to average
         |               |      |                     |      |  adult size by the
         |               |      |                     |      |  next spring; both
         |               |      |                     |      |  captures at same site.              |
         |               |      |                     |      |
  No. 19.|Female         |      |                     |      |This female was about a
         |July 5,  1950  |61-1/2| 92-1/2 (regenerated)|  4.7 |  year old when first
         |June 14, 1951  |73    |111 (regenerated)    |  8.2 |  captured; loss of weight
         |June 29, 1951  |74    |106 (regenerated)    |  5.0 |  in July 1951 was caused
         |               |      |                     |      |  by its laying a clutch
         |               |      |                     |      |  of eggs. All three
         |               |      |                     |      |  captures were within a
         |               |      |                     |      |  15-foot diameter.                  |
  -------+---------------+------+---------------------+------+--------------------------

    [Illustration: FIG. 12. Sizes of immature skinks of successive
       annual broods, grouped in biweekly or monthly intervals, with mean,
       standard error, standard deviation, and extremes shown for each
       group.]

A certain small percentage fail to attain minimum adult size or breeding
maturity by the time of emergence from their second hibernation. Among
77 individuals marked as young either soon after hatching or in spring
and early summer, and recaptured the following spring, only one had
failed to grow to adult size. It was 46.5 mm. in length when marked on
June 13. When recaptured on April 25 of the following year, it had grown
to a length of 59 mm., still short of minimum adult length. During the
interval between captures it had maintained about the average growth
rate. Its failure to attain maturity was obviously the result of its
early retardation, and probably late hatching was primarily responsible.
Although this is the only individual with known history, which failed to
attain breeding maturity after its second hibernation, occasional
specimens are taken in spring which are somewhat below adult size but
seem too large to be young hatched the preceding summer. Obviously, the
incidence of such failure from year to year would be influenced by
weather conditions, and an unusually cool summer may result in such
delayed laying and hatching that an unusually large proportion of young
might fail to attain sexual maturity at the usual time. At more northern
localities, the percentage of such failures might be expected to
increase. At the northern edge of the range attainment of breeding
maturity may normally require more than two years. Such delayed
development would result in a drastic reduction of the reproductive
potential which might be critically limiting to the species, even in an
otherwise favorable environment, as the population would be unable to
replace rapidly enough the individuals eliminated by normal mortality
factors.

In contrast to the delayed development of those that have failed to
attain maturity at an age of two years, is the accelerated development
of those that have already more than doubled in length before the first
hibernation, and continue to grow rapidly after emergence. By late
spring they are already approaching adult size, perhaps even before
laying has occurred, and while breeding is still in progress. It is
certain that in northeastern Kansas there is no breeding by such
accelerated individuals approaching adult size at an age of nine or ten
months. Farther south in the species' range with a much longer growing
season, there is perhaps some possibility of such early breeding by
first-year individuals. This would reduce by more than half the length
of time required for a generation, and would tremendously increase the
reproductive potential. With such added impetus to its reproduction the
species might be able to withstand greatly increased predation pressure,
or other mortality factors.

    [Illustration: FIG. 13. Growth curves of successive annual broods
       (designated by the year of hatching), superimposed to bring out
       differences in trends resulting from changes in weather from
       year to year.]

Extremes of acceleration or retardation are relatively rare in the
population studied. Nevertheless, in April there are some individuals
between 50 and 60 mm. in snout-vent length which cannot be classified
with certainty as to their age group, and might be either accelerated
individuals about nine months old or retarded individuals about 21
months old.

The spread in size for any given age group is especially large, if data
from different years are combined. A typical individual, having a
snout-vent length of 25 mm. at hatching in mid-July may have attained 30
mm. by early August, 35 mm. by late August, and 45 mm. by the time it
hibernates late in September. Emerging shortly before the middle of
April it may grow to 50 mm. by the end of May, 58 mm. by the end of
June, and more than 60 mm. by the end of July when it is a little more
than a year old. By the time of its second hibernation it may have
attained a length of from 65 mm. to 70 mm., and emerges from this
hibernation as a breeding adult.

    [Illustration: FIG. 14. Records of growth of immature individual
       skinks, both hatchlings and yearlings, that were marked in one
       year and recaptured the next.]

In reptiles in general there is a wide range in adult size, and the
extent and rapidity of continued growth after attainment of sexual
maturity and minimum adult size is still insufficiently understood.
Information bearing on this problem was obtained in the present study
from the recapture of marked skinks already measured as adults. It is
evident that the growth rate of the young, amounts to as much as 15 mm.
per month in snout-vent length in the late summer period from hatching
until hibernation, averages perhaps three or four mm. per month in the
summer after emergence from the first hibernation, and tapers off
rapidly as adult size is approached.

One hundred of the skinks marked as adults or subadults and recaptured
after intervals of months, including, in most instances, one or more
hibernation periods, represent in the aggregate, 87 years of growth.
These records show that after minimum adult size of 65 mm. is attained,
growth slows abruptly, and that by the time a length of approximately 75
mm. is attained in most instances growth has become extremely slow in
males and has virtually stopped in females. Males attain a maximum size
several millimeters larger than that of females. Individuals differ
greatly in their growth, however; some adults continue to grow rapidly
till they near the maximum size, whereas others apparently stop growing
when they are still below average adult size. Unusually large specimens
are not necessarily old, but may have attained their size only a year or
two after reaching maturity through the accelerated growth resulting
from abundant food and predisposing genetic factors. Likewise, unusually
old individuals are not necessarily the largest, but may be only a
little above average adult size. It may be assumed that no growth occurs
during the period of winter dormancy, which occupies approximately half
the year in the population studied. To compute growth rates, in those
recaptured after an intervening hibernation, periods of hibernation,
arbitrarily estimated as six months, were subtracted from the time
elapsed between captures.

    Table 11. Average Growth Rate in a Selected Sample of Skinks
       of Adult Size.

  ============+====================+====================
              |        Males       |        Females
              |----------+---------+----------+---------
   SIZE GROUP | Average  | Number  | Average  | Number
              |growth mm.|of skinks|growth mm.|of skinks
              |per month |in sample|per month |in sample
  ------------+----------+---------+----------+---------
  65-68 mm.   |  1.4     |   11    |   .8     |   12
  69-72 mm.   |   .7     |   12    |   .4     |   21
  73-76 mm.   |   .7     |   13    |   .3     |   21
  77-80 mm.   |   .4     |    7    |  ....    |  ....
  ------------+----------+---------+----------+---------

Opportunity to compare the rapid growth of young during their first year
of life with the relatively slow continued growth after attainment of
sexual maturity is afforded by the records of skinks caught and marked
while yet immature and recaptured in two or more successive years after
their attainment of sexual maturity. The records of selected individuals
of this group are presented below. With the exception of number three,
all in this series are of the 1949 brood, and probably all hatched
within a two-week period.

    Table 12.--Records of Individual Skinks Marked as Young and
       Recaptured Repeatedly After Attainment of Adult Size, Showing
       Trend of Progressively Slowing Growth.

  =======+==================+==========+=====================+======+============================
         |                  |Snout-vent|                     |Weight|
         |      Date        | length   |    Tail length      | in   |
         |                  |  in mm.  |      in mm.         | grams|      Remarks
  -------+------------------+----------+---------------------+------+----------------------------
  No. 1. |Male              |          |                     |      |At an age of 33 months
         |April 12,     1950|   43     | 71                  |  1.5 | this male was far short
         |August 30,    1950|   56     | 56 + 21             |  5.4 | of maximum size, and
         |May 23,       1951|   68     | 59 + 32             | .... | smaller than some
         |April 28,     1952|   73     | 62 + 38             |  6.6 | males a year younger;
         |                  |          |                     |      | all four captures within
         |                  |          |                     |      | a 65-foot diameter.
         |                  |          |                     |      |
  No. 2. |Male              |          |                     |      |At an age of approximately
         |July 5,       1950|   61     | 92-1/2 (regenerated)|  5.2 | one year this
         |July 28,      1950|   64     | 97 (regenerated)    |  5.4 | male was approaching
         |May 3,        1951|   68     | 96 (broken stub)    |  5.8 | small adult size; when
         |June 21,      1951|   72     |101-1/2 (regenerated)| .... | last captured at an age
         |May 1,        1952|   78     |101 (regenerated)    | .... | of 34 months, he was a
         |                  |          |                     |      | large adult. All five
         |                  |          |                     |      | records within a 190-foot
         |                  |          |                     |      | diameter.
         |                  |          |                     |      |
  No. 3. |Male              |          |                     |      |This skink was nearly a
         |June 22,      1949|   65     |111                  | .... | year old and nearing
         |May 4,        1950|   72-1/2 |115                  |  7.3 | adult size when first
         |June 17,      1950|   73     |116                  |  7.8 | captured; recaptured
         |May 15,       1951|   80     |125                  | .... | in each of the four
         |May 13,       1952|   82     |125                  | .... | succeeding years, he
         |April 6,      1953|   82     |104 (regenerated)    | .... | showed slowing growth.
         |                  |          |                     |      | He was near the maximum
         |                  |          |                     |      | size at the time of his
         |                  |          |                     |      | last capture when he
         |                  |          |                     |      | was about 57 months
         |                  |          |                     |      | old, and evidently had
         |                  |          |                     |      | stopped growing (for
         |                  |          |                     |      | movement see No. 2,
         |                  |          |                     |      | p. 110).
         |                  |          |                     |      |
  No. 4. |Female            |          |                     |      |This individual, marked
         |July 13,      1949|   27     | 34-1/2              | .... | when less than two
         |June 1,       1950|   54-1/2 | 93-1/2              |  3.1 | weeks old, had grown
         |August 21,    1951|   74     |119                  | .... | to nearly the maximum
         |May 1,        1952|   76     |123                  | 10.0 | female size at an age of
         |                  |          |                     |      | 34 months; all four
         |                  |          |                     |      | captures within a
         |                  |          |                     |      | 175-foot diameter.
         |                  |          |                     |      | (See Figure 24).
  No. 5. |Female            |          |                     |      |
         |April 15,     1950|   43     | 70                  |  1.4 |All six records within a
         |June 5,       1950|   52-1/2 | 87                  |  2.8 | 65-foot diameter (See
         |May 25,       1951|   71     | 82 + 29             | .... | Figure 21).
         |September 28, 1951|   73     |111 (regenerated)    | .... |
         |April 26,     1952|   74     |113 (regenerated)    |  7.4 |
         |April 24,     1953|   76     |114 (regenerated)    | .... |
         |                  |          |                     |      |
  No. 6. |Female            |          |                     |      |Hatched in July 1949,
         |April 21,     1950|   46     | 75                  |  2.1 | this skink had attained
         |May 7,        1950|   48     | 15 (broken stub)    |  2.0 | the maximum female
         |May 3,        1951|   74     | 29 + 57             |  8.5 | size at an age of a little
         |May 2,        1952|   78     | 25 + 64             | .... | more than three years;
         |August 27,    1952|   79-1/2 | 95 (regenerated)    |  8.3 | (for movement see
         |                  |          |                     |      | Figure 25).
         |                  |          |                     |      |
  No. 7. |Female            |          |                     |      |Hatched in July 1949,
         |June 5,       1950|   51     | 82                  |  2.5 | this skink was 11
         |July 13,      1950|   59     | 93                  |  3.9 | months old and about
         |July 29,      1950|   64     | 98                  |  4.4 | half-grown when it was
         |August 21,    1951|   69     | 80 (broken stub)    |  5.0 | marked.  When last
         |May 28,       1952|   73     | 83 + 9-1/2          | .... | caught at an age of 35
         |                  |          |                     |      | months it was of average
         |                  |          |                     |      | adult female size,
         |                  |          |                     |      | having grown less than
         |                  |          |                     |      | numbers 4 and 6 at the
         |                  |          |                     |      | same age. All five captures
         |                  |          |                     |      | were within a 60-foot
         |                  |          |                     |      | diameter (Fig. 24).
         |                  |          |                     |      |
  No. 8. |Female            |          |                     |      |Hatched in July 1949,
         |April 26,     1950|  50-1/2  | 78-1/2              |  2.7 | this skink was of average
         |May 24,       1951|  74      |107 (regenerated)    | .... | adult female size
         |April 28,     1952|  78      | 93 (regenerated)    |  8.5 | and was breeding in
         |April 23,     1953|  80      | 93 (regenerated)    | .... | May 1951; it grew
         |                  |          |                     |      | nearly to maximum female
         |                  |          |                     |      | size in the next 11
         |                  |          |                     |      | months. All captures
         |                  |          |                     |      | within a 70-foot diameter.
  No. 9. |Female            |          |                     |      |
         |July 5,       1950|  60      | 95                  |  4.5 |All three captures at the
         |August 6,     1951|  71      |106-1/2              |  5.6 | same site.
         |May 28,       1952|  72      |110                  |  8.5 |
         |                  |          |                     |      |
  No. 10.|Male              |          |                     |      |Hatched in July 1949,
         |April 23,     1950|  46-1/2  | 66 (regenerated)    |  1.8 | this male grew less
         |June 13,      1950|  52-1/2  | 26 + 3              |  2.7 | rapidly than most, and
         |September 2,  1950|  66      | 32 + 51             |  6.2 | in the spring of 1953
         |May 29,       1951|  67      | 33 + 58             | .... | was smaller than some
         |August 3,     1951|  70      | 94 (regenerated)    | .... | others that were a year
         |March 27,     1953|  74      | 78 (regenerated)    |  7.1 | younger, or even two
         |                  |          |                     |      | years younger.
  No. 11.|Female            |          |                     |      |
         |April 26,     1950|  50-1/2  | 78-1/2              |  2.7 |This skink had attained
         |May 24,       1951|  74      | 87                  | .... | maximum female size
         |April 28,     1952|  78      | 72 + 21             |  8.5 | when she was a little
         |April 23,     1953|  80      | 73 + 20             | .... | less than four years old.
  -------+------------------+----------+---------------------+------+----------------------------

Differences in their growth rates therefore reflect differences in sex,
individual vigor, and local situation, in individuals living at the same
time and within the same general environment.

Changing weather, and other factors that vary from year to year cause
marked differences in the dates of important events in the annual cycle,
and in the stage of development at any given date. Data are available
for five successive annual broods of young, those of 1948, 1949, 1950,
1951, and 1952, and each brood differs from the others to some extent,
as shown in Figures 11 to 13. In 1949, for instance, young hatched
relatively early, and probably most of them were active by the middle of
July. They made rapid growth in August, averaging larger than young
hatched in other years on any given date in late summer. However, they
retired into dormancy early in the fall. Cool and dry weather in early
September ended their activity for the season. In 1950, young hatched,
on the average, at least three weeks later, about the first of August,
but they remained active until late in September, and by hibernation
time had partly caught up to the stage of development attained by the
young of 1949. Most young of 1951 hatched late in the first half of
August, and at first were smaller than those of 1950 and much smaller
than those of 1949 on corresponding dates, but favorable weather in the
early fall hastened their development. By early September they had
caught up and passed the stage of development of young of 1950 and by
the time they retired to dormancy in late September, they had reduced by
half the size-advantage of the young of 1949 at the time these latter
retired into hibernation. The young of 1951 appeared to be few in
numbers, and a lack of competition may have been a factor in their rapid
early development.

    [Illustration: FIG. 15. Records of growth in another group of
       recaptured young that grew less rapidly than those of Fig. 14.]

The young of 1948, first sampled after their emergence from their first
hibernation in mid-April of 1949, were then somewhat intermediate in
size as compared with those of 1949 and 1950 at the same times of year.
Their subsequent development was rapid; by late May they had caught up
and passed the stage reached by the 1949 young at the same time of year.
The young of 1950 after having a late start, were further set back by
cold weather in April 1951 delaying their emergence from hibernation. As
a result they were still unusually small in late April and May. Even
though they grew rapidly subsequently, they were consistently smaller
than those of other broods on corresponding dates. Favorable fall
weather prolonging the 1951 growing season into late September beyond
the time of retirement in other years may have permitted many of them to
attain adult size.

    [Illustration: FIG. 16. Records of immature individual skinks marked
       and recaptured within the same growing season, showing the trend of
       rapid growth, and differences in growth rate between individuals.]

The varying fortunes of the several annual broods studied were closely
correlated with weather trends, and suggest possible effects of slight
changes in climate. An unfavorable sequence of weather might bring about
drastic reduction of the population without causing any direct
mortality. A late spring in two successive years would have cumulative
effect in delaying emergence and breeding of adults the first year, and
delaying in the second year emergence of the young, already retarded by
the lateness of their hatching. If this sequence were followed by onset
of unusually cool and dry weather in early September, or even in late
August, the young might be "caught short," and forced to hibernate
while still in the 50-60 mm. size class. Emerging the following spring,
they might have failed to mature sexually, reducing by perhaps half the
number of productive adults. At the northern extreme of the species'
range, length of growing season may be more critical than extremes of
temperature in limiting the numbers and distribution. Growing seasons
that average long enough and warm enough to permit attainment of
maturity by onset of the second hibernation period may be essential to
the species. While no two annual broods of young in the same locality
come under exactly the same weather influences, extremes of retardation
or acceleration continuing throughout development are relatively rare.
Retarding effects of unfavorable weather causing delayed breeding and
hatching, may be offset by prolongation of warm weather in the fall thus
delaying hibernation, or by warm spring weather hastening emergence from
hibernation.

Under favorable conditions an adult female produces about ten offspring
annually of which about half are females. It is calculated that if all
survived, after ten breeding seasons, the progeny of an original female
might have increased to a population of more than 97,000, under the
climatic conditions of eastern Kansas, permitting attainment of breeding
maturity late in the second year of life. In the same ten year period
under climatic conditions delaying maturity until late in the third year
of life (as seems normally to occur in _E. septentrionalis_ and _E.
skiltonianus_, and probably in _E. fasciatus_ at the northern edge of
its range) the original female would have produced a population of
somewhat less than 7,800 assuming that all survived. With a long growing
season such as occurs in the southern part of the range, it seems
theoretically possible (though not probable) that individuals might
mature before the end of their first year, in time to participate in the
next breeding season. If this should occur the original female might
produce a population of more than 120 million by the end of the tenth
breeding season.


CHANGES IN PATTERN

Progressive alteration of the color pattern is more rapid in males than
in females and is synchronized with growth. During the first year of
life changes in the pattern are gradual, and consist chiefly of loss in
vividness. The blue of the tail is slightly dulled. The light lines
become suffused with brown and the dorsolateral dark areas become paler,
with light brown areas appearing on the corners of the scales and
gradually spreading to replace the original black. In skinks that are in
the second year of life the striped pattern although still conspicuous
is made up of two shades of brown instead of the earlier black and white
markings.

    [Illustration: FIG. 17. Records of another group of immature skinks
       marked and recaptured within the same growing season.]

Even in hatchlings, the dorsal part of the rostrum and the inter-nasals
are of a somewhat neutral brownish color, matching neither the light
lines nor the dark interspaces of the striped body pattern. With
advancing age this neutral brown color gradually spreads posteriorly on
the head so that the striking lyrate marking of the bifurcated dorsal
stripe on the head in the juvenile become obscured by the time the skink
has grown to small adult size, at 21 months. The top of the head is then
dull brown, with a slightly mottled appearance caused by the different
intensity of pigmentation in different areas. The stripes though still
discernible, are faint and inconspicuous. Dorsally, on the body, the
stripes are still conspicuous, but are dull and lacking in contrast. At
this stage, the dark lateral area is retained with intensity of
pigmentation scarcely diminished.

