Body Temperatures of Free-Ranging Platypuses, Ornithorhynchus anatinus (Monotremata), with Observations on their Use of Burrows

Abstract

Body temperatures (T*h) of free-ranging platypuses were monitored by means of radiotelemetry; although fluctuations of up to 2.8�C occurred in some individuals, most T*b measured were close to 32�C, even during immersion in cold water for up to 12 h. Platypuses spent up to 51% of their day foraging in water, and during such activities 71% of the animals studied used more than one particular burrow. One platypus maintained its T*b, while swimming in water of 0�C in a partly frozen river for at least 5 h. The platypus is a competent homeotherm which maintains a constant T*b in the face of the considerable thermal stresses imposed on it during winter in the southern part of its range.