At dawn, the bats return to their roost and defecate before entering. In the summer, the colonies prefer a very hot area with temperatures as high as 131 degrees fahrenheit. Usually, the colonies form in an attic, but sometimes are found behind siding or under bridges. Single males can be found under bark and in rock crevices as well as the same types of areas where maternity colonies occur. Sometimes groups of males can be found in caves.
Colonies are usually close to bodies of water because of the types of insects available there.
Otherwise bats feed among trees in open areas. In the winter, the bats hibernate in caves or mines in the eastern part of their range. During hibernation, Little Brown Bats find the areas of the cave with high humidity and where the temperature stays a few degrees above freezing. They form clusters in which the more exposed need to increase their metabolism in order to stay a few degrees above air temperature. Negative Little Brown Bats harbor fleas and mites, and may harbor trematodes, cestodes, and chiggers.