    Table 13. Normal Range of Variation in Dorsal Striping of Head
       and Body, and in Color of Tail According to Age and Sex.

  ===================+================================+============================
                     |       Condition of stripes     |       Color of tail
  Age, Size and Sex  |-----+--------+----+-----+------+--------------+-------------
                     |Sharp|Distinct|Dull|Faint|Absent| Original     | Regenerated
  -------------------+-----+--------+----+-----+------+--------------+-------------
  Small young        |     |        |    |     |      | bright blue  | bright blue
      body           |  X  |        |    |     |      |              |
      head           |  X  |        |    |     |      |              |
                     |     |        |    |     |      |              |
  Larger young       |     |        |    |     |      | bright blue  | duller blue
      body           |  X  |        |    |     |      |              |
      head           |  X  |  X     |    |     |      |              |
                     |     |        |    |     |      |              |
  Young adult female |     |        |    |     |      | dull blue    | gray-blue
      body           |  X  |  X     |    |     |      |              | to brown
      head           |     |  X     |  X |  X  |      |              |
                     |     |        |    |     |      |              |
  Young adult male   |     |        |    |     |      | mostly dull  | gray-blue
      body           |     |  X     |  X |     |      | blue         | to brown
      head           |     |        |  X |  X  |  X   |              |
                     |     |        |    |     |      |              |
  3 year adult female|     |        |    |     |      | mostly       | mostly
      body           |     |        |  X |  X  |      | brown and    | brown and
      head           |     |        |    |  X  |  X   | gray with    | gray
                     |     |        |    |     |      | scattered    |
                     |     |        |    |     |      | blue scales  |
                     |     |        |    |     |      |              |
  3 year adult male  |     |        |    |     |      | mostly       | brown
      body           |     |        |    |     |  X   | brown;       |
      head           |     |        |    |        X   | occasional   |
                     |     |        |    |     |      | bluish scales|
                     |     |        |    |     |      |              |
  Old adult female   |     |        |    |     |      | brown;       | brown
      body           |     |        |  X |  X  |  X   | occasional   |
      head           |     |        |    |     |  X   | bluish scales|
                     |     |        |    |     |      |              |
  Old adult male     |     |        |    |     |      | brown        | brown
      body           |     |        |    |     |  X   |              |
      head           |     |        |    |     |  X   |              |
  -------------------+-----+--------+----+-----+------+--------------+-------------

In tracing the gradual ontogenetic changes in the striped pattern, from
the vividly contrasting colors of hatchlings to the dull, patternless
coloration of old adult males, five descriptive terms have been applied
to the successive stages: "sharp," "distinct," "dull," "faint," and
"absent." To most individuals below minimum adult size, the term "sharp"
is applicable, although there is some loss in vividness in the larger
young, as compared with hatchlings. Fading of the original striped
pattern proceeds more rapidly on the head than on the body. Upon
emergence from their second hibernation at an age of about 21 months,
the skinks, mostly grown to adult size, and ready to mature sexually,
still show but little sexual difference. They retain the hatchling
pattern essentially unchanged, but with colors dulled and contrasts
reduced. Within a few weeks the newly matured males undergo relatively
rapid color change as the breeding season progresses. The stripes tend
to fade and blend into the dark areas adjacent to them. In the
two-year-old males stripes are distinct to dull on the body and faint or
absent on the head, while in females of the same age group, body stripes
are sharp or distinct.

Table 13 refers to adult pattern and coloration as they appear in the
breeding season. After the breeding season, in late spring and early
summer, when the red suffusion of the head and neck has faded in adult
males, the original striped pattern, after having been almost completely
suppressed may again become discernible. Individuals of the same size
differ in extent of pattern change, and the color descriptions made of
individuals were not sufficiently detailed to show fully the changes
occurring between successive dates of capture. However, most large adult
males taken later than mid-June had at least some trace of the striped
body pattern and many of them had become so much like females in
appearance that close scrutiny was necessary to determine their sex.
They were especially like females in having the dark lateral area
extending forward onto the cheek and setting it off sharply from the
paler temporal region above it. In breeding males the head has no such
dark markings and is suffused with red.


GROWTH AND REGENERATION OF THE TAIL

Even among those skinks which have never broken their tails there is a
wide range of variation in relative length of tail. This is partly a
matter of relative growth since the proportions change during the course
of development. Also there may be slight sexual difference and there is
much individual variation. In fetuses still well below hatching size,
the tail length is less than the snout-vent length. For instance, an egg
in a natural nest 12 days short of hatching contained a fetus that had a
snout-vent length of 14 mm. and tail length of 12 mm. (Figure 18). In
the late stages of fetal development the tail growth is relatively
rapid. At hatching, the tail is considerably more than half the total
length. In a large series of young with snout-vent lengths from 30 mm.
down to hatching size of 25 mm. or less, the tail length averaged 130.8
per cent of snout-vent length. In larger young, up to a snout-vent
length of 40 mm. or more, the tail continues to lengthen more rapidly
than the body. In skinks that are about two thirds grown, the tails
average relatively longer than in either larger or smaller individuals.
In the sample representing the size class 50-54 mm. snout-vent length,
the tails average 163.3 per cent of the snout-vent lengths, whereas in
groups of adults of various sizes and both sexes, the tail length is
near 155 or 156 per cent of the snout-vent length. Sexual dimorphism in
tail length is slight if it exists at all; in adult males, tails
averaged a little longer than in adult females.

    [Illustration: FIG. 18. Diagram showing relative tail-length (as a
       percentage of snout-vent length) in skinks of different size
       groups that retain their original tails unbroken; in the early
       stages of growth the tail becomes relatively longer as size
       increases, but the trend is reversed before adult size is attained.
       For each series the mean, standard error, standard deviation,
       and extremes are shown.]

When a skink's tail is broken, there is almost no loss of blood. The
fractured surface is rough and irregular, with exposed muscle masses
protruding on the detached end and corresponding concavities on the end
of the stump tail retained by the lizard. The concavities are soon
filled with oozing blood, and a thick scab forms. As healing begins, the
broken end presents a flat, slightly irregular surface. When the scab is
sloughed off, a slightly convex surface of delicate, pale-colored new
skin of the regenerating tail, is exposed. At first, no scale structure
is discernible. As growth proceeds, the new tail takes on a bluntly
conical shape. During the early stages of growth, it is well set off
from the original portion by the abrupt taper at the point of contact
and by its paler coloration and different texture, with no scales
discernible at first, and later with fine and granular scalation. The
new tail elongates until the more abrupt taper beyond the point of the
break is no longer noticeable, and the coloration, surface texture and
scalation match that of the original portion so closely that it is
difficult to determine where the break occurred or even to ascertain
that there has been one. On the regenerated tail, however, the scales
are less uniform in size and less regular in shape. The regenerated
tail, being different from the original in internal structure, with a
cartilaginous rod replacing the vertebral column, is less fragile and
subsequent fractures are most likely to be on the part proximal to the
regeneration. Nevertheless, fractures of regenerated tails occur
occasionally. In old skinks especially, the tail eventually may consist
of three or more distinct segments including the basal remnant of the
original tail and the successive regenerations. When a break in the
regenerated tail occurs, the detached portion is relatively inert, and
is capable of only feeble twitching movements in contrast with the
lively wriggling normally displayed in a newly detached tail that
includes part of the central nervous system.

    [Illustration: FIG. 19. Relative lengths of original and regenerated
       portions of tails in skinks which have had their tails broken and
       regenerated; for each individual, length of each part of the tail
       is expressed as a percentage of the snout-vent length.]

Rate of growth in the regenerating tail is controlled by a variety of
factors, such as age, condition, and activity of the individual, and
site of the fracture. A break occurring early in the skink's lifetime
results in regeneration more complete than occurs in an adult sustaining
the same type of injury. The regenerated tail eventually may be longer
and thicker than the lost part if the lizard is young and still growing.
But the regenerated tail is never so long as the original one would have
been. Regeneration is most extensive in those tails broken near the
base. The farther from the base the break occurs the shorter is the part
regenerated. As a result, tails that have had time to regenerate do not
differ greatly in total length regardless of where the break occurred.
However, the nearer the break is to the base, the shorter is the total
tail-length after regeneration (Figures 19 and 20). If only the tip of
the tail is lost, regeneration may not occur. In the skinks examined
that had regenerated tails the proportions varied over a wide range.
Presumably, in many, growth of the regenerated portion was still
incomplete.

    [Illustration: FIG. 20. Diagrams showing typical extent of tail
       regeneration in skinks having tails broken at different points,
       × approximately 2/3. Original parts of the tails are at the right.]


    Table 14. Records of Regeneration of the Tail in Individual Skinks
       Marked and Recaptured.

  =================+==================+==========+========================
                   |                  |Snout-vent|
    Age and Sex    |  Date            |length    |   Tail length
                   |                  |in mm.    |     in mm.
  -----------------+------------------+----------+------------------------
  No. 1.           |June 1,       1951|   73     | 38 (newly broken)
    Adult male     |June 26,      1951|   73     | 38 + 14
                   |August 17,    1951|   76     | 40 + 45
                   |April 29,     1952|   76     | 40 + 45
                   |                  |          |
  No. 2.           |May 28,       1949|   51     | 46 (newly broken)
    Immature       |October 15,   1949|   69     | 51 + 21
                   |                  |          |
  No. 3.           |June 11,      1950|   49     | 49 (newly broken)
    Immature       |September 2,  1950|   63     | 63 + 31
                   |                  |          |
  No. 4.           |August 10,    1950|   62-1/2 | 60 (newly broken)
    Immature female|June 14,      1951|   68     | 62 + 17
                   |                  |          |
  No. 5.           |August 14,    1950|   67-1/2 | 77 + 4-1/2
    Adult male     |September 3,  1950|   68-1/2 | 77 + 6-1/2
                   |April 27,     1951|   69     | 78 + 9
                   |                  |          |
  No. 6.           |April 7,      1950|   67     | 38 (newly broken;
    Adult male     |                  |          |      separated end 66)
                   |July 27,      1950|   71     | 39 + 47-1/2
                   |                  |          |
  No. 7.           |May 28,       1951|   70     | 18 (newly broken;
    Adult male     |                  |          |      separated end 100)
                   |June 14,      1951|   71     | 18 + 1
                   |September 22, 1951|   76     | 19 + 29 + 7-1/2
                   |                  |          |
  No. 8.           |June 12,      1951|   72     | 33 (recently broken)
    Adult male     |July 28,      1951|   76     | 36 + 31
                   |                  |          |
  No. 9.           |May 2,        1951|   45     | 47 + 1
    Juvenile       |May 14,       1951|   45     | 47 + 3
                   |May 19,       1951|   45     | 47 + 5
                   |                  |          |
  No. 10.          |June 7,       1952|   64     | 51 (recently broken)
    Subadult female|June 24,      1952|   64     | 51 + 11
                   |                  |          |
  No. 11.          |August 19,    1949|   42     | 40 (newly broken)
    Juvenile       |June 13,      1950|   58-1/2 | 58 + 28
                   |August 5,     1950|   63     | 62 + 31
                   |                  |          |
  No. 12.          |May 17,       1951|   78     | 20 (newly broken)
    Adult male     |June 12,      1951|   78     | 20 + 13
  -----------------+------------------+----------+------------------------

Under favorable conditions regeneration occurs at a relatively rapid
rate. After a period of healing the new tail grows with a sudden spurt,
making most of its gain in length within a few weeks. Then growth
abruptly slows or ceases altogether. In young similarly rapid growth of
the regenerating tail occurs, but subsequently the increase is more
gradual corresponding to the over-all growth of the lizard. In numerous
adult skinks marked, and recorded as having well-regenerated tails, the
proportions recorded at subsequent captures months or years later were
still just the same, demonstrating that extent of regeneration is not
proportional to elapsed time. Those adult skinks having unusually long
regenerated tails presumably are individuals in which the original tail
was lost early in life, and the potentiality for regeneration is
probably somewhat less in older individuals, especially those that have
stopped growing.

Successive records of selected individuals are listed in Table 14 to
illustrate trends in regeneration of the tail. In those instances in
which the tail is referred to as "newly broken" the separation usually
occurred as an accident at the time the lizard was captured, while in
those designated as "recently broken" separation had already occurred in
some earlier accident but regeneration was not yet perceptibly underway.
In the "Tail length" column, plus signs separate the original portion of
tail, on the left, from the regenerated portion, on the right.

As in many other kinds of lizards, the tail in the five-lined skink
serves as a reservoir for fat, which may be drawn upon for nutrition in
time of food scarcity. An individual that is in good condition has a
plump and rounded tail. Fat comprises much of its bulk. Upon emergence
from hibernation this fat supply is not noticeably depleted. Brooding
females in the latter part of the incubation period have the supply of
caudal fat most noticeably depleted, and their tails may appear
emaciated, with kinks on the terminal portion. It is my impression that
in adults the capacity for storage of fat is most developed in the
females, and that their tails vary in proportions more than do those of
males. The capacity to shed the tail easily seems somewhat inconsistent
with this function of fat storage. Loss of the tail sometimes involves
loss of a large amount of reserve fat. Many detached tails that were
broken accidentally at the time of the skinks' captures were weighed. In
those that were broken off near the base and were not previously
regenerated, weights were usually 16 to 20 percent of the lizards' total
weights.



Movements


Data obtained concerning the movements of these skinks demonstrated that
individuals tend to limit their activities to small areas thoroughly
familiar to them, and wander but little. Although the nature and extent
of movements in reptiles in general, and in lizards especially, are
poorly known, my findings are perhaps what might be expected from the
studies of earlier workers on various other species of reptiles.

Goin and Goin (1951:29) observed that _Eumeces laticeps_ in Florida
lives in hollow stumps, each individual excluding other adults from its
stump but tolerating young. Movements have not been studied in detail in
any member of the Scincidae, however. The observations of Goin and Goin,
and those of other authors, seem to indicate that _E. laticeps_ is
territorial, and that each individual centers its activities about a
tree or snag, regularly using the same hollow as a shelter and home
base. In contrast, _E. fasciatus_ is not territorial and has no regular
home base.

The iguanid genus _Sceloporus_ is perhaps better known than any other
kind of lizard as regards its movements. Studies by Newman and Patterson
(1909), Stebbins and Robinson (1946), and Fitch (1940) on three
different species have shown that individuals of _Sceloporus_ keep to
small individual areas, and that territoriality is well developed, in
some species at least.

Among other reptiles, turtles are much better known, as detailed studies
of movements have been made on several species, of which the life
histories and ecology have been thoroughly investigated (Nichols, 1939;
Cagle, 1942 and 1944; Woodbury and Hardy, 1948; Stickel, 1950). They
have been found to have well-defined and fairly extensive home ranges,
which are not defended as territories. Studies of movements in several
different kinds of snakes, by Blanchard and Finster (1933), Stickel and
Cope (1947), Fitch (1949), Lowe and Norris (1950), and Carpenter (1952)
have shown that these reptiles usually have definite home ranges, which
may be several or many acres in extent. Their home ranges are not
defended as territories against other members of the species. In
general, turtles and snakes have been found to occupy home ranges that
are much larger than those of lizards.

Most information concerning movements of _Eumeces fasciatus_ has been
obtained from the recapture of marked individuals. Actual distances of
travel, and the time, frequency and motivation of movement was
uncertain. A skink marked, recorded, and subsequently recaptured at a
second location may have wandered widely in the meantime, visiting
points relatively remote from either location of capture. The two points
of capture may be within a home range regularly or occasionally covered
by the individual in the course of its routine activities; or the second
point may have been recorded only after a permanent shift of activities
away from the area within which the original point was located. Various
types of movements probably were involved.

Interpretation of the records is difficult because of the paucity of
direct observations on the behavior and movements of skinks under
natural conditions. Often when one is alarmed, it will run as much as 30
feet, in a fairly direct course, to a tree or bush or rock where it can
find refuge. Undisturbed individuals move about slowly and circuitously.
It is difficult to keep one under observation for any length of time
because of the secretive habits causing it to keep under cover, as much
as possible while moving about, and to hide in response to any slight
disturbance.

It is obvious that individuals shift their activities from time to time,
occupying new areas either abruptly or by gradual stages. Even though a
successful skink has a life span of several or many years, the
populations on the small study areas were found to be much altered from
one year to the next. Presumably this change was brought about largely
by shifts in home ranges. Several shifts of hundreds of feet were
recorded, but the chances of recovering marked individuals that moved so
far were relatively poor because their movements generally took them
beyond the limits of the study area to locations where recapture was
unlikely. Skinks often were caught at their hiding places beneath rocks
or other sheltering objects. In many of these instances it was evident
from the position, temperature and state of activity of the lizard that
it had been in the open but had become alarmed as the collector drew
near and had retreated unnoticed to its shelter just before capture,
whereas in other instances it was obviously at rest in its chosen
shelter. Except for females in their nest burrows individuals were not
ordinarily recaptured regularly at the same hiding places. They may seek
new hiding places after each period of activity.

However many of the skinks captured were taken again, after long
intervals, near the same places. Time elapsed between successive
captures for different individuals ranged from one day to 47 months. Of
the total of 323 recaptured by September, 1952, approximately half, 162,
were taken after intervals including one or more hibernation periods. In
appraising home ranges and detecting the occasional shifts over a
relatively long time span, chronology of the records needs to be taken
into account. Records clustering about the same center seem to indicate
continued occupancy of an established home range. However, when one or
more early records are well separated from one or more later records, a
shift in range seems probable. In some instances successive records
were progressively farther from the starting point suggesting two or
more shifts in the same direction from an original home range.

Although recorded movements varied from a few inches to hundreds of
yards, the most noteworthy feature in general was the short distance
between points of capture (considered in relation to the potential
mobility of the lizards) after days, weeks, months or years. In many
instances no movement was demonstrable, even though successive points of
capture were not exactly the same. Named natural landmarks, mostly
trees, boulders and logs, well distributed over the study area, were
used as a basis for locating points on the map. Direction and distance
in feet to the nearest landmark was recorded for each site of capture,
but for distances of more than 25 feet estimates were made to the
nearest ten feet. Usually at least one landmark was available within a
50-foot radius from any point where a capture was made. Occasional
estimates made for distances of more than 50 feet, or even more than 100
feet, in the absence of suitable landmarks nearby, were sources of
inaccuracy. For such estimates errors of up to ten feet were common, and
some errors of greater magnitude were made.

For most individuals successive sites of capture tended to cluster
within a small area, but the occasional outlying capture sites indicate
that each individual does range outside the area in which its activities
are concentrated. These occasional excursions cannot be consistently
attributed to any one ecologic requirement, nor are they limited to any
particular time within the season of activity. Adult males, however,
tend to make longer movements in the brief period of concentrated sexual
activity, thereby increasing their chances of finding mates. Similarly,
adult females may wander beyond their usual ranges in search of suitable
nesting sites. The home range may be thought of as consisting of a small
central portion where activities are largely concentrated, and an outer
area several times as large, familiar to the animal but used to a lesser
extent by it. The activities gradually become more diffuse farther from
the central part of the home range. In the five-lined skink, home ranges
are unlikely to approximate the circular shape because they are molded
with respect to environmental features that are not uniformly
distributed. A rotting log, an old tree with decayed hollow base and
nearby fallen slabs of bark and dead limbs, a rock outcrop with numerous
deep holes and crevices, or a group of flat rocks in a forest glade
fulfill requirements not met in the surrounding habitat with the result
that home ranges are built around them. Consequently a home range may
be long and narrow, with maximum diameter several times the minimum
diameter.

