Body temperature rhythm of the tree shrew, Tupaia belangeri.

The circadian rhythm of body temperature of the tree shrew Tupaia belangeri was studied by telemetry. The amplitude of the daily (or circadian) variation was found to be much larger than that of most endotherms (amplitude approximately 5 degrees C) and the bimodal shape of the rhythm differed from the cosine waveform that characterizes the temperature rhythms of most other species. In free-running conditions, as well as in the entrained state, the temperature rhythm remained synchronized to the rhythm of locomotor activity.