Thermal Ecology of the Tropical Iguanid Lizard, Leiocephalus schreibersi

Abstract

-The Hispaniolan lizard, Lezocephalus schreibersi, precisely maintained a narrow range of body temperatures (Tb) (R = 36.7, SE = 0.17 C) that was significantly above concomitant air (Ta) and site (Ts) temperatures throughout all but the last hour of their emergence period. Lizards moved frequently between shade and sun throughout the day. Hourly basking frequency of the population was greatest (80%) when most lizards were emerging from their burrows (0900-0959 h), gradually declined to 35% at midday, then oscillated between 20-40% for the remaining afternoon hours. An hour before the majority of lizards entered their borrows (1700 h), movement markedly decreased and Tb declined to overlap Ts, as lizards appeared to relax thermoregulatory behavior. An important feature of this species' thermoecology is that the elevated and relatively stable Tb of Leiocephalus schreabersi permitted the lizards to be physically active during the entire day; rising ambient temperatures during the day never reached the maintained Tb Of this stenothermic species. In addition, no seasonal effects (November vs. May-June) were detected in the above thermal profile.