noun
ectotherm
A biological term for an animal that relies on external heat sources to regulate body temperature, such as reptiles and amphibians.
爬虫類は外温動物の代表例だ。
Reptiles are a typical example of ectotherms.
内温動物 (endotherm) refers to animals that generate internal heat to maintain body temperature, such as mammals and birds, contrasting with 外温動物.
変温動物 (poikilotherm) is a broader term for animals whose body temperature varies with the environment; 外温動物 is a subset emphasizing external heat dependence.
Compound of 外 (outside) + 温 (warmth) + 動物 (animal), a modern scientific term calqued from English 'ectotherm'.