What does homoiotherm mean?
A homoiotherm is an animal that keeps its internal body temperature within a relatively narrow range despite substantial changes in environmental temperature. Mammals and birds are the best-known examples, while creatures such as fish, reptiles, and many invertebrates are generally classified as poikilotherms because their body temperatures vary more markedly with their surroundings. The distinction is not simply between animals that feel warm and those that feel cold; it concerns how body temperature is regulated. A homoiotherm may become very hot in intense heat or cold in severe cold, yet ordinarily maintains a characteristic temperature through physiological mechanisms such as sweating, shivering, changes in blood flow, and metabolic heat production. In scientific writing, “homoiotherm” is sometimes interchangeable with “homeotherm,” though it is a comparatively specialized form. The word is especially useful in discussions of animal physiology, thermoregulation, adaptation, and the ecological consequences of different thermal strategies.
nounAn animal that maintains a relatively constant internal body temperature despite changes in environmental temperature, especially a mammal or bird. The term is used chiefly in zoology and biology in contrast to animals whose body temperatures vary substantially with the environment.
- An animal that actively maintains a relatively constant body temperature, particularly a mammal or bird.
"Birds and mammals are homoiotherms, with body temperatures that remain nearly constant across a wide range of surroundings."
"The researcher compared the heat-conserving behaviour of several mammalian homoiotherms."
"Unlike a poikilotherm, a homoiotherm can remain active in environmental temperatures that would be hazardous to a cold-blooded animal."
The regular plural adds the ending -s.
"Marine mammals and birds are well-studied homoiotherms."
A homoiotherm is a technical name for the animal behind the familiar idea of being warm-blooded.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does homoiotherm come from?
“Homoiotherm” combines forms derived from Greek homos, meaning “same,” and thermos, meaning “heat.” Its development reflects the Greek sense of maintaining heat at essentially the same level, in contrast to a body temperature that varies with external conditions. The closely related English term “homeotherm” comes from the same Greek elements and has substantially the same zoological meaning.
Related word forms
How homoiotherm is actually used
This is a specialist biological term, normally used in comparative physiology and zoology. It is closely related to “homeotherm” and distinguishes animals with relatively stable internal temperatures from poikilotherms, whose body temperatures vary with the environment.
Easily confused with homoiotherm
Both terms denote an animal that maintains a relatively stable body temperature, with homoiotherm being the more specialized Greek-derived zoological term and homeotherm the more general English term.