THE NATURAL HISTORY OF THE
RED-TAILED SKINK, EUI\ECES
RO7BERT HUGrHE' MOL'UNT
A~ DIjERTTION PF.EIINTFD TO THE I..r...DLlATE Ef*IJNCIL OF
THL UINI\'ET.IT~ OF FLOPEDi .
IN PARTLtl. FULFILLMENT OF THL REQUIREMENITS FOR THt
DLGPE OF DO~CTDk OF )HllilabPHI
UNIl'ER51T1' O3F FLORIDA
I express my deepest appreciation to Dr. Archie Carr for his di-
rection of thrs research, for the inspiration and encouragement. which
he so aptly provided during the courseof the study, and for his inuralu-
able aid in composing this dsisertatLLon, to Drs. E. C. bowree, A. H.
Laessle, J. N. La~ne, Carl Monk, and V. 1. Riemery for their suggecstions
concerning the study and for reading and correcting the manuscript, to
Dr. Alan D. Conger for his technical and material assistance in the
experimentation on temperature relationships, to Mr. Wilfred Net11 of
Silver Springs, Florida, who contributed nsny specimens and was helpful
in many other respects, tj Mr. Sam Teljord, J~r. who not o~nly supplied
m~uch live material, but also took an extremely active interest in the
research and provided valuable advie and constructive criticism; to
Miss Esther Coogle, who assisted In the preparation of the map and
orber litures, to Hessrs. Robert Mc~arlane and Timothy Brown for their
time and effort in helping to sojlve my photographic problems, and to
Messrs, C. W. Myers, Howard M. Hutchlinson, ULlliam O, Wirtz, and
Andrew Beckenbach, who, amoni many others, contributed living: specimens
for use in this study.
I am grateful to the Socrety of Sigma Xi for its financial support
of this project and to the N~ational Science Foundation for its award of
a Summer Fellowship enabling mer to devote the necessary time to the
study during a crucial period.
Fina=LLy, I wish to ehank the Biology Department, the Florida State
Museum, the College of Arts and Sciences, and the Graduate School of the
University of Florida for the splendid cooperation and assistiance giviin
me during the period of research.
TABLE OF CONTENT;rS
ACKN~OYLEDGMENTS . .. .. .... .. .. . ..~ ~~ ..
LIST OF TABLES .. ... ... .. .. .. .. .. .. vi
LIST OF FIGURES . ... .. .. .... . . . . vil
INFTRODUCTION .. ... .. .. .. ... .. .. .. . 1
GENEPALME1710DS ......................... 2
GEOGRAPHIC RANGE ... . ... .. ... .. .. 6
ECOlLlrGCAL DISTRIBUTIONS AND COILLECTI[IG METODS .. .. ... 1
TfEMPERATURE RELATIIONSHIPS .. .. .. . .. . .. . . 15
LOCOMO~TION . .... ... .. .., . ... .. . .. 23
FOOD RABITS ... . .. ...... .. .. . . . 5
FEEDINGC BEHAVIOR .. .. . ... ,,,. .. . .. 31
AprNrUAL CYCLE OF REP~RODUCTION AND ACTIVITY . ... . .. ... 33
Courtship and Mating .. ... .. .. .. .. ... 33
Homosexual behavior .. .. .. .. . ... .. .. 4
Fighting .. .. .. ... . .. .. . . 7
Preovtposition Period ... . .. .. . .. .. .. 52
Nests .. ... .. .. .. . . ... .. .. 58
Ovipostolon and Eggs .. .. .. .. .. .. .. .. .. 60
Brooding ,,. . .. . ... .. ... .. .. 61
Hatching and the Hatchlings .. .. ... .. .. .. 64
Growth and De veIopment .. . .. .. .. .. .. 6
Pascnesting Activity . ... .. .. ... .. 75
PREDATIO3N A:TD PARASITISM . .. . .. .. . .. . 6
POPULATIIONI DYNAMICS ... .. ... ... .. .. . .. 78
Dispersron and Structrie .. .. .. .. .. .. ... 78
Density and Movements .. . .. .. .. . ... 18
SUMMARY ANDCONCLUSIONS..............,.. .. 81
L1TERATURE CITED ..............,.. ..... 84
BIOGRAPHICALSKETCH ................... .... 86
LIST OF TABLES
1 Frequency of occurrence of food Itemsi in dLgeatlve
tracts of Eumeces eat116161 -... -. -. - ----
2 Frequency of occurrence of food Ltems In digestive
tracts of Eumcies egregtus by season (Study
Azea, Levy County, FLorida) .. .. .. .. .. .. 29
3Size of female parent, number of eggs per clutch,
and dates oE ovtlpositron and hatching for la
clurches of eggs of Eumeces egregius (19h0) .. .. 59
4 Measurements of freshly lard Pggs of' Eumecesa
freAlujh In ma~limeters .. .. .. ... .. .. 61
5Size in milllameters of Eumeces egreglrus at hatching
by geographic locality . .. .... .. . .. 67
t Crowth data In mlllimeters onl six groups of sibling
Eumaces egregius.............,...,.. 68
1 Locality records for Eumeces agregrus as of June, 1961 , 4
2 Habitats of Euneces rkregtus .. .. .. ... .. 9
3 Field and laboratory observations on temperature rela-
tlonships of Eumeces egrefius .. .. . .. ... 21
S Breeding catoration in male Eurmeces egjregius .. . ... 34
5 Seasonal variation in size of ganads of male Eum3eces
egreyius (Studv Area, Levy County, Flozida) . ... 35 '11
6 Mating of Eumreces ecgregius ,. .. .. .. .. .. .. 4
7 Mating scars on female Eumeces ~egregius .. .. .. .. 40
8 Aggressive behavior in male Eumees egregius .. .. .. 51
9 Seasonal variation in relative frequency of capture of
make and female Eumeces egregius (Study Area, Levy
County, Florida) .. .. .. .. .. . ... 53
10 Seasonal and sexual variation in feeding habits of
Eumeces egrecgius, as indicated by proportions of
individuals having empty guts (Study Area, Levy
County, Florida) . . ... .. .. .. .. .. 54
11 Seasonal change in size OE eggs or follicles in female
Eumeces egregiusi (Study area, Levy County, Florida) 57
12 Average increase in anaut-vent length from time of
hatching for six groups of sibling Eumeces egredius III
reared Ln the laboratory ... . .. . .. .. 70 ill
13 Geographic and sexual variation in size of adult
Eumeces egre6:ius .. . .. .. .. .. .. .. 73
I NTR~ODUCT ION
The red-called skink, Eimeces egreglrs Baird, Is a small, losso-
rial lizard locally distributed In the southeastern United States. The
decision to undertake a stud, of the natural history of this species
was prompted by several consideratrjns. First, there was a scarcity
of information on the lide htatory and ecology of' this lizard, a
scarcity charactertatic of fossorial reptiles in general. Furthermore,
VIlfred Neill had discovered a novel method of collecting this species
which midht, for the first time solve the problem of obtaining ade-
qurate materila for such ai stud;. Firally, E. egregius occurs chiefly
in a peculiar type of terrain vbtch supports some of the most fasci-
nating and l~ttle-known ecolog~ical commuinities of the Southeast.
The present paper deals largely with the ecological and behavioral
aspects of the natural history of the red-tiL~ed skink. Some inter-
esting information related to the problem of geographic variation was
uncovered during the course of the investigation, this willl be presented
at a later date,
Efforts were made to obtain data on the life history and ecology
of as many populations of Eumeces egregifus as time would allow. For
intensive study a population of skinkcs inhabiting an area conatting
roughly of the eastern one-fourth at Levy County, Florida, was
selected. This area, hereinafter designated "the Study Area" (Fig. 1),
is part of an extensive tract of sandhill country stretching from the
Suwannee River on the north through parts of Alachua, Gilchrist, Levy,
and Marion Counties southward to the northwestern corner of Lake
County. Through this portion of their range, red-tailed skinks appeedr
to be especially abundant.
The Study Area ase usually visited at 10-day intervals from
September, 1959, to October, 1960. On these vietts skunks were
located and observed, ecological data were obtained, and a sample of
specimens was collected for further examination and study, (Collecting
methods are discussed in a Later section.)
ecological data were recorded for each capture. in most instances
the temperature of the air was determined, as well as that of the soil
in which the 1Lzarrd was located and that of the sall 3 cm below ground
level. The lizard's temperature was taken whenever practicable (see
page 17). A Schultheis "lquick-reading"' thermometer was used for all
determinations (see Bogerts 1949).
Most captured lizards were killed, examined, and preserved, al-
though;;rme were kept in captivity for varying periods of time. Initial
PIC. 1. Locality records for Eumeces rrgl as of June, 1961.
Genrealized distribution of suitable habitat is indicated by stippling,
examrinatton consisted of determining snout-vent length and tail lenjth,
nectag charaectrs likely to be altered by preservation, and searching
for eitoparaSiteS. Skinki were preerrved in the convenrlonal siunner,
After a month or m-ore the speCtinens~ were remeasured. It was found
that, on the averse, r per cent shrinkag~e had occurred, necessiratesb
dlsEinect on between mcasurement s of freshly killled and preserred
The dlsejrlve tract of each lizard was examined and the food
Liems were Lddnuited. Internal parasites were removed and preserved
for later Ldanufarcation. Measurements of testes and ovarian and out-
ducaL aggs were made vich atviders. To measure a live skink, the
specimen was put into a test tute and allowed to qui~et down. By
plaCing a milllimcter scale under the tu~be, the desired measurement coulld
be made. All data werd recorded ojn McBee Keyserr CardE printed specifi-
ialli, tor usre in this study,. These were later coded.
Captirve speirtains were held in gla2s terrarla filled to a depth
of 3 co i cm useh sand. They were fed mostl. on laboratorv-reared
Germian~ r-aches (ltelrlla germanicJ), tcrmiites (Isopters), and mieal-
worms trinibr o malt r )~ri. Pood ras supplied dally. Roaches were
prevenred from tescpLnd by imeartng a thin film of a baseline-mi~neral
oil mixture ar;ound the Inner ed~ea of the terraris, Water was supplied
to the capiivej in Syracuse watch glasees.
Bumeces earegius ranges throughout most of florida and northward
at least to the Fall Line in Georgia and Alabama (Fig. 1). There is
only one record for an occurrence outside the Coastal Plain. Mecham
(1960) reported the capture of a specimen 3 miles northwest of Wadley
in Randolph County, Alabama. This is approxtirately 38 miles narch of
the Fall Line. It is possible that the species occurs sporadically in
the lower Piedmont of both Gerorgia and Alabama,
westward, the range extends at lenet to Rale County, Alabema.
Here I was able to collect one specimen from an area 8 miles east of
Moundville. I suspect that the Black warrior and Tombigbee Rivers
mark the western boundary of the range. Considerable time was pent
searching for speciniens west of these rivers, particularly in the sand-
hill country of washington County, Alabama, but none were found. The
species has never been reported from South Caroline. The meatern limit
of the range is apparently the Savannah River.
ECOLOGICAL DISTRIBUTION AND COiLLECTING MElTRODS
The most important ecological factor determining the dispersion
of Eumeces egr~elius appear to be the aspects of soil ecructure and
moisture conditions. Seldom is this species encountered where the sail
La not friable and well drained. However, there are differences
between the habitat of the mainland and insular populations which
require separate consideration of these two groups.
