ectotherm

American  

[ek-tuh-thurm] / ˈɛk təˌθɜrm /

noun

Zoology.

1. a cold-blooded animal.

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ectotherm Scientific  

/ ĕk′tə-thûrm′ /

1. A cold-blooded organism.

2. Also called poikilotherm

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Other Word Forms

• ectothermic adjective

Etymology

Origin of ectotherm

First recorded in 1940–45; ecto- + therm

Explanation

Unlike a bird or mammal that regulates its own internal body temperature, an ectotherm relies on its environment to keep its body warm, like a lizard basking in the sun. Any animal that can't produce its own warmth or internally regulate its body temperature is an ectotherm. Some examples of ectotherms are reptiles, amphibians, and fish. For example, a snake might lie on a rock in the sun to raise its body temperature, and then lounge in the shade to lower it. While ectotherms are often referred to as "cold-blooded," this term can be a little misleading, as ectotherms' blood isn't actually cold; it's just that their body temperature changes with the environment.

Example Sentences

"Endotherm and ectotherm vertebrates may process cognitive tasks in fundamentally different ways due to differences in brain organisation," the authors argued.

From Salon • Feb. 2, 2024

An ectotherm such as an alligator has an SMR of 60 kcal/day.

From Textbooks • Jun. 9, 2022

Fort Worth Zoo ectotherm curator Diane Barber said Olaf will remain in Texas but 200 toadlets will be released in Puerto Rico.

From Seattle Times • Nov. 22, 2019

At rest, a bumblebee’s temperature varies, like that of a traditional ectotherm.

From Washington Post • Nov. 27, 2015

"Doesn't that suggest that there's an adaptive value in being either a good ectotherm or a good endotherm, but not in the middle?"

From BBC • Jun. 12, 2014