The Natural history of the red-tailed skink, Eumeces Egregius Baird

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The Natural history of the red-tailed skink, Eumeces Egregius Baird
Mount, Robert Hughes, 1931-
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vii, 86, 1 leaves. : illus. ; 28 cm.


Subjects / Keywords:
Animal feeding behavior ( jstor )
Eggs ( jstor )
Female animals ( jstor )
Food ( jstor )
Keys ( jstor )
Lizards ( jstor )
Mating behavior ( jstor )
Scars ( jstor )
Skinks ( jstor )
Soil temperature regimes ( jstor )
Biology thesis Ph. D ( lcsh )
Dissertations, Academic -- Biology -- UF ( lcsh )
Skinks ( lcsh )
Levy County ( local )
bibliography ( marcgt )
non-fiction ( marcgt )


Thesis - University of Florida.
Bibliography: leaves 84-85.
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August, 1%l


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.



ACKN~OYLEDGMENTS . .. .. .... .. .. . ..~ ~~ ..

LIST OF TABLES .. ... ... .. .. .. .. .. .. vi

LIST OF FIGURES . ... .. .. .... . . . . vil

INFTRODUCTION .. ... .. .. .. ... .. .. .. . 1

GENEPALME1710DS ......................... 2

GEOGRAPHIC RANGE ... . ... .. ... .. .. 6


TfEMPERATURE RELATIIONSHIPS .. .. .. . .. . .. . . 15

LOCOMO~TION . .... ... .. .., . ... .. . .. 23

FOOD RABITS ... . .. ...... .. .. . . . 5

FEEDINGC BEHAVIOR .. .. . ... ,,,. .. . .. 31


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


Table Page

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

Figure Page

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



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.


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



1- *




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

bur rows.

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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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)

Roaches 81.9
Cariblatella lutea 18.5
Arenivage floridensis 3.9
Unidentified 1,
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
Centipedes 1.3
Scorpions 0.8
~ITermi~tes (vinged) 0.4
Termites Cuorkers) 0.4
Locustid grasebappers 1.3
Ant lions 0.4
Ants 0].4
Errwigs 0.4 11.8 75.0
Amphipods 100.0
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
''Early "Late
"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
Centipedes 1.9

Scorpions 1.9
TermLres (vrnged) .
Grasshoppers 3.3
Ant lIons 1.9
Anrs 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

these specimens.


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



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




9 a



** *

** **** *

** *

* ***ese *




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

that area.

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
right, tva,

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

co~mmn there.

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

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

her hold.

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

!. 48

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

activity described.

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-

M .


""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.

Preovigosition Period

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



90 -


5 0-

z 30~ ---

20 -0


(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

ii/////iiiiiiiiiiiiii//////ii :I//////////iiiiiiiiiiiiiiiiiii////////i



90 E-



22 60

~- 50

DJ 40

2= 30

of 20





(2 4)





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

and May.

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

nC cw.
r l c
(I P0
r0 "E

D re

S*- rr D

A r' W

r ID r.

n DM

D #Z

ul i

Sm o5***

c a re

m "U r

" li A i

a3 r
" -1r




5 ** *

* agg








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

April 3

April n

April 1

April Li

April 12

April ?1

May 5

May 13

May in

Nay 20

May 23

May 15

May 29

June 13

May 24

May' 20

May 31

June 5

June 3

June 1--15

June 17-18

June ?1-22

June 2 -25

June ?9

July 1

Jul 3

July 13-14













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
(Srudy Area)

Levy County, Fla. j 10t. 1-1.0l 10.4 .0-, 6. 3
(Study Area)

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 -



4 I


~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,
-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
QO *

,0 .8 r

h)g n re NQ sa

N3 set N 34 *7



a. u

.5 "

as O

** e
Y u

E aI
U t

r, D


U -4

"u B


p0 m

. .

r 9 *v cr e
4 --a .a

Crl ri 3 on ,o as

as~ as a g) a

S 33 u u o
l"I "i


a >Du

la ul e

,:u e1 --a

g Y.b
10 we U
Gno u

C 00

0 S

a~ O

r: n
to a





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.

,s $(3)


/ a$(4)

* rd' (4)
~- $ (2

Mno Coa
, .*,-




3 O


/ ; .


1 1 1 1 1 1 1

0 20 40 60 80 100 120

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
-(20) (10)
wI~ (5 13\3) -

50 -


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
Cou~nt tes.

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.

Postne~sting Actality

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.


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

fulvius fulvius),

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-

ground paassges.


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,
1951: 79.

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.
29: 591-606.

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.
019: 1-19.

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

Superiisoryr Comitiltee: