Experts say that in the past, the population of the Gray
Bat exceeded 7 million specimens. In 1980, the total
population was estimated at 1,575,000 bats.
Reasons For Endangerment:
The main causes of the Gray Bat's decline are the
disturbance of its habitat be amateur speleologists and
the killing of bats be vandals. Also contributing to its
endangerment is the drop in the number of mayflies, the
bat's main food source, due to pollution of the waters
and deforestation near the openings to caves. Other
threats to the bat include the use of pesticides and
collisions with gates at the entrances to caves. The
gates were put up to keep people out.
In 1976, the U.S. Department of the Interior considered
the Gray Bat in danger of extinction, and laws were
enacted to protect it. Measures were taken to protect all
of the major caves used by the bats during the winter as
well as the important sites where the famales give birth.
The Gray Bat's future is still uncertain.
The Indiana Bat has a soft, fine, chestnut-colored coat
on its back and a pinkish color under the belly.
*Length: 1.5 to 2 inches
*Weight: about .25 oz.
*Wingspan: 9 to 10 inches
The Indiana Bat lives in the eastern United States. Its
general territory extends from New Hampshire in the
northeast, to Alabama in the south, and as far west as
Oklahoma. Some small colonies also are found in
northwestern Florida. Members of this species gather in
enormous colonies during the winter for hibernation.
This bat's favorite food is moths, but other insects also
are an important part of its diet. It usually hunts for
insects in foliage found along weterways and in forests.
In the summer, pregnant female bats gather in small
colonies in cavities of dead trees to give birth.
Colonies usually are made up of about 25 females. Each
gives birth to only one lffspring. Births occur at the
end of June or the beginning of July.
*The Indiana Bat travels distances of 22 to 300 miles to
reach hibernation sites.
*It hibernates in the coldest parts of caves, where the
temparature is between 36 and 46 F.
*If the bat wakes up during hibernation, it uses large
amounts of stored body fat and jeopardizes its chance of
Estimated Remaining Population:
In 1960, the Indiana Bat population consisted of about
640,000 specimens. In 1975, the population dropped 28% to
about 460,000. The reduction was particularly evident in
Kentucky, where the population decreased from 209,800 to
55,800. The total population grew to about 509,000 in
1978. In the winter of 1985-1986, three new colonies were
Reasons For Endangerment:
The primary reasons for this species' endangerment are
human disturbance and inadequate protection of the caves
where the bat resides.
The Indiana Bat is protected by the 1973 United States
Endangered Species Act in all of the states where it
lives. A few of its caves and mines have gained the legal
status of Critical Habitat. Others have become state or
federal property, and now enjoy partial protection from
Endangered throughout its range, Federal Register, March
The Indiana bat is a medium-sized myotis, closely
resembling the little brown bay (Myotis lucifugus) but
differing in coloration. Its fur is a dull grayfish
chestnut rather than bronze, with the basal portion of
the hairs of the back dull lead colored. This bat's
underparts are pinkish to cinnamon, and its hind feet
smaller and more delicate than in M. Lucufugus. The
calcar (heel of the foot) is strongly keeled.
RANGE AND POPULATION LEVEL:
The Indiana bat occurs in the midwest and eastern United
States from the western edge of the Ozark region in
Oklahoma, to southern Wisconsin, east to Vermont, and as
far south as northern Florida. In summer it is apparently
absent south of Tennessee; in winter it is apparently
absent from Michigan, Ohio, and northern Indiana where
suitable caves and mines are unknown. About 500,000
individuals of this species still exist.
PRODUCTION AND DEVELOPMENT:
This bat has a definite breeding period that usually
occurs during the first 10 days of October. Mating takes
place at night on the ceilings of large rooms near cave
intrances. Limited mating may also occur in the spring
before the hibernating colonies disperse. Hibernating
colonies disperse in late March and most of the bats
migrate to more northern habitat for the summer. However,
some males remain in the hibernating area during this
period and form active bands which wander from cave to
cave. Limited observations indicate that birth and
development occur in vary small, widely scattered
colonies consisting of 25 or so famales and their young.
