What causes some animals to hibernate during the winter?

Hibernation occurs in some animals as a survival strategy during winter when food is scarce. During hibernation, an animal’s metabolic rate drops significantly, reducing its need for food and allowing it to conserve energy. Animals such as bears, ground squirrels, and bats enter a deep sleep-like state, where their body temperature and heart rate decrease. This allows them to survive for weeks or months on stored body fat until warmer conditions return and food becomes more readily available.