Have you ever watched a worm move? They don’t move very fast, do they? Unless they’re in the belly of a bird — a place no worm wants to be! — they don’t fly south for the winter. It’s also highly unlikely that they drive or take the bus. So where do they go in the winter?

If you’re a regular visitor of Wonderopolis, you probably already know that earthworms are good for gardens. But gardens don’t grow year-round. So what do earthworms do with their time in the winter when they’re not gardening?

The answers to these questions depend in part on what type of worm you’re talking about. There are a lot of different types of worms. Would you believe there are over 4,400 different species of worms around the world? It’s true!

Of those thousands of types of worms, over 2,700 of them are species of earthworms. Only a fraction of those can be found in the United States. Still, American gardens are called home by at least 30 different types of earthworms.

Some earthworms choose to live their whole lives in the ground’s upper layer of soil and leaves. These earthworms never burrow deep into the soil, so cold winter temperatures kill them.

To keep their species alive, however, they lay eggs in tiny sacks that protect the eggs from freezing or drying out during the winter. In the spring, the eggs hatch and a whole new group of worms is born to repeat the life cycle.

Other earthworms, such as the night crawlers often used as fish bait, live close to the surface in warm weather and down deep in cold weather. When winter hits, these worms burrow down below the frost line.

The frost line — sometimes called frost depth or freezing depth — is the depth at which the groundwater in soil usually freezes in winter. The frost line varies based upon climatic conditions. It can usually be estimated based upon latitude. The farther north you travel, the deeper the frost line.

In the United States, the frost line ranges from zero feet (in warm areas like Florida) to six feet or more (in cold areas like Alaska). To survive freezing cold temperatures, worms must burrow to an area below the frost line wherever they live.

Night crawlers, for example, can burrow to depths of six feet or more. When they burrow down below the frost line, they nest in small chambers at the bottom of the tunnels they dig. Since worms can’t breathe if their skin dries out, they coat the sides of their nesting chambers with a slimy mucus to keep them moist through the winter.

Once worms burrow far enough underground, the soil stays at a fairly constant temperature that keeps the worms warm through the winter. This warmer soil down deep acts like a warm blanket and insulates the worms from the cold.

Night crawlers don’t really hibernate like some animals do in the winter. If there is a warm spell during the winter, night crawlers will occasionally come back up to the surface for a while until it gets cold again. When spring returns, worms make their way back to the surface.


44 Join the Discussion

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    • We like those guesses about tomorrow’s Wonder, Jesse! Thanks so much for being a GREAT Wonder Friend and leaving us another AWESOME comment! :-)

  1. Hey guys, it’s me coming to say that earthworms are cool and nightcrawlers are creepy. But, anyway, I always go fishing in the Summer, Fall, Winter, and the Spring. Hope that didn’t sound weird. This website is really cool. I get on whenever I am told or if I want to, but I don’t comment all the time because sometimes I get short on time or I never finish the comment. Well, anyway like Amoolya said, I think tomorrow’s wonder is going to be about a Leap year. Bye.

    • We don’t think that sounded weird at all, Austin! We think it sounded like a Wonder Friend who has something cool to say about worms and LOVES to go fishing! We think that ROCKS, actually! Thanks for visiting today’s Wonder! :-)

    • We think they’re pretty cool, too, Shundee! Thank you for stopping by today’s Wonder of the Day® and leaving us a comment to let us know you were here! :-)

  2. We learned a lot about worms! Last week, we read a book called Wiggling Worms at Work where we learned a little about earthworms. From reading that book, we learned about underground tunnels and chambers. You helped us learn more about worms! We did not know that worms coat their tunnels with mucus to keep them moist. We also did not know that there were 4,400 different species of worms!!! Wow!!!! Thank you Wonderopolis! We love Wonderopolis! :)

    • Well, we LOVE receiving comments like yours, Mrs. Rist’s 2nd Grade Class! We really enjoy hearing all the cool things our Wonder Friends learn when they visit a Wonder of the Day® together! Thank you for letting us know what YOU learned today and also for sharing that you had some background knowledge about worms before you explored today’s Wonder! :-)

  3. Here are some of our thoughts and questions about worms:

    1. How do worms form their mucus?
    2. What is mucus?
    3. How thick is a frost line?
    4. How deep down is Wisconsin’s frost line?
    5. How do worms not get cut in half since their bodies are so thin and rocks are so sharp?
    6. Does where the frost line is depend upon how cold it is?
    7. How do worms dig so fast?
    8. I think worms eat the dirt (for how they dig).

    Now, here are some of our predictions about tomorrow’s Wonder of the Day:

    1. How leap days are made?
    2. Who created February 29.
    3. Why does February have only 29 days.
    4. It might be about sports–the Brewers play the Yankees every four years.

    • WOW, 2/3 Class–New Century School–Verona, WI! You guys REALLY did some great extra WONDERing about worms today…we’re SUPER proud of you! We’d really like to know the answers to some of those AWESOME questions you guys came up with, too! We also want to say, “high five!” for sharing those predictions about tomorrow’s Wonder! We can’t wait to visit Wonderopolis tomorrow to see if you guys were correct about one or more of them! :-)

  4. I think worms go in the ground during winter. They hibernate, which means they sleep. I think they sleep for seven hours. When they are awake, they stay in the ground, but they eat. I think they like to eat apples, bananas, blueberries oranges, including the peels. For fun, worms like to go for long walks even though they don’t have legs. They also like to crawl. They do not like fishing! Who wants to be bait?! If they want to, worms can get married. This keeps them out of trouble.