On the mainland the skrnks occur chiefly in sandhill and scrub
associations rad In xeric hammocks (Carr, 1940, Kauffeld, 1941; Tel lord,
1959; LeBuff, 1960). Sandhtil associations, variously known as "long-
leaf pine--curkey oak," "'high ptne land," and "rolllng sandy pine land,"
occur on many, if not most, of the very sandy, well-drained soils of
the southeastern coastal plain (Fig, LA), The dominant trees include
longleaf pine (Pinue australls), turkey oak (Quercus laevis), and
occasionall, bluejack oak (q. cineres). Two viregrasses (Sporabolus
gracilis and Artstida stricta) are often the most important herbs,
Frequently, much of the ground surface is almost completely bare. Scrub
associations occur In Florida and along the coast of Alabama on certain
excessively drained sands (Fig. 2B). The dominant trees are usually
sand pine (Pinus clausa) and a number of scrubby evergreen oaks. The
shrubs, rosemary (Ceratlola ericoldes), scrurb-palm (Sabal econla), and
say-palmetto (Serenos repens), are often abundant. Ground cover La
frequently sparse. Keric hammock is generally less common; it is con-
sidered by Laessle (19;2) to be the seral stage succeeding both scrub
IIIII d III1I1111111ill111 assc;~Lttone. Live oakl (q. v irginiane)~ domina tee and
ground111111111111111~1 never1~ (n va)ria;e '" r detaiLs Condetaing the peture of the
phat 45 tcigtions aggyd d1111~?~ to in this* diacy/4.iron,,7a~ e Lasele, 1942
"""""" d"""" "" 9 5" """
Or""""""" z""nan cl""in E# p"ioedi t lid"treicld
"""""""" rad hrug ksad, ry oi 4$"inTomb outy Car
(Jansea,""" 19") ude te n "dyre" tFot "ihng Gori
aroun H~i ,inlrkd usalliytig ded lles ovi;ying thelr pone tMast oorrrr lte; uch
deposite1,,rlllllllll are4) normally toori; shllowny~r tospot ecuor sa~hndhil agesci-
ilttons(y ;.btLerd apy nevehthes hbe sll raigd
M Asum (1960) reported thk~it the Ipwcihain mentioned earlier from
((IIIIIWn~~dolph County, AIibwea, has collected "under a flate rock in a granitic
(l~;outeropping os!"i$#uera adriC exrtent." McConkey (1957) mentions a sp~et-
IIIn collected in a "mawry diimp Locality besslee a hammock anld a tlLa-
upIIIIods." I conrsid~r this-oecucurnce highly unusual far this arpacies.
My experience in colecting thil 10pard from 72 different Locall-
ties lloiiud as to asp~ect that within the range iat the spectcee all natural
irll3C ollf 100 pcreree-or ears; in tasetnt fAvoryble for the growth of tend
ping,;! tuskey: tlk, or zdamary dra supporting sad-stcled skink popular
flieni. This isr contingelt, of course, upon k+uch Ardiar having been
zoogeographically accessible to the red-rall, and upon man's acrive-
cles, or floods, not havang resulted Ln their exterminaation from a
gI en area.
In a paper presented by Wilfred T. !Jelli at the 31th annual
meetln3 of the American Sodiecy of Ichchyologists and Herpetalogists
In 195;, he observed that the red-talled skunks in sandhill habitat
near Siliver Springs, Mlarton County, Florida, usually dwelt In the
mounds of sand thrown up b, "sand beetles"' (Scarabseidae, Geotruplnae),
and that thej were occasionall? found in mounds of the gopher tortolse
(Co2hr121 Polyphemus) and the eastern pocket gopher (Ceomg6 pinetts).
He estimated that during; winter and early spring Ibout 70 per cent of
the red-tailed skinks In the area were living In beetle "push-ups" and
Raking through mounds and push-ups (Fig5. ZAi of burrowing animals
proved to be a htghly effective method of collecting the skinka in
sandhill associations. However, i found pocket gopher mounds more
productive. than beetle push-ups. Of 422 specimens collected Ezom
sanihtll associations, 326 were taken from pocket gopher mounds, and
only 31 from beetle push-ups. Except for Lee absence in extreme
southern Florida and in the Piedmont, Geomvrs plnetis ranges over almost
exactly the same area as does the red-talled skink. This apparently
reflects a srmLlarity between the two forms in many of theit ecological
requiremene, especially : soiL Structure, and probably indicates similar
patterns of drspersal for the two.
Skinks were also collected In sandhill habitats by overturning
and caking beneath logs, boards, tin, and other objects (28 specimens),
Three specimena, the only ones encountered above ground, were found
under fallen leaves. The remaining 3 represent chance encounters by
persons digging in sand.
In scrub associations red-tailed skinks were never found in
G2eZEy mounds or beetle push-ups. Eventy-eight specimens were cal-
lected in scrubs, and all these were taken by raking under detritus
with a potato take. Most were located within 5 cm of the surface and
were found under such things as dead palmetto fronds, decayinB Spanish
mass, and rotting logs. Scrub-collecting was most rewarding in areas
where there was little ground cover. For detasle concerning this
method of collecting, see Telford (L959).
Red-tailed skinks have been collected on the following islands:
Dry Tortugas, Key West, Stock Island, Upper Hatecumbe Key, Big Pine
Key, Indian Key, and Key Largo (Monroe County, Florida); from Cedar
Key Airstrip Island and Seahorse Key in Le\-y County, Florida, and from
Merritt's ileand, Brevard County, Florida. Some of the Monroe County
records are old. The present distribution of the skink in the Florida
Keys may have changed considerably over the years. DuEllman and
Schwartz (1958) suspect that "the species probably ranges throughout
the chain of islands." I found specimens on Key west, Stock leland,
and Key Largo. There is little doubt that the species stall exists on
Big Pine Key. Hany of the smaller keys are subject to complete inun-
dation. during severe burrieanes, however, and it is doubtful that a
population rrould survive such an ordeal.
On the Keys the skinkb frequent beaches and other areas where
there is sufficient soil for burrowing. Carr (1940) noted their
occurrence in piles of rock, debris, and wave-washed wrack and stated
that Ln the Upper Keys they are abundant among rocks a few feet above
the water on railroad embankments. Duellman and Schwartz (1953) found
them twerneath scenes in shaded, sandy arras on Key West and Stock Telauid.
I found none under tidal wrack along the shorelines of the Keys. No-
where in the Keys did the sipecies appear to be abundant, either Ln
Febr~ury or June of 1900j.
Red-catled skunks were collected at Cedar Key Airstrip laland by
turning and digding; beneath the tLdal rack. Most were found at or
above the spring ride mark Irnjdr wrack which was dry or only slightly
moist. Three specrmens were caught on the airstrip itself by dLaging
beneath small prles of Jead grass. Artcmpts to collect the skink from
Cedar Key proper were unsuceessful, although conditions here seemed
ideal for its exiscence. Tlhe scrub surrounding the Cedar Key cemetery
particularly varrantr further Lnvestigation. The presence of the
red-tall on Seahorse Key, Eome 3 Blies ouL from Cedar Key, was fifsE
reported by Wharton (1958). During the present study, 18 specimens
were collected on Seahorse Key, all of which were found associated with
Etial wrack along the windward abore of the Island. On Metriu r's
island specimens were collected by digging under detritue on k~nolls in
dry, scruhbb flatwoods and in scrubs,
There is 10ttle doubt that red-called sk~inks Inhabit maYne more of
the rslands Just off the Florida coast. There 1s every reason to suspect
that they occur in the scrub on Marco Island Ln Collier County (Duell-
man and Schwartz, 1058), but I was unable to demonstrate their presence
on either of two trips to that fascinating locallty. The islands around
the mouth of Charlotte Harbor near Fort Myers likewise warrant investi- 1
Under natural conditions the temperature of an acrlhe lizard does
not necessarily correspond to the amblent air temperature but usually
falls withan a relativel, narrow range which cends to be a generic or
speclifc characteristic (Bogert, 149.9 Pitch, 1956, 1953)1. Apparently,
most Ilrards inhabiting temperate regioos regulate their temperatures
chiefly by their beharlor. Those whtch hare been most intensively
studied are species which spend considerable time above ground, and
thermoregulat ion in these depends to a large extent upon the relative
amount of direct insolation absorbed. Thus, thev backt in the sun when
therr temperatures fall below the optimal range and seek shelter when
they get coo hot. Litcle Ls known of the thermal relations of fosso-
rlal lizards. The following obiserruttons may be of ralue In this
Thermoregulatic~n in E. egregius le not dependent upon the amount
of direct aunlight received but seemingly upon the ability of the
indrviduals to move readily through the sell from one temperature
stratum to another. This, I think, has a strong bearing on the frequent
occurrence of E_. egreglus in mounds of Geomys and sand beetles. While
searching for red-rails In these mounds in sandhall associations, I
often encountered other fossorial and semi-fossorial reptiles. The
crowned snake (Tantilla coronata) and the sand skink (Neoseps reynoldsi)
were regularly found in the mounds. The worm Lizard (Rhrneurs florid~an)
and -sJcarlet kingsanke (Lamapropeltis doliata) were each found on 3 occar-
sions. Collecting in mounds was most profitabit when mound tempera-
tures were between 250 and 3(o and somewhat higher chan those of the
soil beneath. These conditions obtain most frequently during the
cooler months of the year on certain clear or partly cloudy days from
about 10:00 a.m. until late afternoon.
The sail in the mounds is leas densely packed than that about
them, and dries more rapidly and thus heata more quickly in the sun than
the surface soil. I suggest that during cool, sunny weather the mounds,
when available, serve as convenient basking eltes for such reptiles as
those listed and therefore aid in solving their thermoregulatory prob*
lemos. During the hot weather vbich prevails throughout most of the
extreme Southeast from May through September, and during prolonged
periods at cool, cloudy weather, few animals of any kind were discovered
in the mounds. Under these weather conditions it is unlikely that the
mound temperatures would be more favorable than those in the soil below.
I have already mentioned that, despite its occurrence in scrub
habitat, Eegeregius was never collected In scrubs by raking through
Geomys mounds, nor, for that matter, were reptiles of any sort. I can
of fer one possible explanation. Scrub soil (St. Lucle sand) is usually
coarser (Laessle, 1958) and perhaps drains more readily than the soils
supporting sandhill associations. The surface layers of the St. Lucle
soil may, then, warm more rapidly than the sandhill soils. Such being
the case, the reptiles might be less inclined to frequent mounds in
I freucatti captured red-tailed skunks within a few seconds
after thev were first distuirbed. In such cases I often mleasured the
clojcal temperatu~res of the herards. A total of 50i such records were
To supplement the field data on temperature relationships, I con-
ducted laaoratory Experiments designed to provide information on tem-
perature preferences. These bxperiments werE conducted under the
supervision of Dr. Alan D. Con,:er of' the Biology Department, Universlry
of FLo~rida, who sud~ested the design of the apparatus and was Instrra-
mental In procuring the equipment for its construction.
A sheet of brass :1u cm long anid 1.7 mm thick was fashioned into
a trough J.t inm vide and 3.6 cm long. A lu0, em section of the trough
was iompletell enclosed in a bojx of 1,2:-inch plywood, the bottom ana
sides of which were provided with an inside lining of several layers
of fiberglass Insulation and one layer of aluinulnm folk The top of
the boxr was hanged and was lined on the Inside with one layer of
fiberglass insulatron. The troudh was filled with alr-dry sand to a
depth of 2.5 em. The leg at one end of the trough was immersed In cee
water at u Heat from a 200l-watt incandescent Light bulb was applied
to the other end, and the apperstus vas allowed to remain undisturbed
for 2 hours. A stable cemperacure gradient ranging from 11a to 30j0 was
produced along the enclosed portion. Up to within t0 cm of the heated
edld or up to 36.50. the gradient was almost uniform, changing at the
rate of approximately to per u.L cm. Past this paint the change became
Increasingly more rapid.
eight Lizards, all sexually mature males of approximately the
gasC' size (43-45 mm rnout-vcen length), were used in the laboratory
experiments. They were captured on April 21, 1961, at a site in the
Study Area 6 miles south of Bronson, Levy County. between experiments
the lizards were kept in terraria and fed reaches and termites. Each
individual could positively be recognized by peculiar structural
features or marks. Two experiments were conducted on each of the fol-
Lowing days: May 6, 13, and 17, 1961, according ca the following
The 8 lizards were randomly divided into 2 equal groups. The
skins in one group were distributed at random in the trough, along
which the temperature gradient had been produced and allowed to
stabilize. The lizards usually burround into the sand ulthin a few
seconds. The box was then closed and left undisturbed for 90 minutes.
The Lizards were from a~ll indloations sexually inactive and had dis-
played no aggressive tendencies as captives. There wne no reason to
assuime that under the circumstances, they would not tend to distribute
themselves in accordance with their preferred temperatures. At the
and of the 90-minute period the box was reopened and the temperature of
the sand was determined at 5 cm intervals and recorded. To restrict
subsequent movement DE the lizards, pieces of cardboard were inserted
into the sand at 10 em intervals, at right angles to the long axis of
the trough. The lizards were located and removed, and the identity of
each was recorded along with the temperature corresponding to the post-
tion in the trough at which the individual had been found, The expetl-
ment was then repeated using the other group of animals.
