Before exploring this topic, discuss with children about what happens during winter. You may want to screen the Seasons or Winter movies as a review. How do some animals survive winter in places that are very cold? Discuss with children and write down their ideas. Explain that some animals hibernate or go into a deep sleep during the colder months to save energy. This movie will introduce hibernation and explore how animals prepare for the winter.
Review with children that hibernation is a state that some animals enter in the winter in order to survive a period when food is not readily available. Animals that hibernate enter a temporary sleep-like condition in which their body temperatures drop significantly and their heart rate and breathing slow drastically. As a result, the animals use up less energy than when they are active. Hibernating animals, such as bats, ground squirrels, mouse lemurs, and European hedgehogs, do not need to eat or drink because their metabolism slows and their bodies can live off of stored fat.
Consequently, before going into hibernation, animals must store up fat. Some animals will lose half their weight over the winter, so it is important for them to bulk up in the fall. We recommend watching the Fall movie together as a review. A black bear can gain as much as 30 pounds per week! Ground squirrels bulk up, too; they also create safe, dry nests for themselves, and line the nests with food for their awakening when the cold weather is over. Scientists believe that animals use temperature and amount of daylight to dictate when to begin eating and when to go into hibernation. When temperatures increase at the beginning of spring, the animals wake up. Some animals, such as bears, sleep for most of the winter but wake up intermittently and forage for food when the temperature is a little warmer. These animals are not true hibernators; they actually enter a milder state, called torpor, in the winter. During torpor, an animal’s body temperature does not drop as much.
Hibernation, like Migration, is a way for animals to survive the changing seasons and environment. It is important for children to understand why some animals enter hibernation during the winter, and not to focus too much on what is a “true” hibernation and what is not. Instead, stress big ideas. Animals get energy by consuming food; because there is less food available in the winter, animals enter hibernation to conserve energy and to survive the winter. Also, for animals like the ground squirrel or the black bear, who have not developed winter Camouflage, it is a way to ensure avoiding predators.