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Warm-blooded animal species can maintain a body temperature higher than their environment. In particular, homeothermic species maintain a stable body temperature by regulating metabolic processes. The only known homeotherms are mammals and birds. Other species have various degrees of thermoregulation. Animal body temperature control varies by species, so the terms "warm-blooded" and "cold-blooded" give a false idea of there being only two categories of body temperature control, and are no longer used scientifically. The terms are still in everyday use. ==Terminology== In general, warm-bloodedness refers to three separate categories of thermoregulation. *Endothermy is the ability of some creatures to control their body temperatures through internal means such as muscle shivering or increasing their metabolism (Greek: ''endon'' = "within", ''thermē'' = "heat"). Some writers restrict the meaning of endothermy to mechanisms that directly raise the animal's metabolic rate in order to produce heat. The opposite of endothermy is ectothermy. *Homeothermy maintains a stable internal body temperature regardless of external influence and temperatures. This stable internal temperature is often, though not necessarily, higher than the immediate environment (Greek: ''homoios'' = "similar", ''thermē'' = "heat"). The opposite is poikilothermy. Mammals and birds are Homeothermic animals. *Tachymetabolism maintains a high "resting" metabolism (Greek: ''tachys/tachus'' = "fast, swift", ''metabolēn'' = "throw beyond"). In essence, tachymetabolic creatures are "on" all the time. Though their resting metabolism is still many times slower than their active metabolism, the difference is often not as large as that seen in bradymetabolic creatures. Tachymetabolic creatures have greater difficulty dealing with a scarcity of food. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Warm-blooded」の詳細全文を読む スポンサード リンク
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