Field observations and laboratory results are shown In Fig. 3.
Temperatulres of lizards taken In the field ranged from loo to 300
Those with temperatures below 2 a were noticeably elu~ggih In their
movements and were taken when selil conditrans were such that mainte-
nance of higher temperatures would seemingly have been Impossible. It
soon became evident that If the field observations were to be meaning-
ful, they would have to be Grouped Into tvo classes. Some~ were made on
days when the Lizards couldJ select from a relatively wide range of
temperature levels in the sell, others on days w~hen to seemed that they
could not. Aiccrdingly, in Fig. 3, the observations made on days when
the air temperature was :50 or over are distinguished from those muade
during cooler weather. Usually, when the air temperature was 250 or
above, most eunlit Geomys and beetle mounds contaedne some soil in the
j;0 to 300 range.
Based on the former class of observations, it appears that the
preferred temperature range for E. egressus lies between 2bO and Jgo
The mean for these observations Is 29,50. The results of laboratory
ehperimecnts Indicate a somewhat higher range. The three occasions on
wh~ih indulduJals were found in the 160 to 130 range can probably be
attributed to escape attempts. in each of these case the Ilzard was
found lifng against the cold end of the trough ulth rts snout to the
corner. IF these are excluded from consideration, the mean of the
observations is 31.20, li higher chan the correspondent mean calcu-
laedJ from the field data. it is possible that these differences are
due to faulty technique, or to inade~uacy of the samples involved. The
possibility of seasonal differences In temperature preference should
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1 I I I --' cD cu
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v a c c
not be discounted. The laboratory experiments were conducted inr May,
whereas most of the field observations were made from October to
There were no detectable differences among the individuals used
in the laboratoryr tests with regard to temperature preference. DLEfer-
ences were undoubtedly present but were probably slight, since the
test animals were all of the same sex, of approximately the same size,
and from the ease population.
There seems to be little doubt that, despite the inconsistencies,
the preferred temperature for E. egregious is lower than that for the
Great Plains skink (Eumeces absoletus) or for the five-1Lned skink
(Eumeces fasciatus) determined by Fitch (1956) to be 34,00 and 33.00,
The laboratory method employed inr this study, or a modification
thereof, appears to be entirely satisfactory as an aid in studying the
temperature relationships of almost anry fossorial reptile. Such forms
as Rhineura floridana constitute exceptions, since they dealccate
rapidly in dry soil. The method would seem to be particularly well
suited to studies of a comparative nature. I suspect, for instance,
that gravid female E. egregius tend to occupy unrmer soil strata than
do other individuals. Thia method could be used to test this hypothe-
asi. Geographic variation tu temperature preference, as well as dFi-
farences due to stage of development could perhaps be detected.
Several kinds of locomotion are used b; red-tailed skunks. A
forabing individual progresses In Jerky, erratic fashion, using both
front and hind limbs, whiich are reduced in size and relativel; feeble.
Occasionally the skink will press its hind lege back against the tall
and 4110= for a short distance, the bod; and tall exhibrting alight
lateral undulatory movements. While moving in this majnner, the lizard
frequently uses its front legs to effect chances in direction. They
may ilso be used to pull the body along.
Red-tailed skrnks are capable of rapid submergence in Loose soil
and are remarkable adept at 'sana-svimming," alchaugh not nearly~ so
prafildent at chis sctivitt as Neoseps reynoldst, Plunging tes anout
rntor the srlt, the skink presses the front i~mbs against the body,
pushes skth the hind Ilimbs, and, rlth bod, and call undulating laterally,
disappears beneath the surface. It then uses undulatory "awnmming;"
mosementes to progress through the soil. There Is no Indication that
the limbs play any role In thra type of locomaclon. The soil may be
entered at almost any. angle- a skink chat has been startled normally
enters at a greater angle than Is urual in unlhurried submergence.
On a relativel; hard-packed surface, a frightened red-called
skink may wriggle away 11ke a small snake. Rapid sidevise undulalt ons
of the bodyi and taiL augmented somewhat by the limbs drive the lizard
forward. This type of locomotion is sometimes seen in an individual
pursuing fast-mou~ng prey.
From the standpoint of locomotion, then, Eumaces agegu appears
to occupy a position somewhere between the generalized skinks, e.g.,
Eiumaces fasciatus, and the highly specialized burroverr like luoseE*
The sorla refzerince ca food habits of Eume~cess arerptus is that of
Hamlton and Pollack (1956). They examined the dijestive tracts of 3t
specroans, -3 of whtch iontained foca (:0 from Ft. Benning, Georgia,
and I each from Sr. Petersburg, Key West, and Bonrta Springs, Florida).
The; recorded the following food items (figure following item Indicates
number of specimens in unicn lceu vas found) ant, 5, spider, 5,
Orthopters, 5, Cjlioptera, -, 1se-ptera, 2, Hemlprera, ', mite, 1.
Lepidoptera larns, 1, pseudoscorpton, 1, Neuroptera (ant Lion), 1, and
Among woU specimens preserved dartag the presence stud., 257 con-
tained food. I could detect no differences berveen sexes nor aman, the
venous~ size-classes vrch regard to relative proportions of major
ilasses of food (cems present in the allmentary cracts. There likevue
appeared to be no outstrandin, JLiferences amon; the various mainland
populjtions In this regard.
The food hautrt of the populations an Cedar Key Airstrip IsLland
and Seahorse Key appear to be rather speclaltzed and Lizards frjm these
places are therefore considered separatel,. I did not obtain data on
food habits of populationS Ln the Florida Keys (Monroe County).
Roaches, spiders, and crlikets weri bi far the most Important food
Ltems for mlatniand Itzerdj, occurring in -1.0, 36.?, and 10.;1 per cent
of the traits, respectivel, (Table 11. The splders were mostly mall
Mainland Coedr Key
Food (tems habitatab Airstrip Island Sepaorse Key
(232) (17) (8)
Cariblatella lutea 18.5
Arenivage floridensis 3.9
SSpiders (mostly Lycosidae) 36,2
Elaterid beetle larvae 4.7
Beetle larvae (other) 5,9 50.0
Beetle adults 1.7 12.5
Lepidoptera larvae 0.8
~ITermi~tes (vinged) 0.4
Termites Cuorkers) 0.4
Locustid grasebappers 1.3
Ant lions 0.4
Errwigs 0.4 11.8 75.0
Isopods 0.4 5.9
Fiddler crab 5.9
Unidentified insects 15.5
Figures in table are percentages of total number of individuate
containing food in each group. These totals are shown in parenthesea.
(See also Table 2 and Fig. 7.)
Sandhill and scrub associations.
TABLE 1. Prequency of occurrence of food items in digestive
tracts of Eumeces egreggse.a
volf spiders (Lycoslidae). Roachies were of several species, Cariblatella
lutea bELD6 the RiosL iomportant and occurring In at least 18.5 per cent
of the tracts. Probably, most of the roaches listed as unidentifiedd"
belonged to chis species also. Gartbljtella Lutes Is abundant In
sandhtli habLtats. At night it crawls on the ground surface and among
the leaves and branches of the turkey oak trees, During the daylidht
hours most probably take shelter in underground burrows of Geomys,
gopher cantoises, beetles, and other such animals and in holes resulting
fr~o the decay of large roots. I never encountered this species La and
about rotting logs, where other roaches are Common, but I found numer-
ous individuals in Geomvs burrows.
The reach, Areatuaga florldentls, was eaten by 3.9 per cent of'
the maintand Lizards. This is a fossorial Insect and is highly adapted
for suc~h an exiscence, being able to move rapidly through the sol1 Ln
much the same manner as do mole crickets (Cryrllotalpinae). It is
occasionally found in the mounds of Geomys and sand beetles.
ALthough termites and elaterid beetle larvae are readily eaten by
captive skinks and are abundant in sandbill and scrub communities, obey
play a relatively annor role in the diet of Eumeces edregies, occurring
in, respectively, O,$ and 4.7 per cent of the tracts. Grasshoppers oc-
curred In only L.3 per cent.
These data indicate that E. eereatus spends little time above
ground, at least in reltacvely exposed attuations. The only food Ltems
definitely suggearing surface activity were the grasshoppers. The htgh
Incidence of ILyoaLd spiders, crickets, and the less specialized
roaches In the diet may be Lndieative of what I consider to be an
(mportaIIInt feature of the daily routine of the lizards, namely, thllt of
prouting about in pre-existing subterranean passages in search of food.
If most of the skinksl hunting is done in thar; fashion, termites~iand
elaterfd beetle larvae would be Isrgely unavailable as food iterme,
since they live in burrows much too- sm(11 to accommodate the red-tails.
The food habits of E. e~gregius contrast sharply with those of
Neose21 reynoldst, a fossorial skink coexisting with the red-tail in
parts of central Florida. Termites and elaterid beetle larvae consti-
cute a large proportion of the food of this species (S, R. Telford, Jr.,
unpublished data)* Neoae21 to a more highly specialized burrover than
E* HIe~g igru and is correspondingly better equipped to locate these
insects and use them as food.
Seasonal variation in food habits is indicated for the red-tailed
skinks inhabiting the Study Area. In Table 2 the food data on speci-
mens collected in the Study Area are grouped according to periods
roughly corresponding to autumn, early winter, late winter, and spring.
Roaches are eaten more Frequently during the winter months then to
autumn and spring. The opposite to noted for crickets, which are least
important as food items during the winter months. MIy observltions
indicate that this seasonal variation in food habits reflects changes
in the relative abundance of the prey, their patterns of activity, or
both, rather than shifts in microhabitat or food preference on the
parts of the lizards.
The diet of the skinks collected on Cedar Key Airatrip Island
consitteed almost entirely of cruttaceanl. Amphipods occurred in every
tract examined. These animals wrere present in large number in the
tldal wrack under which che skiniks were collected. One specimen had
eaten a small fiddler irab, and another, an isopod. The only non-crus-
caceans were 2 earwigs, I In eaith of two cracts, whtch together masde
up 11.e. per cent of the total, and a beetle larvae an one rract.
TIABLE 2. Frequency of occurrence of food Ltems in digestive
tracts of Eumeies agregLas by season~ (Study Area, Levg County, Flortua).
Period and Ier centofl speeches cnntalug fooda
"Autumln" winter" v~nrer" "Spring"
Sep, Oct, Nov Dec, Jan Feb, Mar Apr, May
Roaches 31.r 54.0 503.0 12.5
Caritblarella lutea 1w3 3. t..
Arent;aba floridentsj 2.9 3.3 1?.5
Unidentified 14.3 18. 19.2
Spiders (mojstly Lycosidae) ;0.0 0. 3b.r 11,5
Crrckers 31- .1 19.1 50.O
Beerle larvae 2.9 2.3 5.3
Beetle adults 1.9
Lepidoptera larvae 2.9
TermLres (vrnged) .
Ant lIons 1.9
Diptera adults '.3
Unidentiiked Inject; to 1.D 5.j 3i.5
aFigures In table are percentages of total
containing food In each group. These totals are
(See also FuE. 7.)
number of Individuals
shoun in parentheses.
The specimens examined from Seahorse Key were collected under what
appeared to be the same circumstances as those from Airstrip Island,
I.e., along the share under ridal wrarck which teemed wi th amphipods.
However, no amphipods were found in any of the 8 specimens collected
whose tracts contained food. Earwigs, on the other hand, occurred In
all but 2 of the cracts, and a small scarab beetle appeared Ln 1
atamach, I cannot explain the absence of amphipods in the tracts of
pitch (195r) described the f'eeding beharier aE Eumeces t'aci~ates
in considerable detail. I vas unable to observ eE. egregies In the act
of ieeding in nature, but, based on numerous laboratory obsertations,
I conclude that there are few fundamental dtheorences between its
feeding behavior and that of E. insciatus. LLve German reaches were
kept in the Ilzrds' terraria almost all the timle. The coaches usually
remained hidden beneath accumulations of detricus on the surf ace 3f
the sand. A lizard, upon making its appearance on the surface, would
begin to crawl about, probing beneath the detritus with its snout.
When a roach was flushed from cover, a lively chase usually eniued.
