Complementary nature of heat production and heat intake during behavioral thermoregulation in the rat.

Rats were trained to work for radiant heat in a cold environment in an apparatus that permitted the simultaneous measurement of metabolic heat production. Reductions in behavioral efficacy produced either by a decrease in reward duration or intensity or by an increase in response effort resulted in a reduction in behavioral heat intake, an increase in metabolic heat production, and no change in body temperature. Thus, autonomic and behavioral temperature regulation interact to produce a constant body temperature.