torpor A state of adaptive hypothermia used by endotherms in order to save energy. In torpor, the body temperature of an animal may fall to within 1 °C of the environmental temperature, which in some cases may itself be at about or even just below freezing. All metabolic processes slow down to as little as one-twentieth of the normal rate. A state of torpor is entered during hibernation and when resources are insufficient to allow the maintenance of body temperature.

tor·por / ˈtôrpər/ • n. a state of physical or mental inactivity; lethargy: they veered between apathetic torpor and hysterical fanaticism.

torpor (tor-per) n. a state of sluggishness and diminished responsiveness: a characteristic of certain mental disorders and a symptom of certain forms of poisoning or metabolic disorder.

torpor See heterotherm.