What comes to mind when you think of hibernation?

I’m sure sleeping doing nothing for a long time sounds great. Especially in the cold winter months of the Balkans. Although sleep connotes rest for humans, this situation is very different for animals that will hibernate. Especially for bears.

Like all living things, bears’ bodies expend energy. They meet their energy needs by eating food. It is much more difficult to find food in the wild during the cold winter months. hibernation, bears; It is a state of lethargy in order to be protected from winter conditions such as lack of food and low air temperature and to live longer. Hibernation is actually a state of paralysis. During hibernation, the bodily functions of bears slow down. They do this to save energy. Body temperature drops. Their breathing and heartbeat slow down. Their bodies also begin to burn calories more slowly. And their defecation stops. These changes allow the bear to survive longer on its own body fat. This way, bears and other animals can live longer without eating. Also, bears consume most of their body fat during hibernation. But they retain most of their muscle and bone mass. This is a very interesting situation for scientists. If people do not use their muscles for a long time, they lose these tissues. But the same is not true for bears. Most hibernating creatures emerge from their nests or dens when the winter is over without any problems with muscle and bone loss.

The hibernation period for bears ranges from 3 to 5 months. While the winter season starts in November in cold climates, it starts in late November and December in warmer climates. It is seen that this process continues until February and the end of February.

Some bears spend the winter in an area about 1.5 meters wide, which they make by piling up tree leaves and branches. In other words, it is much more likely than you think to come across a hibernating bear while walking in the forest.

A species of black bear native to the Americas can give birth without waking from hibernation. These bears do not leave their places to care for their cubs. They feed their young with the fat they store in their bodies for months. This process is probably the most effective way to get rid of postpartum excess weight. In addition, the mother bear does not fail to protect her cubs. A hibernating mother bear can sense the presence of someone within 15 meters of her lair. The bear, whose heartbeat suddenly accelerates, awakens from its slumber. Which means, “It’s impossible to sneak up on a hibernating bear.”

A threatened bear may wake up quickly to defend itself. This is because bears’ body temperatures drop only a few degrees when they hibernate. This helps them wake up much faster compared to other animals. Many other species lower their temperatures to nearly freezing for hibernation. For example, a field squirrel’s heart beats 300 times a minute when awake, and 3 or 4 times a minute during hibernation.

Although most people think of hibernation as deep sleep, this is not entirely true. In fact, bears may wake up and move around their burrows during this time. This is especially true if they sense danger. Bears have been known to even leave their nests if they are harmed.

Apart from these, some animals become lethargic just like they are in hibernation in order not to be affected by the unusual weather conditions of the summer months and withdraw to their shelters where they can lower their body temperature. This state is called summer sleep (estivation). The main problem of hibernating animals is water, and when they enter the hibernation mode, their metabolism focuses on not losing water. Some crocodiles, fish, snails and frogs may hibernate. The body temperatures of warm-blooded animals in hibernation approach ambient temperature; however, the body temperatures of warm-blooded animals that sleep normally do not change.

Onur Erkaya, 11/2022