As colder weather approaches, what changes do you make? You probably start to wear heavier clothing, including long pants, long-sleeved shirts and coats.

You may also break out the gloves and a hat if the temperature drops below freezing. But do you think about moving far away or sleeping for the next several months? Probably not…

But that’s exactly what many animals do when the sunlight fades and temperatures begin to drop. Since animals can’t shop at the local grocery store for their food, they have to figure out how to make it through the cold winter months when their food supplies may become threatened.

While animals will often grow thicker fur and store up food, many animals face a serious choice about how to survive the winter: move or hibernate. Which option they choose depends a lot on how big they are, how much energy they use and what they like to eat.

For some animals, it’s easier to migrate (move) to a new area that’s either warmer or has more food. For example, many species of birds migrate south in the winter to stay warm and find new sources of food to last them throughout the winter.

For other animals, it might take too much energy to migrate. Instead, many animals choose to hunker down for the winter and hibernate.

Cartoons and stories may make hibernation seem something like a long nap, but in fact it’s something quite different. Animals that hibernate actually enter a state much like a coma.

When hibernating, an animal’s breathing and heart rate slows significantly. Its body temperature drops — sometimes by quite a bit.

It stops eating and often stops going to the bathroom, too. All of these changes allow the animal to survive by using very little energy.

When you take a nap, your body undergoes some minor physical changes during sleep. Sleep, however, is mostly a change in mental state, and it’s usually easy to snap out of.

When your alarm goes off, you can usually get up and be ready to function fairly quickly. When animals hibernate, however, their bodies undergo significant physical changes that are not always easy to snap out of.

In fact, hibernating animals often show signs of sleep deprivation when they emerge from hibernation. When an animal comes out of hibernation, it often needs a lot of sleep over the next several days to resume normal functions.

Not all animals hibernate in the same way, though. When some animals hibernate, they appear dead and will have little activity during the entire time they are hibernating. These “true” hibernators include woodchucks, bats and ground squirrels.

Other animals, such as bears, may go in and out of hibernation during the winter, waking more easily and being more active throughout the hibernation period. These “light sleepers” include bears, skunks, raccoons and opossums.

Even cold-blooded animals, like snakes, turtles and frogs, hibernate. Since they can’t warm themselves up, they have to find ways to protect themselves from the cold.

Snakes, for example, might go underground. Frogs and turtles, on the other hand, often bury themselves in mud below the frost line.


28 Join the Discussion

1 Star2 Stars3 Stars4 Stars5 Stars  (28 votes, avg. 4.54 out of 5)
  1. What a great descriptive video! We loved the baby bear, it was so cute. We learned a lot about hibernation and talked about a movie we have seen that showed some of the animals mentioned that hibernate (Over the Hedge). We didn’t know there were two types of hibernation, ones that sleep and look dead and others, like bears, that are light sleepers and can wake up and go back to sleep. It was also very cool to learn that even once bears wake up from hibernation, that they are still tired and feel like they didn’t sleep enough, and that it can take a few days to get back on their schedule. We know that when we sleep too long sometimes it makes us more tired, too. Thanks for another great wonder!

    • WOW! Thanks for leaving us another super comment, Kerrick Elementary School! We’re so happy to hear that you learned so many new things about hibernation from exploring today’s Wonder together! Over the Hedge is a great reference for a lot of our younger Wonder Friends…thank you for sharing it! :-)

  2. Man, I had no idea all these things go on during hibernation. Man, Wonderopolis, you guys know everything. Thanks for teaching me!

    • Thank YOU for visiting today’s Wonder of the Day®, Kendall! We like how you spelled your name backwards! We think one of our other Wonder Friends might have tried that trick today, too! :-)

  3. Guess who I am! I thought today’s wonder was going to be about bears, I just knew it! I think tomorrow’s wonder is about a vehicle with an engine! I really liked this wonder. One time, when I was at a zoo, I saw the bears getting fed! It was really cool to see them trying to find all of the hidden food! I think the best thing was putting the blueberries in the log!

    • Let us see…hmmm…we think you are our Wonder Friend…Missy! :-)

      Thank you for leaving us such a super great comment today and for sharing your personal connection to today’s Wonder of the Day®! We like visiting the bears at the zoo, too! :-)

    • We’re doing GREAT Mary, how are you doing? Thank you for hanging out in Wonderopolis today and leaving us this comment! We hope you learned some new things from visiting today’s Wonder of the Day®! :-)

  4. I’m new to this site! It’s really cool. And it teaches me a lot! We have two bears named Brutus and Buckeye. I go to the Columbus Zoo! They have Polar Bears!!! How many people work with this page? I’m guessing a lot! How old is this site? It does not look that old.