    • Happy Tuesday, Cheezy P! We really liked your comment! It was very clever how you WONDERed about worms in such a creative way! Thank you for visiting today’s Wonder of the Day®! :-)

  5. I don’t use worms for fishing bait. Instead, I use hot dogs because hot dogs are really good bait for fishing because the second time I ever went fishing, I caught a huge large-mouth bass! Just remember, always use the skins of a hot dog for bait. Do you have any wonders about fishing? If so, please send a link in your comment back!

    P.S I think tomorrow’s wonder is about Leap Year.

  6. We like to snuggle under a warm blanket and read books when it’s cold outside. If it’s not too cold, we also bundle up and play in the snow! Sledding is one of our favorite activities. We also like ice skating, snow shoeing and skiing. We’re just glad we don’t have to burrow six feet down like the earth worm does. :)

    • Hello, Sandi! Thanks so much for sharing some of the SUPER ways you and your family like to wait out the winter! Those all sound like LOTS of fun! We hope you have a WONDERful day today! :-)

    • Thanks for letting us know some of the cool facts you learned about worms by exploring today’s Wonder, Trucker Buddy! :-)

  7. Some of us think earthworms are cool. Others thing they are gross! We all think that the information was interesting. This Wonder of the Day gave our teacher the heebeejeebees!

    • Hello, McPherson’s Fourth Grade Class! We think it’s GREAT that you guys have differing opinions about worms! Thanks so much for letting us know you thought today’s Wonder was interesting…that makes us super happy! :-)

    • That’s super awesome, Adel! We think it ROCKS that you learned new things about worms by exploring this Wonder, and that worms are now your favorite animal! Way to go! :-)

  8. Hello Wonderopolis,
    I didn’t know that there are so many earthworms. I like to go fishing ……sometimes. Once I caught a pregnant catfish, it went back in the lake. I have a wonder for you, WHERE DO FRUIT GET THERE COLOR?

    • That’s a really cool story about catching a pregnant catfish, Rylie! We bet she was super thankful to be released back into the lake! Thanks for sharing your idea for a future Wonder of the Day®, too…we think it’s GREAT! Did you know there are LOTS of Wonders about FRUIT? Check them out by clicking on this link: http://wonderopolis.org/category/fruit/. Happy WONDERING! :-)

  9. I always thought that they lay eggs and then the parents die. Do they die or stay under ground in the winter? But otherwise, I never really knew that. That’s really interesting.

    • Thanks for leaving us another great comment, Kaitlyn! We appreciate that you are exploring several Wonders in Wonderopolis today! Some worms lay eggs and some worms dig deeper into the ground for the winter…so, you are right on both points! Way to go! :-)

    • We really enjoyed reading all those AWESOME blog posts your kindergarten students wrote about worms, Mr. Flinn! They were GREAT! We encourage our Wonder Friends to check them out, too! :-)

  10. Hi wonderopolis! I have learned so much about where worms go in the winter. Worms are a lot more interesting then I thought they were. I learned that there are 4,400 different species of worms around the world. I also learned that where worms go in the winter depends on the type of worm. The coolest fact I learned though was that to keep their species alive by laying their eggs in tiny sacks that protect them from freezing or drying in the hot or frigid weather. One question I have is why some worms choose to live their whole life on the upper layer of soil and the cold weather ends up killing them?

    Thank you Wonderopolis!

    • WOW! You sure learned a lot about worms today, Team McNeil 20! We think that’s AWESOME! We really like your question about why certain worms live the way they do, too! Nature is a FUN thing to WONDER about, isn’t it? :-)

  11. We are learning about Worms in our class. We don’t know if this is a fact or fictional tale… Can a worm still live even though they get cut? We WONDER if having 5 hearts might be a factor in keeping it alive?

    • WOW, we are so happy to hear that the WONDERful students in Mrs. Olson’s class are WONDERing about worms! How FUN! :)

      Worms can survive is part of their body becomes detached– it’s called “regeneration.” We Wonder if you can do some research of your own to find out how these worms can regenerate! We are very proud of all our Wonder Friends today! :)

  12. Our children at kindergarten have been wondering how worms breathe under the soil and have been coming up with lots of imaginative ideas.

    • That is SUPER news! We are so very proud of our awesome Wonder Friends in Ms. Hughes’ Kindergarten class! HOORAY for WONDERing! :)

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Have you ever wondered…

  • Where do worms go in winter?
  • What is the frost line?
  • Do worms lay eggs?

Wonder Gallery

worm_shutterstock_29707060Vimeo Video

Try It Out

Ready to hibernate? If it’s cold where you live, you might think that hibernating sounds good about now.

What do you like to do when it gets cold outside? We like to snuggle up under a thick blanket and sip hot cocoa while we watch favorite movies with our family. What types of things does your family do when the weather outside turns frigid?

Did you know that you can help your parents save money and keep your house warmer during the winter? It’s true! Here are a few simple things that you can help your family do to make your house cozy during the long winter months:

  • Make sure all the windows and doors in your home are fully closed. If you have them, help your parents switch out your screen doors and windows for more energy-efficient glass storm doors and windows.
  • Keep cold air from seeping in under doors by making homemade door draft snakes!
  • Help your parents turn off all outdoor water sources. Remembering to turn off outdoor water sources can prevent the pipes in your house from freezing.
  • Keep the warm air inside your house by closing blinds and curtains over windows. This is especially important when temperatures drop at night.


Still Wondering

In ReadWriteThink’s Digging Up Details on Worms: Using the Language of Science in an Inquiry Study lesson, children research worms in order to create a classroom habitat. This lesson incorporates reading and writing across content areas, as well as math and science.


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