What does homoiothermy mean?
Homoiothermy is the biological capacity or condition of keeping the internal temperature of the body relatively constant despite changes in the surrounding environment. Mammals and birds are familiar examples: they can remain active in cold or hot conditions because they generate and regulate heat through physiological processes such as shivering, sweating, and changes in blood flow. The term comes from Greek elements meaning “same” and “heat,” reflecting the relative stability of body temperature. It is closely associated with homeothermy, an alternative spelling and frequently used synonym, and contrasts with poikilothermy or ectothermy, in which an animal’s body temperature varies substantially with its surroundings. Homoiothermy is chiefly used in zoology, physiology, palaeontology, and evolutionary biology. Although the term can describe the condition of an individual animal, it also refers more broadly to this mode of temperature regulation across species and lineages.
nounThe biological condition of maintaining a relatively constant internal body temperature despite changes in environmental temperature. It is characteristic of endothermic animals such as mammals and birds.
- The maintenance of a relatively constant internal body temperature regardless of changes in environmental temperature.
"The evolution of homoiothermy allowed mammals to remain active across a wide range of climates."
"Birds and mammals are well known for their homoiothermy."
"Researchers study the origins of homoiothermy in early vertebrates."
The plural is rare; the term is normally used in the singular or uncountably.
"The study compared different homoiothermies among extinct and living vertebrates."
Homoiothermy is nature's built-in thermostat: it lets an animal keep its body temperature steady while the world around it changes.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does homoiothermy come from?
The word was formed in scientific English from Greek homoi(o), meaning “same” or “like,” and thermē, meaning “heat.” Its components reflect the maintenance of a nearly uniform internal temperature. Related English words such as thermal, thermic, isotherm, and thermometer share the same Greek element for heat.
Related word forms
How homoiothermy is actually used
This is a technical biological term. It is usually treated as uncountable when referring to the general physiological condition, and it is more common in scientific writing than in everyday speech.
Easily confused with homoiothermy
Homeothermy is a less common spelling of the same biological term and is often used interchangeably with homoiothermy.