A homeothermic (or "warm-blooded") animal is one that can keep its core body temperature at a nearly constant level which is distinct from the temperature of the surrounding environment (that is, to maintain thermal homeostasis) . This can involve not only the ability to generate heat, but also the ability to cool down if necessary.
Diverse mechanisms can come into play to regulate body temperature, such as shivering (to generate heat from muscle contractions), blanching (circulatory changes to direct less heat to the skin), flushing (circulatory changes to radiate more heat from the skin), panting or sweating (to increase heat loss through evaporation).
See also: poikilothermic, endothermic