The usual concept of home range, as a finite area with well defined
boundaries is not entirely satisfactory for an animal with the habits of
the five-lined skink. The skink spends much of its time in inactivity
underground or otherwise concealed and sheltered, and when it does move
about it takes advantage of natural travel-ways over rock surfaces, tree
trunks, and logs. If a log happens to be the home range center, the
skink may travel the length of the log many times without making a
comparable trip at right angles to this axis of travel, although it may
make short side dashes to secure food. On more extended forays, the
directional sequence of movements is largely controlled by the
distribution of suitable cover and travel routes, as the skink avoids
both open areas and dense vegetation. Outlying portions of the home
range probably are not uniformly covered but are reached only
occasionally as the lizard is led along some natural travel route, or
after it has visited, in succession, a series of locations attractive in
providing shelter or food.

Marked skinks were recaptured at distances up to 680 feet from points of
original capture. Considering only the most remote points of capture for
those individuals recaptured more than once, the average recorded
movement for the entire group of 323 recaptured skinks was 58 feet. This
figure provides a basis for comparing vagility of this species with
others. Eliminating some individuals of indefinite status, the average
movement for 75 adult males was 69 feet; for 102 adult females, 45 feet;
and for 112 young, 61 feet. For the adult females, home range data are
biased by the fact that many were caught repeatedly at or near their
nests. It is not clear whether females that do not have nests range less
widely than males.

Only 15 individuals, less than five per cent, had moved more than 250
feet. These longest movements were: 680 feet, adult female, 26 months;
680 feet, adult female, 10 months; 680 feet, subadult male, one year;
650 feet, young to adult male, 22 months; 640 feet, subadult to adult
female, two years; 535 feet, young male, 11 months; 510 feet, adult
male, 11 months; 490 feet, young (sex undetermined), 10 months; 450
feet, young male, 13 months; 350 feet, young (sex undetermined), 10-1/2
months; 335 feet, adult female 13-1/2 months; 275 feet, adult male, 35
months; 275 feet, adult male, 24 months; 270 feet, young to adult male,
12-1/2 months.

For those skinks caught on only two occasions, at different places, the
single movement record provides some clue as to the location and size of
the home range. No evidence was obtained to indicate that the
activities of these lizards center at fixed home bases. It may be
assumed that any two successive captures of the same individual
separated by a substantial time interval, will be distributed at random
to each other within the area to which the animal's activities are
confined. The varied techniques of capture, by hand and with different
types of traps, would help to secure random distribution of capture
sites. If the home range were covered uniformly by the animal in the
course of its activities, any two random capture sites would be on the
average separated by a distance equal to half the home range diameter.
If the animal tends to concentrate its activities in the central part of
the home range, as seems to be the case, the capture sites will be
correspondingly closer together. For the 196 skinks that were caught on
only two occasions, average movement was 62 feet. Within this group the
42 adult males that were recaptured only once had averaged movements of
58 feet. One had made an exceptionally long movement of 510 feet, which
obviously was not entirely within its home range. Excluding this one
long movement, the remaining 41 had moved on the average, approximately
47 feet (Table 15). Among the other skinks caught only twice one of 61
females and 8 of 93 young had likewise made such long shifts that it
seemed inadvisable to include them in computing the size of the home
range.

Distance between points of capture showed little correlation with
elapsed time. For 24 of the adult males that were recaptured in the same
year they were originally marked, the average distance was 49 feet,
whereas in the 17 others recaptured after one or more hibernations the
average movement was 45 feet. For adult females, the corresponding
figures were, respectively, 22 feet and 29 feet; and for young, 33 feet
and 66 feet.

For those individuals recaptured twice, at different locations, the
three points of capture show to a greater or lesser degree the position,
and, in part, the extent of the home range. Of course, all three points
may be concentrated near the center of the home range, or they all may
be scattered along its edges. In general, however, each point will lie
somewhere between the center and edge of the home range, separated from
each of the other two points by a distance of, on the average,
approximately a home range radius.

Table 15 shows that adult males and young tend to range more widely than
adult females, and that young tend to shift to new areas more frequently
than do adults. Many of the recorded movements (in addition to the long
ones that were excluded from the home range computations) may have
involved short shifts in ranges. If all such shifts could be definitely
identified and eliminated from the computations, actual home ranges
might be considerably smaller than those indicated by the present set of
data. Home ranges approximately 90 feet across for adult males and
young, and a little more than 30 feet across for females are indicated.
Actual area of a home range would amount to only a fraction of an
acre--from about one-seventh to less than one-fiftieth. The dash of an
alarmed skink to a place of refuge, though involving at most only a few
seconds, may traverse a large part of its home range. Through long
association the lizard is thoroughly familiar with the terrain, so that
it can take full advantage of the peculiar features in escaping,
hunting, traveling or resting.

    Table 15. Distances Between Successive Sites of Capture for Marked
      Five-lined Skinks on Study Areas, Indicating Home Range Sizes.

  =======================+============+==========+===========
                         |            |          |   Number
                         |  Average   |          | of skinks
                         |  maximum   |          | discarded
                         |  distance  |  Number  |   from
                         |  in feet   |    of    |   sample
                         |  between   |  skinks  | because of
    Age, Sex and Number  |  points    | included | relatively
        of Captures      |    of      |    in    |    long
                         |  capture,  |  sample  | movements,
                         |   and      |          | indicative
                         |  extremes  |          | of shifts
                         |            |          |  of range
  -----------------------+------------+----------+-----------
  Adult males            |            |          |
    Individuals captured |            |          |
      just twice         | 47 (225-0) |    41    |     1
    Individuals captured |            |          |
      just three times   | 47 (130-0) |    18    |     0
    Individuals captured |            |          |
      four or more times | 91 (200-0) |    17    |     2
                         |            |          |
  Adult females          |            |          |
    Individuals captured |            |          |
      just twice         | 16 (90-0)  |    56    |     4
    Individuals captured |            |          |
      just three times   | 25 (90-0)  |    25    |     3
    Individuals captured |            |          |
      four or more times | 28 (90-0)  |    15    |     1
                         |            |          |
  Young                  |            |          |
    Individuals captured |            |          |
      just twice         | 45 (160-0) |    85    |     8
    Individuals captured |            |          |
      just three times   | 46 (150-0) |    14    |     0
    Individuals captured |            |          |
      four or more times | 82 (175-0) |    14    |     2
  -----------------------+------------+----------+-----------

Relatively few marked individuals were caught four or more times at
different sites. For these individuals listed below the distribution of
the sites is more or less indicative of shape and size of the home range
in some instances. For some of them successive locations of capture are
shown and possible home ranges are outlined in Figures 21-25.

    [Illustration: FIG. 21. Map of Skink Woods study-area, showing chief
       physiographic features and landmarks, and showing also successive
       sites and dates of capture of a marked male skink and two marked
       females, suggesting extent of home ranges.]


ADULT MALES

No. 1: Seven captures in two years, on May 13, 1950, May 12, 1951, and
in 1952 on April 28, May 1, 2, 4 and 6, these seven locations well
distributed over a stretch of rocky slope 275 feet in greatest diameter.
The fifth location was only 20 feet from the original, whereas the last,
only four days later, was the most remote, suggesting that the whole
area covered may have been within a home range.

No. 2: Seven captures in 46 months, skink not fully grown when first
captured on June 22, 1949; 275 feet south on May 4, 1950; had moved from
this second location 150 feet west northwest on June 17, 1950, and this
third location together with the last four, on May 15, 1951, and May 13
and 15, 1952, and April 6, 1953, were all within a 20 foot diameter.
Evidently two shifts in range were involved.

    [Illustration: FIG. 22. Sites of successive captures of two marked
       adult males in the Skink Woods study-area.]

No. 3: Six captures, all at different locations, in 22 months, on July 5
and 28, 1950, May 3 and 23, and June 21, 1951, and May 1, 1952. The
190-foot-wide area was probably all within a home range, as the fourth
and fifth sites were those most remote from each other.

No. 4: Six captures in 21 months, in 1950 on August 14 and September 3,
in 1951 on April 27 and August 21, and in 1952, on May 28 and 30. The
four 1950 and 1951 locations were within a 30-foot diameter, whereas the
two 1952 locations were 150 feet farther east, and even nearer together,
suggesting a shift in range.

No. 5: Five captures in five months, all within a 40-foot diameter, on
April 24, May 7 and 28, June 14, and September 22, 1951. The first and
third locations were at almost the same spot.

No. 6: Five captures all at different locations, in 23 months; in 1950
on July 27, in 1951 on April 30 and May 25, and in 1952, on May 1 and
June 28. The second, third and fourth locations were all within 45 feet
of each other and of the first, but the last was 110 feet from the
first, possibly representing a shift.

    [Illustration: FIG. 23. Sites of successive captures of three marked
       adult males in the Skink Woods study-area.]

No. 7: Four captures in two months, at approximately the same place on
May 1 and 5, 1950; on May 30 had moved 35 feet farther north along
ledge, and on July 1, 25 feet farther in the same direction.

No. 8: Four captures in one year, all at approximately the same place
along rock ledge, on June 17, 1949, and April 21, May 3 and June 15,
1950; trapped three times and once caught by hand.

No. 9: Four captures in one year, on April 7 and 11, and July 27, 1950,
and April 14, 1951, the four different locations all within a 30-foot
diameter.

No. 10: Four captures in 22 months, in 1950 on July 7, and again on July
23, 175 feet farther north; on May 25, 1951, 200 feet east of second
location, and on May 2, 1952, 30 feet from third location. At least one
shift in range probably occurred, from 1950 to 1951.

No. 11: Four captures in 36 days, in 1951 on April 30, May 8 and 15, and
June 5. The last two captures were made in the same trap and were only
15 feet from the original location, but the second location was 130 feet
from both. Because the time span was short and the lizard returned from
the most remote point, it seems probable that all four records were
within its home range.

    [Illustration: FIG. 24. Sites of successive captures of marked
       skinks, a male and two females, in the Skink Woods study-area.]

No. 12: Four captures in 11 months, all within a 50-foot diameter, in
1951, on June 1 and 26, and August 27, and in 1952, on April 29.

No. 13: Four captures in 15 days, all in July 1949 within a 10-foot
diameter.

No. 14: Four captures in 22 months, July 22, 1950 (as subadult), in
1951, on May 8 and June 5, and on May 13, 1952. Second location 295 feet
southwest of first, third 30 feet north of second, and fourth 650 feet
east of second and third. Probably two shifts of range were involved.


ADULT FEMALES

No. 1: Six captures in 26 months; in 1950 at the same place on June 4
and 13, in 1951 on May 26 it had moved from the original quarry ledge
location 680 feet south southeast down the slope to the pond rock pile,
where recaptured on June 9, and in 1952 on May 21 and July 22.

No. 2: Six captures at four locations all within a 25-foot diameter, in
13 months; June 5, 1950, and May 25, June 18, 26 and 29, 1952. On each
occasion this female was hiding in a nest burrow, but she shifted to new
nest sites as a result of disturbance by the investigator or flooding
when there were unusually heavy rains.

    [Illustration: FIG. 25. Sites of successive captures of a marked
       male and a marked female, each taken in three different years
       in the Skink Woods study-area.]

No. 3: Five captures in 34 months, all within a radius of a few yards,
at the pond rock pile, on August 8, 1949, June 5 and July 23, 1951, and
May 15 and June 4, 1952.

No. 4: Four captures in 34 months, all within a radius of a few yards at
the pond rock pile, on August 8, 1949, June 7, 1950, May 30, 1951 and
May 21, 1952. It is notable that this female was taken only once in
each of four different years, her occupancy of this rock pile seemingly
continuing throughout the duration of the study.

No. 5: Four captures in two months, in 1950 on April 15, and on April 26
had moved 50 feet south; on May 23 she was approximately 50 feet from
both second and third locations, and on June 5 was between second and
third locations.

No. 6: Four captures in 23 months, all within a 20-foot stretch of
ledge, in 1950 on June 5 and 17, in 1951 on August 22, and in 1952 on
May 1.

No. 7: Four captures in one year, in 1951 on May 19, June 12, June 24,
and in 1952 on May 21, all four locations within a 15-foot diameter.

No. 8: Four captures in 23 months, in 1950 on July 5 (as a subadult), in
1951 on August 6 and 15, and in 1952 on May 28, all within a radius of a
few yards at the pond rock pile.

No. 9: Four captures in 13 months, on August 2 and 3, 1951, and May 28
and August 31, 1952. From the original location successive sites were 30
feet southwest, 20 feet south southwest, and 30 feet north.


YOUNG

No. 1: (male) Five captures in 33-1/2 months; marked as hatchling on
July 13, 1949, and recaptured on June 1, 1950, 175 feet northwest down
slope. Subsequent locations of this lizard, as an adult, were, in 1951,
on August 21 and 24, and 1952 on May 1, 80 feet east, 80 feet east, and
70 feet northeast from the second location.

No. 2: (male) Five captures in a little more than one year, all within a
radius of a few yards at the pond rock pile, in 1949 on August 23, and
in 1950 on June 7, July 23, August 19, and September 3.

No. 4: (male) Four captures in 11 months all within a 30-foot stretch
along the ledge, in 1950 on July 4, and in 1951 on May 6, 14, and 25.

No. 5: (male) Four captures in one year, in 1950 on September 4, and in
1951 on May 11, June 14, and August 21; the first and last locations
were together separated from the second and third, also together, by
about 20 feet.

No. 6: (male) Four captures in 13 months, in 1950 on April 19, June 5
and June 6, and in 1951 on May 14. All four locations were linearly
distributed along the ledge, the second and third near together 30 feet
north of the first and the fourth 30 feet south of the first.

No. 7: (sex undetermined) Four captures in one month, on April 24, and
May 2, 4, and 21, 1952, well scattered within a 70-foot diameter.

No. 8: (female) Eight captures in 25 months, in 1950 on June 5 and 9,
and in 1951 on May 25, August 15, and September 28, and in 1952 on April
24 and 26. All were within a 150-foot diameter, the first three all
within 40 feet, the fifth and sixth near together but 35 feet north
northeast from the first group, the last three all within a 90-foot
diameter and all to the north of the first five. At least one shift
probably was involved.

No. 9: (female) Five captures in 28 months, in 1950 on April 21 and May
7, in 1951 on May 3, and in 1952 on May 2 and August 27. The first three
captures were all at approximately the same location, from which the
fourth was 60 feet north and the fifth was 130 feet east.

No. 10: (female) Five captures in 24 months; in 1950 on June 5 and 13,
and July 29, in 1951 on August 21, and in 1952 on May 28. From the
original location successive captures were 50 feet west, 35 feet west
northwest, 40 feet west, and 50 feet west.

Less complete records of the movements of other individuals are included
along with growth data, on pages 79 to 82 and 87 to 88.

Sizes of home ranges are affected by the type of habitat. For instance,
the pond rock pile approximately 70 × 30 feet, must have constituted the
entire home range for the many individuals living in it, since it was
surrounded by areas that did not provide suitable habitat. No less than
212 five-lined skinks were taken in this small rock pile area in four
seasons, and it is obvious that many of these were occupying it
simultaneously since a substantial proportion of the total were caught
there in more than one year. This rock pile provided in particularly
concentrated form the essential habitat requirements, such as an
abundant and varied arthropod food supply, an almost infinitely large
number of hiding places beneath and between the rocks, basking sites,
and flat rocks with damp soil beneath, suitable for nests. In open woods
home ranges tend to be larger or, at least, more elongate. Scattered
distribution of such habitat features as flat rocks and outcrops,
stumps, logs, and glades with patches of sunlight, may induce an
individual to extend its activities over a more extensive area. For some
of the adult males for which largest numbers of records are available,
showing repeated movements back and forth within a definite area which
seemingly constituted a home range, movements of 275 feet, 225 feet, 170
feet, 165 feet, 150 feet and 130 feet, respectively, have been recorded.
For one young which grew to the size of a subadult during the period
covered by the records, movements within a 150-foot diameter were
recorded. These individuals all had home ranges substantially larger
than the average. It seems that in the five-lined skink there is no
fixed size or shape for a home range, but that it varies within rather
wide limits depending on age, sex, and perhaps individual peculiarities
and on the presence and distribution of essential habitat features
within the general area.

Most of the young that were recaptured had grown to subadult or adult
size, so that the movements they made as young cannot be separated from
those made when they were full grown or nearly so. For 40, however,
recapture records are available while they were still less than 56 mm.
long. One of those was an exceptionally long movement of 215 feet,
obviously involving a shift of range. For the other 39, the average
movement was 34 feet, almost intermediate between the average movements
of adult males and females. Observations on recently hatched young have
given the impression that they keep to narrowly limited areas probably
only a few yards in extent at first. For instance, at various times
several members of a brood of young have been observed foraging
simultaneously but independently on the same 10-foot log, within a few
feet of each other. For periods of up to more than a week they had
failed to disperse any farther than this from the nest, although
probably never returning to the nest itself after having left. In
subsequent weeks, however, the young are likely to shift their
activities from the immediate vicinity of the nest site to more
favorable nearby areas, and gradually extend their ranges. By the time
they are one-fourth grown they are ranging over areas larger than those
used by adult females.

Some of the shifts in range are probably forced upon individual skinks
by changes in seasonal distribution of food, shelter and other
requirements, causing them to abandon certain areas and invade others by
gradual stages, without venturing far, at any time, into unfamiliar
surroundings. Occasional individuals apparently get lost and undergo a
period of wandering before they re-establish a home range. An individual
venturing slightly beyond the border of its home range might lose its
orientation and fail to return, especially if it left under conditions
of stress, as when pursued by an enemy, or a rival of its own species.
Several individuals originally captured in the vicinity of the quarry or
nearby ledges, were subsequently recaptured at the pond rock pile more
than 200 yards away. In these instances it may be that the lizard
wandered from its home range along the ledge, and finding itself in
thick woods, with nearly continuous canopy permitting insufficient
sunlight, and with few rocks for shelter, it continued down the slope to
the lower edge of the woods, crossed a ditch, and a 100-foot stretch of
grassland, and finally reached the exceptionally favorable habitat
provided by the rock pile.

The extent to which memory persists through the season of dormancy is
little known, but great change takes place in the habitat during the
colder half of the year when the lizard's activity is suspended. Even if
the area is one that is free from gross disturbance by man or large
animals, the changes occurring are so great that the area might be
scarcely recognizable from the lizard's viewpoint. Herbaceous vegetation
mantling the soil, at the height of its development in late summer, will
have died, dried out and the leaves and stalks will have been matted
down by wind, rain, and snow, and incorporated in the surface layer of
soil by the next spring. Shrubs and trees having shed their leaves,
present contours quite different from those in autumn. Holes and
crevices familiar as avenues of escape, will have been sealed, by the
weather collecting and compacting surface debris. Less extensive changes
are involved in the occasional blowing down of trees and dead snags,
erosion of gullies, deposition of sediment and drift wood, and
disintegration of logs. Many of the invertebrates which are the main
food sources in late summer, are unavailable in early spring, being at
different stages in the life cycle or annual cycle of abundance; and
those kinds which make up the bulk of the spring diet likewise are often
unavailable in fall. These changes in location of food supply, shelter,
and other needs, and the seasonal change in microhabitat, breaking the
established routine of conditioned responses to habitat features would
seem to promote shifts in range after emergence from hibernation. The
available records tend to bear out this supposition. Of the 15 skinks
recorded as making long movements of more than 250 feet that almost
certainly involved shift in range, only one was recaptured the same
season; the other fourteen had passed one or more hibernations.

