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Wild Winter Snoozers

Many animals spend the winter in a sleep-like state. These five may surprise you!

Brrrr! It’s getting chilly in the northern part of our planet. When it’s cold out, people wear sweaters and scarves to stay warm. But what do animals do? 

Some animals hibernate. Their bodies slow down to save energy. This adaptation helps them survive the harshest months of the year. “It’s a way to avoid periods when there’s very little to eat,” says Mark Brigham, a biologist at the University of Regina in Canada. 

Hundreds of species hibernate—but each does it a little differently. Here are four animals that snooze through the winter in unusual ways. 

To breathe in frozen swamps, alligators stick their noses through the ice.

Ice-Defying Alligators

Last January, George Howard was walking through the Shallotte River Swamp Park in North Carolina, where he works as a manager, when he noticed something strange. The swamp had frozen over, and poking through the ice were the snouts of 18 American alligators! 

Alligators live in the southeastern United States, where it’s usually warm year-round. But if the weather cools to below 20°C (70°F), their bodies start to slow down. The reptiles stop eating and don’t move around much. That’s because alligators are cold-blooded. Their body temperature changes depending on the surrounding environment.

If the gators sense that the swamp is near freezing, they stick their noses up through the water’s surface so they can breathe. The sight is unusual because of the typically warm climate where alligators live. “If it doesn’t get cold, then it doesn’t happen,” says Howard.

Ladybugs hibernate in large groups. Their coloring warns predators that the beetles taste bad.

Snuggling Ladybugs

This colorful group of ladybugs is like a giant slumber party! To survive winters, thousands of the tiny beetles cluster together. 

Ladybugs usually live alone. But when temperatures drop, the insects release chemicals into the air. The substances signal other ladybugs to huddle together, says Laura Lavine. She’s a scientist at Washington State University who studies insects. The ladybugs form a pile and snooze until spring. Scientists aren’t sure why they snuggle together. One theory is that being in a large group helps protect individual beetles from being eaten by predators like birds. 

Ladybugs find their way inside cracks, under tree bark, and even inside homes. “They squeeze into the craziest places,” Lavine says.

During hibernation, the arctic ground squirrel’s body temperature can drop below freezing.

Supercool Squirrels

Many hibernating animals lower their body temperature to save energy. But no mammal’s body cools as much as the arctic ground squirrel’s. Its body can reach -2.9°C (27°F). At that temperature, any other mammal would die, says Cory Williams, a biologist at the University of Alaska Fairbanks.

In the summer, the squirrels stuff themselves with leaves and berries, almost doubling their body weight. During hibernation, the animals don’t eat or drink. Instead, they rely on the extra fat they’ve stored to get the energy they need to survive. 

Arctic ground squirrels live in the northern-most parts of the U.S., Canada, and Siberia. They hibernate for up to nine months in their underground burrows! Can you imagine spending that long in bed?

Can you spot this common poorwill on the ground? It’s the only bird known to hibernate.

Frozen Birds?

Many birds migrate to warmer places during winter. There’s only one bird in the world that’s known to hibernate: the common poorwilll, which lives in western North America.

In the fall, the birds prepare for winter the way many animals do: They put on weight. As temperatures drop, the birds sit on the ground, cool their bodies, and slow their body functions. They stay still for up to 10 weeks.

Sitting out in the open could be risky for a bird. But the common poorwill’s coloring serves as camouflage, hiding it from predators like foxes, says Brigham. 

The birds look frozen, but they are alive. When they are ready to become active, the birds take 20 minutes to warm up and fly away. 

Painted turtles like this one have an odd adaptation to allow them breathe when they hibernate underwater.

Butt-Breathing Turtles

You may have noticed painted turtles basking in the sun on rocks or logs in your local pond. The reptiles live in water, but they breathe air through their lungs like humans do. So what happens if a layer of ice traps the turtles underwater?

During the winter, painted turtles hunker down at the bottom of the pond and start breathing through their butts! The thin skin in that area of their body can absorb oxygen that’s in the water. The turtles can hibernate like this for up to 100 days, says Jacqueline Litzgus, a biologist at Laurentian University in Canada. They don’t freeze because the water is slightly warmer at the bottom of the pond.

Painted turtle babies are different. If it’s cold when they hatch, they hibernate in nests on land. The babies’ body temperature can drop as low as -15°C (5°F)!

Continue the Learning Journey
What You Need to Know About Hibernation

Watch a video about why animals hibernate.

As you watch the video, think about how animals hibernate to survive the winter. Imagine that you live in a place with extremely hot or extremely cold weather. What would you need to do to survive these extreme temperatures? Create a survival guide with tips and tricks for surviving the coldest winters or hottest summers. Be sure to include illustrations in your guide!

Do you have a favorite winter activity? For example, you might enjoy sledding down a snowy hill or taking part in a holiday celebration. Write down one or two of your favorite things about winter. Then ask your friends and family members what they love to do in the wintertime. Write down their answers. Was there any activity that was more popular than the rest?

Build a Line Graph

Here’s how to turn your temperature measurements into a line graph. 

Many hibernating animals know winter is coming because they sense the changing temperature. What’s the outdoor temperature like right now where you live? How is it going to change over time? Record the temperature in degrees Fahrenheit at the same time every day for a week. Then turn your data into a line graph using the slideshow above! A line graph is a type of chart that shows how information changes over time.

This article was written by Alessandra Potenza for SuperScience magazine.

Image Credits: Shallotte River Swamp Park (header); Scott Leslie/Minden Pictures (alligator); Garry Gay/Alamy Stock Photo (ladybugs); Staffan Widstrand/NPL/Minden Pictures (squirrel); Ingo Arndt/Minden Pictures (baby squirrel); All Canada Photos/Alamy Stock Photo (owl); Rick & Nora Bowers /Alamy Stock Photo (bird); Christina Prinn/iStock/Getty Images (turtle)