Upon being captured, smaller roaches were cheweid for a few seco-nds
and wallawed entire. Before swallowinb: adult. roaches, the lazards
frequently pulled off their legs and wings.
Termatej, when placed in the terraria, were plaicked from the sur-
face cheved once or twice, and swallowed. Aut Irons (Myrma.ileonidae)
were eaten by the captives rl chcy were jibhted before they worked
therr way into the sand. At least once an ant lion was recotered from
beneath the surface and eaten. A skink was prowlind on the surface In
a terrariumu in vbich several ant leons had built their chiaracctelrisa
pits. Suddienly be stopped and peered intzntly into o~ne of thise pits.
He ruickl, plunbed his snour rlate the sand at the bottom of thie pic,
retrieved an ant lion, and chewed and swallowed it. ApparenL~r the
lizard had det~eted the insect's presence by the shifting of the sand
at the bottom of the pit,
In hatchlings feeding is accompanied by much movement of the tail,
This behavior becomes greatly exaggerated it: the prey is active and
difficult to subdue, or if the Lizard Is disturbed by the presence of
another individual. It becomes less pronounced with increase in age,
Swallowing a relatively large food item is accompanied by a
considerable amount of head and neck movement. The head is nodded up
and downl, while the neck is flexed laterally. Such actions tend to
force the food intor and down the esophagus.
Some skinks become came enough to accept food from one's fingers.
They take not only freshly killed insects held before them, but also
fragments of dissected insects, after first touching these with their
ANNUAL CYCLE OiF EPLRODUCH(ON AND ACTIVITY
Courtship and Mating
The peak of courtshrp and mjting activity In Eumeces egreg~us
occurs in fall and water, not In the spring as In most other species
of lizards Inhabiting temperate North America. Then the sexually
mature males becomer brlybhtly suffused with yellow, orange, or reddish-
orange along the lower sidej of the body and usually on the lower
itps, chin, and on the sldes of the neck (FLg;. GA). in an occasional
individual che entire rventer Is so suffused (Fig. uB). In dark
individuJls the lellov-orang~e shades tend co be stronger than In
lighter ones. This coloration normally persists in the males through
the period of sexual inactavity but gradually becomes less pronounced.
Showy~ colors are commonly exhibrted by male members of the various
species of Eumeces. The current consensus appears to be that such
coloration serves, along with odor, as an important means of sex
recognlrton (see Etans, 19591).
The suffusion disappears In preserred specimens. After ?o hours
in 10l per cent formalln the suffused areas become rose-colored and
fade completely after a month In 30 per cent isopropyl alcohol.
in the Study Area in 1959 mat ing apparently began some t he during
September or October. Males collected during October had enlarged
tes-tes (FiG. j1, and In some the orange suffusilon had begun to inten-
st[!y. Three mature fema~les collected during the first week of this
FEC. 4. Breading coloration In male Eumeces egrgu. Usually,
this coloration Is confined to the sides of the body and neck and to
the lower lips and chin as in A above (upper from Levy County, Florida;
lower from Putnam County, FLOrida). In an occasional individual the
venter is suffused with breeding coloration, as In those shown in B.
Both these spe~cimens are from the Florida Keys, where this condition
is most frequently encountered.
... .. .
I I' I r I
** **** *
* ***ese *
'ur~ FJI ~ILS~I IH~IY JO
month, howyverC~i~~~ had apparently not mated (esee page 43). Maited females
were collected on November 3, and by mid-December, all mature fieal~es
taken had mated. Making activity in this population probably continued
through January and into February. The testes of the l~ee in the
I)Study Area mere most enlarged during November and December and became
progressively smaller thereafter.
Among captive mature Hizards collected in the Study Area during
September, 1959, the first signs of sexual activity we~re observed on
October 8. On this date a male unsuccessfully attempted to mace with
one of two females being held in the same terrariumn. The first success-
ful mating was not known to occur until November 6. Natings among
captives were most common during December.
All evidence indicates that fall and winter mating is the rule
for most of the other populations of E. cnregius. Sexually active
makes were collected from the =Fall Line hills region of Georgia in
September. it is likely that mating begins somewhbat eariter here than
farther Couth. Females which had recently matred were collected in
Florida from the Lake Oales Ridge in January and February and from the
lower east coast in Hiartin County in February. The attuation in the
Florida Keys is not clear. On February 2, 1960, six mature males were
collected at Key West. All these specimens were brilliantly suffused
(Fig. 4) and appeared to be at a peak of sexual readiness. Babbitt
(1951) reported a mating between two red-tatts at Key west on March 13,
1946. It is possible that the mating period either i~s more prolonged
or reaches a peak later in the season in the populations inhabiting
Bat-bltt's brtef account has been the onl) published record of
courtship and nating in Eumneces eyreglus. In it he stated that the
entire procedure lasted 25 aninutes, of which 5 minutes were spent in
copula. He did not descrlbe details, nor did he mention the position
assumed by the copulatinp Lizards.
I watnessed courcship and mdEjrns behavior amond captive specimens
on at least '5 separate occasions, involving Lezards from almost every
portion of the range of the jpecies. The sequence of ajlor events was
the same in everj instance, although the timing was variablee. There
appeared to be no trenchant geographic variation in the manner 10 which
courtship and making was accomiplljhed. Furthermore, indlrividuls from a
particular geographic area mated equally as readily with chose from
other locjlitres as with lizards from the same locallrit regardless of
differences in morphology and ioloration.
My obsen~ationi indicate that la chis species scent Ls not only
the most important factor causing sexual excitement la the male, but
also in enabling: him to locate and recognize a fema~le. Males frequently
become sexually aroused almost Immnediately upon beiny placid in ter-
rarla with females, e.en Li the lattermy completely burled in the sand.
The behavior of a male so stimulated Ls distlnctive, The basial portion
of the tail shows rhythmic, lateral vibrations. When the tail 1s short
jnd stubby, it ma9y \Lbrate along its entire lendth. A t tioes these
vabrCtoLns become so Intense: as to cause the entire bodly to shake. In
the Intervals during which the tall is not actually vibrating, peri-
staltic-like waives of muscular actLvitY run through the basal half,
while the rall Itself may show slight undulatory movement. At times
these mey be accompanied by a moving of the pelvic region in a circular
manner against the substrate.
A sexually excited male progresses slowly and deliberately, his
body and legs quivering almost imperceptlbly. Any movement on the part
of another lizard will immediately attract his attenclon and cause hrm
to investigate. If the other 11sard is sexually immateure or is a mem-
ber of another species, the aroused male approaches to within 2 or 3
centimeters, then turns away. If it is another male, he may avoid Lt
entirely or display aggresalve behavior (see below). In case it is a
sexually mature female, the male moves up quickly and touches his tongue
to the nearest part of her anatomy. Any slight movement by the female
at chrs time will cause him to seize her in his jaws at the nont con-
venient spot. The female nearly always makes an apparent effort to
escape, which may be resolute or somewhat half-hearted. The resolute
attempt, which is usually frantic, La invariably successful, and Ln
most case probably indicates a lack of physiological predisposition on
her part toward sexual activity. Such a female, on making good her
escape, twitches and waves her tail excitedly and may quickly disappear
beneath the surface.
A female sufficiently motivated intrinsically and extrinsically
struggles fEebly for a moment and begins to crawl slowly forward. Her
body begin to twitch at Intervals of approximately one-half second.
The male at this time may tug at the female and actually drag her
around for a moment. Sooner or later she curns her head toward the
male and begins to crawl in a cight, circular path.
Meanwhile, If the male had initially chanced to seize her by a
fold of sKin on either side of the anterior half of the trunk, he
rreaLDS this cDriginal grip. If nor, at Some point In the preliminary
maneuvering he will shift his hold to this position, whereupon he
bodins otgorously stroking the back of the female unth his front foot
nearest her. These stro~king motions are also displayed by male Igeoseps
revnoldst darlna courtship and mating (Telford, 19:91. The female
continues to crawl In a circular path, her body twitching somewhat
convulsively, while the male half-crawls andl knif-drags himself along
beside her, peralatentlyr stroking her back. Occasionally the male
brings a handfoot into play, brushinb it over the female's pelvie
region. The crawling on the part of the female lasts from one-half to
ten (usuall, from two to five) minutes, When she stops, the male curves
his body sharply, brings 10 over that of the female, andl begins to
oaneaver the poseriur porto~n in such a nuwnner as to bring che uinder-
aurface of his pelvic region into Justaposirion vich that of hers.
Norm~ally the female raises her pelvic region and archen her tail
3lightly, chus facili~ltaun assumption of the mairln; position. The
male usually coils has call from one to one and one-half times about
the basal portion of her call before Eterting the appropriate hemipenis
and inserting Lt Lnto her partially open vent. Copulating red-tatted
skinks are shown in Fig. c~.
BarrinJ same rather severe disturbance, this position Is maintained
for 12 to 50 (asually for about :5) mtnutes. During this time there Is
Itttle notteeable activity on the part of either individust, except for
an occasional twitchrng of the female accompanied by stroking by the
FIZC 6. Making of Eumeces egbregius. In this species the m~ale
grasps the female issuediatelJ" behind the front. leg and directs his
body first over then under that of the female.
FIG. 7. Mating scars on female Eumeces ergu. These charac-
terfiatic V-shaped scars, located ilmmediately behind the front legs,
result from the bites of the makes during mating, The lizard on the
left shows one scar; the one in the middle, three; and the one on the
mele. Occaslonall, wh~en warm sunlight falls upon the copulating Le-
ards, the males appear to fall asleep in this position. While in
coEyla the lizards pay little attention to their surroundings, even to
the point of allowing themselves to be picked up and handled. The
entire courtship .nd mattag; procedure may last up to 80 minutes..
The female as a rule terminates the act of coitus by crawling
slowly forward, whereupon the mrale releases his hold, and the two go
their separate vays. The miale moves 11ttle or remains perfectly still
for as much as a minute or more after copulation, all the untle holding
his peltic region off the sand while Inverting his hemipents. He may
then forage for awhile or may, at once disappear beneath the surface.
On several ocua~lons copulation did not occur, even though the
Initial phases of courtship were completed in what appeared to be an
orthodox manner. Such instances usually involved a small male and a
large female. On one occasion a male -r2 rnum In snout- *et length trred
to mate utth a female SS mmv. The point in courtship was reached where
the male had, after several unsuccessful attempts, managed to selze
the female by the left side, and she had begun to crawl in a circular
path. This went on for about 15 minutes, during which tim~e the male
had on several occasions brought his bad, across that of the female and
attempted to achieve ufnt-to-vent contact. Edch time she would raise
the base of her tall slightly, but apparently, correct positioning was
never effected. Jhe 1nally began to burrow Into the alnd, whereupon
the male released her.
[he following notes were mad~e on Mo~reber -, 1959, on the court-
ship and matilng of a pair of captive red-tarled ski.nks collected from
took and setized her by right side of neck and immedi-
ately began "stroking" or scratchingg" her back with ble
left front foot. This lasted about 80 seconds with
female crawling continuously.
11:00 a. m. FLamale began twitching posterior part of body, turned
toward male and began to crawl in tight circle, body
jerking slightly every 1/2 second or so.
11:05 a. m. Female was still crawling In circle with male holding on
tightly, trying to keep body parallel with that of female
and occasionally to straddle her.
11:06 a. m. Bale was breathing hard and fast. Female stopped cranting,
and with body still in circle, began twitching pelvic
region about three times per second.
11:07 a. m. Hale brought body over that at female, curved and twhated
it so as to bring vent into contact with hers. Female
raised tail in apparent effort to cooperate. Male coiled
tail about that of female.
11:08 a;. m. Copulation apparently began. Both animals were quite still
except for alight twitching movements on part of female,
these occu~rrogi at intervals of about 5 seconds. Each
time female tu~ttend, male vigaOrusly stroked her back.
11:09 a. m. Both anitmals very still.
11.1- a. m. Penate vitcihed twice, male stroked her for about 3
LL 2;1 a. m. Pensale dtrucgled for moment, then became still ekcrep for
an occasional twitch, Male didn't stroke this time.
11 ?3 a. m. Female bean to make around, and tr~te to bite male.
After a few seconds she freed herself from male and dog
into sand, Hale remained quier holding hind quarters off
of' sand while inverttng hemipents.