In the course of the study approximately 30 individuals were released or
accidentally escaped at places other than the locations where they were
originally taken. Some of these were young hatched in the laboratory,
some were of unknown origin, their locality tags having been lost before
release while they were being handled in the laboratory, or escaped from
defective cloth bags while they were awaiting processing or release, and
some taken on remote parts of the Reservation or nearby land were
deliberately released on one of the study areas with the idea that they
would replace skinks of the same sex and age, recently eliminated
through an accident of trapping or handling. Ten were released in Skink
Woods, ten at the pond rock pile, eight at the laboratory building, and
two near Rat Ledge. In no instance was a transferred skink known to have
found its way back to an original home range, although some might have
done so with fairly short trips of only a few hundred feet, and the
chances of recapturing them would have been good. Therefore it seems
that homing instinct is either wholly lacking or but feebly developed.
The incidence of recaptures was low, only four for the entire group,
suggesting a tendency to wander away from the area of release before
settling down on a home range. One young found on May 11, 1950, in the
laboratory where it probably had escaped, was released in Skink Woods,
and was recaptured three times in the summer of 1951, in what seemed to
be a home range within 80 feet of the point of release. Another young
of unknown origin released in Skink Woods on May 18, 1950, was
recaptured six days later 160 feet away. Five hatchlings from a clutch
of eggs incubated and hatched in the laboratory, were released in Skink
Woods on August 8, 1952. The following April two of them were
recaptured, only 20 feet and 25 feet respectively, from the point of
release. The movements and dispersal of this group from the point of
release probably paralleled that of a typical brood dispersing from its
nest after hatching under natural conditions. An adult male captured
just off the Reservation was released at the pond rock pile on May 15,
1952, and was recaptured there on June 2 and June 4. In general, skinks
transferred from their original location seem soon to settle down in a
new range if the habitat is favorable, but establishment of a home range
may or may not be preceded by an initial period of wandering.



Food Habits


McCauley (1939:151) examined contents of 25 alimentary tracts of _E.
fasciatus_ collected in Maryland as the basis for the most extensive
account of the food habits yet published. One tract contained a broken
_Eumeces_ tail, possibly that of the lizard that ate it, which had a
recently broken stump tail. A half-grown skink contained numerous
_Eumeces_ scales, and McCauley interpreted this as indicating that it
had fed on another of its own species or of _E. laticeps_. As no other
hard parts of the assumed victim were in evidence, these scales may have
been the lizard's own slough. (In the present study it was found that
eating of the slough was far more frequent than cannibalism.) Arthropod
prey included: 11 orthopterans (4 undetermined, 3 unspecified
grasshoppers, 2 gryllids, 1 blattid, 1 acridid); 10 coleopterans (7
undetermined, 1 each of rhynchophoran, cerambycid, carabid, staphylinid
larva, elaterid adult and larva); 8 spiders; 5 pulmonate snails; 5
flies; 3 undetermined; and one each of lepidopteran larva and adult,
ant, dragonfly, thysanuran, and sow bug.

In Ohio, Conant (1940:31) noted food items consisting largely of
grasshopper nymphs and small beetles. He found that in captivity these
skinks would eat mealworms, crickets, grasshoppers, spiders, roaches,
and newborn mice, and a few individuals would lap egg from a mixture of
chopped meat and eggs. One large male killed and ate a small common
swift (_Sceloporus undulatus_). Netting (1939:162) mentioned newborn
mice, birds' eggs and small lizards as possible prey, although stating
that this species is mainly insectivorous.

Taylor (1936:61) describing the feeding habits of lizards of this genus
wrote: "The food consists of a very extensive variety of insects and
insect larvae, Arachnida and occasionally small crustaceans. In a few
specimens traces of plant material have been observed, but I regard this
as being most probably of accidental introduction in the diet. Probably
the most surprising fact about the diet of the forms examined is that
ants are absent." In the present study of _E. fasciatus_, the trends in
general bore out Taylor's findings concerning absence of ants from the
diet, although three ants were found among more than 600 other food
items. These three, one of them a larva, were of the two largest species
among the many kinds of ants found in the area of the study. Most of
these local kinds of ants are below the minimum size of prey ordinarily
taken by the skinks. Colonies of small ants, _Aphenogaster_ sp., for
instance, are abundant in the soil beneath flat rocks in the same
situations where the skinks are found, and constitute most of the food
of the small toads, _Microhyla olivacea_, which were abundant in the
same habitat and microhabitat as the skinks, especially in the Skink
Woods study area (Freiburg, 1951:383).

Burt (1928:56) without citing specific records, stated that "The food of
_E. fasciatus_ consists largely of insects and spiders," but in another
paper (1928:62) he listed contents of two stomachs, including a wood
roach (_Parcoblatta_), a cricket (_Gryllus pennsylvanicus_), a
grasshopper, and 2 spiders (attid and lycosid). Smith, summarizing the
findings of other authors (1946:350), stated that "The food consists of
various small insects, insect larvae, earthworms, spiders, etc. Small
vertebrates such as young lizards and mice are sometimes eaten." In a
later work Smith (1950:188) altered this statement slightly: "The food
consists of almost any small moving animal, including many kinds of
arthropods and even small vertebrates."

Many authors have mentioned predation on mammals by these skinks, but
without citing specific instances, which must be rare indeed, for the
smallest newborn mice seem to be near the maximum size of objects that
could possibly be swallowed by the largest adults of the common
five-lined skink. Various early records and statements pertaining to
predation on small vertebrates by five-lined skinks probably pertain in
most cases to _E. laticeps_, which is much larger than _E. fasciatus_,
and more powerful.

Barbour (1950:102) recorded stomach contents of an _E. fasciatus_
collected in Harlan County, Kentucky, as consisting of 60 per cent
Arachnida, 30 per cent adult Lepidoptera, and 10 per cent ants, by
volume. Werler and McCallion (1951:250) mentioned that on two occasions
these skinks in Virginia were seen to eat tenebrionid beetles and
larvae.

Webb (1949:294) fed captive skinks with field crickets (_Gryllus_) and
noted that the lizards tended to seize them by the pronotum, and then
worked forward to the head, chewing vigorously to disable them. The
seized crickets attempted to defend themselves by striking the lizards'
faces and eyes with the cerci and tibial spines. Webb also offered his
skinks newly hatched snails, _Helix aspersa_, which were noticed and fed
upon when they moved. In one instance, he noted that a skink found a
quiescent snail, and swallowed it after testing it with the tongue a few
times.

McIlhenny (1937:232) has published a remarkable account of observations
on the foraging behavior of a large adult male skink (stated to be _E.
fasciatus_ but almost certainly _E. laticeps_) in southern Louisiana,
which climbed among vines on the side of a house and attacked nests of
wasps, _Polistes pallipes_ and _P. bellicosus_, shaking out the larvae,
pausing to crush and swallow the few adults that lit on it and
attempted, unsuccessfully, to sting. After many larvae had been shaken
to the ground the skink descended and made a leisurely search, eating
them in seemingly prodigious quantities. Several times it climbed back
into the vines to shake out more larvae, and each time retrieved from
the ground those it could find. After feeding to repletion it returned
to its habitual shelter in a hollow live oak fifty feet from the house.
In a two-week period, however, it returned frequently to raid the wasp
nests in the vines, and eventually it had attacked all of the 32 nests
that were originally present, completely destroying many of them.

In the course of the present study direct observations on the food
habits of skinks rarely could be made in the field. Most of those seen
had been alarmed by the presence of the observer, and already had begun
a dash for shelter. Others not sufficiently alarmed to take cover, were
affected by an observer's presence, so that usually they ceased their
normal activities and crouched attempting to conceal themselves or
slithered nervously from one vantage point to another, on the alert for
any sign of danger.

On September 1, 1951, a young skink (30-35 mm. snout-vent length) was
discovered on the cement walk just outside the laboratory building,
holding a cricket (_Nemobius_) which evidently it had just caught. When
I came out of the building, the skink, alarmed, ran about ten feet,
holding the cricket by one leg. The cricket was still alive but was
nearly immobilized, except for twitching of its antennae and mandibles,
and evidently it had already been shaken and battered. After maneuvering
about the cement walk the skink ran through the open door into the
building. Though seeming to be uneasy at my proximity it was still
mainly intent on subduing and swallowing its prey. Following, I caused
the skink to take alarm. It dashed back through the door to the walk
outside and still carrying the cricket, it ran along the walk to the
steps leading up to another building and climbed onto the first step
where its uneasiness soon subsided. The cricket was remarkably large in
proportion to the skink itself, being of approximately the same
diameter, with a length nearly half that of the skink's snout-vent
length. Nevertheless, in about five minutes the skink had swallowed it
entire. As swallowing began, on the cement step, the skink was in bright
sunshine of early afternoon. In less than a minute it seemed to become
overheated, and dragged the prey back several inches into shadow. While
swallowing was still in progress, it again ran forward till its anterior
half was in sunshine, seemingly regulating its body temperature by these
frequent shifts.

A similar encounter between a larger juvenile and a cricket
(_Ceuthophilus_) was observed on May 9, 1953. After I had stood for
several minutes beside a rock ledge in woods, my attention was attracted
by a rustling sound in dry leaves. The skink, emerging onto the ledge
from a cavity beneath exposed hackberry roots had its head raised high
and was darting about, peering into crevices and examining its
surroundings with unusual animation. After several seconds the cricket
hopped into view. Possibly it had been injured already, as it moved
deliberately, with short hops. Instantly the skink darted in pursuit,
following its erratic course persistently, as it made several hops. In a
few seconds the skink caught the cricket, bit it vigorously, and
battered it against the rock ledge with violent lateral shaking. Several
times the cricket was knocked from the skink's jaws, but each time it
was quickly retrieved. In a few seconds its struggles were subdued, but
the skink continued to worry it, dropping it and retrieving it dozens of
times. The skink seized the cricket by one of the large rear legs, which
was snapped off with a sudden vigorous shake. The skink then dropped and
lost the detached leg, and ran back to seize the cricket again. The
performance was repeated with several other legs and the antennae, until
most of the appendages were eliminated and the body was softened by
continued biting and chewing. Then although the cricket was of body
diameter almost as great as the skink itself, the lizard swallowed it
head first, engulfing it with violent gulping movements. After the
front end of the prey had entered the gullet, muscles of the throat and
neck were brought into play in forcing it farther down. Swallowing
movements were snake-like, the lizard turning its head at right angles
to the body to squeeze the morsel down.

At the pond rock pile on May 7, 1952, a small adult male was watched as
it moved about over the rocks. A lycosid spider (_Pardosa lapidicina_)
carrying an egg sac was basking on an inclined rock surface. When the
skink had come within a few inches, it made a sudden rush at the spider
which escaped easily. As this common rock-living spider can move with
almost incredible speed, skinks probably do not often catch them in the
open.

Captive skinks, in taking their food, seem to rely much less than some
other lizards on movement of the prey as a means of detecting it. An
active and hungry skink often failed to notice a spider or insect moving
about on the opposite side of the terrarium a foot or more away.
However, on many occasions, skinks moving about the terrarium and coming
upon a motionless prey item have been seen to stop and examine it
intently for several seconds, then grasp it, often in a tentative and
hesitant manner, after testing it with the tongue. Sight and scent seem
to be about equally important in prey recognition, each supplementing
the other, and often functioning simultaneously. As many of the animals
preyed upon are secretive and would seldom be found in the open by day,
it seems that much of the prey is found in hiding places--in leaf litter
on the forest floor, beneath flat rocks or at their edges, and in chinks
and crannies of decaying logs, stumps, and tree trunks. Some of the prey
animals taken are of types that are more active and swift than the
skinks themselves. Presumably the olfactory sense is the more important
in detecting prey that is motionless or concealed. Stebbins (1948:202)
studied the nasal structure of _Eumeces_, and compared it with that of
other lizards. He concluded that the extensive mucus-secreting and
olfactory surfaces suggest relatively efficient humidification of
inspired air and efficient olfaction in lizards of this genus. In
captivity five-lined skinks thrived when provided with ample moisture
and shelter and food and kept within the proper temperature range. The
reactions of these captive skinks to various small animals introduced
into their terraria provided clues as to their food preferences, but
also were misleading in some instances. On many occasions hatchlings and
young of various sizes were kept with adults of both sexes and
subadults, but no instances of cannibalism were ever recorded in
captivity. No hostility was seen except between adults, mainly in the
breeding season. Young of the little brown skink, _Scincella laterale_,
kept with adult _E. fasciatus_, and small enough to be eaten by them,
likewise were unmolested. Small snakes such as _Diadophis_,
_Carphophis_, and _Storeria_ placed in terraria with the skinks evoked
no strong reaction. Occasionally mild avoidance reactions were aroused
but the skinks were never seen to display any hostility and readily
became accustomed to such cage mates. Mealworms, the most readily
available food for the captive skinks, were generally accepted by those
that were hungry and sufficiently warm, but were taken with little
enthusiasm. They were seldom noticed unless the skinks were within a few
inches. Skinks sometimes tested them with their tongues and examined
them intently then moved away without eating them. Earthworms, offered
on several occasions, were not eaten. Harvestmen, seemingly of the same
kind as those found in scats, were ignored by some captive individuals
and taken by others but with some signs of distaste. Ants were ignored.
Scarabaeid beetles, that seemed small enough to be eaten, were attacked
unsuccessfully, as they were too heavily armored to be crushed in the
skinks' jaws. Wasps (_Polistes_) placed in terraria were avoided, as
were carabid beetles and reduviid bugs. A spider placed in the terrarium
usually aroused one or more skinks to animated pursuit, as soon as it
moved. Even spiders that seemed to be too large to be swallowed were
sometimes pursued and attacked. Occasionally freshly killed prey was
taken, especially spiders and wasp larvae. Of invertebrates minute forms
are not taken, while certain ants, and various others of the kinds of
insects most common on the study areas and often found rather closely
associated with the skinks and using the same shelters, were never
represented among the recorded food items. Carabid beetles (_Brachinus_,
_Calosoma_, _Lebia_, _Harpalus_, _Pasimachus_), and reduviid bugs
(_Melanolestes_, etc.) seemed to be especially abundant and available,
but habitually avoided possibly because of their noxious qualities.
Diptera were entirely absent from the sample in the present study--they
and many other insects are so much quicker than the skinks that
ordinarily these insects cannot be caught. Foliage-living insects and
those that are strong and persistent fliers, are rarely available as
prey.

A total of 738 food items were recorded in the present study. Arachnids
with 360 items, and insects with 319, together made up 92 percent of
these food items. There were 334 spiders (most were not definitely
identified, but four were thomisids, 40 were lycosids, and 79 were
salticids, the latter group including 27 of the genus _Phidippus_); 26
harvestmen (_Leiobunum vittatum_ and others); 149 orthopterans (51
ceuthophilid crickets, 31 gryllid crickets, 27 tettigoniid locusts; 17
unspecified, 14 roaches, 9 locustid grasshoppers); 80 indeterminate
insects; 39 beetles (mostly carabids and scarabaeids within a narrow
size range); 19 larvae (13 lepidopteran, 2 coleopteran, 1 ant, 3
indeterminate); 2 ants (_Camponotus herculaneus_ and _C. castaneus_); 2
wasps; 1 moth; 1 centipede; 59 snails (31 indeterminate, 18 _Gastrocopta
armifera_, 8 _Retinella electrina_, 1 _Strobilops labyrynthica_, 1
_Hawaia minuscula_); 23 sloughed skins of the skinks themselves; 2 skink
eggs; and 2 skink hatchlings.

This sample is based on combined sets of data from analysis of stomach
contents and of "scats." The two sets of data present somewhat divergent
trends, and perhaps neither is adequately representative of the food
habits in the geographic area represented. A total of 620 food items
found in scats represented an average of 1.67 items per scat, whereas in
80 stomachs containing food the average was 1.44 items per stomach. Of
the skinks killed and dissected more than half had empty stomachs. Many
of them were, however, found inactive in shelter so that it was obvious
that they had not foraged recently. Many were not killed immediately and
they may have had time to digest any food in their stomachs.

Determinations of the prey down to species were possible in relatively
few instances; usually only the family or the order could be determined.
Those who have attempted food habits studies of insectivorous small
vertebrates will appreciate the obstacles encountered. The invertebrates
available to the skinks in the area of the study included many thousands
of species. A large number of these species, perhaps the majority,
belong to groups still not thoroughly studied, so that their taxonomy is
in a state of confusion. Ordinarily the prey is crushed in the jaws and
battered on the ground before ingestion; diagnostic structures are often
broken or lost, making identification far more difficult. Prey animals
taken are often in immature or larval stages which lack the
distinguishing features presented by adults. Even the combined efforts
of a team of specialists on each of the prey groups involved probably
would not have sufficed to obtain generic and specific identification of
every item found. In the present study, however, all determinations were
made by the writer, with the aid of the small reference collection at
the University of Kansas Natural History Reservation.

The 80 specimens used for stomach contents analysis nearly all came from
localities off the Reservation, but all within a ten-mile radius
thereof. A dozen localities were represented by these specimens, and
within each locality specimens were taken in somewhat different
situations. Therefore the stomach contents analyzed represents a wide
range of ecological conditions, including many different microhabitats.
All the stomach contents were collected in late April, May, and
June--within the first half of the skinks' active season. Trends might
be expected to differ in late summer and fall.

The food items from stomachs included: 38 spiders (8 of the salticid
genus _Phidippus_, 5 lycosids, 4 thomisids, and the remainder
unspecified); 15 insect larvae (7 of them lepidopteran and one
tentatively identified as an ant, _Camponotus castaneus_, the rest
unspecified); 13 unspecified insects; 10 crickets; 9 roaches; 9 snails
(5 of them _Gastrocopta armifera_); 7 beetles; 4 sloughs of skinks; 3
grasshoppers; 2 grouse locusts; and one each of cave cricket
(_Ceuthophilus?_), ant (_Camponotus castaneus_), moth, centipede, sow
bug, and egg of a skink. The egg was probably laid by the female that
ate it, since she was found brooding an unusually small clutch of only
three eggs.

The condition of food items found in stomachs varied greatly. Some were
nearly intact, while others were fragmentary and represented by only a
few of the more durable and indigestible parts. The larvae of various
insects found in stomachs examined are especially noteworthy, since but
little comparable material was found in the much larger group of items
identified from scats.

