 Dear students, in this topic we shall discuss the thermostatic role of hypothalamus in mammals. Dear students, a homeotherm's body temperature control system is similar to a mechanized thermostatic control system. Such a system has a temperature sensor, a set point temperature, a thermostat and a heating unit. This analogy to mechanized system is applicable to endothermic heat production and control in the zone of metabolic heat regulation. In this zone, endothermic heat production linearly increases with decreasing ambient temperature. Animals may have many temperature sensors in various parts of the body which send their input to the thermostat. To maintain the body temperature at the set temperature, thermostat may activate the mechanisms of either heat producing or heat exchanging or heat conserving or heat loss mechanisms. The required mechanism may change the temperature according to which the thermostat activates. Dear students, the temperature sensitive neurons and nerve endings are found in the brain, in the spinal cord, in the skin and many other sites of the core of the body. These temperature sensors give their input or provide their input to the thermostatic centers in the brain. Dear students, the mammalian thermoregulatory center is located in the hypothalamus. Although mammals have many other thermoregulatory centers, the major thermoregulatory center is in the hypothalamus. This hypothalamic thermostat is considered as the body's thermostat, which is highly sensitive to temperature changes. Hypothalamus is a thermostatic regulatory center. If the hypothalamus is cooled, it produces an increase in metabolic rate and a rise in body temperature. If it is experimentally heated up, it evokes a drop in body temperature. This hypothalamic thermoregulatory center is highly sensitive to temperature sensitive neurons. Some of these neurons respond to increased hypothalamic temperature. When these neurons activate, they activate heat dissipating mechanisms, that is, vasodilation, panting and sweating. When other types of neurons are found, they respond to the temperatures dropping below the set temperature. When these neurons activate, they respond by activating the heat-conserving responses and heat-producing responses. For example, brown fat metabolism or shivering or non-shivering thermogenesis. All these responses are activated on cooling effects on hypothalamic regulatory center.