Body temperatures of the large, flightless dung beetle Circellium bacchus have been measured during walking, ball making and ball rolling, but were not significantly different from black bulb temperatures. Circellium is thus strictly ectothermic, unlike winged dung beetles, which are endothermic during terrestrial activity as well as in flight. Keywords: Circellium bacchus, Dung beetles, Endothermy, southern Africa.