Who Hibernates ... and Who Doesn't?

Dec 3, 2017

December 6 - December 12

Discover Nature this week as Missouri’s wildlife den up or hibernate to avoid the cold.

Winter is a challenge for wildlife and many species have various methods of surviving the cold.

Some animals leave the state and don’t come back until spring. Others find sheltered dens and sleep until spring. Some remain in Missouri and stay active through the winter, but they still have specials ways of handling the cold weather.

Woodchucks, or groundhogs, are considered true hibernators. In late summer, they fatten up to prepare for a deep sleep that usually lasts until winter is over. They conserve energy reserves while sleeping by lowering their body temperature by about half and their heartbeat down to about four beats per minute from the normal 160 beats per minute.

Other true hibernators include Franklin’s ground squirrels, meadow jumping mice and some species of bats.

Though bears are widely thought of as hibernators, technically, they aren’t.  A bear’s sleep is not as deep as a groundhog’s. They fatten themselves before winter and their heart rate drops, but their body temperature doesn’t go down much. This is probably because black bear females are usually pregnant when they sleep, and the babies growing inside them need warmth. Bears can even nurse in their winter dens.

Frogs, snakes and turtles don’t hibernate, but they go into what’s called torpor, or a dormant state that closely resembles death. Green frogs spend winter in the mud at the bottom of ponds and box turtles bury themselves in soft ground. Snakes find shelter in a den or crevice and may spend the winter in a tangle of other snakes–sometimes not all the same species.

Chipmunks, skunks, raccoons and opossums don’t hibernate, but they stay under cover and nap during the coldest parts of winter. Their naps might last weeks, but when the weather turns balmy, they venture outdoors.  Watch for tracks, scat and chew marks as sign of their winter activity.

For information on watching wildlife through the winter season, go online to MissouriConservation.org.