When the weather turns cold and insects are scarce, the little brown bat goes into hibernation. AT DAY - Bats asleep inside cave, hanging onto crevices in the cave wall. The bats crawl into small crevices or hook their claws into ceilings. Then they hang upside down, and go into a state of deep hibernation. The little bats can now survive six to eight months on very little energy.
Bats wake up from time to time to urinate, drink and mate.
Uninterrupted sleep for little brown bats averages between 12 and 19 days but may last as long as 93 days. Moisture from cave walls and condensation droplets on their fur are the usual source of water during hibernation. In Newfoundland, in early April, the pregnant females begin their spring migration to summer roosting sites where they establish maternity colonies. The males either roost alone or form small separate colonies by themselves. The gestation period is two months, or so, depending on available food and climate.