The Thermal Physiology of the Feathertail Glider, Acrobates Pygmaeus (Marsupialia:Burramyidae).

Abstract

Feathertail gliders are small arboreal marsupials from south-eastern Australia. Laboratory studies found that body temperature was labile and varied by 3.5°C throughout the day. Body temperature (Tb) control was stricter at low ambient temperature (Ta). Within the narrow thermal neutral zone (TNZ, 34.0-35.1°C), the basal metabolic rate was 2.11 W kg-0.75 (mean body mass 14.0 g) which is 13% lower than expected for a marsupial. Mass specific thermal conductance decreased with T, and the fleshy gliding membranes did not appear to contribute to the insulation. Huddling in groups of four or eight significantly reduced an individual's energy use. During torpor, Tb fell to close to Ta, the lowest Tb being 6.9°C, but torpor rarely lasted longer than 24 h. Groups of feathertail gliders often became torpid and showed a similar pattern of oxygen use during torpor to that seen in individuals. Some groups contained both torpid and normothermic individuals. This situation may benefit the torpid animals by reducing the cost of arousal and increasing the rate of rewarming.