Cold-blooded animal is an animal that has little physiological control over its body temperature. Many cold-blooded animals, including most water animals, are warm when their surroundings are warm and cool when their surroundings are cool. Almost all animals are cold-blooded except birds and mammals, which are warm-blooded. See Warm-blooded animal.
Some cold-blooded animals can control their body temperature to a certain extent by varying their activities. For example, the body of an active cecropia moth produces so much heat by muscular action that the animal becomes warmer than its surroundings. Most cold-blooded land animals adjust their temperature by moving to different surroundings–into sunlight when they become too cool and into shade when they become too warm. Scientists refer to cold-blooded animals as ectothermic or poikilothermic.