L 12 a. m. Hemipents completely ~inverted. Hale burrowed into sand.
After each majtty act a V-shaped scar ts left on the urndersrde of
the female (14. I). This scar, resulting from the male 's btte, re-
m~alns clearly defined for Erom i to 2 months afterward, becoming
decreasingly canspicuous thereafter. Often a trace of this scar can be
seen for as long as h months iollowing copulation.
Of 1'6 iemale sklnks collected having mariting scars, ninety had
only L scar, the rest 2 or more. More than 2 were found on 5 spect-
mens, and on i of these, were clrarly distangu~ishable. Courdering
only srarred specimens, there appeared to be no correlation between the
number of scars per female and the date of collection relative to the
height of the mating season. Also, I could establish no correlation
between the number of scars and the size of the individual.
Matian scars occurred on the left sides of j4 specimens and on the
ripht srdes of ;1. Included in these totals were 34 individuals which
had acquired the scars on both sides, There was no correlation between i
geography and scar location,
It appears, then, that most females mate only once per season,
Among, captives I observed no reluctance on the part of a female
skink to copulate a second time but after this there was a distinct
tendency in most instances for the individual to avoid males. Only one
captive female mated as many as 3 cimes.
In the position they assume during copulation, red-tailed kinks
may be uniqlue among Nlorth American species al Eumaces. Every account
of mating In other North American forms describes the male as grasping
the female, usually by the neck, and immnediately directing his body
under, not over, that of the female. hating has been described for
E. fasciatus (Fitch, 195j), the broad-headed skink (E. Laticags)
(Coin, 1957), the prairie skink (E_. septantrlanalte) (Breckenridge,
1943), and E. obsoletus (Smith, 1946).
The copulatory position in Ndosepe reynoldsi (Telford, 1959) ney
be similar to that in E. egreglus. Moreover. Telford Informs me that
he has seen mating scars on female Neoargs which are similar to those
on female red-tails. Upon examining a number of specimens of the
little brown skink (Lyggsnma laterale), I noted V-shaped scare on the
undersides of several Lndividuals. These were located just behind the
forelimubs, and I assume they were making scars. This may indicate that
mating positions are similar for L. laterale and E. egregious.
I never witnessed sexual activity among red-tailed sklnks in the
field, although I spent many hours at the height of the lasting season
in areas where the kinks were extremely abundant. This rataea the
qupseton as to where chese acti-citres normnally take place. A considera-
tron of the mating act ItSElf [iay: offer some clues. I consider one of
che most siignifiiant featrurae of the act to be the prolonged period of
Eime during; vbkch the indt.1duils are actually, In cygula. In Imny Liz-
ards, if not most, this period lasts no lanZer chan a Eew minutes.
Probably, Indirvlduals so engaged are considerablj' more vulnerable to
attack by predotors than If the:, are separate andl foraging.. Thes wuuld
be especially true Lf nating cook place Ln relatthely, exposed places.
FollowrnZ this line of reasoning one can speculate that E. cgregius
normally mates in sheltered situations such as the burrows and passage-
was constructed by GecimesJ and Cogherus. It is possible that the ma~ting
observed by babbitt at Ksy west was unusual for the species. Another
possibllty~ rs that, oving to the specralrzed habitats occupied by the
skinks on the Florida Kepy (see page 135, matings in the open are more
While 1 neced considerable variation from came to time in the
decalls of the process, every instance of councship and macing I ob-
serve4d involved the same sequence ofl behadloral events. The sexually:
ecEited male, characteri-ed by his qulvering body and less and inter-
mattenrly: strac~ing rall, nosed and licked the female, onen served her
somewhere on the body or call. The female, if willing to mace, even-
tuall, responded by turning toward the male and crawling rn a tight,
circular path. Invariably she Jerked or twdtched her body from th ie
to time during the proceedlasse, and invariably the male stroked her
back. A srimLlar ruacing position was assumed in every rase, with the
male graspind the female on the side of the anterior portion of her
Crunk vbile arching his body over hers and curving it back under in
such a manner as to achieve vent-to-vent juxtaposition. In conclusion
it may be said that courtship and mating in Eumaces egreyfun is for the
most part a highly stereotyped aIffair. i
Homosexual behavior was observed only among female E. egregius.
In the fall of 1960, six female lizards, each of which had laid fertile
eggs during the previous spring, were being held in a terrarlum. Only
one of: these six, a large individual from Highlands County, Florida,
had been in contact ulth a male subsequent to the nesting period,
having been taken from the terrarium~ and allowed to mate vith a male
from Polk Caunty, Florida, on October 27. Pottowing this mating she
was Immediately put back with the other females.
At 11:00 a. m. on November 14 this Lizard ase seen attempting to
"copulate" with one of the smaller females. They had assumed a posi-
tion which, upon superficial examination, seemed identical in every
respect with that In the normal maettng act. As far as I could tell,
the only behavioral feature Lacking, except for actual penetration, was
the back-stroking activity normally displayed by the male member of a
copulating pair, The smaller female was apparently making every attempt
to effect cottus and was even twitching her body in the prescribed
manner, For 20 minutes the lizards remained in this position. Finally
the endller one began to craul forward, whereupon the other released
On 8 subsequent occasions during November and December I saw
homosexual behavior displayed by the lItarde In this terrarium. Three
different indilviduals at one clue or another assumed the nsle role in
aborilre arttmpts to copulate. Whether this highly abnormal behavior
on the part of a female lazardl is brought on by intrinsic stimuli,
extrinjic stimuli, or both is not evident. The fact that both mated
and unused Individuals jhowed it obviously compl~aeate the matter,
Capt Ire male skinks frequent Ly fought dur ing mat ina season. Cer-
tain males were particularly bellrJerent. One of these was a small
(43 unr anoni-Jent Length) individual ;sllectedl at Fort Benning, Georgia,
on September 10, 1900. Thrs rsale, which was brightl, suffused with
orange-yellow on the lower sidEs, neck, and chin, exhibited sexual
readiness to a mrkedci degree. In the presence of a mature female he
would at on~e begin to show courtship behavior.
On Oictober 10j, 196, this skink was placed in a terrarium con-
taming 4 laboratory-reared lizards, each In its first year. Two of
these were thle male offspring; of a fema~le from the Lake Wa les Ridge of
Polk County, florida. Each was -r6 m~ in anou~t-vent length. Another
was a ;l mm~i rrale from Levy Cou~nty parents. ALL chree males were
sexually maiture. I had never observed any aggressive tendencies among
any of these indi~lduals. The fourth was a mature female, an offspring
of the female from Polk County mentioned abore.
After prowling about the terrarium~ for a few seconds the Georrgia
male began vibraring his call and quivering slightly In sexual excite-
ment. The female at this time waE Completely hidden from view. Con-
tinuing his exploration of the terrariumu, he either avoided or paid
little attention to the two Polk County males, whrch, together with the
Levy County male, were foraging on the surface, However, upon every
encounter with the Levy County mate, he would attack and bite htm
savagely. if the smaller skink happened to be moving, the Georgia male
would advance quickly and bite him on the tail, usually at a spot just
to the rear of the vent.
The younger Lizard responded by thrashing violently for a moment
and, upon jerking loose frdmn the jaws of his adversary, moving rapidly
to the opposite end of the terrarium, where he nervously twitched and
waved his tail. If, upon being confrcuted by his tormentor, the smaller
skink remained qluietr the attack was more ceremonial. The Ceorgla 11:-
ard would approach to within 2 or 3 cm, turn his side toward the other,
and move up close in jerky, sidevtise fashion, After momentarily
nudging him with his snout, he would bite the smaller one, usually
about the basal portion of the tail.
After being harassed in this manner for about 15 minutes, the
Levy County male burrowed into the sand, whereupon the Georgia lizard
was removed from the terrortum. On the following day the Levy County
male was dead. I suspect that this individual may have been diseased
or in an otherwise weakened condition from the beginning.
The Georgia male use involved in numerous other fights, particu-
larly with a 1rst-year, sexually mature male whtch had been collected
August 1, 1960, near winter Haven, Polk Councy, Florida. This lizard,
approximately the same size as the Georgia male, lived in a terrariumn
with 3 immature individuals of Georgia parentage and 3 laboratory-reared
young adults (2 males pad 1 female), the offspring of a Levy County.
female. I had never noted any aggressive behavior between any of the
residents of rhts terrarium. On several occasions I introduced the
Georgia male into this terrarium. In nearly every instance a fight
ensued almost imrmediately between him and the Polk. County male. The
two appeared to be almost equally matched, and the flg~hts often asated
as long as 25 minutes. Usually, the Polk County male would terminate
the battle by retreating from the scene.
These fights were, 11ke courtship and mating in this species,
iharacterized by ritualism. The combatants would eidle up to one
another, Jerking and quivering, unth their bodies bent ridiculously in
5-shaped curves, and their heade directed downward (Fig. 8A). Suddenly
one would seize the other. The latter would immediately attempt to
reciprocate, and, if successfully, there ensued violent thrashing, vich
each individual rapidly twistlng his body over and over. This lasted
only a second or so and normally resulted In each skink gaining his
freedom from the other's hold. This was followed by a resumption of the
Most frequently the skunks bit one another about the head and
basal half of the call. when a "head-hold" was secured by either in-
dividual, the other was obviously at a disadvantage, being unable to
grasp his adversary (Fig. 88). A lizard caught thie way would usually
crawl about for a few seconds and suddenly free himself by aimulcane-
oursly jerking and twisting. Other fights were noted from thme co time
between various males but were usually one-sided and of fairly short
duration. while observing these fights, I frequently got the distinct
impreselon that the aggressor was endeavoring to break off the tall of
the other lizard. A majority of the large (over 47 mms to length) male
PIC. e, Aggresstve behavior La male Euineces e A. Two
males just prior to fighting. Both are displaying the "aggressive atte
tude," in which the body is heat into an S-ahaped curve, and the snout
is pointed downward. B. Une male has been seized by the head and is
thus prevented both grasplug the other. In this predicament he all
crawl forward very slowly for a few seconds, then free himself by vio-
""1sk IIIII11111&40 colecedfr ) g ve n poplillt tion were marke d ivih lc ra, meetl
oll lbieh llAR probaoEbly be attributed to fighting.
Capt(lle~ll yelll~~ feae 11sards shoved no aggreasolve behavior of any kind
excef pt llwhlllien ty were brood ing. Judg ing from s om of the se a ts found
on i~L'~ldErught individuals, havever, I sus~peec that they do occasionkilyy
fight under natural conditions.
Th~ period between mating and oviposition in 1, egreguina is
unusgili1y long for a skink. The longest such period observed was 186
days. The female in question mated on Novemrber 17, 1959, ase isolated
L~iihibiCately, and laid five fertile eggl on April 12, 1960. In the
1959-60 sei'san all mature females colleuted after December bed appar-
ently mited. All those kept in captivity laid fertile eggs during the
spring. Prolonged preoviposition periods, involving sperm-storage! or
delayed~ fertlization, have been reported In a number of adakes and in
turtles, but not, as far a~s I know, in Haaords.
Folle~ag 1 or 2 matings the fentles enter a1 phase of relatiVE
inactivity, which I call postmating quiescence, in the laboratory,
Wh~LkCi dere;...ldom seen on the surthee for 3 to L weekC 4tter mating,
and during this period they fed sparingly or not at all. In the Study
Area posmacing quiescence was indicated by the relative infrequency
witilruhich female werre collected frais GCgoggs and beetle mo~unds during
and shortly af ter the mating edklson (Fig. 9). Also, ;lrelatively large
number of the Sh~iales collected during thid th~ie had no food in thetz
putl (Fig. 10).
Il l 1111111111111111111
O I MALES,
z 30~ ---
3 L.'e FEMALES
OCT rnOV DEC JAN~ FEB MAR APR:
(91 (40I) (3S!1 (47) (391 150) (25)
FIG. 9. Seasonal mariation Ln relative frequency of capture of
male and female Eumeces ~eglu (Study Area, Levy County, Florida).
Tocal numbers captured during each of the months Is shown an parenthe-
seE. .N~dCIy all Of these [Lzards were captured in Geomva or beetle
I I T
OCT-NOV DEC-JAN FEB-MAR APR-M~AY
FIG. 10, Seasonal and sexual variation in feeding habits of
EumPOee agregius,1 as indiiested by proportions of individuals having
empty guts (Study Area, Levy County, Florida), The total number of
eaceh sex captured during the period indicted Is shown in parentheses.
