Hibernation, Migration and Estivation

Climate is the usual weather of a place over a long time. It varies greatly in different habitats such as the arctic, a rainforest, or a desert. There are many survival strategies in the animal world for dealing with the climate of an area. Animals may respond to the climate by hibernating, estivating, brumating, or migrating. When winter comes it is very hard for animals to find food for energy.

In the winter some animals hibernate in a den, burrow, hollow log, rocks or a cave. The animals’ body temperature drops, breathing slows down and they sleep. It is very difficult to awaken them. Most animals eat large amounts of food to store up fat before hibernation. Bears are extremely efficient hibernators. During hibernation, animals stop eating and excreting. Preparation is required to hibernate and some animals prepare a den and line it with leaves and mud for insulation. Polar bears dig tunnels in the snow. Small animals tend to hibernate because it would require an enormous amount of energy for their body size to migrate. Hibernation in reptiles is sometimes called brumation.

When an animal enters a hibernationlike state in the summer it is called estivation. Estivation is another form of sleep or dormancy. Many animals hibernate and estivate. Animals that estivate are trying to escape things happening in their environment. This happens often in hot desert climates. Estivation protects these animals from high temperatures and drought. Their breathing and heart beat get very slow and the animal doesn’t need as much food and water to live since food is fuel for energy and they aren’t using much. Animals don’t move, grow, or eat during this time. When hot and dry times come, theses animals will usually find themselves a safe place to sleep, usually underground. Some examples of estivators are: lungfish, earthworms, bees, frogs and toads, snails, turtles and lizards. Many animals are hibernators and estivators: earthworm, bees, snakes, frogs, snails.

Torpor is a term for short term hibernation. The black capped chickadee and hummingbird are good examples of this. It only lasts for a few hours and saves them a lot of energy. It is used by many species of birds and insects.

Migration is the large scale movement of an animal species from one place to another. Migration is usually tied to seasonal changes in weather and feeding or breeding patterns. Some animals migrate to a warmer climate in winter. The caribou, a large deer-like animal that lives in northern climates, has the record for the longest overland migration (2,000 miles in a year). some other animals that migrate are: Arctic tern, monarch butterfly, geese, ducks, storks, hummingbirds, whooping cranes, robins, eels, salmon, whales, and turtles.

Activities: Use a large map to show migration routes or use small plastic models of animals that they can group according to those that migrate and those that hibernate, estivate or brumate.