Nature and animals
Certain animals hibernate because food supplies become scarce during the winter months. By going into a long deep sleep, they bypass this period completely, waking up when food becomes more plentiful. Bears are most commonly associated with hibernation (although they are not considered true hibernators, because their body temperature doesn’t lower significantly), but a variety of animals take advantage of this evolved adaptation, including the jumping mouse, little brown bat, eastern chipmunk, woodchuck, and certain species of ground squirrels. At least one bird is known to be a hibernator—the poorwill, which lives in western North America. It is believed that a compound in the blood of hibernators known as HIT (Hibernation Induction Trigger) lets animals know when it’s time to prepare for hibernation. Shorter days, diminishing food supplies, and colder temperatures all appear to influence HIT, though the exact mechanism remains a mystery. Hibernators tend to eat a lot of extra food in...