BEHAVIORAL, THERMAL, AND METABOLIC CHARACTERISTICS OF A WINTERING LIZARD (ANOLIS-CAROLINENSIS) FROM SOUTH-CAROLINA

1. Anolis carolinensis, the most northerly distributed member of its n eotropical genus, does not hibernate, but facultatively basks during d ays with direct sunlight throughout the December to March period. 2. B oth sexes were primarily inactive (92% of emerged time), infrequently foraging (6.4%), interacting socially (1.3%), or responding to predato r threats (<0.1%). 3. Because subjects infrequently moved (averaging 2 cmh(-1)), apparent thermoregulatory behaviour (i.e. sun/shade shuttli ng) was rarely observed. 4. Body (T-b) and concurrent air (T-a) temper ature relationships for emerged lizards were: maximum TbS range of 33- 34 degrees C, a mean T-b of 23 degrees C, and a mean T-b-T-a different ial of 2.4 degrees C (ranging up to 15 degrees C). 5. Several criteria characterized winter A. carolinensis as being passive, thermal genera lists. 6. Mean monthly oxygen uptake for wintering A. carolinensis was estimated at 0.924 December), 0.686 (January), 0.884 (February), and 1.118 (March) Ml g(-1) day(-1). 7. The total estimated energy expendit ure for the four months by the average male (3.8g body mass) and femal e (2.9 g body mass) was 1.99 and 1.52 kcal, respectively, which is equ ivalent to 0.21 and 0.16 g of lipid metabolized, respectively (approxi mate to 6% of body mass). 8. Compared to metabolic rates at the specie s' 32-35 degrees C preferred T-b range, the 23 degrees C average T-b o f emerged lizards represented a 60% reduction in energy expenditure. W e speculate that the observed basking T(b)s reflect an adaptive trade- off between nonbasking TbS for minimum metabolic costs and optimally h igh TbS to facilitate physiological processes (e.g. gonadal recrudesce nce), but at a threat to lipid reserves.