Body temperatures in some Australian mammals. 4. Dasyuridae.

Abstract

Body temperatures (TB) were measured in seven species of dasyurid marsupials ranging in size from 11 to 6700 g; these were: Sminthopsis laripinta, Sminthopsis crassicaudata, Antechinus flavipes, Dasycercus cristicauda, Phascogale tapoatafa, Satanellus hallucatus, and Sarcophilus harrisii. Daily TB cycles showed amplitudes from 0.8 to almost 4 degC. Mean TB during the active period ranged from 37.4 to 38.8°C, and in the quiet period from 34.0 to 37.0°C. Minimum TB in some individuals approached ambient temperature (TA) to represent daily aestivation. Low TA (5-10°C) did not reduce the TB but at a high TA (40°C), elevation of TB to 39-39.5°C was observed. The TB was strongly dependent on the state of the animal with increments of 3-4 degC seen between sleep and maximum activity; and rates of increases as high as 0.5 degC per min. The physiological responses of this closely related group were very uniform. This marsupial family does not appear inferior to higher mammals in any aspect of thermoregulation although the responses are more diverse than in nonhibernating placental mammals.