Body-Temperature and Diurnal Activity Patterns in the Platypus (Ornithorhynchus-Anatinus) During Winter

Abstract

Using implanted radiotransmitters, we monitored body temperatures in five platypuses ranging freely in the Thredbo River in Australia's southern alps between April and October 1988, where the water gets as cold as any that a platypus is likely to encounter. Activity pattern showed a distinct daily cycle. No evidence of hibernation or even brief periods of torpor was found, all individuals maintaining body temperatures close to 32-degrees-C throughout the winter (mean+/-s.d., 32.08 +/- 0.75-degrees-C, range 29.2-34.6-degrees-C, n = 2237). No differences were found between the means or the variances of body temperatures of animals during day-time rest in stream-bank burrows and those during night-time foraging in winter at temperatures as low as 1.0-degrees-C.