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How Many Naps a Day?!

Researchers found that chinstrap penguins take more than 10,000 naps a day!
Closeup of a penguin with a black stripe running from under its chin to the back of its head.
© Polina Melnyk/
These penguins know how to get their rest!

Except for a possible afternoon nap, most people get all their sleep overnight. But chinstrap penguins get their rest in a very different way. Scientists say these birds take more than 10,000 naps a day!

Scientists learned about this surprising sleep pattern by studying a group of chinstrap penguins in Antarctica. In addition to filming the birds, scientists placed devices in the neck and brain muscles of 14 penguins so they could record any brain activity related to sleep. They found that the penguins took 10,000 very short sleeping periods called microsleeps. Each little nap was only four seconds long! But all that dozing adds up—chinstrap penguins end up getting 11 hours of sleep every day.

A penguin chick sits under an adult penguin with its eyes closed and a speech bubble says Mom, are you awake.
© Pascaline Daniel/Shutterstock; Photo illustration Encyclopædia Britannica, Inc.

This sleeping pattern may seem odd, but scientists say it probably helps the penguins survive. Chinstrap penguin eggs and chicks are often hunted by other bird species. When one penguin parent leaves the nest for days to do some hunting over the ocean, the other parent must guard the eggs or chicks alone. It wouldn’t be very safe for a protective penguin parent to relax into a long snooze.

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Did You Know?

Sleep helps our brains take in and store new information. How much sleep do we need?

Adult humans need between seven and nine hours of sleep per night. Teens need eight to 10 hours each night, and kids aged 6 to 12 need nine to 12 hours.

An adult, a teen, and a child sleep in side by side beds showing how much sleep each needs per night.
© Tartilastock/, © pixelparticle—iStock/Getty Images Plus; Photo illustration Encyclopædia Britannica, Inc.

Don’t Sleep on These Facts!

© peter_qn/, © Panyajampatong/; Photo illustration Encyclopædia Britannica, Inc.

Not all animals sleep in the same way. For proof, just read the article about chinstrap penguins farther up on this page! But almost all animals need to sleep. Here are some surprising facts about animals and sleep.

Koalas sleep for up to 22 hours a day—more than any other animal! 

Giraffes sleep for about four and a half hours a day.

Cows can sleep while standing up. (They lie down when it’s time to sleep deeply.)

Dolphins rest only one half of their brains at a time, so the other side can stay awake and aware of predators.

Scientists think animals sleep to restore their brains, but a recent study found that even animals without brains, like jellyfish, seem to sleep. That means we still have a lot to learn about the purpose of sleep!

The Scoop on Penguins

Four penguins stand on a beach with boulders and greenery in the background.
© Lcodacci/

Not all penguins like to chill. Did you know that some species, like these South African penguins, live in warmer parts of the world?

Learn more about penguins at Britannica!

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Word of the Day


Part of speech:

: to walk with short steps while moving from side to side like a duck

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