As colder weather approaches, what changes do you make? You probably start to wear heavier clothing, including long pants, long-sleeved shirts, and coats.
You may also break out the gloves and a hat if the temperature drops below freezing. But do you think about moving far away or sleeping for the next several months? Probably not…
But that’s exactly what many animals do when the sunlight fades and temperatures begin to drop. Since animals can’t shop at the local grocery store for their food, they have to figure out how to make it through the cold winter months when their food supplies may become threatened.
While animals will often grow thicker fur and store up food, many animals face a serious choice about how to survive the winter: move or hibernate. Which option they choose depends a lot on how big they are, how much energy they use, and what they like to eat.
For some animals, it’s easier to migrate (move) to a new area that’s either warmer or has more food. For example, many species of birds migrate south in the winter to stay warm and find new sources of food to last them throughout the winter.
For other animals, it might take too much energy to migrate. Instead, many animals choose to hunker down for the winter and hibernate.
Cartoons and stories may make hibernation seem something like a long nap, but in fact it’s something quite different. Animals that hibernate actually enter a state much like a coma.
When hibernating, an animal’s breathing and heart rate slows significantly. Its body temperature drops — sometimes by quite a bit. It stops eating and often stops going to the bathroom, too. All of these changes allow the animal to survive by using very little energy.
When you take a nap, your body undergoes some minor physical changes during sleep. Sleep, however, is mostly a change in mental state, and it’s usually easy to snap out of.
When your alarm goes off, you can usually get up and be ready to function fairly quickly. When animals hibernate, however, their bodies undergo significant physical changes that are not always easy to snap out of.
In fact, hibernating animals often show signs of sleep deprivation when they emerge from hibernation. When an animal comes out of hibernation, it often needs a lot of sleep over the next several days to resume normal functions.
Not all animals hibernate in the same way, though. When some animals hibernate, they appear dead and will have little activity during the entire time they are hibernating. These “true” hibernators include woodchucks, bats, and ground squirrels.
Other animals, such as bears, may go in and out of hibernation during the winter, waking more easily and being more active throughout the hibernation period. These “light sleepers” include bears, skunks, raccoons, and opossums.
Even cold-blooded animals, like snakes, turtles, and frogs, hibernate. Since they can’t warm themselves up, they have to find ways to protect themselves from the cold. Snakes, for example, might go underground. Frogs and turtles, on the other hand, often bury themselves in mud below the frost line.