By this time in the winter, a lot of people wish they could just take a nap and wake up in the springtime! How do bears do it?
Well, for starters, not all bears do hibernate. Polar bears remain active all year, as do some bears in warmer climates, like pandas and sun bears. But others, like grizzlies and American black bears, are able to slow down their bodies in the winter months and sleep through until the spring. Grizzlies’ body temperatures drop, but not black bears’– in fact, for a long time, scientists didn’t consider black bears to be true hibernators because their bodies were too warm. But they fit the bill for other important hibernation criteria– they remained inactive and went months without food, water, or going to the bathroom (or the bear equivalent, since most bears don’t have bathrooms). A hibernating bear’s heartbeat slows down, and it gets all the nutrition it needs from its fat stores that it built up in the months before the winter. Bears can hibernate for up to eight months, depending on the region they live in.
But why would an animal need to hibernate in the first place? It has to do with energy conservation. Keeping your body alive and healthy takes more energy when you’re awake than when you’re asleep, and in the winter months when nutritious food is scarce, it makes more sense for bears to hunker down and sleep through the hard times and then come out again in the spring!
Photo by Ltshears