The scatological material was even less satisfactory than the stomach
material in providing determinable food items. The scats of these skinks
are, roughly, 10 to 20 mm. long and two to four mm. in diameter, usually
cylindrical and almost straight, and capped at one end with a white
chalky deposit of uric acid. Superficially they have some resemblance to
bird droppings, but are different in texture. The uric acid deposit is
loose and crumbly, and much less compact than that with bird feces, and
the food residue is much less completely disintegrated than is similar
material in feces of birds. Common small snakes which might produce
feces of similar size, include the ring-necked snake (_Diadophis
punctatus_), the worm snake (_Carphophis amoenus_), and DeKay's snake
(_Storeria dekayi_), but their feces have a much higher moisture
content, lack the definite shape of the skink scats, and ordinarily do
not contain readily recognizable residue of the prey. The six other
species of lizards on the Reservation, the collared lizard (_Crotaphytus
collaris_), brown skink (_Scincella laterale_), prairie skink (_Eumeces
septentrionalis_), Sonoran skink (_E. obsoletus_), six-lined racerunner
(_Cnemidophorus sexlineatus_) and glass "snake" (_Ophisaurus
attenuatus_) might produce scats indistinguishable from those of the
five-lined skink. However, none of these lizards except the relatively
rare and secretive brown skink, occurred in either of the two situations
where most of the scats were collected and it is highly improbable that
the scat collection included any material from species other than the
five-lined skink.

The scats consist mainly of chitinous fragments of arthropod prey.
Usually the prey fragments are so well comminuted, mixed, and scattered
that reconstruction is difficult. Degree of disintegration differs
greatly, depending not only on the type of prey eaten, but probably also
on the condition and temperature of the lizard, and the amount of other
food in its digestive tract. Arthropods which have recently undergone
ecdysis and have the exoskeleton still thin and soft are no doubt
digested much more completely than those that have more heavily
sclerotized parts. In spiders the chelicerae are more resistant to
digestion than are other parts of the exoskeleton, and frequently
appear, intact or nearly so, in the scat contents. The fangs being even
more resistant, were sometimes found separately when no other cheliceral
parts were recognizably preserved. Frequently large fragments of the
carapace, with some of the eyes or all of them, were found. Spider
abdomens sometimes were distinguishable, but were collapsed and
compressed. Spider legs conspicuous in most of the scats, were so
broken, tangled, and distorted that they were of little diagnostic
value. In harvestmen, dorsal shields were nearly always fairly intact;
but only small fragments of the elongate slender legs were found and
they were mostly broken off when the attacking skinks battered the
phalangid against the ground before swallowing it. The horny outer wings
of crickets, roaches, and beetles usually were in recognizable though
fragmentary condition. Occasional heads of insects often were found
fairly intact. Insect legs were sometimes intact, sometimes broken into
sections or crushed and fragmented. The thorax was usually represented
by scattered fragments of chitin, and the abdomen by the separate chitin
bands of each body segment.

Shells of snails were sometimes found nearly intact in the scats,
although showing the effect of the digestive juices in their extreme
brittleness. In other instances all that remained of the shell was the
inner columella, and small scattered fragments.

Certain of the items eaten were probably so thoroughly digested as to
leave either no hard parts at all, or minute and nondescript parts that
were not recognized. The common small slug _Deroceras laeve_, for
instance, would seem to be just as suitable and available for food as
the various kinds of snails, but it was not recorded in either stomachs
or scats. Having no hard parts except the vestigial internal shell, it
probably would not be recognized in scats, even though it had been
eaten. Various insect larvae, having thin outer cuticles and virtually
no hard sclerotized structures except in the head, likewise probably
would leave no recognizable parts. Molted skin of the skinks themselves
seemed to be little altered by the digestive processes.

    Table 16. Frequency of Occurrence by Months of Various Types of Prey
       in a Collection of 371 Scats of Eumeces fasciatus.

  =========================+========+======+======+======+=======+=======
                           |   May  |      |      |      |       |
                           |  (and  | June | July | Aug. | Sept. | Total
                           | April) |      |      |      |       |
  -------------------------+--------+------+------+------+-------+-------
  Spider                   |        |      |      |      |       |
    unspecified            |   32   |  32  |  16  | 100  |   10  |  190
    salticid               |   10   |  18  |   5  |  31  |    7  |   71
    lycosid                |    7   |   1  |   3  |  18  |    4  |   33
  Harvestman (phalangid)   |  ....  |   7  |   1  |  16  |    2  |   26
  Orthopteran              |        |      |      |      |       |
    unspecified            |  ....  |   4  | .... |  14  |  .... |   18
    cricket (ceuthophilid) |  ....  |   6  |  11  |  31  |    2  |   50
    cricket (gryllid)      |    2   |   1  | .... |  16  |    1  |   20
    grouse locust          |    3   |   2  | .... |  17  |    2  |   24
    grasshopper            |  ....  | .... | .... |   6  |  .... |    6
    roach                  |    1   |   2  | .... |   2  |  .... |    5
  Beetle                   |    4   |  13  |   1  |  11  |    2  |   31
  Ant                      |  ....  | .... |   1  | .... |  .... |    1
  Wasp                     |    1   | .... | .... |   1  |  .... |    2
  Caterpillar              |    1   | .... | .... |   1  |    1  |    3
  Other insects            |    3   |   8  |   6  |  45  |    5  |   67
  Five-lined skink         |        |      |      |      |       |
    slough                 |    2   |   1  |   3  |  12  |    1  |   19
    hatchling              |  ....  | .... | .... |   1  |    1  |    2
  Snail                    |        |      |      |      |       |
    unspecified            |    3   |   6  |   6  |   8  |    6  |   29
    _Gastrocopta_          |  ....  |   2  | .... |   8  |    1  |   11
    _Retinella_            |    1   |   1  | .... |   6  |  .... |    8
                           +--------+------+------+------+-------+-------
      Total                |   70   | 104  |  53  | 344  |   45  |  616
  -------------------------+--------+------+------+------+-------+-------

The collection of 371 skink scats originated mainly from two places on
the Reservation nearly three-quarters of a mile apart, the pond rock
pile and an old wooden bridge across a ravine. On the weathered planks
of the bridge, the scats were conspicuous and could be easily gathered
in quantity. At the pond rock pile, where skinks were especially
abundant and were intensively studied, their scats were frequently
noticed on the large rocks where they hunted and basked. A third smaller
collection of scats was made in the vicinity of the laboratory buildings
and adjacent rock walk frequented by a few skinks. A small number of
additional scats were collected elsewhere on the Reservation, but
ordinarily the scats were so inconspicuous in the woodland situations
where skinks occurred under typical habitat conditions, that few were
found. The rock pile, bridge, and vicinity of buildings are not typical
of the species' habitat and might offer somewhat different choices of
prey items.

The 30 scat collections were made in 1951 and 1952. Seasonally, the
sample of scats overlapped but little the sample of stomach contents,
and was concentrated in the latter half of the growing season. The
distribution by months was as follows: April-2; May-38; June-60;
July-29; August-213; September-26. Most of the scats probably were
deposited within a few days of the time they were collected, because
scats disintegrate and disappear rapidly in the field where they are
exposed to rain, wind and dung-feeding insects.

No clearly defined seasonal trends are revealed in Table 16 but the
monthly samples, except that for August, are scarcely adequate for this
purpose. Approximately equal numbers of scats were collected at the two
main stations, the pond rock pile and the bridge, but some kinds of
items were unequally represented in the two samples.

    Table 17. Comparison of Frequency of Occurrence of Various Food
       Items in Two Different Small Areas, Based on Scat Analysis.

  ======================+=================+=================+==================
                        |   Total from    |  Percentage of  |  Percentage of
                        | both collecting | total in bridge |  total in pond
                        |    stations     |     sample      | rock pile sample
  ----------------------+-----------------+-----------------+------------------
  Spiders (all)         |        292      |        63.3     |        36.7
    salticids           |         67      |        79.2     |        20.8
      _Phidippus audax_ |         16      |       100.0     |
      _Phidippus sp_    |          3      |                 |       100.0
    lycosids            |         33      |        36.3     |        63.7
  harvestmen            |         28      |        57.1     |        42.9
  ceuthophilids         |         39      |        30.8     |        69.2
  grouse locusts        |         25      |        92.0     |         8.0
  crickets              |         26      |        42.3     |        57.7
  snail                 |         34      |        61.9     |        38.1
    _Gastrocopta_       |         11      |        91.0     |         9.0
    _Retinella_         |          6      |        50.0     |        50.0
  ----------------------+-----------------+-----------------+------------------

Spiders, harvestmen, and snails were well represented in both samples.
In the bridge sample, salticids (especially _Phidippus audax_), grouse
locusts, and the snail _Gastrocopta_ were more numerous. In the rock
pile sample lycosids, and especially ceuthophilid crickets were more
abundant. The ceuthophilids were notably numerous among the rocks, and
many of them were caught in the wire funnel traps placed there for
skinks.

Little is known concerning the quantitative food requirement of any kind
of lizard. Five-lined skinks fast for at least half the year during the
period of dormancy, from September to April. When they emerge from
dormancy in spring most of them are plump and appear to have lost little
weight in the course of their long fast. In the season of activity,
obviously the quantity of food consumed fluctuates according to
temperature and activity of the lizard. Most of the prey taken falls
within a fairly narrow size range. The prey ordinarily is swallowed
entire or nearly so. This imposes a definite upper size limit. The skink
of course lacks the ophidian capacity to ingest relatively enormous
objects. The mental symphysis and pectoral girdle would prevent
ingestion of an object much larger than the skink's body diameter, but
soft-bodied and flexible arthropods of body diameter approximately equal
to that of the skink may be ingested. Typical food items are of such
size that from one to three of them fill the stomach to capacity. On one
occasion, in an attempt to feed a brood of young recently hatched in the
laboratory, I dropped into their jar a mass of newly hatched house
spiders (_Theridion tepidariorum_). As these minute spiders swarmed over
and around the skinks, the lizards gave little heed to them except
occasionally to jerk or scratch in irritation. One skink, however, was
seen to snap up a spider which ran near its snout. The adult female
_Theridion_ from the same web was then introduced into the skinks' jar,
although it seemed too large prey for these small lizards, as its
abdomen was fully as large as their body diameter. When it ran, the
hatchling skinks immediately became alert and several chased it biting
at it in frantic excitement. They had difficulty in grasping its smooth
rounded surface, but eventually one did catch it and eat it. Full-grown
mealworms averaging 26 mm. in length, and approximately .11 grams, are
somewhat smaller than the usual prey of adults. In captivity hungry
adult skinks took from one to nine such mealworms at a meal. However,
they could not be induced to feed daily over periods of weeks, even when
kept at high temperatures. Over a period of 64 days an adult male kept
at approximately 80° F. in the daytime and 10 to 15 degrees lower at
night, ate a total of 30 mealworms, which, in the aggregate, weighed
approximately 42 per cent of his body weight. In 35 days under the same
conditions an adult female ate 24 mealworms, approximately 32 per cent
of her body weight.

    [Illustration: FIG. 26. Map of University of Kansas Natural History
       Reservation showing locations of the four study areas (shaded)
       where most data on five-lined skinks were obtained.]



Predation and Parasitism


ESCAPE REACTIONS

Like other members of the family Scincidae, _Eumeces fasciatus_ tends to
be secretive in its habits and it depends on concealment rather than
speed, aggressive behavior, or noxious qualities to escape its enemies.
As compared with lizards in general, or with other members of the genus
_Eumeces_, five-lined skinks are relatively unspecialized in their
behavior, and retain a good deal of versatility. While primarily
terrestrial, they are able to burrow and climb. Their reactions toward
prey and natural enemies vary greatly according to circumstances.

They are less secretive than many other kinds of skinks. Nevertheless
the numbers active on the ground surface at any one time, even under the
most favorable weather conditions, probably are only a fraction of the
total population. For instance, in two or three hours of intensive
search in Skink Woods, in which almost every square yard of the area was
inspected, a dozen skinks constituted an unusually good catch. Seldom
were as many as 20 seen--and most of these only when uncovered in their
hiding places. At the pond rock pile, often half a dozen or even more
could be seen simultaneously or within the course of a few minutes, as
they basked or darted about over the rock surface. These, however,
represented only a small part of the number known to occur in the rock
pile, which could be observed in its entirety from one spot. At other
times, especially in late summer and early fall, even when weather
seemed favorable, cursory search of each of the study areas failed to
reveal a single individual. Presumably at such times the majority of
individuals of the dense population were sheltered deep underground in
relatively inaccessible hiding places. Others which escaped attention
may have been climbing on tree trunks or logs, or may have been foraging
on the ground but close to hiding places into which they darted
undetected. The habit of "freezing" in response to a potential danger is
commonly noticed in these skinks, and usually it is effective in
concealing them.

Having elongate bodies and short limbs, five-lined skinks are not
especially swift of foot, but the jerkiness of their movements provides
compensatory elusiveness. One sufficiently warm to be fully active is
nervous in its actions. Even when resting or basking it is likely to
shift its position frequently, fidgeting, blinking, and panting,
obviously on the alert for any sign of danger. In moving about, it
usually progresses only a few steps at a time, with frequent pauses
sometimes only a fraction of a second in duration. These numerous stops
allow the animal to examine the terrain immediately ahead of it, and
perhaps avoid blundering within reach of a lurking enemy.

Ontogenetic change in the color pattern is of significance in connection
with the secretive habits. The red facial suffusion of the breeding male
renders him more conspicuous in his natural surroundings, but this
bright color is ephemeral. It is developed as a warning, for display to
other males. Otherwise, in the adult male the color of dull brown is
inconspicuous in its natural surroundings, usually against a background
of leaf litter, dead stems, and soil. In the juvenile the contrasting
pattern of dark brown ground-color, five longitudinal light stripes, and
a vivid blue tail, is far more conspicuous. The young skink might seem
to be handicapped in its chances for survival by this conspicuousness.
However, in snakes it has been shown that a vivid striped pattern,
characteristic of forms that are fast moving and live in dense
vegetation, serves to conceal motion, and aid its possessor in confusing
and eluding pursuers. The young skinks, being far more active than the
adults, may use the striped pattern more effectively in this way. Often
when a young skink is startled in its natural surroundings, and takes to
cover, the observer does not see its outlines at all, and is conscious
of it only as a flash of blue. On many occasions, while walking in the
woods, I have had my attention attracted by a faint rustling of dry
leaves, and have received such a fleeting impression of the flashing
blue tail as to be uncertain whether or not I had actually seen a skink,
until, raising a flat rock or other shelter, I found that one actually
was present, concealing itself in the nearby hiding place. The erratic
movements of a frightened skink that is warm and fully active, make it
exceedingly elusive. With sudden lashing movements of its heavy tail and
hindquarters, it may flip its body about, facing first in one direction
and then in another, as it pauses before or after a rush for shelter.
The sudden reversals of direction are so confusing to the pursuer that
the skink may often escape by hiding after a few seconds of pursuit,
even though the situation provides no shelter where the lizard is
entirely secure. The tail-flip described is characteristically given at
the instant the lizard reaches shelter such as a crevice, or hole, and
just before it disappears. By the instantaneous pivoting of its body,
throwing its tail in an arc, in the direction of its original course,
the lizard creates the optical illusion of having moved beyond the point
where it has taken to shelter. The peculiar writhing movements of the
tail of juveniles that are moving about in the open accentuate the
conspicuousness of the vividly colored tail, and suggest that this
conspicuousness may be advantageous to the lizard in serving as a decoy
to catch the attention of predators and distract them from the lizard
itself.

In hatchlings the mortality rate is high. Tails are broken frequently in
those that survive, suggesting that the tail may be useful in diverting
enemies from the lizard itself. Among 121 young of the smallest sizes,
(snout-vent lengths in the range of 23 to 29 mm.) 7.4 percent already
had broken tails (not including, of course, those in which the tails
were broken while the skinks were being captured). In slightly larger
young, those in the 30-34 mm. range, perhaps averaging one month old,
nearly one-fourth had lost their original tails. In those in the 35-55
mm. size class, mostly one to three months old, about half have already
lost parts of their original tails. In those that are in the size group
65-69 mm. normally attained at an age of a year, approximately
three-fourths have regenerated tails, and in adults the proportion with
unbroken tails is even smaller--down to 16.5 percent in females of more
than 75 mm. snout-vent length. In adults the incidence of broken and
regenerated tails is slightly higher in females than in males. Defense
of nests and sluggishness in the females during the time that they are
excavating the nest burrows and guarding their eggs may result in their
tails being broken more frequently.

Tree-climbing is a common means of escape and it is curious that many of
those who have described the habits of _E. fasciatus_ have either failed
to note it at all or have minimized arboreal habits. Taylor (1936:59)
cited two instances of tree-climbing but stated: "Only rarely is this
form seen in trees, at least in the western part of its range." Conant
(1951:30) stated: "They seldom climb trees, contrary to the habit of
_laticeps_ and _inexpectatus_." Hudson (1942:42) mentioned seeing an
adult that escaped by climbing the side of a hollow tree in southeastern
Nebraska.

In the present study, tree-climbing as a means of escape was observed
frequently, probably more than two hundred times in all. It was
characteristic of both sexes and all ages, and was one of the commonest
responses to danger. In summer when skinks were fully active, they
usually moved too rapidly to be caught by hand either in the open or
where they were uncovered when I turned over rocks or other shelter. To
obtain specimens in any numbers at such times, an understanding was
essential of the somewhat stereotyped behavior pattern involved in their
escape by tree-climbing. A skink that was alarmed in the course of its
foraging or basking on the ground litter was likely to run directly to
the nearest tree trunk, often a distance of several or many yards, and
start up it, instantly disappearing to the far side of it. The trees
climbed were usually small, two to eight inches in trunk diameter;
however, in the second growth forest where the study was made, large
mature trees were relatively scarce. Having started up the tree trunk
and concealed itself on the side opposite from its pursuer, the skink
usually stopped one to five feet from the ground and waited quietly for
the danger to pass. A vine of Virginia creeper, poison ivy, grape or
moonseed, or a shrub such as gooseberry, providing screening foliage at
the base of the tree trunk, furnished the type of sheltered situation
that the skink was most likely to choose as a stopping place. The most
effective technique for catching the lizard was to move slowly around
the tree trunk at a distance of at least 20 or 30 feet and look for the
lizard clinging to it. Having located the lizard, the collector might
take careful note of its position, then return to the opposite side of
the tree and approach, unseen, to close range to make a sudden grab
around the trunk. This ruse often succeeded; more frequently it failed,
because of the lizard's adroitness in dodging, or failure of the
collector to gauge its position accurately, or a slight shifting of its
position between the time it was seen and the time when an attempt was
made to catch it. The response of the lizard to the unsuccessful attempt
to seize it depended on whether or not it was touched, and in which
direction it was driven. It might drop to the ground and burrow into
leaf litter or dash away to other shelter, or it might stay on the tree
trunk and spiral rapidly upward out of reach. Because of the
squirrel-like tendency to keep the tree trunk between it and the
pursuer, the skink usually could be relocated only after some
maneuvering. Having climbed the tree trunk to the bases of the main
branches, the skink usually showed little inclination to move out along
them but tended to hide in the crotches or to spiral back down the
trunk. Often a long stick or pole was used effectively to drive a skink
back down the trunk by touching or pushing it on the upper side. A skink
maneuvered to the lower part of the tree trunk was never loath to leave
it in a dash for other shelter, which might be another tree trunk
nearby. In moving downward or horizontally on a tree trunk or limb, a
skink allows its heavy tail to bend downward from its own weight. The
tail probably handicaps the lizard's climbing to some extent, and those
with short regenerated tails have an advantage.