During Dccember and Janurary many females had cenered the phase of post-
mating quiescence (ser text). During F~bruary and March most fem~las
were feeding actively and developing fat streak. During Aprit-and nay
the =abdolminal cavities of many females were almost completely filled
with eggs, and the yuLs oF such lizards we~re usually empty.
Female postmating qumaceince probably results in an increase in
the efficiency of courtship and mating activity in bths species. The
rutting males would be less likely to detect and court the inactive and
previously mated females, and, accordingly, superfluous sexual activity
would be lessened.
During February and March female lIrards were collected in the
Study Aren with much greater regularity than earlier, and the guts of
only a few of these were empty. Apparently, chts period is one of In-
tensive foraging on the parts of the females. Their tails, become heavyr
with stored food. In Harch and April their bodies become noticeably
drstended vich eggs. As the eggs occupy more and more of the body
cavity, the digestive tracc gradually becomes so crowded that digestion
and elimination are apparently hindered. This would account for the
increase noted in per~cntage of females vich empty guts during April
In Fig, 11, the diameter of the largest ovarian follicle or ovl-
ducal eg~g is plotted against the date of preservation for each female
collected from the Study Area and preserved during 195q-b0. Small
(under 0.5 rrm), nearly translucent follicles were present in obviously
Immuature specimens. The advent of' sexual maturity wias marked by a
rather abrupt increase in the sizes of the follicles which at the asne
cine became 3paque and creamy or yellowish tn color. After this initial
enlargement the follicles showed little change io size until February,
when secondary follicular enlargement began In some females. By late
March most females contained enlarged follliles. Size increase con-
tlnued through March, and ovulation began In April.
Ct fl r
r l c
S*- rr D
A r' W
r ID r.
c a re
m "U r
" li A i
5 ** *
1 111 111
v u O3 1 O O
in a paper presented at the 37th annual meeting of the American
Society of Ichthyologists and Helpatologists in 1957, Wilfred T. Nleill
reported finding a nest of E. egregius in deep eand abouct 6 feet
beneath the surface. Hamilton and Pollack (1958) report that on June
15, 1950, a neat of this species was uncovered at a depth of 4 inches
in sandy sail at Ft. Banning, Georgla. These reE the only published
references to natural nests of the red-tailed skink,
No natural nests were found during the present investigation, but
I observed nesting activity among captive specimens on a number of ac-
casians during 1960 and 1961. Between April 3 and June 15, 1960, 14
captive females nested (Table 3), Gravid females were individually
confined In wide-mouthed, Gallan-sized glass jare containing about 8 cm
of slightly maintened sand. In nearly every instance the female con-
structed her nest cavity against the bottom of the jar. The nests were
ordinarily clearly visible from beneath. The cavities were more or
less rounded and measured from 4 to 8 cm across and about 2 cm In
depth. Each nest nas completely enclosed and had no paneageway to the
Although these jars were examined almost daily, and nests were
observed in all stages of construction, only once was a lizard seen
actually hollowing out a cavity. She was crawling around slowly,
pushing back the sand with the sides of her head and neck. She stopped
after a minute or so, apparently having been disturbed by my presence.
Several days elapsed between the -apparent completion of any nest -aEnd
TABLE 3. Size of female parent, number of eggs per clucch, and
dates of o~lposition and batchinZ for 14 clutches of eggs of Eumeces
e~egi ~ (1960).
Snoult-ventr Number Nrumber of deys
length of of eggs Date of Date of becueen ovi pos L ion
female (mm) in ilutch oviposn~ian hatching and hatching
June 2 -25
aThis clutch waj taken from female and held
newsprinr until time of hatching.
in jar uith moistened
che ap strance of the first eggs. The shortest auch period was 3 days,
and the longest, 10.
Ovipoeition and Eggs
Since I never actually saw the laying of the first egg of any
clutch, I was unable to determine the exact amount of time required for
a given individual to complete oviposition. For clutches of 4 to 6
eggs, this time ranged from approximately b to allmost 24 hours. The
average period was probably 12 to 15 hours.
Far 13 clutches laid in the laboratory the number of eggs per
clutch averaged 6.8, ranging from 2 co 9 (Table 3). Ramnilton and
Pollack (1958) reported 2 clutches of five eggs each.
The eggs are described by Hamilcan and Pollack (1958) an ellipti-
cal and dull white when laid, with some shaving a faint yellowi~eb tiat.
Table 4 summnarizes measurements made an 4 clutches of freshly laid
eggs. Mean length and mean vridch of the eggs in each of 3 Florida
clutches are significantly greater (5 per cent level) than correspond-
ing means for a Georgia clutch.
The shells of the eggs are leathery and thin. One egg. broke when
accidentally dropped on a wooden floor from a height of about 27 cu..
About 1 week before the eggs hatch, their shell develop cransluent
areas, through which the fetuses are plainly visible.
The eggs become larger as development proceeds. The eggs in a
clutch laid by a female from Highlands County, Florida, showed an
average increase of 4.0 mmn in length and 3,0i mm In widch from the time
they were laid until just before hatching. Correspondi~nd figures for a
c lucch Laid by a Georgia iemal e ar giv.en by Hamilton andl Pollack (19583)
TABLE L4. Measuremoents of freshly lald eggs ot Euece~is egregtus
in m ill Iime ter.
No. eggs Rangle in Mean Range In Me~an
Female colleictd at: In clutch lenach length width width
FL. Benoing, Ga.a 8. 5- 9.0: 9.9 5.u-5.: s.2
Lety County, Fla. 5 9.t--10.5 10.0 :.9-c.6 c.3
Levy County, Fla. j 10t. 1-1.0l 10.4 .0-, 6. 3
Hitghlands Co., Fla. i 1l. L-ll.t- 10.6 E. 0-t..7 6.5
(Lake Wales Ridge)
aData on this clutch taken from Hamilton and Pollack (1958).
The incubtation period varied from 51 days for a clutch laid on
April a to Zj days for one laid on June 13. Temperature was apparently
the most important factor In determining the length of the period.
Br~oodin behavior amonj members of the genus Eumaces h~as been
studied and discussed b) several workers, incluJlding Nobl and Mason
(1933), Ficch (19r5 ), Jan Evans (159). The aiciiitles of the brooding;
females of the various species are probably similar in most respects.
Generjlly, they appear to consist of cleaning and turning the eggs,
protecting them from certain formrs of pretation, and mlulmlznlo the
effects of desicstton by .ectacally ablfting the position of the nest,
and, at least in E. fasciatus, by voiding the contents of the bladder
when the;;need Arises. In E. obsorletus the female Assists in the
hatching process and attends the young for several days after watching.
The brooding instinct appears to be highly developed in E. egre-
Atue. In fact, brooding females I observed normally remained In their
nest cavitiwa constantly, neither feeding nor drinking, from the time
the nests were made until the young had watched and dispersed. The
longest such time wee 56 days.
The brooding Lizarde frequently turned their eggs and cleaned ~
them vich their tongues. Cleaning may be essential for proper develop-
ment, particularly in the early stages. On several occasions I removed
eggs from nests and attempted to hatch them in the absence of the
females, These eggs were kept in closed jars containing malatened
newsprint and were turned daily. Eggs cared for by the female for
several days before removal usually developed normally, freshly la~id
eggs (less than one day old) so used wrere invariably attacked by
fungus. Perhaps freshly laid eggs are coated with a film conducive to
mold groveh, and this Is removed early by the female's licking.
Occasional turning of the eggs appears to be important to develop-
ment. The following observations may be significant. One large female
(58 mmt rnout-vent length) constructed a nest cavity in which she laid
six eggs. Twelve days after laying she was discovered on the surface
in a weakened condition, She refused both food and unter and died two
days afterward. All of her eggs had spoiled, but not, apparently, front
molding. it seemed that they had been paid little attention, and each
had yellowed on one side and become slightly abrunken. They may have
spoiled from not having been turned.
Brooding females probably protect their nests from certain forms
of Predation. Once 1 made a slight opening into a nest cavicy occupied
by a female brooding over one egg. While observing through the bottom
of the jar, 1 allowed a Iu-cm Tantllla ioronata to put its head through
the opening and into the nest. The lizard nosed the Intruder for a
moment, then brt him savagely. The snake withdrew its head immediately,
NextL, I introduced the head of a 38-cm Thamnophis slrtalis Into the
cavityr. The lizard watched the snake's head attentivel and showed no
signs of alarm. When it moved closer, she backed against the far side
of the ca~ity but still made no attempt to desert. I then withdrew the
snake, waited for a minute or so, then eased his head into the cavity
again. This time the lizard bit the snake on the lip and immediately
backed away. I thrust the snake's head farther into the cavilty, but
the lizard did little but make mild attempts to avoid it. It seems
certain such scLrons on the part of a brooding female lizard might
discourage small prediatorsj.
On flve o~ccstens I removed eggs from nests re take measuremence.
The females made no attempts to defend their nests against my Intru-
sions and did not desert then until the eggs were completely exposed.
Only. one female resumed brooding the eggs after they had been remok~ed,
measured, and replaced. In this case I had removed the eggs on the day
following ovtpositlon and had destroyed the nest cavlt; in the process.
After measuring the eggs, I placed them togerther on the surface of the
sand in the original nest jar. Tuelve hours later they had not been
moved, and the Lizard was lying under the sand next to the bottom of
th& -p;~ir. I then hallowed out a small cavity about 6 mm in front of the
Ltp of beir snout, placed the eggs in this cavity, and covered it wi~th a
flat piece of bark. Six hours later, she was in the cavity heated
about the eggs, vbere she remained for the rest of the incubation
I could not determine if the females assist in the hatching proc-
ess. At hatching thme they mooved nervously about, touching the emlerging
and newly emerged young with their tongues. i did not observe a female
actshily helping a hatching to emerge from the shell. After the young
dispersed from their nests, their mothers paid them little aLttenton,
By this time the mother skunks were noticeably emaciated. Their talla,
which had earlier been heavy and well rounded, aere now shrunken. They
began feeding inuediately, however, and within a month or so were nor-
mal in appearance.
Noble cad Mason (1933) suggested that the incubation period for
eggs of Eumieces inaciatus may be shortened a~s a result of heat transfer
fran the body of the brooding female, Fitch's observations (1956)
failed to confirm this view. Evans (1959) fuund no evidence for this
phenomenon in Eumeces absoletus. I took numerous E_. egregius nest
temperatures to within 0,2lo, and in no case were they different from
those of the surrounding soil.
hatching and the Hatchlings
Hatching in Eumeces egregius ase briefly described by Hamilton
and Pollock (1958). The following is based on their description and my
own observarnons. About days prlur to hatchlin, the fetus can bi
seen srne~lng about within the egg. Moisture oomes iru~m the egg and
form; small droplets externally. The appearane of this moisture mya
corinide with brcaince of one or more of the extraembryonic mem~branes.
The shell 18 punctured by a sudden thrust of the snour, directed for-
used and upward against the rnner surface of the shell. A slit about
mmn~ Long appears, through which the head protrudes. The slite is
presumablyllj made with the aid of the Egg tooth, which is lost durring the
first or second day.
After the init al break-chrough, the ou~ng skink may remain In
the cgg, with only its held protruding, for hours or more. I never
saw a hatchitnd emerge in less than i hours. The Lizard moves but
little durlIII this period, and, it' molested, is likely to draw Its headt
back l1ll0 the ead.
After emerdgly, the hatchllags spend the firsr & Or i hours lying
qulIely. snd broeahing deepli once etery 3 to a seconds. A4 bii of the
yalk sac protrudes frrom the abrlicus of each. By the end of the first
1- hours, they are fairly active and are usually beginning to moult.
By' the end of the second day, th ambilictc heal and rnoul1ting is com-
plcte, or nearly so.
Dijperjal from the nest ordinarily takes place during the third
dayi. Ibe hatchlings arre 11sel and feed readILy on termites and srrall
reaches. WThiLe foradias, the*, keep their tails almost co~natantly In
mot ion. The basal half moses from side to side, abhile the remainder
vriggles In sinuous curves. This trait is jlso seen La the hatcblings
of E. obsoletus (Grant, 1927), and In the hatchlings and Juveniles of
Edathet(~IIIIhittenthu (lt~isoe, 1957) 4tbd E. f~~itabanothe.~ Cich, 1954).
