Which term describes the state of winter sleep in animals?

The term that describes the state of winter sleep in animals is "hibernate." Hibernation is a physiological state that allows animals to conserve energy by significantly lowering their metabolic rate during the cold winter months when food is scarce. During hibernation, an animal’s body temperature drops, its heart rate slows, and it may not eat for extended periods. This adaptation helps animals survive harsh conditions without depleting their energy reserves.

In contrast, estivation refers to a similar state that occurs in response to heat or drought conditions during the summer. Circulate does not describe a state of sleep or dormancy but rather a process related to movement, such as the circulation of blood in animals or the movement of air or water. Rest simply indicates a state of inactivity or reduced activity but does not encapsulate the biological and physiological changes that occur during hibernation. Thus, hibernation is the specific term that accurately describes this winter survival strategy.