THERMOREGULATION BY THE SPOTTED TREE MONITOR, VARANUS-SCALARIS, IN THE SEASONAL TROPICS OF AUSTRALIA

1. Varanus scalaris was studied in the wet and dry seasons by measurin g body temperatures (T-b) in the field and in a laboratory thermal gra dient, acid by calculating operative temperatures (T-c) in conjunction with microclimatic data. 2. In the field, predawn T(b)s in the wet se ason were higher than in the dry season, and this is attributed to env ironmental conditions. Wet season T(b)s were also higher during the da y, but this is attributed to the behaviour of the lizards because T(e) s indicated that the thermal environment was not limiting. The mean mi dday T-b was 38.9 degrees C in the wet season and 35.6 degrees C in th e dry. 3. In the laboratory, the lizards selected a mean T-b of 38.1 d egrees C in the wet season and 35.2 degrees C in the dry season. Thus, in both the field and the laboratory, the lizards maintained T(b)s ap proximately 3 degrees C lower in the dry season. Copyright (C) 1996 El sevier Science Ltd