Why do bears sleep during winter?

Large Mammals

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by Mya Kagan (whyzz writer) >> more about the author

Because there’s less food to be found in winter, many types of bears spend the cold months in a quiet, sleepy state that allows them to conserve energy and survive without food!

Bears who sleep through the winter usually spend a total of about four to six months sleeping in a den that they have built. In order to use less energy, the bear’s heart rate slows down from about 70 beats per minute to about ten beats per minute. Their body temperature also lowers by about ten degrees Fahrenheit.

As the weather starts to warm back up, sleeping bears emerge from their dens! Prior to starting their winter sleep, bears gain extra weight that their bodies use for fuel during the foodless winter. – By the time spring has come around, most bears have lost about 25-45% of this extra storage! With new food now available, the bear starts the cycle over again, eating plenty all spring and summer in preparation for the coming winter!

Many people refer to a bear’s winter sleep as “hibernation,” although according to the physiological definition of hibernation, bears don’t qualify as hibernators. To be considered hibernation, an animal’s body temperature has to drop even more than a bear’s does while it sleeps. Some examples of animals who are considered “true” hibernators include bats, hedgehogs, and many kinds of fish.

Winter Habits

What are some other animals you have learned about who have special habits for the winter?

For example, many birds fly south every winter in order to migrate away from the cold. Squirrels also prepare themselves for winter in a special way – by collecting and storing nuts all summer long, in order to have something to eat when it gets cold!

Can you think of any other animals with special winter habits? What kind of special winter habits do you have which help you to stay warm too??