Birth usually takes place during June with each female
bearing a single offspring. About 25 to 37 days are
required for development to the flying stage and the
beginning of independent feeding. Migration to the
wintering caves usually begins in August. Fat reserves
depleted during migration are replenished largely during
the month of September. Feeding continues at a
diminishing rate until by late November the population
has entered a definite state of hibernation. The
hibernating bats characteristically form large, tight,
compact clusters. Each individual hangs by its feet from
the ceiling. Every 8 to 10 days hibernating individuals
awaken to spend an hour or more flying to join a small
cluster of active bats elsewhere in the cave before
returning to hibernation.
Limestone caves are used for winter hibernation. The
preferred caves have a temperature averaging 37 degrees
fahrenheit in midwinter, and a relative humidity
averaging 87 percent. Some records are rather scarce. A
few individuals have been found under bridges and in old
buildings, and females and juveniles is limited to
riparian and floodplain areas. Creeks are apparently not
used if riparian trees have been removed. Males forage
over floodplain ridges and hillside forests and usually
roost in caves. Foraging areas average 11.2 acres per
animal in midsummer.
WHERE ARE THEY FOUND?
Indiana bats are found over most of the eastern hald of
the United States. However, large hibernating populations
are found only in Indiana, Missouri, and Kentucky.
Smaller populations of Indiana bats at either winter
hibernation sites or at summer roost and maternity sites
have been recorded from Alabama, Arkansas, Connicticut,
Florida, Georgia, Illinois, Iowa, Maryland,
Massachusetts, Michigan, Mississippi, New Jersey, New
York, North Carolina, Ohio, Oklahoma, Pennsylvania,
Tennessee, Vermont, Virginia, and West Virginia.
DOES IT MATTER IF THE INDIANA BAT GOES
Bats, including Indiana bats, seem to
play an important role in the ecosystems where they live.
They may be important in controlling numbers of insects
as this is their food soource. One of their prey species
is the gypsy moth, an important forest pest. As sicj.
they are biological insecticides that do not have the
adverse affects caused by poisonous insecticides.
Managing for Indiana bats, particularly
management for summer habitat, benefits the forest
community and many wilodlife and aquatic animals and
plants in that community. Management for IOndiana baty
summer habitat includes ensuring that forested arteas
along waterways remains forested. This helps aquatic
species because forested stream and river banks filter
sediments(and associated contaminants) during heavy rains
which helps to maintain or improve water quality.
The Value of Dead and Dying
Management of summere habitat also
includes ensuring that dead and dying trees are
available, rather than harvesting all trees as they begin
to die. This is very important for the forest community.
Many wildlifespecies, other than Indiana bats, use dead
and dying trees. Animals that use dead and dying trees
include most woodpeckers, nuthatches, chickadees, screech
owls, squirrels,and raccoons. Dead and dying trees are
used by these animals as a food source (critters eat the
bugs, fungi,and other organisms that cause decay) and as
shelter(cavities). Also, as trees die and decompose, the
logs provide food and shelteer for many animals and their
decomposition adds nutrients to the forest soils. Forests
that are harvested for commercial timber with trees being
removed as soon as they begin dying, often require heavy
doses of fertilizer to compensate for the nutrients that
those soils are not getting from decomposing trees.
Indiana bats are unattractive but fascinating creatures
that have an important role in their ecosystems, benefit
humans by eating nuisance and pest insects, and add to
our biological diversity. Management for their habitat
results in good forest management that benefits many
aquatic and forest creatures.
Humphrey, Stephen R. A.R. Ritcher, and J.B. Coper. 1977.
Summer Habitat and Ecology of the Endangered Indiana Bat,
Myotis sodalis. J. Mammal. 58:334-346.
LaVal, R. K., R.L. Clawson, W. Caire. 1977. Foraging
Behavior and Nocturnal Activity Patterns of Missouri
Bats, With Emphasis on the Endangered Species Myotis
grisecens and Myotis sodalis. J. Mammal.5800:592-599
LaVal,R.K., R.L. Clawsonl, W. Caire, L.R. Wingate, and
M.L LaVal. 1976. An evaluatio of the status of Myotime
Bats in the Proposed Meramec Park and Union Lake Project
Areas , Missouri School of Forestry, Fisheries and
Wildlife, University of Missouri, Columbia 136pp.
U.S. Department of Agriculture. 1975. Endangered,
Threatened and Unique Mammals of the Southern National
Forests. U.S. Forest Service, Atlanta, Georgia. 121pp.
U.S. Department of Interior. 1978. Species Accounts for
Sensitive Wildlife Information System(SWIS). Fish