BODY TEMPERATURES OF CAPTIVE TORTOISES AT HIGH-ALTITUDE IN ZIMBABWE, WITH COMMENTS ON THE USE OF LIVING MODELS

It is difficult to devise physical models which precisely mimic the bo dy temperatures (T-b's) of large reptiles in the field. Studies of lar ge reptiles have the compensating advantage that individuals can be fo llowed for long periods, so that translocated individuals can be used as 'living models'. We compare T-b's of two tortoise species in an enc losure in Harare (altitude 1500 m) with those in the field at Sengwa ( 900 m), where mean air temperatures were about 5 degrees C higher. Kin ixys spekii, which occurs naturally near Harare, had similar T-b's at the two sites (means 27.6 and 27.0 degrees C, respectively). Geochelon e pardalis had significantly lower T-b's in Harare (29.1 degrees C) th an at Sengwa (32.6 degrees C), even though activity was shifted toward s midday in Harare. The inability to reach high T-b during activity ma y explain the absence of G. pardalis near Harare, and the distribution of this species in southern Africa.