above for several consecutive days seemed to be a necessary stimulus for emergence from hibernation; emergence was in the last week in March or the first week in April in Florida. Hatching was found to take place in late June or early July. Adults were last seen before retiring into dormancy in the latter half of September and young of the year remained active into October some two or three weeks later. The skinks observed all lived in hollow water-oaks. When the population was at an especially high level, in the late summer of 1949, each hollow oak was inhabited by one young and one adult. Territoriality and mutual exclusiveness of adults and even of young seems to be implied. The skinks were seen eating spiders, ants, and cockroaches.
Neill (1950:115) mentions one sizable colony of E. laticeps living in a treeless urban area, in Georgia and depending for shelter on piles of metal drums and other industrial equipment. Evidently, however, this was an exceptional situation. In another paper, Neill (1948b:109) described the specialized hibernation site requirements of laticeps in Georgia; the skink retires inside large, rotting pine stumps, especially those that are leaning. He states (1948a:157) that in Georgia, laticeps is most common in the Coastal Plain and is much less numerous above the Fall Line (the line between the Coastal Plain and the Piedmont). Deckert (1918:31) wrote of “Plestiodon fasciatus” in the vicinity of Jacksonville, Florida, where only E. laticeps and E. inexpectatus occur: “Inhabits hollow trees, always near water. Blue-tailed ones often live around human habitations.”
With regard to the ecological traits of E. inexpectatus that distinguish it from fasciatus, authors are much less definite, and evidence is somewhat conflicting as the differences are relatively minor. Engels (1949:269) noted the occurrence of E. inexpectatus on two low islands of submarine origin, off the North Carolina Coast, Harkers Island and Shackelford Banks, and he surmised that the absence from them of E. fasciatus and E. laticeps must have some ecological significance, since all three species occur on the adjacent mainland. Most of the island inexpectatus were taken from beneath loose bark of standing trees, while mainland fasciatus was taken from beneath loose bark of fallen trees.
Barbour and Carr (1940:129) wrote of inexpectatus in the vicinity of Miami, Florida: “… it seems to be the only one [of the five-lined skinks] which has adapted itself to life under the rather specialized environmental conditions existing in its rocky and decidedly tropical habitat. It is one of the very few forms which have established themselves on some of the waterless and poorly vegetated islands on both coasts of the peninsula. E. inexpectatus is much less arboreal than either laticeps or fasciatus. Although it climbs trees when pressed, it is usually found on the ground among leaves or about fallen logs, and particularly about stone walls or old buildings made of cut rock.”
On the other hand, Neill (1948a:157) states that in Georgia, inexpectatus is often observed basking on tree trunks, and though adults often forage on the ground, they dash for the nearest tree when disturbed, usually climbing to a considerable height before halting. The juveniles, however, are said to climb only rarely; they hide beneath objects on the ground when they are pursued. Neill stated that E. inexpectatus occurs in dry pine forests where laticeps and fasciatus are lacking, as well as in moist or even swampy woods. E. inexpectatus often forages on the sides of old buildings.
Hoffman (1953:172), in discussing means of differentiating between inexpectatus and fasciatus in Virginia, states that there are ample differences in color and behavior as well as in scalation. He describes the color difference (blue color of tail of juveniles extending anteriorly beyond pelvis; light stripes reddish-orange on head, sublateral line present, in inexpectatus) but he does not describe the differences in behavior. He states that inexpectatus is the most abundant lizard in southeastern Virginia. Carr (1940:76) also states that inexpectatus is less arboreal than laticeps and is often found under logs and boards in dry sand.
E. inexpectatus thus seems to be adapted to a somewhat drier, more open, habitat than that typical of fasciatus, but it is not clear whether either species is more arboreal in habits. It is to be hoped that the present inconclusive summary will draw attention to the problem and will lead to more critical comparisons of the habitats and behavior of the two species by herpetologists in the southeastern states. The differences, both ecological and morphological, that distinguish inexpectatus from fasciatus are of a degree usually found between subspecies of the same species. The extensive geographic overlap between them is indeed remarkable in view of the slight degree of differentiation, morphologically and ecologically. They are, however, complementary in part in their ranges, while laticeps shares all parts of its range with either one or the other, or both of them (see Figures 4 and 5).
Fig. 4. Geographic distribution of Eumeces inexpectatus, as indicated by published records; only marginal and near-marginal records are shown, excluding those of doubtful validity.
Under present conditions, with these three species so similar in habits and so extensively overlapping in geographic range, it is difficult to visualize a barrier such as would have been required for allopatric speciation of the type, usual in vertebrates, to have occurred. One might be tempted to postulate sympatric speciation, with the parent form, presumably fasciatus, giving rise to the other two by abrupt mutations. However, the demonstrable antiquity of the five-lined skinks would allow ample time for divergence, allopatric speciation, and subsequent disappearance of the barrier and intermingling of populations. The displacement of floras and faunas that occurred in the Pleistocene, with the successive advances and retreats of the continental ice sheets might have had some part in bringing about the present overlapping distribution, after the disappearance of the original barrier. Such a barrier might have been an eastward extension of the central grasslands to the Atlantic Coast at a time when the climate of the continent was warmer and drier.
Fig. 5. Geographic distribution of Eumeces laticeps, as indicated by published records; only marginal and near-marginal records are shown, excluding those of doubtful validity.
Habitat and Limiting Factors
Temperature and Moisture Relations
For approximately half the year, at the latitude of northeastern Kansas, five-lined skinks are dormant. In early fall, even before the advent of cold weather, they are hard to find apparently having begun their retirement into the sheltered situations where they spend the winter, even though they may not be fully dormant at that time.
Remarkably little is known of the hibernation habits of this species or of reptiles in general for that matter. The limit of tolerance to low temperatures, the type of insulating medium, the moisture relationships, the specific stimuli which cause the animal to retire to its hibernation site or to emerge from it have not been determined. On only a few occasions have natural hibernating sites or the dormant skinks in them been observed by zoologists. Linsdale (1927:78) recorded one found in a sawdust pile late in the winter of 1924 in Doniphan County, Kansas. Hamilton (1948:211) found skinks of this species hibernating in Grant Parish, Louisiana, in hollow logs 18–20 inches in diameter, five in one log and three in another, on January 23, 1943. Frost in the damp wood almost reached the lizards, which were in a torpid condition. These observations were made when the temperature was 36°F. after the weather had begun to moderate following an unprecedented four-day cold wave when temperatures dropped to within a few degrees of 0°F. In both logs the skinks were accompanied by hibernating