Homeothermic animals:
Homeothermic animals maintain body temperature within a relatively narrow range despite environmental change. In birds and mammals this is usually achieved through endothermy: cellular respiration and other metabolic processes generate heat internally. Heat production can rise through shivering, non-shivering thermogenesis, muscle activity, and hormonal elevation of metabolism. Insulation, vasoconstriction, counter-current exchange, sweating, panting, and behavioural choices regulate heat gain and loss. Because sustaining metabolic heat requires fuel and oxygen, these animals generally have co
Ref: Evolutionary Analysis, Herron & Freeman, 5th Ed., Ch. 10