    • Those are all AWESOME questions, Alex! Wonderopolis is a little over a year old. Because we share a new Wonder of the Day® every day, that means there are over 400 Wonders for you to explore here! There is a great team of people here in Wonderopolis that work hard to make each Wonder the best it can be so Wonder Friends like you can learn something new each day! Thanks for leaving us so many great comments today and for letting us know all the cool things you learned about! :-)

  5. This site is cool. My class has been writing to your site, Mrs. Lewis’ class. I LOVE animals, one of my favorite animals is a Huskey. I wonder how long a bear can sleep? I have two dogs, a fish and five butterflies. Do you have any animals?

    • Hi, Ella! We think it is really neat that you have butterflies as pets along with your dogs and fish! Where do you keep them? What do they eat? We are really WONDERing about butterflies now! :-)

      There are lots of animals here in Wonderopolis! We like to visit them at the zoo, see them in nature, and keep some as pets, too! Thank you so much for leaving us such a great comment today. Please tell Mrs. Lewis that we think she is AWESOME for sharing Wonderopolis with her students! :-)

  6. The animals are soooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo cute when they sleep! I wish I could hug them!!!!!!!!!!!!!!!!!!!!!!!!

    • That’s such a nice thing to say, Natalia! Thank you for exploring this Wonder of the Day® about hibernation and leaving us a comment! :-)

    • Thanks for telling us your sister’s name, Raina! We’re super glad you BOTH like visiting Wonderopolis and learning new things! :-)

  7. WOW! It is very cool that birds can fly all the way to the south from the north while some animals have to hibernate because they do not have enough energy to move. Also I never knew that babies of a bear is so cute.

    • Hello, Shota! We’re so happy that you stopped by Wonderopolis today to learn a little more about hibernation! Thanks for sharing some of the new facts you learned! :-)

  8. That is an easy question… MEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

    • Naps are GREAT for giving your brain and body a rest and for helping energize you for the rest of the day, Andrew! Thanks for leaving us this comment today! :-)

    • WOW! Thanks for saying such super nice things about Wonderopolis, Jessie! We really appreciate your excitement and are SO HAPPY you enjoy learning new things here and visiting the Wonders of the Day! :-)

  9. Wow, I never knew that bears even had a choice of migrating. I also did not know that animals can fall into a coma while asleep. My two vocabulary words that I learned are coma, and hunker. After this, I wondered how does a bear know when hibernation is over?

    • That’s a SUPER question, Team McNeil 12! You got us WONDERing about that, too! We did some extra exploring about how an animal knows when to stop hibernating, and we found out that it’s closely related to the temperature outside. When it gets cold outside, the animal gets ready to hibernate. When the weather starts to warms up, the animal’s internal body clock tells them it’s time to wake up and enjoy springtime! :-)

  10. Bears are my favorite animal on the planet! I don’t know why people think that they’re mean and dangerous and people want to kill them? I think that if you don’t get too close to a bear who has cubs, they won’t heart you. They’re just protecting their cubs!

    • You’re right about the mamma bears protecting their cubs, Katlyn! They can be VERY protective! Thanks so much for sharing your opinion of bears with us today! :-)

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Have you ever wondered…

  • Who takes the longest nap?
  • How is hibernation different from sleep?
  • Which animals hibernate?

Wonder Gallery

resting bear_shutterstock_23970511Vimeo Video

Try It Out

Ready to hibernate? Of course, if you’re like many children, you may not like to take naps. If you ask your parents, though, they would probably jump at the chance to take a nice long nap.

Since humans don’t have any particular season when food is scarce, there’s no reason for you to hibernate. It can be fun to imagine what it might be like to hibernate, though.

How would you prepare to hibernate? Where do you think you’d like to sleep for a couple of months? Your bed? A comfortable recliner? The couch? An underground den?

What would you take with you? A fluffy blanket? A music player to listen to some soothing tunes? A good book to help you get sleepy? Ear plugs to keep noises from waking you up?

How would you stock up on food in advance? What would you eat? Would you head to an all-you-can-eat buffet and pig out? Or would you fill up on your favorite foods from home?

Now imagine that you actually hibernated and slept for three months in a row. Think about what you might think and feel when you wake up.

What’s the first thing you would do? Would you be curious about what’s happened while you were asleep? How would you find out?

Think about these things, and then write a short story about your imaginary hibernation experience. Email us your story when you’re finished. We’d love to read about what you believe it would be like to hibernate!


Still Wondering

Check out ReadWriteThink’s Facts About Brown Bears fact sheet to learn about brown bears, including their habitat, eating habits and hibernation practices.


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