ABSTRACT
The short beaked echidna (Tachyglossus aculeatus) is one of three extant species of Monotremata, or egg-laying mammals, and the only one known to show torpor. The field studies of G. C. Grigg provided the first records of body temperature from a group of undisturbed echidnas in their natural habitat. These studies clearly established that echidnas show a classical mammalian pattern of hibernation with bouts of hibernation lasting 2-3 weeks interrupted by spontaneous arousals. The first measurements of body temperature were made by de Miklouho-Maclay who stated "It is possible that during the winter months the echidna is subject to a state of hibernation, which may also to a certain extent depress the usual temperature of the body". In the marmot, the eutherian hibernator most comparable in size to the echidna, reproductive activity is concentrated in the first 2 weeks after emergence.
