Little brown bats use a wide range of habitats and often use human-made structures for resting and maternity sites. They typically roost in caves and mines in the winter, and they can be found in trees, artificial structures, bat houses, under rocks and in piles of wood in the summer.

The Little brown bat (Myotis lucifugus) is an endangered species of mouse-eared microbat found in North America. It is similar in appearance to several other mouse-eared bats, including the Indiana bat, Northern long-eared bat, and Arizona myotis, to which it is closely related.

Humans frequently encounter the little brown bat due to its habit of roosting in buildings. Colonies in buildings are often considered pests because of the production of waste or the concern of rabies transmission. Little brown bats rarely test positive for rabies, however.

Little brown bats are small bats, but medium-sized among the species of Myotis in Washington. Their fur coloration is variable, with individuals in Washington ranging from yellow or olive to blackish, and their fur is usually longer and glossier than in other similar Myotis species.

The little brown bat is found in abundance throughout the northern United States into Canada. It is present in lesser numbers in southern states and is absent from the southern Great Plains. Little brown bats also live in high-elevation forests in Mexico.

The little brown myotis is abundant throughout forested areas of the U.S. as far north as Alaska. It ranges from Alaska to Labrador and Newfoundland (Canada), south to southern California, northern Arizona, and northern New Mexico.

In its western range, the little brown Myotis prefers mountainous habitat and riparian areas in a variety of forest types. It can often be found roosting in man-made structures such as buildings, attics, and bat boxes in towns and open, arid areas.

Habitat. Before white-nosed syndrome devastated bat populations, little brown bats were the most common bat species in the northern half of the Lower Peninsula in Michigan accounting for roughly 60 percent of all mist net captures.

The little brown bat's range is a large portion of North America from Alaska to Labrador, south into central Mexico. Its distribution in the southern U.S. is spotty, and it is absent from much of Florida and Texas.