Description: The Indiana bat is medium-sized. Its fur is dull gray and chestnut in color. The basal portion
of the hairs of the back are a dull lead color. The calcar (the bone attached to the foot) is strongly keeled.
Life History: Indiana bats are migratory. Approximately 85 percent of the known population hibernates
in just seven caves. Indiana bats mate in the fall and begin to enter hibernation in October. Males tend to be active
longer into the fall, but are in hibernation by late November. Sperm is stored during the winter and females become
pregnant soon after emergence in late March and early April. Young are born in June and July. Females and their
young roost in small colonies (50 to 100 individuals) under tree bark during the summer months. Colonies are usually
located along streams where the bats forage for flying insects. Not much is known about male roosting behavior.
Young bats are able to fly approximately a month after birth.
Habitat: For hibernation, Indiana bats need limestone caves with stable temperatures of 39° to 46°F
(4-8°C) and 66 to 95 percent humidity. Low cave temperatures allow the bats to maintain a low metabolic rate
throughout hibernation. Only a small percentage of caves meets the specific conditions required by Indiana bats.
During the summer, they can be found under bridges, in old buildings, under tree bark, or in hollow trees. Indiana
bats forage above small- to medium-sized streams. Streams lined with large, overhanging trees are preferred.
Distribution: The Indiana bat is found primarily in the midwestern and eastern United States. The largest
populations are in Arkansas, Indiana, Kentucky, Missouri, and Tennessee. Eastern Oklahoma is the western limit
of its range. The present Oklahoma range includes Adair, Delaware, LeFlore, and Pushmataha counties. It is now
rare in Oklahoma, and usually only scattered individuals are found. They may be in company with gray bats.
Causes of Decline: Indiana bats are subject to both natural and human threats. Periodic flooding of
winter caves and the collapse of cave or mine ceilings both pose threats. However, the most serious threat to
Indiana bats is the disturbance of hibernating colonies by spelunkers or vandals. Pesticides, the commercialization of
roosting caves, and the channelization of streams also pose threats to the species.
Recovery Needs: The top recovery tasks for the Indiana bat include: 1) preventing disturbance to
important winter caves by erecting warning signs and fences or gates; 2) protecting foraging areas and nursery
roost habitat from destruction; and 3) educating the public of the consequences of disturbing hibernating bats and
of the importance of bats in nature.
Other information: Indiana bats hibernate from October to April, and caves containing Indiana bats
should not be entered during this time. Disturbance of hibernating bats is a major cause of the decline of the species.
A recovery team has been appointed and the recovery plan was revised in 1983.
