 Warm-blooded, warm-blooded animal species can maintain the body temperature higher than their environment. In particular, homeothermic species maintain the stable body temperature by regulating metabolic processes. The only known homeotherms are birds and mammals. Other species have various degrees of thermoregulation. Cold body temperature control varies by species, so the terms warm-blooded and cold-blooded those still in everyday use suggest a false idea of there being only two categories of body temperature control, and are no longer used scientifically.