Indiana Bat

(Myotis sodalis)

Indiana bat
Indiana bat by John MacGregor


Federal Status:   Endangered

Kentucky Status:  Endangered

Description:  The Indiana bat is a small to medium-sized bat, 3 to 3 ½ inches in length, with a wingspan of about 10 inches. It has dark gray to brownish black fur. Characteristics that help distinguish it from similar species include a pinkish nose, small hind feet with sparse, short hairs that do not extend beyond the toes, and a keeled calcar. Its hair is less glossy in appearance than that of little brown bats.

Range:  The Indiana bat is found throughout much of the eastern United States from Oklahoma, Iowa, and Wisconsin, east to Vermont and south to northwestern Florida.

Distribution in Kentucky:  See Map

Kentucky Occurrence Summary:  The species is found across the state with winter distribution being limited to karst/cave regions.

Habitat:  During the winter, Indiana bats prefer limestone caves with stable temperatures of 39 to 46 degrees F. As with the gray bat, few caves meet the specific roost requirements of the species. Subsequently, more than 85% of the population hibernates in less than a dozen sites. During the summer, Indiana bats typically roost under loose tree bark. Primary maternity roost trees are usually within canopy gaps in a forest, along a wooded edge, or in a fence line. These habitats provide the tree with greater solar exposure which in turn helps young develop faster. Indiana bats forage in a variety of forested habitats and edges, as well as along rivers and streams.

Life History:  Indiana bats mate in the fall and begin entering hibernation in October. Males tend to be active later in the fall, but are hibernating by late November. During hibernation, Indiana bats cluster tightly together and, as a result, are sometimes called the “social” bat. Having stored sperm over the winter, female bats become pregnant soon after emergence in late March and early April. Females emerge from hibernation and migrate to summer habitats before the males. During summer, maternity colonies can be found under loose tree bark and usually consist of fewer than 100 individuals. Some males to not migrate and spend the summer near the hibernacula; others roost in similar habitats as the females but in smaller numbers. Females bear a single pup in late June or early July. Young bats are able to fly within one month after birth. Small moths are a major part of the diet of Indiana bats, but many different kinds of flying insects are taken.

Threats:  Decreases in Indiana bat populations have been caused by several factors, most of which are the result of human activity. Indiana bats suffered losses in the past because humans altered cave entrances. Structures built to restrict human access to caves have also hindered the movement of bats. These structures also cause changes in air flow, temperatures, and humidity levels and make caves less suitable for bats. Human disturbance is always a factor with hibernating bats, and because Indiana bats gather together in large numbers during the winter, they are even more vulnerable to disturbance. Thousands of Indiana bats have also died at the hands of vandals but now the most important hibernacula are protected. Some bats are lost periodically to flooding caused by natural events or human activity. Loss of forest habitat may be affecting maternity and foraging areas. As with all bats that feed primarily on insects, Indiana bats have probably suffered declines due to use of pesticides. The newest threat to the species is white-nose syndrome, a devastating disease found in North America that is caused by a “cold-loving” fungus. It has caused unprecedented mortality in some of our hibernating bat species like the Indiana bat, especially in the northeastern U.S.

Hibernating indiana bat Hibernating indiana bat
Photo by John MacGregor
Large cluster of hibernating Indiana bats Large cluster of hibernating Indiana bats
Photo by John MacGregor
Small cluster of hibernating Indiana bats Small cluster of hibernating Indiana bats
Photo by John MacGregor
Indiana bats hibernating in cave crevice Indiana bats hibernating in cave crevice
Photo by John MacGregor
Indiana bat under loose tree bark in summer Indiana bat under loose tree bark in summer
Photo by John MacGregor
Little brown bat (left) and Indiana bat (right) Little brown bat (left) and Indiana bat (right)
Photo by John MacGregor