In the summer, males and females live apart from each other, with the females forming nursery colonies in hollow trees or under bark. The young bats are born in late June or early July. One young is born per year and the bats become independent from their mothers after 25 - 37 days. Indiana bats use echolocation to find their way around. They use their vision for long distance homing and navigation.
Bats enter the warmer parts of the cave in early fall and remain alert.
They leave the cave at night to forage and build up body fat. During hibernation, they gather on a flat surface, either a ceiling or a wall. The groups are smaller in the warmer parts of the cave. Females enter into hibernation soon after they reach the cave, but the males hold out to copulate with the incoming females. As winter progresses, Indiana bats move to cooler parts of the cave.