When the weather turns colder, animals have to get ready for winter. Animals have found ways to survive the cold winter. Some migrate while others hibernate. What is the difference between hibernation and migration?
Hibernation and migration are two different ways animals survive the winter. When an animal hibernates, its body temperature drops and its heart rate slows down. The animal goes into a dormant state and hibernates until spring comes. Animal migration is when a group of animals travels to another place before winter. There, the animals are warmer and have more food during the winter.
Migration is seasonal, so animals usually return to their original habitat when winter is over. Animals migrate to find food, breed, or find a place to hibernate. When a group migrates, how do the animals know where to go? Some animals use their sense of smell and others use landmarks to find their way. The position of the sun and stars may also help animals navigate during migration. Another method for navigating is by using Earth’s magnetic field.
Many animals migrate for different reasons. One reason is to find a better place to breed. Young salmon swim downstream to reach the ocean. When it’s time for them to breed, salmon migrate back upstream to where they are safe from predators. Sea turtles return to the same beach each year to lay their eggs. Another reason is to find food. Geese fly together to warmer places where there is more food. To prepare for their migration, the birds store up fat so they don’t have to eat during the journey. Gazelles, zebras, and wildebeests travel in large groups to places that have water and fresh grass. Animals also migrate to warmer places. Monarch butterflies migrate to survive the cold winter. Many generations of these butterflies rest on trees along their return journey. Little brown bats migrate to warm caves and spend the winter there.
Animals need to get ready for hibernation before winter comes. During winter, animals hibernate to conserve energy when there is not much food around. To prepare for hibernation, animals collect food during autumn. Some animals eat before hibernating all winter, while others store food for later and have to wake up to eat it. Before hibernating, animals must find a warm place to spend the winter. When an animal hibernates, its body temperature drops and their heartbeat slows down. The animal uses its stored fat to survive through the winter. Animals know when to wake up because the temperature outside changes. Never wake up a hibernating animal, as it would have to use up all of its stored energy just to warm up, and that may cause the animal to die.
Many animals hibernate in different places during the winter. Bats and bears spend the winter in caves. Squirrels hibernate in a cozy den. Honey bees and wasps huddle together in a nest to stay warm. Snakes hibernate together in a burrow. Fish swim to the bottom of the lake before it freezes. Frogs and turtles burrow into the mud. Earthworms bury themselves underground.
During winter, most animals have to migrate or hibernate to survive the cold. Migrating animals travel in large groups to warmer places where they will have enough food. Hibernating animals sleep through winter in a warm place until spring comes.
