What signals animals to hibernate?

Hibernation is a state of inactivity and metabolic depression that animals enter during the winter months. It is a way for animals to conserve energy when food is scarce and the weather is cold. Hibernation is triggered by a combination of environmental cues, including:

* Day length: As the days get shorter in the fall, animals start to produce more melatonin, a hormone that signals the body to prepare for hibernation.

* Temperature: When the temperature drops, animals start to slow down their metabolism and store fat.

* Food availability: When food becomes scarce, animals start to enter hibernation in order to conserve energy.

Some animals also rely on other cues to trigger hibernation, such as the availability of water or the presence of predators.

Once an animal enters hibernation, its body temperature drops, its heart rate and breathing slow down, and its metabolism decreases. This allows the animal to conserve energy and survive for long periods of time without food or water.

When the weather warms up and food becomes more abundant, animals wake up from hibernation and resume their normal activities.