Thermoregulation and Torpor in the Sugar Glider, Petaurus Breviceps (Marsupialia:Petauridae).

Abstract

Sugar gliders (Petaurus breviceps) from south-eastern Australia regulate their body temperature at 36.3 deg C at ambient temperatures less than 31 deg . Standard metabolic rate was 2.54 W/kg0.75 (mean weight 0.132 kg) and the weight-specific thermal conductance was 9% lower than predicted by weight for a marsupial. Individual sugar gliders entered torpor after starvation; the torpor lasted for less than 16 h. The body temperature of torpid gliders remained above 15 deg at ambient temperatures as low as 8 deg , and the metabolic rate was higher at 8 deg than at 15 deg . Arousing sugar gliders seemed to use both anaerobic and aerobic mechanisms of heat production. Groups of gliders huddled in the cold, reducing the lower critical temperature from 27 deg to 16 deg . Starvation of groups of sugar gliders did not always induce torpor in all gliders. The oxygen consumption rate of a group of 4 torpid sugar gliders at an ambient temperature of 8 deg was lower than that of a single glider under the same conditions. Huddling seems to be the most important mechanism for energy conservation for P. breviceps and torpor may be used to overcome short-term reductions in winter food supplies.