The following extracts from my field notes are selected as typical
illustrations of the climbing habit as a response to danger.

September 15, 1948. A skink darted across the trail in front of me, to a
tree 18 inches in diameter and climbed to a height of five feet where it
stopped. Each time that I moved to approach and examine it, the skink
was disturbed, and darted jerkily higher up the trunk until it was well
out of reach at a height of about ten feet.

May 2, 1949. Seeing an adult male skink lying in the open, I attempted
to stalk it, but it became alarmed, ran to a shagbark hickory about six
inches in diameter, and soon had climbed to a height of 25 feet.

June 4, 1949. Juvenile, basking a few inches above ground on trunk of an
elm ten inches in diameter, took alarm at my approach, and climbed
rapidly out of reach, where it concealed itself in thick foliage.

June 22, 1949. Movement two feet above ground on an elm sapling
attracted my attention; an adult male and a juvenal skink were clinging
to the trunk only a few inches apart, and neither moved as I approached
and examined them from a distance of less than three feet. The
concealment afforded by numerous short twigs with thick foliage
apparently caused them to feel secure.

September 21, 1949. A juvenile was noticed climbing eight feet above the
ground on a locust trunk. As I approached the skink continued upward to
a height of approximately 15 feet above the ground where it disappeared
around the trunk and could not be relocated.

July 7, 1950. A nearly grown juvenile ran to an elm sapling four inches
in diameter, and climbed up out of reach. When the skink reached the
main crotch, it turned facing downward alertly. By reaching up with a
long stick and poking it on the hindquarters, I succeeded several times
in chasing it part way down the trunk, but each time it ran back up to
the crotch and returned to the same position.

July 26, 1950. A hatchling uncovered beneath a flat rock ran to a nearby
oak tree about four inches in diameter and climbed to a height of five
feet before it was caught. An adult female seen foraging in the open ran
to a dead shrub and climbed one of the stems, inclined at an angle of
about 45°. Ascending this stem she was unable to get more than three
feet above the ground, and was easily captured. Another adult female
seen foraging in the open ran to an oak about three inches in diameter,
climbed rapidly to a height a little more than a foot above the ground,
and concealed herself under the stem of a poison ivy vine twined about
the tree trunk.

July 27, 1951. A female brooding her eggs dashed out of the nest when
the flat rock covering it was lifted, ran 15 feet to a hickory sapling
and climbed it.

May 1, 1952. An adult male found beneath a rock ran to a small tree ten
feet away, climbed up on the opposite side, and stopped about a foot
above the ground. My first attempt to seize it failed and it ran around
the trunk and stopped at a height of four feet. The next try was
likewise unsuccessful, and the skink dropped to the ground and burrowed
into leaf litter.

May 15, 1952. An adult male startled as it basked in a patch of sunlight
in thick woods, dashed 25 feet without stopping, to an osage orange tree
and disappeared behind the base of the trunk. Moving to the far side of
the tree I located the skink clinging to the trunk two feet above the
ground. My attempt to catch it failed and it spiralled up the trunk to a
height of ten feet. When I poked at it with a stick, it crouched close
to the trunk allowing the stick almost to touch it, then it spiralled
down the trunk and could not be relocated.

June 23, 1952. When I struck the trunk of a partly dead ailanthus tree
with a brush knife to determine whether it was hollow, a juvenile darted
out of a cavity five feet above the ground, ran farther up the trunk,
and disappeared into another small hole. An adult male was seen running
across the vertical wall of a building, clinging to the rough asphalt
siding. When it was alarmed it ran to a crevice and hid.

A more unusual escape-reaction was observed on May 25, 1952, at
Tonganoxie State Lake, by Sydney Anderson, who recorded that a skink,
alarmed by him at the edge of the water dived and hid among submerged
rocks. Similarly, Boyer and Heinze (1934:194) record of this species, in
Jefferson County, Missouri: "When pursued they do not hesitate to take
to the water and are very agile swimmers over short distances at least."
Parker (1948:25) wrote that in western Tennessee _fasciatus_ sometimes
showed a preference for habitat in the vicinity of water, and, if other
concealment was not available, it would usually take refuge in the
water.


NATURAL ENEMIES

Little is known concerning the kinds of predators that destroy
five-lined skinks, or their importance in its ecology. In studies of the
food habits of various predatory birds and mammals, workers often have
been interested chiefly in items of direct economic bearing, and have
tended to lump as "lizard" or "reptile" material that might have
included _Eumeces fasciatus_. I have been able to find only a few
specific references to predation on it. Nevertheless many kinds of
predators probably utilize it as food, at least occasionally. Owls
probably seldom have opportunity to prey on these skinks, which are not
known to be active after dark. Nestling broad-winged hawks observed in
1954 were found to have eaten an adult and a subadult five-lined skink
on June 13 and June 23. The Cooper's hawk and red-shouldered hawk also
are probable predators as both are known to feed upon small reptiles.
Mammalian predators which might be expected to take skinks occasionally
include the red fox, gray fox, bobcat, mink, weasels, skunks, opossum,
armadillo, moles, and shrews. Snakes, especially those of the genera
_Elaphe_, _Lampropeltis_, _Cemophora_, _Micrurus_ and _Ancistrodon_, may
include some of the chief predators on the skink. Certain larger lizards
also may prey upon it.

Of these several potential predators, only the opossum, armadillo, and
snakes (_Elaphe obsoleta_, _E. guttata_, _Lampropeltis triangulum_, _L.
calligaster_, _L. getulus_, and _Ancistrodon contortrix_), Sonoran skink
and the greater five-lined skink (in confinement) have actually been
recorded as preying on _Eumeces fasciatus_ but circumstantial evidence
has been obtained for the mole (_Scalopus aquaticus_) and short-tailed
shrew (_Blarina brevicauda_). The short-tailed shrew may be one of the
major predators on the skink. This shrew prefers the same habitats and
occurs throughout the skink's extensive range. Like the skink, it is a
characteristic inhabitant of the hardwood forests of the eastern United
States, but its range extends farther north and west. A high proportion
of the skinks examined had scars, usually on the sides or dorsal surface
of the body, or of the tail near its base--wounds which must have been
made by a small, sharp-toothed animal. For example, in May 1951,
eighteen per cent of 155 skinks captured on the study areas had such
scars. The incidence seemed to vary according to age and possibly sex;
the scars were present in 22.9 per cent of the adult males, 25.5 per
cent of the adult females, and only 9.8 per cent of the yearlings (these
three groups being represented by approximately equal numbers in the
sample). As the scars are more or less permanent, adults could be
expected to show a much higher incidence than young. Females, being
inclined to stay in their nest burrows and defend them against small
predators, may receive more wounds than the males, which are quicker to
escape. None of the invertebrates present on the study area is
sufficiently large or powerful to inflict such wounds, and none of the
birds, reptiles, or amphibians has a dentition capable of producing
them. The wood mouse (_Peromyscus leucopus_) is the most abundant small
mammal in the skink's habitat; other rodents present in relatively small
numbers include the prairie vole (_Microtus ochrogaster_), harvest mouse
(_Reithrodontomys megalotis_) and pine vole (_Microtus pinetorum_). Both
voles and harvest mice have been known to kill skinks caught in the same
traps with them, but individuals experimentally placed with skinks in
captivity have failed to molest them and it seems likely that the
attacks in traps were motivated by extreme hunger or self defense. The
irregular scars from lacerated wounds characteristic of the skinks bear
little similarity to rodent bites, in which the long, sharp-edge
incisors make slit-like punctures. Other small mammals abundant in the
places where skinks were studied were the insectivores: the common mole,
short-tailed shrew, and least shrew (_Cryptotis parva_).

On one occasion when a large five-lined skink was put in a terrarium
with a recently captured short-tailed shrew, each displayed strong
aversion for the other. The skink crouched, attempting to conceal itself
in the end of the terrarium farthest from the shrew, and resisted
efforts to drive it toward the shrew. In exploring the terrarium the
shrew several times sensed the skink's presence, and then scampered away
in frantic haste. The skink also rushed away several times when the
shrew came close enough to disturb it. Three days later, when the shrew
had become accustomed to the terrarium, the test was repeated, with
different results. The shrew, having finished the food left for it, was
noticed moving about the terrarium, sniffing and testing objects with
its tactile snout, obviously hungry and searching for more food. The
skink was then dropped near it. In a few seconds the shrew sensed the
skink's presence and pounced upon it, and bit hard on its back. The
skink reacted with a violent flexure of its body which caused the shrew
to release it instantly, and both rushed away in opposite directions.
After a few seconds the shrew located the skink again, and moved up to
it with little hesitation but with nervous alert sniffing, and delivered
another quick bite after which the two separated as before, the skink
showing signs of injury. Soon the shrew attacked a third time, and bit
the skink's tail severing it near the base. As the skink rushed away,
the detached tail performed lively squirming movements, but the shrew
seized it, held it down, and began to eat the exposed flesh on the
broken end as the tail writhed. After rapid nibbling it would drop the
tail, and leaving it temporarily would explore the terrarium. Several
times on these trips it encountered the skink and renewed its attack. As
death of the skink seemed imminent, it was then removed, and it survived
with no apparent ill effects. The wounds inflicted by the shrew bore
close resemblance to those noticed on skinks in the wild. It seemed
almost certain that _Blarina_ had inflicted most of these wounds or all
of them. On subsequent occasions several other captive shrews that were
tested, quickly killed and ate skinks that were introduced into their
containers. The least shrew, _Cryptotis_, likewise occurred in all
situations where skinks were taken, and in some localities was more
abundant than the larger _Blarina_. Bites inflicted by these two kinds
of shrews might be indistinguishable, but because of its larger size,
_Blarina_ would seem by far the more formidable enemy.

Reynolds (1945:367) found _E. fasciatus_ to be the most frequent reptile
in a collection of opossum scats from Missouri, with two occurrences in
100 fall scats and ten occurrences in 100 spring scats. Sandidge
(1953:98 and 101) recorded one of these skinks among numerous other
items identified from stomach contents of sixty-six opossums. Probably
the opossum is a frequent predator on this skink. Although no specific
instances were obtained on the area of the study, flat rocks a few
inches in diameter frequently have been found flipped over, larger ones
and those solidly anchored in the ground have been found partly
undermined by opossums scratching away the loose dirt at their edges.
The rocks found disturbed by opossums were typical of those used as
shelter by the skink. On many occasions wire funnel traps set for skinks
and other reptiles along hilltop rock ledges were found to have been
disturbed, either shifted in position or with their rock shelters
removed, or rolled downhill or broken open. Similarly, heavy flat rocks
used to cover pitfalls, to protect the small animals falling into them
from predators, often were found to have been shifted somewhat, or
completely removed. When such raids became frequent and troublesome,
steel traps were set beside the reptile traps to discourage the raiders
or catch them and determine their identity. On several occasions
opossums were caught and somewhat less frequently, spotted skunks
(_Spilogale interrupta_). These skunks probably prey regularly on
lizards including the five-lined skink. However no definite records were
obtained. Crabb (1941:356-358) in his food habits study of the spotted
skunk in southeastern Iowa, did not record this or any other species of
reptile among the items identified in 834 scats. On the Reservation both
opossums and skunks were, in many instances, attracted to the reptile
traps by the insects and other arthropods in them, rather than by
lizards. The striped skunk (_Mephitis mephitis_) is another of the
predators which probably feeds upon the five-lined skink occasionally on
this area.

In the contents of 103 armadillo stomachs collected in west-central
Louisiana, in 1947 and 1948 I found the broken tail of one _Eumeces
fasciatus_. The lizard itself evidently had escaped (Fitch, 1949a:88).
Many clutches of lizard eggs were found in the contents of the armadillo
stomachs and some of these probably were eggs of _Eumeces_, which are
similar to those of other small lizards in the same region (_Anolis
carolinensis_, _Sceloporus undulatus_) in size, shape, and color.

Among 217 identified prey items from stomachs and scats of Sonoran
skinks (_Eumeces obsoletus_) from northeastern Kansas were remains of
three hatchling five-lined skinks. Taylor (1953b:212) recorded that a
_Eumeces laticeps_ shipped from Arkansas to Kansas ate an _E. fasciatus_
that was with it in the container. Several authors have recorded
predation on _Eumeces fasciatus_ by snakes of various kinds in
captivity. Conant (1951:211) recorded that one was eaten by a blacksnake
(_Coluber constrictor_) placed in the collecting sack with it. Anderson
(1942:211 and 216) recorded that a king snake (_Lampropeltis getulus
holbrooki_) and a young copperhead (_Ancistrodon contortrix_) each fed
upon them. Hurter (1911:184) recorded that a milk snake, _Lampropeltis
triangulum syspila_, placed in a bucket with a _Eumeces fasciatus_ was
found swallowing it a short time later and its tail had been broken off.

Ruthven (1911:268) mentioned that stomachs of milk snakes, _L. t.
triangulum_, collected in Michigan contained remains of five-lined
skinks. Ditmars (1907:352) wrote that stomachs of several _L. t.
elapsoides_ contained _Eumeces_, and Wright and Bishop (1915:167) wrote
of the same kind of king snake in the Okefinokee Swamp region: "It
feeds on ground lizards, skinks, swifts, and other snakes and lizards."

Mr. Richard B. Loomis is of the opinion that the five-lined skink is one
of the chief food sources for the milk snake (_L. t. syspila_). Having
kept many of these snakes in captivity and experimentally offered them
different types of prey, he found that individuals inclined to feed
would avidly seize and eat skinks and young mice, but other proffered
prey, small adult rodents, snakes, or lizards other than _Eumeces_ were
either rejected or were taken with some hesitation. These milk snakes
have habitat preferences similar to the skink, which would seem to be
one of the most available food sources. Loomis recorded in his field
notes that a juvenal blotched king snake (_L. calligaster_) 310 mm. in
total length, taken on April 8, 1950, seven miles southwest of Tulsa,
Oklahoma, had eaten a large adult _E. fasciatus_. Another juvenal
blotched king snake that he found under a flat rock near Sunflower,
Johnson County, Kansas, regurgitated an adult five-lined skink. Loomis
also recorded a juvenal rat snake (_Elaphe guttata emoryi_) and a
juvenal pilot black snake (_E. obsoleta_) each feeding on individuals of
_Eumeces fasciatus_ in captivity. Uhler, Cottam and Clarke (1939:622) in
a study of the contents of the alimentary tracts of 893 snakes of 18
species, from the George Washington National Forest, Virginia, found
among the prey items only one skink (species undetermined but most
probably _E. fasciatus_). It had been eaten by one of the two corn
snakes (_Elaphe guttata_) that were examined in the study.

On June 11, 1950, in Skink Woods, a young copperhead 335 mm. in
snout-vent length and weighing 27.6 grams, had a gravid female skink in
its stomach. Another young copperhead (335 mm., 36.1 grams) trapped near
Rat Woods on August 28, 1953, had in its stomach a bob-tailed adult
five-lined skink. Many copperheads collected on the Reservation were
kept in captivity for short periods, and from them a total of 44 scats
were obtained, each scat containing the remains of one or more prey
animals eaten in the wild. Of this total, five scats contained remains
of _Eumeces fasciatus_, which was one of the more frequent items,
although small mammals collectively made up the bulk of the scat
contents.


PARASITES

Skinks, like many other lizards, are likely to be infested with
parasites. Little attention was devoted to the endoparasites in the
present study, but they were noted from time to time. On several
occasions small nematodes and flukes were seen in feces voided by
lizards which were handled. Small white cysts were seen in the body
cavities of several that were dissected.

Harwood (1932:65) examined for endoparasites nine _E. fasciatus_ along
with many other reptiles and amphibians collected near Houston, Texas.
Most of them were infested and five kinds of helminths were identified.
Two of the skinks were infested with _Oswaldocruzia pipiens_, a spirurid
nematode that was also present in various other lizards, snakes, toads
and frogs from the same region; four had _Comocercoides dukae_, an
oxyurid nematode also present in various lizards, snakes, turtles, and
frogs; one had in its intestine _Oochoristica eumecis_, named as a new
species by Harwood, and found only in _Eumeces_; one contained
_Cysticercus_ sp. in its body cavity, present in great abundance as
white globular structures .6 mm. in diameter (Harwood states that
possibly these were larvae of _Oochoristica_). One skink contained
_Mesocoelium americanum_, a dicrocoelid trematode which was found also
in the brown skink (_Scincella laterale_) and DeKay's snake (_Storeria
dekayi_).

The ectoparasites of these skinks consist mainly of chiggers. Wharton
(1952:135) lists three species; _Trombicula alfreddugesi_, _T.
splendens_, and _T. gurneyi_. The first species is the common pest
chigger of humans and domestic animals in the United States, and south
through tropical America. Wharton lists 136 known hosts which are fairly
evenly divided among mammals, birds and reptiles; he lists four kinds of
frogs and toads. _Trombicula splendens_ is a similar and closely related
species which has been recorded from thirty-eight vertebrate hosts
including mammals, birds, reptiles, and a tree-toad. _Trombicula
gurneyi_ belongs to a separate subgenus and it was originally recorded
from _Eumeces fasciatus_ which seems to be one of the principal hosts.

Two of these mites, _T. alfreddugesi_ and _T. gurneyi_, were on skinks
collected on the Reservation, and nearby areas. A four year study of the
chiggers in this general region by Loomis (MS), Wolfenbarger (1953) and
Kardos (MS) has clarified the ecological relationships of the several
kinds of chiggers present, including their local distribution with
respect to vegetation, soil type, moisture and temperature, host
preferences, and seasonal occurrence. At the quarry, Rat Woods and the
pond rock pile, the chigger population consisted chiefly of _T.
alfreddugesi_, while at Skink Woods _T. gurneyi_ was also abundant. In
some local situations where they are among the most abundant of
vertebrates the skinks probably are important as hosts of _T. gurneyi_.
An individual skink may have dozens of chiggers on it at one time but
usually there are fewer.

There are several favorable sites of attachment. The most favored site
is in the axilla. There the scales are minute and granular with exposed
areas of thin and tender skin, and the chiggers are well protected from
dessication and are not likely to be rubbed off as the skink moves
about. Other favorite sites of attachment are: about the insertion of
the hind limb, about the cloacal opening, on the eyelids and on the
toes. Only occasionally are chiggers found attached on the dorsal
surface. When attached in protected spots in the tender skin of the
axilla or groin, they are often in dense clusters of a dozen or more.
Damage to the skin resulting from the attachment of the first chiggers
renders conditions more favorable for the attachment of others. At Rat
Ledge and at the quarry, many of the larger Sonoran skinks (_Eumeces
obsoletus_) were captured, and individuals were far more heavily
infested than were _E. fasciatus_ from the same places. A single Sonoran
skink might be found to have hundreds of chiggers, widely distributed
over its body with concentrations at the axillae, groins, lateral neck
region, and any injured spots where the protective armor of scales was
broken. The reasons for the greater susceptibility of _E. obsoletus_ are
not entirely clear. It is a larger, less active species with coarser
scalation, and is more subterranean in its habits.

