Little Brown Bat

Habitat: Forests, wetlands, lakeshores, rivers, agricultural areas, and developed landscapes. Summer roosts are commonly found in buildings, tree cavities, beneath loose bark, and rock crevices. During winter, they hibernate in caves and mines.

Diet: Primarily mosquitoes, midges, caddisflies, moths, beetles, and other small flying insects captured over water and along forest edges.

Maternity Colony Size: Typically 50–500 females, though colonies of several thousand individuals were once common.

Hibernation Colony Size: From a few dozen to tens of thousands of bats in suitable caves and mines.

Species Notes:
The Little Brown Bat was once one of the most abundant and widespread bat species in New York State and throughout the Northeast. In summer, females gather in maternity colonies to raise their young, often roosting in attics, barns, and other human-made structures, as well as tree cavities and rock crevices.

As a cave-hibernating species, Little Brown Bats spend the winter in caves and abandoned mines where temperatures remain cool and stable. They can live remarkably long lives for such a small mammal, with some individuals surviving more than 30 years in the wild.

Little Brown Bats feed exclusively on insects and play an important role in controlling populations of mosquitoes, beetles, and other night-flying pests. They typically forage over ponds, streams, wetlands, and forest openings using echolocation to locate prey.

Since the arrival of White-nose Syndrome in North America, Little Brown Bat populations have experienced dramatic declines throughout much of their range. Despite these losses, surviving populations continue to persist and reproduce across the Northeast.

Adults weigh approximately 0.29 ounces, have a body length of about 2 inches, and a wingspan of 8–9 inches—only slightly heavier than a quarter.