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

We investigated the usefulness of body temperature (T_b) as a guide to egg-laying in a monotreme mammal, the echidna, Tachyglossus aculeatus, and attempted to quantify changes in T_b 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 T_b 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 T_b change which lasted an average of 43±4 days.