The chiggers that attach to skinks seem to occasion but little
discomfort. There is no local swelling and inflammation such as occurs
in humans. The infestations observed in five-lined skinks were not
sufficiently severe to cause debilitation or any noticeable symptoms.
There is, however, a possibility that chiggers are vectors of
microorganisms causing diseases in reptiles, just as they are for
certain mammals (including humans) in some parts of the world.

Bishopp and Trembley (1935:42) record a single kind of tick, _Ixodes
ricinus scapularis_ Say, the black-legged tick, as parasitic in its
immature stages on _Eumeces fasciatus_. This tick, however, has been
recorded principally from mammals, of which many kinds serve as hosts
for its larval, nymphal, and adult stages.



Population


COMPOSITION

Population structure obviously differs from place to place and from time
to time. Because of the differences in secretiveness and elusiveness
between young and adults and between males and females, true sex ratios
and age ratios are obscured. In the period of weeks between the
emergence from hibernation and the onset of the breeding season, these
skinks tend to be less secretive than at other times, and secondary
sexual and age differences in behavior are minimized. A sample at this
season should be more representative of the true population composition
than samples taken at other times of year. In a sample of 308 skinks
available for the month of April, including the collections made on the
Reservation and on nearby areas, in 1949, 1950, 1951, and 1952, 36.7 per
cent were adult males, 28.3 per cent were adult females, and 35.0 per
cent were young. That these figures cannot, however, be accepted as an
accurate indication of the population composition is shown by the data
from the areas where intensive population studies were made. Data are
most complete from Skink Woods. For 292 adults taken there over a four
year period, the sex ratio was 100:122.6. On this area after the first
year of study a substantial proportion of the individuals recorded were
repeaters from one year to the next, and in some cases for three or even
four successive years. Many could be definitely assigned to a known age
group. By analogy the majority of others could be tentatively assigned
with some assurance on the basis of measurements, and relatively few
were of indeterminate status. By assigning each of these indeterminate
individuals to one or another age group, on the basis of greatest
probability, the approximate composition of the population could be
determined. Of 611 adults, 55 per cent were "two-year olds" (in the
season between their second and third hibernations, which was their
first breeding season). The percentage was not significantly different
in the two sexes.

On the average, a pair of adults produces somewhat more than nine eggs
per year. From the time individuals of a brood start their development
in the egg until they are breeding adults two years later, they undergo
such drastic reduction in numbers that, on the average, approximately
only one per brood survives. Most of the mortality probably occurs
early, especially before hatching, also in the inexperienced hatchlings,
and in the first hibernation. In spring, after emergence from
hibernation, young are generally taken in smaller numbers than are
adults. Their relative scarcity is only apparent, owing to greater
secretiveness, and greater elusiveness when found. In spring, newly
matured adults (age class about 21 months) may be taken in somewhat
larger numbers than young (age class about 9 months). The latter
obviously must be more numerous, in a stable population however, as the
21 month age class necessarily has sustained some loss since it was 9
months old.

Success of the annual brood varies greatly from year to year, depending
on the weather and various other factors. In 1949 evidently conditions
were near optimum; young hatched early and were especially numerous in
late summer. In 1950 these young hatched in 1949 made up 40 per cent of
the total catch (excluding hatchlings) in Skink Woods and were
relatively more numerous than young of the corresponding age group in
other years. In 1951, these young of the 1949 brood, grown to adults,
made up 70 per cent of the breeding populations, as against 36 per cent
for the corresponding class in 1950 and 58 per cent for the
corresponding class in 1952.

Even after attainment of adulthood, any given age group evidently is
subject to annual reduction amounting to at least half its numbers.
Within six or seven years, at the most, the original numbers would be
reduced to an insignificant percentage. At an age of four or five years
individuals probably have attained their maximum size, with obscured
pattern and changed proportions suggestive of advanced age. Occasional
individuals possibly attain much greater age, but certainly few live
more than five years. Like most small animals, the five-lined skink has
a short life expectancy and a rapid population turnover. As compared
with mammals of comparable sizes, the small rodents and insectivores
that are this lizard's community associates and are subject to many of
the same hazards, the skink is notably successful, with a much longer
life expectancy. For these small mammals the life span is seldom as long
as a year. Most kinds of small birds likewise have a life expectancy
less than that of the five-lined skink, although somewhat greater than
that of small mammals.


DENSITY

The population density changes constantly, following an annual cycle
with gradual reduction to its lowest ebb in late June or early July,
then rapid increase to a high point a few weeks later when hatching of
the single annual brood has been completed. In a normally successful
breeding season the population is at least doubled, but reproductive
success varies from year to year, as the population responds to weather
conditions that are favorable or unfavorable, even where the environment
remains fairly stable. In most places, however, local populations
continue upward or downward trends for periods of years in response to
successional changes which cause progressive improvement or
deterioration of local habitats. Local populations are likely to be more
or less isolated from others by areas where the habitat does not exist.
Even in an area of favorable habitat such as a wooded hillside of
several acres, the population is not at all evenly distributed, but
concentrations occur along rock outcrops, and about decaying logs, or
stone piles. In intervening areas lacking such abundant shelter, and
less productive of food, the population is sparse, or there may be no
permanent residents.

In view of these traits, and the difficulty of obtaining a
representative sample, no precise measurements of population density can
be made. During the time required to secure a sample, the population
undergoes change. At the pond rock pile, an area of approximately .05
acre, the skinks were found in remarkably high concentrations, 57 in
1949, 85 in 1950, 37 in 1951, and 51 in 1952. These numbers represent
population densities of, respectively, 1120 per acre, 1960 per acre, 746
per acre, and 1000 per acre. No such concentrations were found
elsewhere, and probably do not occur in natural habitat. The Skink Woods
study area of 2-1/4 acres is typical of favorable habitat in the region
of the study, and the numbers taken there are more significant. For 1949
the 74 skinks recorded comprise an incomplete sample, and the population
density of 33 per acre represented is certainly somewhat too low. For
other years the following population densities (exclusive of hatchlings)
are indicated: 1950, 92 per acre; 1951, 61 per acre; 1952, 49 per acre.
These figures are only approximate, of course, and it is difficult to
judge how accurately they reflect the true numbers. Even the most
intensive collecting may be insufficient to obtain every individual on a
small area. Within each season there are shifts of range by some
individuals, off the study area and corresponding shifts onto it by
others, so that the numbers caught in the course of an entire season are
somewhat too high. The individuals taken on the study area may regularly
range beyond its boundaries to some extent, so that the seeming
population density is somewhat too high. Actually this was probably a
minor source of error for the Skink Woods study area, as nearly half its
perimeter was bordered by an open field uninhabitable for the skinks,
and the remaining perimeter adjoined areas much less favorable than the
central portion.

Census of the population of the study area by a ratio such as the
"Lincoln Index" used in game management studies was scarcely practicable
because of the changing seasonal habits distorting the recorded ratios
of the sexes and of age groups somewhat differently at different stages
of the season. These changing ratios tend to produce an erroneously high
population figure, unless separate computations are made from the data
for adult males, adult females, and young. Census figures obtained by
this method were erratic but seemed to bear out in a general way, the
population figures based on total numbers of individuals taken.

In favorable habitat where they occur in high populations of 50 to 100
per acre in spring, these lizards must attain a biomass of a pound or
more per acre. Biomass in a population probably fluctuates but little
during the course of the annual cycle, even though the number of
individuals changes greatly. The steady elimination of individuals
through various mortality factors, is compensated for by rapid growth of
the young.



Summary


Five-lined skinks were studied for four consecutive years in four small
areas, totalling approximately ten acres, on the University of Kansas
Natural History Reservation, Douglas County, Kansas. The information
gained from intensive study on these areas has been supplemented by data
from skinks collected elsewhere in northeastern Kansas, and from an
extensive literature pertaining to this species.

The genus _Eumeces_, to which the common five-lined skink belongs, has
more than 50 species, occurring throughout Central America, North
America to the latitude of southern Canada, and, in the Old World,
across southern Asia and North Africa. Within the genus, the five-lined
skinks, comprising a dozen species, form a natural group of closely
related forms. In this "_fasciatus_ group" nine of the species occur in
the Orient, Japan and neighboring islands and the adjacent mainland. The
remaining three, including _E. fasciatus_, occur in the eastern United
States. Specific differences are to be found in details of pattern,
scalation, and size, and, in some instances, they were long
unrecognized. _E. fasciatus_ coincides closely in its distribution with
the Deciduous Forest Biome of southeastern North America. An early
Tertiary deciduous forest in Alaska and probably in the Bering Strait
area, evidently growing in a humid, mild-temperate climate, included
genera of plants that are now most characteristic of southeastern North
America along with other kinds now characteristic of forest remnants in
southeastern Asia, and still others characteristic of the western United
States. The _fasciatus_ group seemingly dispersed from a northern center
that may have coincided with the early Tertiary deciduous forest of
Alaska.

_Eumeces laticeps_ almost coincides in distribution with _E. fasciatus_,
but does not occur quite so far north, and unlike _fasciatus_ it occurs
throughout Florida. Young are similar in appearance but _laticeps_ is a
larger, more powerful species, notably arboreal in its habits. _E.
inexpectatus_ much more closely resembles _fasciatus_, and ecological
divergence is slight. It is characteristic of hot and dry rocky areas in
open woods, and is more southern in distribution, although there is
extensive overlap with _fasciatus_ and _inexpectatus_ shares nearly all
of its range with _laticeps_.

_Eumeces fasciatus_ is most abundant in well-drained, open, rocky
situations within its forest habitat. It is scarce or absent in
bottomland forest that is subject to flooding and requires a forest with
openings in the leaf canopy so that sunshine patches for basking are
available. In northeastern Kansas, at least, woodlands that are browsed
by livestock, and have scanty undergrowth, provide better habitat than
those that are protected. _E. fasciatus_ is likely to be most abundant
in cutover woodland, and may reach greatest numbers in artificial
situations, such as old rock piles, or the vicinity of deserted
sawmills. In the north, the species is increasingly confined to open
situations, while in the south it may inhabit heavily wooded areas. An
abundant supply of moisture is a necessity and the species is limited to
a climate of high humidity. Dew normally supplies the source of drinking
water, without which the skinks rapidly become emaciated and die.
Optimum body temperature was determined to be near 34°C., from a series
of temperature readings taken both under natural conditions and in
confinement under conditions permitting behavioral thermoregulation. By
thermoregulatory behavior, active skinks in the wild tend to maintain
their body temperatures near this level over a wide range of
environmental temperatures. They can tolerate body temperatures only a
few degrees higher, but, within a range of several degrees below 34°C.,
efficiency is little impaired and incentive to make readjustment is
slight. At progressively lower temperatures skinks become slower and
less efficient. They are, however, capable of copulation at temperatures
down to 21°C, and of feeding at 16°C. At 10°C. they are slow and clumsy,
barely capable of normal locomotion. At temperatures near freezing they
are torpid; they can survive temperatures a little below freezing, but
cannot survive being frozen solid. More than half the year is spent in
hibernation in northeastern Kansas. Weight loss is slight during
hibernation.

Normally the skinks emerge from hibernation in early April in
northeastern Kansas, several weeks earlier in the southern states and
correspondingly later in the northern part of the range. Maximum
activity occurs in the period of weeks following emergence; interrupted
from time to time by cold weather which necessitates return to
torpidity. After approximately three weeks of activity the adults attain
breeding condition. Breeding males acquire a salmon red suffusion of the
head region. They become pugnacious and fight on sight. Fighting does
not involve territorial defense. In confinement males may mutilate or
kill each other. In their search for females, and fighting, the breeding
males are so much more active and conspicuous than they are at other
times of year that published descriptions usually refer to males as
red-headed, with no cognizance of the fact that this condition exists
for only a few weeks in the annual cycle. Old adult males lose the
striped pattern and blue color of the tail of the young, and are golden
brown, usually a little darker on the sides. Males find females by a
combination of sight and scent. Sexual relations are promiscuous, and
there is but little courtship behavior. The male pursues the female and
grasps in his jaws loose skin at or behind her shoulder region, and
maintains this hold during copulation which lasts about five minutes.
Within a few days after insemination, usually in early May, females
become actively hostile to males. In late May or early June the gravid
females become unusually secretive and excavate nest burrows in damp
soil under flat rocks, or in rotten wood of decaying logs and stumps.
The single annual clutch of eggs is laid in June. The average clutch is
somewhat more than nine eggs, with larger and older females slightly
exceeding younger and smaller females in average productivity. The
female remains in the nest burrow with her clutch most of the time, from
laying until after hatching. She alters the nest burrow, dampens it in
time of drought, keeps the cavity from being filled with loose soil,
prevents the eggs from adhering to the sides or floor of the cavity, and
she may repulse certain small predators capable of destroying the eggs
if they were left undefended. When they are laid, the eggs are
approximately 11 × 7-1/2 mm. and weigh .4 grams or a little less. By
hatching time they have enlarged to 15 × 11 mm. and each weighs about a
gram. Recorded incubation periods vary from 27 days to 47 days;
development of the embryo is slowed at low temperatures, and eggs
experimentally kept in a refrigerator at 11° to 12°C. for periods of
days hatched later than others of the same clutch that developed under
normal conditions, indicating that development was almost halted in the
eggs kept at such low temperatures. Eggs are, however, tolerant of a
wide range of temperature, and can develop in nearly dry soil, or can
survive partial submersion in water for at least two days. Under weather
conditions prevailing in 1951, incubation periods of about six weeks
were recorded. Incubation may be shortened by retention of ova in the
oviducts in early stages of embryonic development. Hatching may occur
from the first week of July to mid-August, but in any one year most
clutches hatch within two weeks of each other. Hatching of eggs in a
clutch extends over a day or two. The hatchling gradually becoming
active inside the egg, slits the leathery shell with its egg tooth, and
spends several hours in the early stages of emergence. After resting
with head and shoulders protruding, becoming adjusted to the outside
environment and gaining strength, it lunges from the egg. For a day or
two after hatching, the young remains in the nest, being slow and
feeble, and handicapped in its movements by the protruding belly
distended by the yolk mass. The female usually remains in the nest
cavity for a day or two after the eggs hatch, showing affinity for the
young by curling around them protectively. Family ties are broken as
soon as the young leave the nest, and they do not return. Hatchlings
average a little less than an inch in snout-vent length, and have a
sharply defined five-lined pattern on a black ground color, and vivid
blue tail. Hatchlings make rapid growth in late summer, and by the time
of their retirement into hibernation, the more successful may have
doubled in length, and may have increased their original weight, of
approximately .3 or .4 grams, more than eight-fold. After emergence from
their first hibernation the young continue their rapid growth. When they
are a year old, some of them are as large as small adults. However, they
can usually be distinguished from adults by the more sharply defined
pattern. These grown young retain the hatchling pattern but the contrast
between stripes and ground color, and between body and tail is not quite
so sharp. Especially in those with regenerated tails, the vivid blue of
the hatchling's tail has become much dulled. By the time they retire to
their second hibernation, the young have mostly grown to small adult
size. A small percentage are retarded in their growth and fail to
mature. Upon emergence from their second hibernation, the grown young
mature sexually and participate in the annual breeding season, in early
May, and they may comprise the majority of breeding adults. The ratio of
new adults to old adults however varies from year to year depending on
the varying fortunes of successive annual broods. The new adults overlap
older ones in size, but are usually distinguishable on the basis of
their coloration, as they retain the striped body pattern (dulled,
especially on the head) and with distinctly blue color on the tail. In
skinks that are three years old or more, the dorsal stripes have become
obscured and partly blended with the ground color, which becomes
progressively paler with advancing age. Metamorphosis is most complete
in old males, which retain no trace of the stripes or of the blue color
on the tail. Old females usually retain the dark lateral area, and the
tail is usually bluish gray, with a blue scale remaining here and there
if the tail has not been regenerated.

Most individuals lose their original tails, however. By the time the
young are approximately two months old, about half have had their tails
broken, and by the time they are a year old and have grown to small
adult size, three-fourths have regenerated tails. Some individuals may
have had their tails broken and regenerated many times. Tails regenerate
rapidly and most of the growth is made within the first few weeks. The
regenerated tail is not so long as the original lost portion.

Individuals tend to stay within small areas which are their regular home
ranges. These ranges are only a fraction of an acre in extent, but vary
considerably in size and shape according to the individual and the
situation. Home ranges of approximately 90-foot diameter for adult males
and young, and a little more than 30-foot diameter for adult females are
indicated. A home range generally centers about some environmental
feature providing shelter and food, such as a log, hollow tree, or rock
outcrop. Activity tends to be concentrated in the central part of the
home range. An individual may continue to occupy the same home range
throughout its lifetime, or it may gradually alter its range, shifting
by slow stages into a new area. Some individuals seem to "get lost" or
voluntarily shift, and settle in a new area which may be hundreds of
feet removed from the original range. Shifts are most likely to occur
after emergence from hibernation, when the lizard finds its habitat
somewhat altered. Individuals released in areas strange to them settled
down and established new home ranges, either immediately or after brief
wandering.

The five-lined skink is a predator, occasionally taking small
vertebrates (lizards and possibly newborn mice) but depending for most
of its food on invertebrates. Of these it takes a wide variety. Spiders
are the mainstay of the diet, and various salticids and lycosids are the
kinds most frequently preyed upon. Phalangids are also eaten. Of
insects, orthopterans (including roaches, ceuthophilid and gryllid
crickets, grouse locusts, and small grasshoppers) are most important in
the food. Larvae of moths and both larvae and adults of beetles are also
taken in quantity. Small snails make up an important part of the diet,
and the skinks often eat their own sloughed skins. Less frequently
taken food items include certain large ants, centipedes, moths, and
miscellaneous insects. Rarely the adult skinks may even eat eggs or
young of their own species. Prey is found by sight and scent, and
consists of almost any small animals within a certain size range (small
enough to be swallowed entire, but large enough to make up a substantial
part of a meal) of types which are not too heavily armored, lack noxious
defensive secretions, and live on or in the ground or decaying wood.
They are ordinarily crushed in the jaws or battered against the ground,
and then swallowed entire.

Natural enemies of the five-lined skink certainly include the
broad-winged hawk and probably other kinds of hawks and also include
various predatory mammals such as the opossum, armadillo, skunks, moles
and shrews; snakes (the copperhead, milk snake, king snake, corn snake,
and probably others), the Sonoran skink and even the closely related but
larger _Eumeces laticeps_. On the Reservation, the short-tailed shrew
was certainly the commonest, and probably by far the most important
natural enemy. A high proportion of the skinks examined had scars
resembling those inflicted by shrews experimentally confined with skinks
in captivity. In time of danger escape reactions vary according to the
type of enemy and the attending circumstances. Frequently an alarmed
skink may escape into a hole or crevice, running directly to it from a
distance of several yards. Under other circumstances a skink may burrow
into ground litter of dry leaves and other debris, or may even dive and
hide underwater. One of the commonest escape reactions is climbing tree
trunks. It occurs even in gravid females that are slow and clumsy, being
weighed down with eggs. Generally the skink stays on the main trunk of
the tree, attempting to conceal itself by utilizing the screening
vegetation that is available. In the young, especially, the bright blue
tail seems to be used as a decoy, for it is carried, arched high and
waved conspicuously as the lizard moves about. Rapid lashing movements
of the conspicuous tail as the animal darts erratically for shelter may
serve to confuse a pursuer, at least as to the direction that the skink
has taken.