Ratchlllillllii;;ing(.bletus yand"[: fasciatus jbowi"l-tqd~ency to iarch the'
taill'~bl vertiiclly; I nottd no erluch tendency La E. :#R~regiusihetchlingal.
ilM~agg $(pt dt on 53 newly hatched C. egreaius;, repreeenting 11
clutek lrlfj 'e gatpised In Trblie 5. Cencrally, th~e largest hatchitag.
Ilaimtp thagel of Lak3 Walrlp Ridge parentagel. Therii sere no **nual differ-
(nts ii in site or external appearahec. of hatchitag8.
SLx ;lai;l:deatermined for 31 laboratory-hatched ski~nks; 11 were
males and 20, feamels. white this differences is not eignitteent at
the 5 per cent level, it dgeaandsa~a more thorough Investigation of this
aspect of the life hi tary.
AI in the case of maeelt 1ards, the hatchitags of E. Eegregfut
differ in arpplirlnce from the adults in deveral respects. The ground
color of tht";hitchling is darker, and the pattern of atriping, iifile
basainelly aimlllar to the;;parental pattern, is usually more distinct.
Th#~l;j ata relatively lar;ger in the hatchling, and the t 11> which is
more vivid in color, is proportionately shorter.
Growth and DeveLopment
I studied growth and devetlophant of 12 sets of eiblings hatched
in the lalboracary, and a~t vathose time intervals maeeaured the individu-
m~al in 6 of these. Two of these 6 were from eggs laid by fespsee taken
from the Lake gles Ridge in highland County, florida, and 1 each from
ENlesrr collected in Levy County, Floriidl; Puenam County, T~~oriday;
Martion County, C~oogia;; and Autauga County, Alabama. All theadC females
had manard prior to blhetng collected. The growth data atr condemped in
Table 6 ind Fjig. 12.
3 Tr -.4 r r
d~~ r? 4 4
I3 4 3Jl
I e -
~I h ~n ~
i ~u J
~n ~n ~n ~n
.~ r ~? ~n u~
1 Tr O
r rr 3 J
u ~ r cr
~ 3 5 3
~n ~ n
~ u r -r r,
-r N N
Br .lr i I 1 12 dod
.0 < Un U ~ ~ s~ .s .. o u
qg E3 .4u3 ~ u b
QA ~ ~ C J -J 000 0 0 L
qlo sD 0
prl we s a
rr)e 4 0 4
,0 .8 r
h)g n re NQ sa
N3 set N 34 *7
r 9 *v cr e
4 --a .a
Crl ri 3 on ,o as
as~ as a g) a
S 33 u u o
la ul e
,:u e1 --a
10 we U
FIG. Ll. Aierage increase in enout-a~nt length from time of
hitching for arx group s o sibling Eumeces r~e ijreared in the labo-
ratory. Numbers of Individuals in Each group Gr sub-prjup are shown In
parentheses. Offspring; of suthern parearage grew faster than those of
northern parentage. Diferrences io g~rowth rate between malesf and
femuales are shown for some groups.
* rd' (4)
~- $ (2
/ ; .
1 1 1 1 1 1 1
0 20 40 60 80 100 120
AGE IN DAYS
140 160 180? 2CO
Marked differences in growth and dEvelopment were noted among
some sets of s~tbitgs. Skinks In the 2 Hidhlandj County 6ets showed
the most tapid growth rates. In 1 ot these each of the 5 Lndividuals
had grown to at least twice its original sile in snout-.ent lenath in
125 days. A slsalarly rapid rate of related~ groutn has been shown for
E. fascLatus du~ring the summer months after hatching (Fitch, 195;),
The western blue-tailed skink (Euneces skiltootlanus), however, re-
quiirpe a full year to double its original sire (Radiers and Memimler,
The Georgia and Alabana red-tailed sklake grew much more slowly.
The Georgia slblinqs showed an rverage; increase in enout-vent length of
56.0 per cent at 139 days of age, and those fromi the Alibama~ parents,
20.0 per cent at 13t Jays. The llzards in the other tuo Florida sets
were Intermrediaat In Zrowth rate. I was unable to get data on growth
rates of the Florida K~eys red-Lailed skinks. Growth rates might be of
value Ln estabitshlyg the intraspecific rlelaionships of these 10aerds.
In morphology the Key lizards appear to be more closely related to those
of northern Florida, Georgia, and Alabama than to the ones In central
and southern Florida (Mc~onkei, 1957).
In all sets in which comparison could be made, females grew
faster than males. The ages between which the behual differences In
drowth rate appeared for each of the florida sets can be seen in Fig.
12. The greatest difference noted was in a HLghlands County set in
which the females averaged 13.3 per cent larger than the males st 182
da y of agie. I *as unable to make postI.E 5e s determinstlans on the
Georgia ernd=41abanar siblings=. In neither of these sets, however, were
there difference~ in size of over 4 Imm,
Sunder laboratory conditions females over 50 mm snout-vent length
And males over 45 mm grew slowly. In eight months of captivity one
female from highlands County grew from 56 to 59 mm, and another, during
this time, grew from 52 to 54 mn. A female from Georgia, 51 mmn In
length at tin~r of capture, grew only L mnm In sirlx onths. Aj male from
the Study Area Increased in sire from 64 to 46 mm in six months.A
Georgia male required ten months to grow from a size of 44 mmn to one
of 86 rmm.
The Isrgest individuals, both in maximum size and in mean adult
size, were found on the Lake Wales Ridge and on Cedar Key Airatrip
Island and Seahorse Key (Fig. 13). Those from Ceorgia, Alabama, and
northern Florida, destanated Bumneces etgregius similes by McConkey
(1956), were smaller by from 6 to 6 mm, Intermediacy in this charac-
ter was noted for the other populations sampled. In every population
studied the largest females were 3 to 7 mrm larger than the largest
ma~les. The largest specimen examined was a female 62 mm In enout-vent
length from the Lake Wales Ridde in Polk County. This apacimen shrunk
to 59 pmo after six months in preservative. In the preserved collec-
tLan of S. R. Telford, Jr. is a female specimen (SRT-640h) from Cedar
Key Airstrip Island measuring 60 mmn. The size of this individual in
Life probably exceeded that of the Polk County fenlale and might be
designated as the record for size for the species. The largest male,
collected on the Lake Hales Ridge in Folk County, was 56 mmn at time of
preservation and six months later measured 53 rnm.
d r (11
z 55C 371 j
wI~ (5 13\3) -
I I II I I LAKE WALES
z CEDAR & RiDGE
GA., ALA., N FLA. KY
FTG. 13. Geographic and sexual vertation In size of adult
Eumeces egrgu. The size of each sample is shown In parentheses.
Females were larger chan males in ever) populatron studied. The
northern Floridda area is north of Levyl, Alachua, Clay, and Sr. Johns
Size could not be used to classify specimens according to age
groups, This is understandable when one Considers the relatively long
sa son over which hatchlings are produced in most parts of the range,
in Florida a period which may 1880 three to four months. I can after
no evidence as to the physiological longetaty of red-tailed skLnka.
Sexual maturity is reached in the first or second year, On the
Lake Wales Ridge all the individuals apparently reach sexual maturity
and mate during the first fall or winter after hatching. Males reared
from eggs laid by females collected from that area began to show the
orange suffusion of sexual maturity at 124 days of age. Both males
and females Ln one sec of lake Wales Ridge alblings were mating at
130 days of age, Macing was observed among the siblings of two other
Lake Hales Ridge sete when they were, respectively, 14Li and 143 days
old. I collected on the Lake Wales Ridge only in January and February,
and it seems significant that no inmmature individuals were among the
20 or so specimens 1 was able to capture there.
In the north-central portion of Florida, some Individuals reach
maturity during the first year, while others do not. In each of two
sets of siblings from Study Area parence, bach males and females were
apparently sexually macure by October 14. At that time one of these
groups was 125 days old and other 135 days. Siblings from Putnam
County And those from Cedar Key Airstrip Island and Seaharse Key parents
matured during the first fall. However, field collecting in north-
central Florida revealed the presencee of immacure lizards In mlany of
the populations as late as March and April. It is unlikely that these
would mate before the following fall.
:None of' the alblinbs amcon2 the Georgia and Alabama sets matured
darty~ the flest fall. These LndlvlduaLs were still immature at almost
1 ;ear of ago. Thts, alonng worth obsirrvatsons made La the h~eld, cead
me to conclude rtht a rrelatlvel, slow rate of growth and development is
iharacte~rnt L of the Fall Line Hills Fpoplartana of E* ideg~tils, and
that, probably, none of the individuals reach ma~turity before 1 year of
age. Other populations worthy o~f rnvestigatlunn in this regard are those
Inhabitins the southern part ionr ut G~eorges and Alabara, extreme north-
ern and northwejtern Florida, the Lower eastern and western coasts of
Flo~rrda, and the Florida Keys.
The size at which sexual natsurity is reached varies between 34r
and 38 nuo snout-vent length for males and between 30~ and <2 mmu for
temales. There appear to be geographtc dilffrences In this iharacter-
rstl;, with the 1Lzards of Lhe more northerly distrtbuted populatltOn
auturrng at slightly smaller sizea than the ones of those to the south.
More da~ta are needed to establish this.
There was nothing unusuJal about the postnesELng actt.Lrtes of
ca PtL'. 6kLnkr. eoth hatihlings and adult females spent considerable
rime foragind, adult ulesLB were SOm~ewhat less actirve DuiCng the study
perted I was unable to collrcL red-tailed skinks Ln either Ccomys or
beetle miounds from m~-May to mid-Se-prtembr !sce page it.). I collected
a few spectmerfns during this time, hiwuser, b; diggi-ng under Exdal
vrack on Cedar Key A~rstrip islandd and Seabase K~el by overturnln;
rockis at KEY West and Stock Island, and by digging under fallen pal-
mettoi iraidj in a acrub In Polk Co mty, Florida.
PREDATOIO AND PARASITISM
Hamilton and Pollack (1956) found red-tailed skunks In the stomachs
of the coachwhip (Kasticoehis flagellurm), blacksnake (Coluber casetric-
tor), and pigmy rattlesnake (Sistrurus milarus) at Fort Benning,
Georgia. I knav of no other literature records concerning predation
on E. ebregius. Only one instance involving natural predation was
noted during the presence: investigation. Un March 14, 19e0, a freshly
ingested tail of one of these skinks was recovered from the stomach of
a 30-cm Lampropeltis dollata collected in a Geomys mound In the Study
Area. This snake often shows semi-fassortal tendencies and eats thz-
ards. I suspect that It Erequently preyed upon red-tailed skinks where
it occurs sympatrically with the latter. Other snakes known to feed on
small reptiles or their eggs and are often members of the same ecologi-
cal communities as red-tailed skunks include the short-tailed snake
(Stilosoma extenuatum), eastern indigo snake (Drymarchan corase
coupert), scarlet snake (Comophara coccinea), and coral snake (Micrurus
Important mammalian predators are perhaps the striped skunk
(Meph (fy mephitis), the spotted skunk (Spilogale 221Elium), and the
nine-banded armadillo (Dasypelets novaemnctus), which are omnivorous
and spend considerable time rooting about in sandy sail. Birds are
probably of little Lmportance as predators Jpon this species.
One hundred twent)-file red-tailed sklnks collected in the Scody
Area had clearly lost their ortganal calls, 72 had not. [ vas uncer-
rain about the taths of bi others. Mo~re large skunks had last thelr
talls than 6maLl ones. There was noJ difference betwee-n sexes in this
read hsve no way: of knowinl how mianyr of the tall losses could be
attributedd to predators, and how many may have resulted from fighting
and courting. i chink it is only log1icl to aJssume that many, if
Indeed not most? we-re lost to predators, and that the tail is of great
importance in enabling a skink to sun~ire a predatory attack. Behat-
loral traits which would tend to enhance the effectiveness of the tail
rn this role have been discussed in previous sections.
The red-tailed skinks collected had few ectoparasites. Trombicu-
ltd maltpe were the ojnly one-` noted and were found on but 4 of the 425
specime~ns examined. Most of these Lizards were taken during the cool
months of the year, however, and one might perhaps expect the Infesca-
tions to be higner during the summe~r.
