On Some Mornings

7/28/2019 On Some Mornings

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On some mornings, you might not feel like getting up. On cold mornings, you might want to stay

snuggled warmly in bed. You might say, Im just going to hibernate today. You mean that you are not

going out. When animals hibernate, it means something very different.

HOW DO ANIMALS HIBERNATE?

An animal hibernates by becoming inactive. It enters a kind of sleep. Many changes take place in the

animals body. Most of the animals that hibernate are mammals. Mammals hibernate in winter, when

its cold.

Animals first must get ready to hibernate. They eat a lot of food. The food gets stored in their bodies as

fat. Then the animal goes into a cave, underground burrow, or some other shelter. It needs to be safe

from cold weather and enemies when it hibernates.

The hibernating animals body makes less and less energy. It makes very little body heat. The animals

body temperature drops.

The animals heartbeat slows down. It breathes slowly. Animals without much energy go into a kind of

very deep sleep.

WHY DO ANIMALS HIBERNATE?

Animals usually hibernate in winter. It is cold outside during the winter. The animals could freeze to

death.

There is not much food around to eat in winter. The animals could starve to death. Animals need food to

make energy. A hibernating animal makes less energy, so it does not have to eat. A hibernating animal

can live off of fat stored in its body.


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Some animals that live in desertsincluding some squirrels and insectsgo into a kind of deep sleep

during summer. This sleep is called estivation. They sleep underground during the blazing heat. Their

bodies slow down so that they do not need to drink water. There is not much water in a desert in the

summer.

WHAT ANIMALS HIBERNATE?

A number of warm-blooded animals hibernate. Warm-blooded animals make their own body heat from

food energy. Chipmunks, ground squirrels, hamsters, and hedgehogs are warm-blooded animals that

hibernate. The common poorwill is the only bird that hibernates all winter.

Some cold-blooded animals hibernate, too. Cold-blooded animals cannot make body heat. Their bodies

are the same temperature as the air or water around them. Frogs, toads, and other amphibians are cold-

blooded animals that hibernate. Lizards, snakes, turtles, and other reptiles also are cold-blooded and

hibernate.

Some animals spend part of their day in a deep sleep like hibernation. This deep sleep is called

dormancy. Bats and some kinds of birds go dormant each day.

DO BEARS HIBERNATE?

Bears spend several months during the winter sleeping in dens. They do not eat. Scientists do not know

whether bears really hibernate. Some scientists say that the body temperature of bears does not drop

low enough for true hibernation.

HOW DO HIBERNATING ANIMALS WAKE UP?

Animals hibernate for several months. Every once in a while, the animal wakes up. Chipmunks and

squirrels eat nuts and other food they have stored in their burrows. Then they go back to sleep again.


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Hibernating animals wake up when their bodies get warm again. The bodies of cold-blooded animals do

not warm up until the outdoor temperature gets warm. Warm-blooded animals may start shivering. This

motion helps their bodies warm up. Small animals warm up and come out of hibernation much faster

than large animals.

Also in Encarta Kids

All articles about animals

Hibernating amphibians

Hibernating bats

Hibernating bears

Hibernating butterflies

Hibernating toads and frogs

Hibernating turtles

Sleep and Dreaming

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On Some Mornings