Hibernation is a state of inactivity and metabolic depression in animals, allowing them to survive periods of cold weather and food scarcity. During hibernation, animals like bears, ground squirrels, and hedgehogs lower their body temperature, heart rate, and breathing rate, conserving energy. This process typically occurs in winter when temperatures drop and food becomes scarce. Hibernating animals rely on stored body fat for energy, waking occasionally to eat or drink. Hibernation helps them endure harsh conditions until spring, when food is more abundant and temperatures rise.