An organism whose body temperature varies only within narrow limits. It may be regulated by internal mechanisms (i.e. in an endotherm) or by behavioural means (i.e. in an ectotherm), or by some combination of both (e.g. in humans, who light fires and wear thick clothes to keep warm in cold weather and wear light clothing to keep cool in warm weather, but who are also endothermic).
Subjects: Biological Sciences — Earth Sciences and Geography.