This skink is parasitized by various helminths, both cestodes and
nematodes, which inhabit the digestive tract and body cavity. Some of
these infest many kinds of amphibian and reptilian hosts, but others may
be confined to the five-lined skink. Their life cycles, and effect upon
the host are not well known. Ectoparasites consist principally of
chiggers. Three kinds have been recorded on the skinks; _Trombicula
alfreddugesi_, _T. splendens_, and _T. gurneyi_. The first two are
common pest chiggers which attack humans as well as a wide variety of
other mammalian, avian and reptilian hosts. _T. gurneyi_ is a less
common species found mainly on _Eumeces fasciatus_ and confined to its
woodland habitat.



LITERATURE CITED


ALLARD, H. A.

  1909.  Notes on some salamanders and lizards of North Georgia. Science,
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ANDERSON, P.

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ANONYMOUS.

  1945.  Principal game birds and mammals of Texas. Texas Game Fish
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AXELROD, D. I.

  1950.  Studies in late Tertiary paleobotany. Carnegie Inst. Wash., Publ.
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BARBOUR, R. W.

  1950.  The reptiles of Big Black Mountains, Harlan County, Kentucky.
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BARBOUR, T., and CARR, A. F.

  1940.  _Eumeces_ in the Miami area. Copeia, 1940:129.


BISHOP, C.

  1926.  Records of some amphibians and reptiles from Kentucky. Copeia,
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BISHOPP, F. C., and TREMBLEY, H. L.

  1945.  Distribution and hosts of certain North American ticks. Journ.
         Parasit., 31:1-54, 18 figs.


BLANCHARD, F. W.

  1922.  The amphibians and reptiles of western Tennessee. Occ. Pap. Mus.
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BLANCHARD, F. N., and FINSTER, E. B.

  1933.  A method of marking snakes for future recognition, with a
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BOGERT, C. M.

  1949.  Thermoregulation in reptiles, a factor in evolution. Evolution,
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  1947.  Moisture loss in relation to habitat selection in some Floridian
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BRADY, M.

  1927.  Notes on the amphibians and reptiles of the Dismal Swamp.
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BRAUN, E. LUCY.

  1950.  Deciduous forests of eastern North America. The Blakiston Co.,
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BRECKENRIDGE, W. J.

  1943.  The life history of the black-banded skink _Eumeces
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BRIMLEY, C. S.

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CAGLE, F. R.

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CARPENTER, C. R.

  1952.  Comparative ecology of the common garter snake (_Thamnophis
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COOK, F. A.

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EVANS, H. E., and ROECKER, R. M.

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FITCH, H. S.

  1940.  A field study of growth and behavior in the fence lizard. Univ.
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  1949a. Road counts of snakes in western Louisiana. Herpetologica,
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  1949b. Studies of snake populations in central California. Amer. Midl.
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FORCE, E. R.

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FREIBURG, R. E.

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GLOYD, H. K.

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GOIN, O. B., and GOIN, C. J.

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GOIN, C. J., and RICHMOND, N. D.

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GOODMAN, J. D.

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HAMILTON, W. J., JR.

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HARTWEG, N.

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HARWOOD, P. D.

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HOFFMAN, R. L.

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HOLLICK, A.

  1936.  The Tertiary floras of Alaska. U. S. D. I. Professional Papers,
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HOYLE, W. L.

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  1940.  Reptiles and amphibians from Georgetown, South Carolina.
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KARDOS, E. H.

  1952.  Biological and systematic studies on the subgenus _Neotrombicula_
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KLOTS, A. B.

  1930.  Notes on Amphibia and Lacertilia collected at Weymouth, N. J.
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LEONARD, A. B., and GOBLE, C. R.

  1952.  Mollusca on the University of Kansas Natural History Reservation.
         Univ. Kansas Sci. Bull., 34:1013-1055, 2 pls.


LINSDALE, J. M.

  1927.  Amphibians and reptiles of Doniphan County, Kansas. Copeia,
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LOGIER, E. B.

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LOWE, C. H., Jr., and NORRIS, K. S.

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LYNN, W. G.

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MANSUETI, R.

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MCCAULEY, R. H., JR.

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MCILHENNY, E. A.

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MILLS, C.

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NEILL, W. T.

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OLIVER, J.

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PARKER, M. V.

  1942.  Notes on the herpetology of Clay and Greene counties, Arkansas.
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         7 pls., 2 figs.


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TIHEN, J. A.

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  1937.  Ecological observations on amphibians and reptiles collected in
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  1951.  Notes on a collection of amphibians and reptiles from Princess
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_Transmitted March 25, 1954._



    []
  25-3559



  UNIVERSITY OF KANSAS PUBLICATIONS,
  MUSEUM OF NATURAL HISTORY


Institutional libraries interested in publications exchange may obtain
this series by addressing the Exchange Librarian, University of Kansas
Library, Lawrence, Kansas. Copies for individuals, persons working in a
particular field of study, may be obtained by addressing instead the
Museum of Natural History, University of Kansas, Lawrence, Kansas. There
is no provision for sale of this series by the University Library which
meets institutional requests, or by the Museum of Natural History which
meets the requests of individuals. However, when individuals request
copies from the Museum, 25 cents should be included, for each separate
number that is 100 pages or more in length, for the purpose of defraying
the costs of wrapping and mailing.

    * An asterisk designates those numbers of which the Museum's supply
      (not the Library's supply) is exhausted. Numbers published to date,
      in this series, are as follows:

   Vol. 1.  1. The pocket gophers (Genus Thomomys) of Utah. By Stephen D.
               Durrant. Pp. 1-82, 1 figure in text. August 15, 1946.

            2. The systematic status of Eumeces pluvialis Cope, and
               noteworthy records of other amphibians and reptiles from
               Kansas and Oklahoma. By Hobart M. Smith. Pp. 85-89.
               August 15, 1946.

            3. The tadpoles of Bufo cognatus Say. By Hobart M. Smith.
               Pp. 93-96, 1 figure in text. August 15, 1946.

            4. Hybridization between two species of garter snakes.
               By Hobart M. Smith. Pp. 97-100. August 15, 1946.

            5. Selected records of reptiles and amphibians from Kansas.
               By John Breukelman and Hobart M. Smith. Pp. 101-112.
               August 15, 1946.

            6. Kyphosis and other variations in soft-shelled turtles. By
               Hobart M. Smith. Pp. 117-124, 3 figures in text.
               July 7, 1947.

           *7. Natural history of the prairie vole (Mammalian Genus
               Microtus). By E. W. Jameson, Jr. Pp. 125-151, 4 figures
               in text. October 6, 1947.

            8. The postnatal development of two broods of great horned owls
               (Bubo virginianus). By Donald F. Hoffmeister and Henry W.
               Setzer. Pp. 157-173, 5 figures in text. October 6, 1947.

            9. Additions to the list of the birds of Louisiana. By George
               H. Lowery, Jr. Pp. 177-192. November 7, 1947.

           10. A checklist of the birds of Idaho. By M. Dale Arvey.
               Pp. 193-216. November 29, 1947.

           11. Subspeciation in pocket gophers of Kansas. By Bernardo
               Villa R. and E. Raymond Hall. Pp. 217-236, 2 figures in
               text. November 29, 1947.

           12. A new bat (Genus Myotis) from Mexico. By Walter W. Dalquest
               and E. Raymond Hall. Pp. 237-244, 6 figures in text.
               December 10, 1947.

           13. Tadarida femorosacca (Merriam) in Tamaulipas, Mexico. By
               Walter W. Dalquest and E. Raymond Hall. Pp. 245-248,
               1 figure in text. December 10, 1947.

           14. A new pocket gopher (Thomomys) and a new spiny pocket mouse
               (Liomys) from Michoacán, Mexico. By E. Raymond Hall and
               Bernardo Villa R. Pp. 249-256, 6 figures in text.
               July 26, 1948.

           15. A new hylid frog from eastern Mexico. By Edward H. Taylor.
               Pp. 257-264, 1 figure in text. August 16, 1948.

           16. A new extinct emydid turtle from the Lower Pliocene of
               Oklahoma. By Edwin C. Galbreath. Pp. 265-280, 1 plate.
               August 16, 1948.

           17. Pliocene and Pleistocene records of fossil turtles from
               western Kansas and Oklahoma. By Edwin C. Galbreath.
               Pp. 281-284. August 16, 1948.

           18. A new species of heteromyid rodent from the Middle
               Oligocene of northeastern Colorado with remarks on the
               skull. By Edwin C. Galbreath. Pp. 285-300, 2 plates.
               August 16, 1948.

           19. Speciation in the Brazilian spiny rats (Genus Proechimys,
               Family Echimyidae). By João Moojen. Pp. 301-406, 140 figures
               in text. December 10, 1948.

           20. Three new beavers from Utah. By Stephen D. Durrant and
               Harold S. Crane. Pp. 407-417, 7 figures in text.
               December 24, 1948.

           21. Two new meadow mice from Michoacán, Mexico. By E. Raymond
               Hall. Pp. 423-427, 6 figures in text. December 24, 1948.

           22. An annotated check list of the mammals of Michoacán, Mexico.
               By E. Raymond Hall and Bernardo Villa R. Pp. 431-472,
               2 plates, 1 figure in text. December 27, 1949.

           23. Subspeciation in the kangaroo rat, Dipodomys ordii. By
               Henry W. Setzer. Pp. 473-576, 27 figures in text, 7 tables.
               December 27, 1949.


           24. Geographic range of the hooded skunk, Mephitis macroura,
               with description of a new subspecies from Mexico. By
               E. Raymond Hall and Walter W. Dalquest. Pp. 575-580,
               1 figure in text. January 20, 1950.

           25. Pipistrellus cinnamomeus Miller 1902 referred to the Genus
               Myotis. By E. Raymond Hall and Walter W. Dalquest.
               Pp. 581-590, 5 figures in text. January 20, 1950.

           26. A synopsis of the American bats of the Genus Pipistrellus.
               By E. Raymond Hall and Walter W. Dalquest. Pp. 591-602,
               1 figure in text. January 20, 1950.

           Index. Pp. 605-638.

  *Vol. 2. (Complete) Mammals of Washington. By Walter W. Dalquest.
           Pp. 1-444, 140 figures in text. April 9, 1948.

   Vol. 3. *1. The avifauna of Micronesia, its origin, evolution, and
               distribution. By Rollin H. Baker. Pp. 1-359, 16 figures
               in text. June 12, 1951.

           *2. A quantitative study of the nocturnal migration of birds.
               By George H. Lowery, Jr. Pp. 361-472, 47 figures in text.
               June 29, 1951.

            3. Phylogeny of the waxwings and allied birds. By M. Dale
               Arvey. Pp. 473-530, 49 figures in text, 13 tables.
               October 10, 1951.

            4. Birds from the state of Veracruz, Mexico. By George H.
               Lowery, Jr. and Walter W. Dalquest. Pp. 531-649,
               7 figures in text, 2 tables. October 10, 1951.

           Index. Pp. 651-681.

  *Vol. 4. (Complete) American weasels. By E. Raymond Hall. Pp. 1-466,
           41 plates, 31 figures in text. December 27, 1951.

   Vol. 5.  1. Preliminary survey of a Paleocene faunule from the Angels
               Peak area, New Mexico. By Robert W. Wilson. Pp. 1-11,
               1 figure in text. February 24, 1951.

            2. Two new moles (Genus Scalopus) from Mexico and Texas.
               By Rollin H. Baker. Pp. 17-24. February 28, 1951.

            3. Two new pocket gophers from Wyoming and Colorado. By
               E. Raymond Hall and H. Gordon Montague. Pp. 25-32.
               February 28, 1951.

            4. Mammals obtained by Dr. Curt von Wedel from the barrier
               beach of Tamaulipas, Mexico. By E. Raymond Hall. Pp. 33-47,
               1 figure in text. October 1, 1951.

            5. Comments on the taxonomy and geographic distribution of some
               North American rabbits. By E. Raymond Hall and Keith R.
               Kelson. Pp. 49-58. October 1, 1951.

            6. Two new subspecies of Thomomys bottae from New Mexico and
               Colorado. By Keith R. Kelson. Pp. 59-71, 1 figure in text.
               October 1, 1951.

            7. A new subspecies of Microtus montanus from Montana and
               comments on Microtus canicaudus Miller. By E. Raymond Hall
               and Keith R. Kelson. Pp. 73-79. October 1, 1951.

            8. A new pocket gopher (Genus Thomomys) from eastern Colorado.
               By E. Raymond Hall. Pp. 81-85. October 1, 1951.

            9. Mammals taken along the Alaskan Highway. By Rollin H. Baker.
               Pp. 87-117, 1 figure in text. November 28, 1951.

          *10. A synopsis of the North American Lagomorpha. By E. Raymond
               Hall. Pp. 119-202, 68 figures in text. December 15, 1951.

           11. A new pocket mouse (Genus Perognathus) from Kansas. By
               E. Lendell Cockrum. Pp. 203-206. December 15, 1951.

           12. Mammals from Tamaulipas, Mexico. By Rollin H. Baker.
               Pp. 207-218. December 15, 1951.

           13. A new pocket gopher (Genus Thomomys) from Wyoming and
               Colorado. By E. Raymond Hall. Pp. 219-222.
               December 15, 1951.

           14. A new name for the Mexican red bat. By E. Raymond Hall.
               Pp. 223-226. December 15, 1951.

           15. Taxonomic notes on Mexican bats of the Genus Rhogeëssa.
               By E. Raymond Hall. Pp. 227-232. April 10, 1952.

           16. Comments on the taxonomy and geographic distribution of
               some North American woodrats (Genus Neotoma). By Keith R.
               Kelson. Pp. 233-242. April 10, 1952.

           17. The subspecies of the Mexican red-bellied squirrel, Sciurus
               aureogaster. By Keith R. Kelson. Pp. 243-250, 1 figure in
               text. April 10, 1952.

           18. Geographic range of Peromyscus melanophrys, with description
               of new subspecies. By Rollin H. Baker. Pp. 251-258, 1 figure
               in text. May 10, 1952.

           19. A new chipmunk (Genus Eutamias) from the Black Hills.
               By John A. White. Pp. 259-262. April 10, 1952.

           20. A new piñon mouse (Peromyscus truei) from Durango, Mexico.
               By Robert B. Finley, Jr. Pp. 263-267. May 23, 1952.

           21. An annotated checklist of Nebraskan bats. By Olin L. Webb
               and J. Knox Jones, Jr. Pp. 269-279. May 31, 1952.

           22. Geographic variation in red-backed mice (Genus Clethrionomys)
               of the southern Rocky Mountain region. By E. Lendell Cockrum
               and Kenneth L. Fitch. Pp. 281-292, 1 figure in text.
               November 15, 1952.

           23. Comments on the taxonomy and geographic distribution of
               North American microtines. By E. Raymond Hall and E. Lendell
               Cockrum. Pp. 293-312. November 17, 1952.

           24. The subspecific status of two Central American sloths. By
               E. Raymond Hall and Keith R. Kelson. Pp. 313-337.
               November 21, 1952.

           25. Comments on the taxonomy and geographic distribution of some
               North American marsupials, insectivores, and carnivores.
               By E. Raymond Hall and Keith R. Kelson. Pp. 319-341.
               December 5, 1952.

           26. Comments on the taxonomy and geographic distribution of some
               North American rodents. By E. Raymond Hall and Keith R.
               Kelson. Pp. 343-371. December 15, 1952.

           27. A synopsis of the North American microtine rodents. By
               E. Raymond Hall and E. Lendell Cockrum. Pp. 373-498,
               149 figures in text. January 15, 1953.

           28. The pocket gophers (Genus Thomomys) of Coahuila, Mexico.
               By Rollin H. Baker. Pp. 499-514, 1 figure in text.
               June 1, 1953.

           29. Geographic distribution of the pocket mouse, Perognathus
               fasciatus. By J. Knox Jones, Jr. Pp. 515-526, 7 figures in
               text. August 1, 1953.

           30. A new subspecies of wood rat (Neotoma mexicana) from
               Colorado. By Robert B. Finley, Jr. Pp. 527-534, 2 figures
               in text. August 15, 1953.

           31. Four new pocket gophers of the genus Cratogeomys from
               Jalisco, Mexico. By Robert J. Russell. Pp. 535-542.
               October 15, 1953.

           32. Genera and subgenera of chipmunks. By John A. White.
               Pp. 543-561, 12 figures in text. December 1, 1953.

           33. Taxonomy of the chipmunks, Eutamias quadrivittatus and
               Eutamias umbrinus. By John A. White. Pp. 563-582, 6 figures
               in text. December 1, 1953.

           34. Geographic distribution and taxonomy of the chipmunks of
               Wyoming. By John A. White. Pp. 584-610, 3 figures in text.
               December 1, 1953.

           35. The baculum of the chipmunks of western North America.
               By John A. White. Pp. 611-631, 19 figures in text.
               December 1, 1953.

           36. Pleistocene Soricidae from San Josecito Cave, Nuevo Leon,
               Mexico. By James S. Findley. Pp. 633-639. December 1, 1953.

           37. Seventeen species of bats recorded from Barro Colorado
               Island, Panama Canal Zone. By E. Raymond Hall and William
               B. Jackson. Pp. 641-646. December 1, 1953.

           Index. Pp. 647-676.

  *Vol. 6. (Complete) Mammals of Utah, _taxonomy and distribution_.
           By Stephen D. Durrant. Pp. 1-549, 91 figures in text, 30 tables.
           August 10, 1952.

   Vol. 7. *1. Mammals of Kansas. By E. Lendell Cockrum. Pp. 1-303,
               73 figures in text, 37 tables. August 25, 1952.

            2. Ecology of the opossum on a natural area in northeastern
               Kansas. By Henry S. Fitch and Lewis L. Sandidge.
               Pp. 305-338, 5 figures in text. August 24, 1953.

            3. The silky pocket mice (Perognathus flavus) of Mexico.
               By Rollin H. Baker. Pp. 339-347, 1 figure in text.
               February 15, 1954.

            4. North American jumping mice (Genus Zapus). By Philip H.
               Krutzsch. Pp. 349-472, 47 figures in text, 4 tables.
               April 21, 1954.

            5. Mammals from Southeastern Alaska. By Rollin H. Baker and
               James S. Findley. Pp. 473-477. April 21, 1954.

            6. Distribution of some Nebraskan Mammals. By J. Knox Jones,
               Jr. Pp. 479-487. April 21, 1954.

            7. Subspeciation in the montane meadow mouse, Microtus
               montanus, in Wyoming and Colorado. By Sydney Anderson.
               Pp. 489-506, 2 figures in text. July 23, 1954.

            8. A new subspecies of bat (Myotis velifer) from southeastern
               California and Arizona. By Terry A. Vaughn. Pp. 507-512.
               July 23, 1954.

            More numbers will appear in volume 7.

   Vol. 8. 1. Life history and ecology of the five-lined skink, Eumeces
              fasciatus. By Henry S. Fitch. Pp. 1-156, 2 pls., 26 figs.
              in text, 17 tables. September 1, 1954.

            More numbers will appear in volume 8.



Transcriber's Notes

Although both juvenal and juvenile both appear in the text. The term
juvenal appears to represent any animal in first year skin, feathers or
fur. Therefore, both words were retained as in the original printed
version. No significant typographical error were found in the text. The
list of Publications was compiled at the end.





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