Rewarming rates and thermogenesis in hibernating echidnas.
We measured body temperatures (T(b)) in 14 free-ranging echidnas (Tachyglossus aculeatus) using implanted data-loggers. An average of 1020+/-744 days of T(b) data was recorded from each animal. The average maximum T(b) was 35.3+/-0.7 degrees C (n=14), and the lowest T(b) was 4.7 degrees C. Detailed analysis of rewarming events from four echidnas showed rewarming time to be dependent on initial T(b) (rewarming time in hours=15.6-0.41T(initial), n=31) with an average rewarming rate of 1.9+/-0.4 degrees C h(-1). Based on an hourly sampling rate, the peak rewarming rate was found to be 7.2+/-0.8 degrees C h(-1) (n=12), which was measured at a mean T(b) of 26.2+/-2.4 degrees C. This rate of heating was calculated to be equivalent to a peak oxygen consumption rate of 1.4+/-0.2 ml O2 g h(-1), approximately 9 times the basal metabolic rate. We found that a plot of rate of change of T(b) against T(b) for the entire data set from an individual echidna provided a useful summary and analytical tool.
Nicol
Stewart C
SC
Anatomy and Physiology, University of Tasmania, Private Bag 24, Hobart, TAS 7001, Australia. s.c.nicol@utas.edu.au
Andersen
Niels A
NA
D000818:Animals; D001143:Arousal; D005260:Female; D006605:Hibernation / Q000502:physiology*; D008297:Male; D004442:Tachyglossidae / Q000502:physiology*; D013648:Tasmania; D022722:Thermogenesis / Q000502:physiology*