Rare, Threatened and Endangered Animal Fact Sheet

Indiana Bat

Indiana Bat, photo coutesy of Dr. J. Scott Altenback

Indiana Bat (Myotis sodalis)
Photograph by Dr. J. Scott Altenbach

The Indiana bat is an average sized bat, with a body length of less than 4 inches and a wingspan of 9-11 inches. It is dull brown with a pink or brown nose. The Indiana bat is also called the Social myotis. These creatures like to live in colonies. In summer, the males form small groups while females gather together into maternal colonies, usually roosting under loose bark or in hollow trees, usually near forested streams. In the winter, Indiana bats will come together to hibernate in limestone caves or mines, called hibernacula (singular: hibernaculum).

Bats are not “rodents with wings”. They are members of the Order Chiroptera, meaning “hand wing”. Their wings actually stretch from their bodies to between what would be their fingers. Also unlike many rodent groups (Order Rodentia), bats can be highly beneficial to humanity. As with the other nine species of bats in Maryland, Indiana bats are insect eaters. One estimate states that a single bat can eat up to 1000 mosquitoes in one hour. Indiana bats will forage for insects at night near the tops of trees and near running water.

The Indiana bat is State- and Federally-listed Endangered and is globally imperiled. It is found only in the Eastern United States (east of Oklahoma). The major cause of the decline is human interference and damage, both to hibernation caves as habitat, and to bat food sources. Interference could come from cavers, biologists, or vandals. These bats have limited fat reserves during hibernation; any disturbance causes them to burn off the reserves, leaving them unprotected against the winter. Indiana bats choose very specific portions of caves; this specificity means they have few options if a cave is disturbed or poorly gated, blocking bat entry. The bats’ food source (insects) becomes contaminated with the increased use of pesticides.

Another cause of decline is the loss of quality habitat, exemplified by forested streams and dead or dying trees which provide loose bark and cavities. Stream channelization, impoundments, and excessive clear cutting destroy summer roosting sites.

In recent years, Western Maryland has hosted several hibernacula; and in 2005, 2 female Indiana bats were tracked from Pennsylvania into Central Maryland during the summer breeding season. Some bats may attempt to roost in human dwellings, i.e. attics and barns. One conservation measure MD Natural Heritage Program recommends is the installation of bat boxes. This will provide roosting opportunities to make up for lost habitat, without having to share your attic.​