Bats are unusual, because they can go into short hibernation states known as torpor throughout the year, lasting from hours to many weeks. In these longer stretches, they will periodically wake up to drink and urinate, or move to a different roosting area. they are very sensitive to disturbance (e.g human interference) as well as changes in temperatures, and will wake up when temperatures rise, increasing their body temperatures by rapidly metabolizing stored fats. That is why if bats are very sensitive to being disturbed when hibernating, and face higher mortality rates due to physiological stress of repeatedly coming out of hibernation.