Scientists Say: Torpor

This state is more than just a deep sleep


Hummingbirds are one of the few bird species that go into torpor at night. This lets them conserve energy when food is scarce and temperatures are cool.


Torpor (noun, “TORE-purr”)

This is a condition of decreased body temperature and low energy use in an animal. An animal that is in torpor is not asleep. It’s torpid. When an animal sleeps, its body temperature and the energy its body uses remain relatively high. But when an animal enters torpor, these plummet. Torpid animals can have extremely low body temperatures and use very little energy. It’s a good way for an animal to survive a time when food may be scarce.

Torpor doesn’t have to last a long time. Some birds, rodents and bats do it daily. Other mammals go into long-term torpor for days, weeks or months.

In a sentence

Hibernation is a kind of long-term torpor.

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Bethany Brookshire was a longtime staff writer at Science News Explores and is the author of the book Pests: How Humans Create Animal Villains. She has a Ph.D. in physiology and pharmacology and likes to write about neuroscience, biology, climate and more. She thinks Porgs are an invasive species.

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