Body temperature as an indicator of egg-laying in the echidna, Tachyglossus aculeatus

We investigated the usefulness of body temperature (Tb) as a guide to egg-laying in a monotreme mammal, the echidna, Tachyglossus aculeatus, and attempted to quantify changes in Tb and relate them to specific reproductive events. Six female echidnas were implanted with temperature loggers and then radio-tracked in the wild for up to 6 years. In reproductive years there was a significant reduction in Tb variability 21.7±2.5 days after final arousal from hibernation, which coincided with the time at which the female entered the nursery burrow. Egg-laying occurred within 2 days of this Tb change which lasted an average of 43±4 days.