What animals spend the winter hibernating? Surely the first that comes to mind is the bear. And it is that, in common ideology, most people immediately think of bears. So, for example, black and brown bears are just two of seven mammals that huddle in burrows or sleep during Alaska’s cold, dark season, for example, but bears are not the only animals that hibernate in winter.
Perhaps the most amazing species that falls into a deep sleep when temperatures drop too low is the Arctic ground squirrel. For hibernation, Arctic ground squirrels burrow about a meter above the ground with an insulating layer of snow on top. These squirrels survive in a catatonic state by reducing their metabolism and core body temperature to approximately -2.7 ° C, the lowest known body temperature for a hibernating mammal.
Arctic ground squirrels can hibernate for up to eight months, but increase their metabolic rates and body temperature for periods of 12 to 14 hours every 20 days or so. Why this pause? Scientists do not know why they wake up periodically, but suspect that they may need to warm up to replenish or remove substances that have been depleted or accumulated during hibernation.
When the weather is cold and food is scarce, animals become inactive to save energy. This is the main reason for going into this deep state of inactivity. During hibernation, the heart rate and respiration slow down and the body temperature drops, as we have seen.
Animals hibernate in many different ways, from snails, which cling to a surface, cover themselves with their slime and thus wait all winter, to hedgehogs, who like to build nests out of grass, leaves and straw, often underground.
Bears, unlike bats, for example, are unusual hibernators due to their large size. They also stand out because they do not precisely fall into a “lethargy” or a decrease in consciousness, like most animals that do hibernate. Bears are aware of their surroundings and can even get up and attack when disturbed in winter.
