"Thunnus" are widely but sparsely distributed throughout the oceans of the world, generally in tropical and temperate waters at latitudes ranging between about 45° north and south of the equator. All tunas are able to maintain the temperature of certain parts of their body above the temperature of ambient seawater. For example, bluefin can maintain a core body temperature of , in water as cold as . However, unlike "typical" endothermic creatures such as mammals and birds, tuna do not maintain temperature within a relatively narrow range.