POIKILOTHERMIC TRAITS AND THERMOREGULATION IN THE AFROTROPICAL SOCIALSUBTERRANEAN MASHONA MOLE-RAT (CRYPTOMYS-HOTTENTOTUS-DARLINGI) (RODENTIA, BATHYERGIDAE)

When acclimated for two months at 26-degrees-C the social Mashona mole -rat Crytomys hottentotus darlingi has a mean (+/-S.D.) resting metabo lic rate (RMR) of 0.98+/-0.14 cm3 O2 g-1 h -1 (n=21), within a thermal neutral zone (TNZ) of 28-31.5 C ambient temperature (Ta). The body te mperature (Tb) of the mole-rat is very low, 33.3+/-0.5 C, and remained stable between 25-31.5-degrees-C (n=28). Above 33-degrees-C, Tb incre ased to a mean of 34.7+/-0.77 C(n=28) (Ta range 33-39-degrees-C). Belo w Ta 25-degrees-C, Tb showed strong poikilothermic tendencies, with Tb dropping to a mean of 26.8+/-1.16 C at 6-degrees-C, whereas above Ta 25-degrees-C, Tb varied in a typically endothermic pattern. The conduc tance is high 0.19+/-0.03 cm3 O2 g-1 C-1 (n=28) at the lower limit of thermoneutrality. The mean RMR at 18-degrees-C (the lowest Ta tested) was 2.63+/-0.55 cm3 O2 g-1 h-1 (n=7) which is 2.6 times that of the re sting metabolic rate in the TNZ.