How do bears hibernate?

The first animal many people think of when they think of hibernation is probably a bear. But there are many other animals who spend the cold winter months hibernating.

Animals hibernate when food runs low and it gets colder, making it too cold for them to go out to search for more food.

Some animals go in to a deep sleep during this time, while others remain active but are slower to conserve energy.

Other animals — like birds — migrate instead of going in to hibernation. They travel to warmer places during the winter where they can find food and stay warm.

Animals who live in hot climates can also go into a form of hibernation called aestivation, which helps them survive extreme heat, drought or lack of food, according to Discover Wildlife.

The Migrating Common Poorwill

There is one bird that does hibernate, however, called the common poorwill of western North America and Mexico. The common poorwill hibernates inside hollow logs or cozy patches of grass, surviving off the insects they ate before going in to hibernation, according to National Geographic.

Like many animals who hibernate, their metabolism, body temperature, breathing and heart rate decrease, so they can conserve energy. The birds can sleep for weeks or even months until spring.

During the warmer months when they’re active, these birds are nocturnal, which means they’re awake at night and sleep during the day. Their feathers are black, gray and brown, and they are about eight inches long.

Bears

Bears that live in cold climates hibernate in their dens when food is scarce. A den can be built in hollow trees, hillsides, caves or under leaves and brush. Bears often find a new den every winter.

Instead of harvesting food for the winter, bears eat more toward the end of the summer and fall — up to 20,000 calories a day and put on up to three pounds each day, according to Yellowstone.org. They eat other animals, fish, berries, insects and nuts.

To survive hibernation, fat stored by eating this extra food breaks down into water and calories for the body to use.

Bears sleep heavily until spring arrives. Their body temperature can decrease as low as 10 degrees Fahrenheit, and their metabolism and heart rate slows down, according to Iowa State Extension & Outreach.

Chipmunks

Chipmunks hibernate by burrowing as far as three feet underground, usually directly under or next to a cover like a tree or large bush to stay protected from predators.

During warm months, chipmunks will nestle nuts in their cheeks, hiding them in their burrows for to save for their winter hibernation.

Bats

Bats are some of the longest hibernators, sleeping deeply for more than six months. They often find space to sleep in quiet caves, barns or buildings, as long as it’s warm, quiet and dark.

Some bats, however, live in warmer climates or migrate to warmer climates when food supply starts to run low.

Box turtles

Box turtles, which have dome-shaped shells with a flat bottom, start to hibernate in September and October.

These turtles can hibernate right in their shells and sleep for three or four months, coming out occasionally for water.

Is there an animal you want to learn more about? Email the Kids Gazette grace.king@thegazette.com.

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