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

by Henry S. Fitch

Age and Sex	Date		Snout-vent length in mm.	Tail length in mm.
No. 1.	June 1,	1951	73	38 (newly broken)
Adult male	June 26,	1951	73	38 + 14
	August 17,	1951	76	40 + 45
	April 29,	1952	76	40 + 45
No. 2.	May 28,	1949	51	46 (newly broken)
Immature	October 15,	1949	69	51 + 21
No. 3.	June 11,	1950	49	49 (newly broken)
Immature	September 2,	1950	63	63 + 31
No. 4.	August 10,	1950	621⁄2	60 (newly broken)
Immature female	June 14,	1951	68	62 + 17
No. 5.	August 14,	1950	671⁄2	77 + 41⁄2
Adult male	September 3,	1950	681⁄2	77 + 61⁄2
	April 27,	1951	69	78 + 9
No. 6.	April 7,	1950	67	38 (newly broken; separated end 66)
Adult male	July 27,	1950	71	39 + 471⁄2
No. 7.	May 28,	1951	70	18 (newly broken; separated end 100)
Adult male	June 14,	1951	71	18 + 1
	September 22,	1951	76	19 + 29 + 71⁄2
No. 8.	June 12,	1951	72	33 (recently broken)
Adult male	July 28,	1951	76	36 + 31
No. 9.	May 2,	1951	45	47 + 1
Juvenile	May 14,	1951	45	47 + 3
	May 19,	1951	45	47 + 5
No. 10.	June 7,	1952	64	51 (recently broken)
Subadult female	June 24,	1952	64	51 + 11
No. 11.	August 19,	1949	42	40 (newly broken)
Juvenile	June 13,	1950	581⁄2	58 + 28
	August 5,	1950	63	62 + 31
No. 12.	May 17,	1951	78	20 (newly broken)
Adult male	June 12,	1951	78	20 + 13

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

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

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

Movements

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

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

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

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

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