There are several animals that hibernate– skunks, bees, snakes, and groundhogs to name a few– but bears and bats are the most well-known. Bears enter their dens for hibernation based on changes in the weather.
Several mammals hibernate during the long, cold winters. Woodchucks are one example of true hibernators. During their hibernation, the woodchuck's heart goes from 80 beats per minute to only four or five. It also drops its body temperature to 60 degrees below normal.
