How do animals survive in winter?

Part 3: Nap time

Henrietta and I already talked about how animals survive winter by migrating or adapting, but what else do they do?

Hibernation

Many animals stay active in winter, either by leaving or adapting, but some survive winter by hibernating. Hibernation is like a very deep sleep.

The black bear is a "champion" hibernator - it can sleep 100 days without eating or drinking. How's that for sleeping in? Bears prepare for hibernation by putting on a lot of fat in summer and fall. In winter, a bear stays in its den, rolled up in a tight ball to keep out the cold. Mother bears hibernate tightly curled up with their cubs. A hibernating bear lowers its body temperature and heart rate to conserve energy.

Checking in to the hibernation hotel

Chipmunks also hibernate, but instead of storing fat for the winter, they occasionally wake up to eat nuts and seeds from the reserves they built up in fall.

Frogs and turtles also hibernate. Aquatic frogs (that live in water), hibernate at the bottom of their pond, just on top of the mud or partly buried. Terrestrial (land) frogs hibernate in soil, or in cracks in logs or rocks. Hibernating turtles bury themselves in the mud. Both frogs and turtles slow down their metabolism (everything in their body slows down) so much that they stop breathing and their heart stops beating. Ice crystals even form in their bodies, and these frosty frogsicles and turtlesicles can appear to be dead! However special "antifreeze" proteins prevent their lungs, heart, and other organs from freezing, so they can successfully come back from the dead in spring!

Turtles preparing to hibernate

Many insects go into a sort of hibernation called "diapause" in winter. This is like putting their bodies on "pause" for the winter, and starting again in spring.

All this talk of hibernation is making me sleepy, since hedgehogs also hibernate in winter. We wake up once in a while though, so I'll still be able to update the blog!