This may sound stupid?

Question

but where do bats go to hibernate? and when do they go into hibernate?

Answer 1

Yes Bats hibernate in cold weather. They also migrate to find food or hibernate. Check out some links to learn more.

Hibernation and Migration

Because insects are not available as food during winter, temperate-zone bats survive by either migrating to warmer regions where insects are available, or by hibernating. Hibernation is a state of torpor (inactivity) during which normal metabolic activities are greatly reduced. Body temperature is reduced and heart-rate is slowed. A hibernating bat can thus survive on only a few grams of stored fat during the approximately five-to-six month hibernation period. Bats usually lose from ¼ to ½ their body weight during hibernation.

Most United States cave bats spend winter hibernating in caves (or mines) and move to trees or building during summer. A few species reside in caves year-round, although they usually use different caves in summer than winter. Most cave bats are very loyal to certain caves and return year after year to the same caves, often to the exact location in the cave where they spent the previous winter.

Tree bats seldom enter caves. They roost in trees during summer days and spend winter primarily in hollow trees. Several species make relatively long migration flights between winter and summer habitats. The millions of Brazilian (or Mexican) free-tailed bats (Tadarida brasiliensis) that spend the summer in southwestern United States caves, such as Carlsbad Cavern in New Mexico, migrate up to 1,300 kilometers (800 miles) to and from their winter roosts in Mexico.