A Long Winter's Rest: How Animals Hibernate

A Long Winter's Rest

1When winter comes, food gets hard to find in many places. Plants stop growing, most insects disappear, and snow covers the ground. Many geese fly to warmer places where food is easier to find. But some animals stay where they are and hibernate. Hibernation is a deep, long rest that helps these animals survive the cold months when there is little to eat.

2Hibernation starts with getting ready. In summer and fall, a woodchuck eats and eats. It munches on grasses, clover and other plants until it has a thick layer of fat under its skin. This fat is stored energy. All winter long, the woodchuck's body will slowly use up the fat instead of food.

3Once the woodchuck curls up in its underground burrow, its body changes. Its heartbeat slows down from many beats a minute to only a few. It breathes much more slowly, and its body temperature drops until it feels cool to the touch. Because its body is working so little, it uses very little energy. That way, its stored fat can last for months.

4Woodchucks are not the only animals that rest through the winter, and each one does it in its own way. Chipmunks rest in their burrows too, but they wake up every so often to nibble on seeds and nuts they saved in the fall. A wood frog hides under dead leaves on the forest floor. Much of the water in its body freezes, and its heart stops beating. When the weather warms up, the frog thaws out and hops away.

5When spring arrives and the days grow warmer, the resting animals wake up. A woodchuck that was plump in the fall comes out of its burrow much thinner and very hungry. Luckily, fresh green plants are starting to grow. Hibernation has carried it safely through the hardest time of the year.