TEMPERATURE AND THE TROPICAL TORTOISE KINIXYS SPEKII - CONSTRAINTS ONACTIVITY LEVEL AND BODY-TEMPERATURE

Movements of five Kinixys spekii were measured continuously during six weeks of their activity season, by thread-trailing. The mean daily mo vement distance was negatively correlated with maximum shade air tempe rature. but not significantly related to minimum temperature, rainfall , or humidity. There was a midday period of inactivity of increasing l ength as maximum air temperature exceeded 29 degrees C. Temperatures o f models suggest that lower activity on hot days was due to the risk o f overheating in this small (mean mass 617 g) tortoise. Kinixys spekii had a mean field body temperature (T-b) of 27 degrees C, which is low compared to other tortoises (including sympatric Geochelone pardalis, mean T-b = 32.5 degrees C), but salivated al a similar T-b (38.4 degr ees C). This pattern also occurs in other small species; mean and maxi mum field T(b)s Of tortoises are positively correlated with body mass, but salivation and critical maximum T(b)s do not vary with body mass. Low field T-b provides a wide safely margin before evaporation of wat er becomes necessary. Kinixys spekii had a short annual activity perio d, with about 95% of sightings in four months (December to March). Mon thly sightings of K. spekii were correlated with rainfall, but not sig nificantly related to temperature or humidify. Seasonal activity is th erefore related to rainfall,but within the rainy season the level and pattern of daily activity is related to temperature.