How do mammals control their body temperature?

Body temperature is controlled by the thermoregulatory centre of the brain. After body temperature is detected by temperature receptors, a nerve impulse transmits this signal to the brain.
If the body temperature is too high, blood vessels widen (vasodilation) and sweat glands release sweat, allowing transfer of heat to the environment, cooling the body.
If body temperature is too low, blood vessels narrow (vasoconstriction), and rapid muscle contraction may cause shivering.
Animals may also change their behaviour to modify their body temperature. For example, an animal might move into or out of the shade to change its body temperature. This is particularly important for cold blooded (ectothermic) animals, such as reptiles.