Nrematodes occurred In the stomachs of 15 specimens, and custodes
In 2. These parasites have been submirtted to an authority for identi-
fication. ;ro efforts were ma~de to find protrozoan symbronts.
Dispersion and Structure
Red-tailed skunks tend to be gregarious. Even in extenalve areas
of seemingly ideal habitat, it was often necessary to hunt for an hour
or so before locating a skink, but almost invariably when one was
encountered, one or more others were found nearby. Some of this
grouping may have been the result of independent reaction to the same
favorable features of the locality. In areas of rolling topography,
for instance, the surmmits of hills and knalls were almost always more
productive as collecting sites than low-lying areas. It is possible
that moisture conditions were more favorable at such sites. There was
no evidence of territoriality among the males. On 4 separate occasions
during the height of the mating season, 2 mature males were found
occupying the same Geomys mound.
Some statements regarding population structure have already been
made (see section entitled Growth and Development). In view of the
selective nature of the collecting methods used in this study and the
marked geographic variation in growth and development La this species,
it seems futile to pursue the matter at greater length.
Denalty and Movements
The greatest density observed was on a hilltop in the Study Area
4 miles southwest of Archer. Here vegetation consisted at a sparse
growth of turkey oak, an occasional rosemary bush, and scattered clumps
of viregress. Approximately 60 per cent of the ground surface was
exposed, About 35 Geomya mounds were distributed m~ore or less at
random over an area of 50 by 70l yards, which included the sumrmit of the
hill. A tatal of Id skinka, 11 females and 7 males, were found within
this area between January :6 and March 24~, 1960. ALL of these were
sexually mature. Sixteen were found In Ggamps sounds, the other 2 we~re
found ujut beneath the surface under a piece of tin. each lizard was
marked by tee-clipping and released immediately. When an individual
was taken from a Geomys mound, the mound was reshaped, and the lizard
was released by allowing It to burrow into the mound.
Only 2 Lizards vere recaptured. Both were fema~les and were found
after approximately one month In Geomys mounds 7 meters and 9 meters,
respectively, from the ones in which they had been taken originally.
If one assumes that the 18 individuals located In the area were
residents, a density of alacsc: 25 mature lizards per acre is Indicated.
Moreover, it is doubtful that all chose inhab~tung the area were caught,
so the actual figure La probably higher.
The presence of pocket gophers, gopher turtles, and sand beetles
probably does much to enhance the carrying capacity of the habicate in
which they construct their burrows. These burrows provide homes and
retreats for vertebrates such as Mephitis mephltts, the Florida deer
mouse (Peromysius floridanus), the gopher frog (Rana areolate), the
diamondback rattleanake (Cratalus adamanteus!, Masticophis flagellum,
and, probably, Eumeces egreatus. In addition their presence would seem
to result in a greater abundance of many invertebrates, which are eaten
by larger animals and by their prey. Possibly there exists In sandhill
;nd scrurb associations a direct correlation between animal blomass and
the extent to which the community has been provided with these under-
SUM~lRYi MID CONCLUSIONS
The red-catted skink La a sma~li, fossortal Ilizrd occurring
locally in Georgia,, Alabama, and Florida. It is found almost exclu-
shely in areas of well-drained, sandy sulls, which In most parts of
the range support sandhill and scrub vegetational associations. There
are no records of its having been collected west of the Blaik Uarrior
or Tombighee~ Rivers, and there ts but one record (Randalph Count:.,
Alabama) for an occurrence outside the Coastal Plain.
Red-tailed skLnks were studied in the Laboratory and in the field
from September, 1959, to July, 1961, to obtain Information on their
bebsvior and ecology. In sandhIl associations they were collected
chiefly by raking through mouinds of sand pushed uip by Geomys pirgetts
and various geocrupine scarab beetles. In scrubs they were taken by
digging under fallen palmetto fronds, decaying Spanish mass, and other
ground litter. Certain insular populations were associated with the
Ltdal wrack along the aborelines.
The preferred temperature range of the red-tailed skink lies
between 2tO sad 34o, Thermoregulation is seem~ngly dependent upon the
individuals' aailary to mnore readily through the sull from one tempera-
ture scratum~ to another. The frequent occurrence of these skinks, as
well as Lleoseys revnoldsi and certain other fossorial reptiles, an
Geomys and beatte mounds can, I think, be attributed to attempts to
increase their body comperatures, the interiors of the mounds can thus
be regarded as l'basking sites.'
Eurmeces agreglus moves through loose soft by Lateral, undulatory,
"iyiswimmng" movements. It Ia not, however, nearly as proficient as
Neaeeps in "eand-swimming." On the surface the short, relatively
feeble legs aid in locomacian.
The food of this 1Lzard consince of small arthropods, and the com-
position of the diet of a given group of individuals appears to be more
a matter of availability than of preference. In scrub and sandhilll
associations, the lizards eat certain reaches, spiders, and crLcktets,
It is suggested that they encounter most of their food while prowling
about in burrows of other animals, probably those of Geoggys pinetis in
most casee. At Cedar Key Airstrip laland and Seahorse Key, amphipods
are the principal food items.
In most parts of the range courtship and rmalng occur chiefly
during the fall and winter. Courtabip is highly ritualistic, and In
most instances the mating act is relatively prolonged, lasting from 15
to 30 minutes. In mating the male seizes the female on the side just
behind a front leg and directs his body first over then under that of
the female. During the mating season the males show bright yellow,
orange, or reddish-orange suffusion about the sides, neck, snd chin,
and sometimes an the belly and throat. Males recogatze females chiefly
by odar. In captivity the males occasionally fight among themselves.
Ramonexual behavior was noted only among females.
After mating, the females become relatively loactive for 3 to 4
week. Following this quiescent period they feed veraciously and
develop fat stores. Nesting actlytty La greatest from April through
June. Nest cavLtles are hollowed out in the soil at depths ranging
from several inches to b feec beneath the surface. Prom three to seven
eggs are usually lald, and the female broads the ilutch constantly from
the t ime of laying until the youn6 have hatched and disperred. During
this time she clesais anid turns the eggs. Theje actuatles ma~iy be
essential for proper development. The female is thought to protect the
nest from certaln forms of predanion.
The rate of growth and developments is highl,' variable. In the
Laborator; young; Lizards of Florida parents grew rapidli and attained
sexual maturity and mated during the first fall. Th;se of' Geortgia 11n
Alabama parents grew more slovly and were still Lamnature ate almost I
:,ear at age.
In all parts of the orange fmeales becameib larger than maales. The
Largest specimen examined, allowing for shrfakcage in preser~ati~an, rs
a female from Cedar Kci Airstrap Island, and measuires 60) mm snout-vent
Red-tailed skunks are probably gregarious. There is no evidenee
of cerritoriality among males. Known predators include Masticophis
flagellum,, Sistrurue mulalrus, Coluberr cont~rictor, and LampropeILti
delliacs, One per cent of the speicimens were parasitized by tronmbledidd
mites, i.5 per cent by nrimacades; and 0.5 per cent by cestode;.
Babbitt, L. H. 1951. Courtship and mating of Eumaces egreglus. Copein,
Bogert, C, Hi. 1949. Thermioregulation in reptiles, a factor in evolu-
tion. Evolution, 3: 195-211.
Breckenridge, NJ. J. 1943. The life history of the black-banded skink
Eurmeces septentrionalis seprentrionalls (Baird). Amer. MLd1, Hat.
Carr, A. F. 1940. A contribution to the herp~etlogy of Florida. Univ.
Floridn Publ. Biol. Set. Ser. 3: 1-118.
Duellman, W. E. and A. Schuartz. 1958. Amphibians and reptiles of
southern FIlorida. Bull. Florida State Mus. 3: 181-326.
Evans, t. T. 1959. A motion picture study of maternal behavior of the
lizard, Eumeces absoletus Baird and Girard. Copeter 1959. 103-110.
Fitch, t. T. 1954. Life history and ecology of the five-lined skink,
Eurmeces fascistus. Univ. Kansas Publ. Mus. Nat. Hist. 8: 1-156.
.1950. Temperature responses In free-living smphibians and
reptiles of northeastern Kansas. Ibid. 8: 417-L70.
.1958. Natural history of the six-lined racerunner (Cnemido-
EMoTgs sextineatus). Ibid. 11: 11-62.
CoLa, O. B. 1957. An observacian of mating in the broad-headed skink,
Erpances laticepe, Rerpetalogica, 13: 155-156.
Grant, C. 1927. The blue-tailed sklak of Kansas (Eumeces guttulatus).
Copein, no. 164. 67-69.
Jansen, R. S. 1954. Notes on the lizard Eumeces egregius In Georgia.
Copeia, 1956* 229.
Hamilton, W. J., Jr. and J. A. Pollack. 1956. The food of some colu-
brid snakes from Fart Benning, Ceargia. Ecology, 37: 519-526.
.1958. Notes on the life history of the red-tailed skink.
Herpetologica, 14: 25-28,
Kauffeld, C. F, 1941, The red-called skink, Eumceces egregius, In
Alabama. Copeia, 19ul: 51.
Laessle, A. M. 1942. The plant communities of the Welaka area. Unly.
of Florida Biol, ScL. Ser. 4: 1-lr3.
.1958. The orig~n and successional relationship of sandhilll
vegetatlan and sand-pine scrub. Ecol, Monogr, 28: 361-387.
LeBu~ff C. R. 1900. The presence of certain herptiles rn southwest
Florida. Herpecologica, L6. 197-198.
McConkey, E. H. 1957. The subspecies of Eumeces egregius, a lazard
of the southeascern United Scates, Bull, Florida State Mus. ?:
Mecham, J. S. 1960. Range extensions for two southeastern kinks.
Herpetalogica, 16. ?22.
Neill, U. T. 1940. Burmeces egreglars in Georgia. Copela, 1940. 266,
Noble, C, K. and E. R. Mason. 1933, Experiments on the brooding
habits of the Lizards EumePces and Ophissaurus. Aoe r. Mus. Ilov.
Rodgers, T. L. and V. H. Memmler. 1943. Growth In the western blue-
talled skink. Trans. San Diego Soc. Nat. Hist, 10). 61-68,
Smith, H. M. 19*6. Handbook of litards. Comstock Publishing Co.,
Irhaca, N. Y.
Tanner, U. W. 1951, A caxonomrc and ecological study of the western
sklink (Eumces skrlL an anus)i. Grear Basin Nat. 17. 59-9i.
Telford, S. R., Jr. 1959. A study of the sand skink, Neoseps
reynoldsi Stejneger. Copela, 1959: 110-119.
Wharran, C. H. 1958. The ecology of the cottonmouths, Ancisrrodon
prsclvorus piscivorus Lacepede, of Seahorse Key, Florida.
Unpubl. Doctoral disserration, Univ. of Florida.
Robert Hughes Mount was born on December 25, 1931, at Lewisburg,
Tennessee. He graduated from Albany High School, Albany, Georgia, In
June, 19501 and entered Alabama Polytechnic Institute (now Auburn
University) the folluming September. He received the degree of
Bachelor of Science In FLsh Management from that institution in June,
1954, and that of Master of Science (Entomulofiy) in June, 1956. He
was employed by the Alabama Agricultural Experiment Station as an
assilstant in encomalogy from June, 1956, until he entered the United
States Army Medical Service Corps the following October. As a medical
entomologist he served both in the United States and in the Far East.
Immerdiately following his release from active duty in September, 1958,
he entered the University of Florida and began his doctoral studies in
Robert Hughes Hount Le single and is a member of Alpha Camma Rho,
Alpha Zeta, Geamma Sigma Delta, Phi Kappa Phi, Sigma Mi (associsce), the
Ecological Society of America, the American Society of Ichthyologists
and Herpetologists, and the Herpetalogists' League.
This dissertatton was prepared under the direction of the chair-
man of the canodidace:'s superrvisory committee and has been approkred by
all members of the commilttee. It was submitted to the Dean of the
College of Arts and Sciences and to the Craduate Council and was
approved as partial fulfillment of the requiirements for thre deg~ree of
Dostor of Philosophy.
August 1.1. 19t1
Dean,2 oiLegg e of A~rl andFi (enlceS
Dean, Graduate School