Homeothermic mammals and birds consume considerable resources maintaining core body temperature within narrow limits. In response to energetic challenge or extreme environmental conditions, some species abandon homeothermy and exhibit torpor or hibernation. Until recently it was thought that species that do not use torpor or hibernation always maintained homeothermy, but it is now known that’s not the case. Variations in the amplitude of the daily rhythm of core body temperature are common in free-ranging animals and that these deviations are due to perturbations to homeostasis in at least energy and water balance.

Professor Maloney is continuing to test other homeostatic systems testing the hypothesis that the amplitude of the daily rhythm of core body temperature provides a measure of homeostatic function and could provide an index of individual fitness.

Using biologging techniques to measure core body temperature and other variables in free ranging mammals and birds Professor Maloney has shown that deviations from homeothermy occur frequently. Those deviations are not associated with environmental temperature extremes (as was thought) but are caused by strain in other homeostatic systems, caused most importantly by reductions in energy and water intake. He is currently trying to understand both the underlying physiological and molecular mechanisms to the heterothermic response as well as the fitness implications of the observed heterothermy.


  • Professor Duncan Mitchell, University of the Witwatersrand
  • Professor Andrea Fuller, University of the Witwatersrand
  • Associate Professor Leith Meyer, University of Pretoria