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An organism, such as a fish or reptile, having a body temperature that varies with the temperature of its surroundings.

[Greek poikilos, spotted, various; see peig- in Indo-European roots + -therm.]

poi′ki·lo·ther′mi·a (-thûr′mē-ə), poi′ki·lo·ther′my (-thûr′mē) n.
poi′ki·lo·ther′mic (-mĭk) adj.


(Animals) an organism with poikilothermic qualities
(Zoology) a variant form of poikilothermic
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.poikilotherm - an animal whose body temperature varies with the temperature of its surroundings; any animal except birds and mammals
animal, animate being, beast, creature, fauna, brute - a living organism characterized by voluntary movement
References in periodicals archive ?
The time step is a day (t) with forcing variable being temperature that from the perspective of the poikilotherm organisms is of varying length in physiological time units (degree-days, dd).
The word homeotherm is used to describe the opposite of poikilotherm.
52) It is noteworthy that both the mammalian as well as the bird embryo have poikilotherm metabolism till birth (homoeothermic condition is provided by parent organism).
Poikilotherm energy requirements support my contention that by the Late Pleistocene the megaherbivores were so rare in the Australian biota that they were not targetted by homoeothermic carnivores, whose paucity suggests that the smaller herbivores were also dispersed.
It is a poikilotherm, never had a dependent childhood, has little or no social life.