poikilotherm, ectotherm

poikilotherm, ectotherm

or

heterotherm

any animal whose body temperature follows that of the surrounding environment. Poikilotherms are described as cold-blooded, but the body temperature may be quite high. Aquatic poikilotherms follow the environmental temperatures closely, but terrestrial forms may warm up from the sun's irradiation or cool through evaporation to an extent varying with the temperature of the surrounding air. All animals apart from mammals and birds are poikilothermous. Compare HOMOIOTHERM.

Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005