 Dear students, in this topic, we shall discuss the temperature relations of endotherms. The homeothermic endotherms include most mammals and birds. They maintain their body temperature relatively constant within a narrow range. This temperature maintenance is independent of the ambient temperatures. Ambient temperatures are very low but a homeothermic endotherm keeps the temperature of the body nearly constant. The temperatures of tissues inside the body are known as the core temperatures. Core temperatures in mammals are maintained nearly constant between 37 to 38 degrees centigrade. In birds, the core temperatures are maintained in the range near to 40 degrees centigrade. The temperatures of peripheral tissues and extremities are known as peripheral temperatures. These temperatures are held comparatively less constant in homeothermic endotherms. These peripheral temperatures are sometimes even allowed to approach the environmental temperatures. Dear students, now we shall discuss the mechanisms of endotherm which include the mechanisms of heat production, mechanisms of heat conservation and mechanisms of heat dissipation. Because endotherms are required for these three things. First, to produce heat. Second, to keep the heat safe. Third, to dissipate the heat, we shall discuss all these three mechanisms in detail. First, we shall discuss the mechanism of heat production. Endotherms use a variety of mechanisms for heat production i.e. thermogenesis. For example, through homeostatic mechanisms, through muscular mechanisms and through hormonal mechanisms. Now we shall discuss the mechanisms of heat conservation. Endotherms use a variety of mechanisms for heat conservation. The most important physiological mechanism in this aspect is the counter-current exchange mechanism. The mechanisms of heat dissipation include a variety of evaporative cooling mechanisms. There are two very important mechanisms in this. One is sweating, sweating or perspiration. And the other is panting. Dear students, the purpose of all these mechanisms of endotherm is the regulation of rates of heat production and heat loss. And the overall result of these mechanisms is the maintenance of body temperature i.e. endotherm.