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Little Brown Bat


Most Ohio bats are descriptively little and brown, including this species. Because of this, bats can easily be misidentified. It takes an experienced scientist to be able to observe the closer details and identify the species. Once thought to be the most common species in Ohio, the little brown bat (Myotis lucifugus) population size has declined dramatically due to habitat loss and White- nose Syndrome.

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The fur on a little brown is a sleek, glossy brown, ranging from dark brown to reddish brown on the back with slightly paler, grayish under parts. The wing membranes are dark brown. The muzzle is furred, and the ears are relatively short. Hairs on the toes extend beyond the claws, unlike the Indiana bat. The bats are between 2.6-4.3 inches long and weigh 0.2 to 0.5 ounces. Their total wingspan is 8.7 to 10.6 inches.


Females go through a process known as delayed fertilization. In the fall, before hibernation, there is a behavioral phenomenon known as “swarming.” At this time, large numbers of bats visit and congregate in a succession of caves just prior to hibernation. Although sperm is transferred to the female during mating in the fall, ovulation and fertilization of the egg are delayed until the female arouses from hibernation the following spring. When the female arouses, she then gestates between six and nine weeks. Pups are typically born between late May and early July. Females normally only have one pup but may have two under good conditions (e.g., available food and appropriate roost site). After four to six weeks, the pups are weaned and able to fly on their own.

Habitat & Behavior

It is thought that little brown bats prefer to feed on small-bodied aquatic insects (caddisflies and mayflies), midges, moths (including cutworm and corn borer pests), leaf hoppers, and plant hoppers. They eat while flying, using their wingtips to bounce (?) prey into their uropatagium (wing membrane) and then grab it with their mouth. Their estimated capture rate is 1 insect every 7 seconds! After feeding, little brown bats may fly to a night roost to digest their meal before foraging for a second time.

During the summer, females form large maternity colonies that can number in the hundreds, while males generally roost alone or in small groups. Little brown bats can use a wide variety of roosts, including houses, barns, and tree hollows. In the winter, little brown bats move to their winter roosts (called hibernacula) where they hibernate. This species is thought to hibernate in small rock crevices, as well as caves and mines from November to March. Caves are included in the Cave Protection Act portion of the Ohio Revised Code 1517. This cave protection act ensures that cave life and habitat is conserved, including bats hibernating within them.