What is the term for when an animal is inactive during the winter?

The term that describes when an animal becomes inactive during the winter is hibernation. This physiological state involves a significant reduction in metabolic activity, allowing animals to conserve energy when food is scarce and the environmental conditions are harsh.

During hibernation, animals often lower their body temperature, slow their heart rate, and reduce their breathing rate, which can lead to long periods of dormancy. This adaptation is crucial for survival in climates where they cannot find sufficient food to sustain normal activity levels.

Migration, while related to seasonal behavioral changes in animals, involves moving to a different location typically in search of better living conditions, rather than becoming inactive. Estivation, on the other hand, is similar to hibernation but occurs during hot, dry periods, usually in summer, allowing animals to escape extreme heat or drought conditions. Aestivation is another term for estivation and serves the same purpose. Thus, hibernation is the correct term for winter inactivity.