In winter, little brown bats hibernate in caves and mines. Colonies of hundreds of thousands have been documented at some hibernation sites. The Yuma myotis is a small bat that ranges in color from light tan to dark brown with white underparts. In summer, females form maternity colonies that may include thousands of individuals. Maternity colonies are found in buildings, under bridges, and in mines and caves.
Males live relatively solitary lives, roosting in buildings or other suitable roosts.
Yuma myotis also use bat houses. Bats leave the nursery roosts in the fall, although their winter habitat is unknown. The evening bat is a small brown bat that ranges east of the Appalachians, from southern Pennsylvania to Florida. West of the mountains, it occurs from extreme southern Michigan and Wisconsin, west to southeastern Nebraska and south through eastern and southern Texas. It is abundant in southern coastal states.