Facts about animal hibernation

310 is the average number of consecutive days an Australian pygmy possum hibernates.
27 is the Arctic ground squirrel's lowest recorded body temperature during hibernation.
300 pounds is how much a Kodiak bear can lose during its winter sleep.
4 is the fewest heartbeats per minute for a small hibernating animal.
30 minutes is how long it takes a little brown bat to raise its body temperature from 36 degrees to 100 degrees.

Hibernation basics
Several species of animals undergo hibernation, a state of dormancy, in order for them to survive prolonged cold winters. The animal's metabolic rate, heart rate, and breathing are reduced, decreasing body demands for food and water to minimal levels. The animal becomes unconscious and completely inactive and is able to survive for long periods on fat stored in its body.

Hibernating animals include the following mammals: ground squirrels, chipmunks, marmots, woodchucks, possums, shrews, hedgehogs, hamsters, skunks, prairie dogs, badgers, some lemurs and some bats. Brown bears enter a prolonged winter sleep during which time their metabolic rates decrease slightly. These bears awaken periodically.
Non-mammals include: some lizards, frogs, toads, newts, snakes, turtles, and bees. There is only one bird on the list, the Western Poor-Will.

Bears enter their winter sleep gradually. For several weeks before they bed down for the winter bears will remain close to the den and gradually become increasingly lethargic during their waking hours. Once the bear enters its den for the last time of the season its heartbeat drops from 50 to 60 beats per minute to around 10. Its body temperature falls slightly, and its metabolic rate slows to about one half.
Generally the colder the climate the deeper the sleep. In more southern climates such as in the Carolinas a bear may awaken to any sound but in Canada a bear might have to be poked to be roused.

Groundhogs, like most marmots, are true hibernators. Asleep in its underground burrow its body temperature drops to a few degrees above freezing. Its respiration slows to one breath every six minutes and its heart rate slows from around 100 to only 4 beats per minute.

Bats have a rapid metabolism. Their heart during flight buzzes rather than beats, at 20 times per second - about the same as a hummingbird. Because of their rapid metabolism bats must find a suitable location to hibernate in that it must be neither too warm nor too cold. If the air becomes too warm the bats will burn off their winter store of fat. If it gets too cold the bats will freeze.

Click here for a live webcam showing a hibernating black bear.