Indiana Bat - October 2003 Species of the Month
Do you usually find "bats in the belfry?"
Can someone be "as blind as a bat?" And, can you get bats "in
your hair" if you go trick-or-treating this month? Halloween offers
the appropriate holiday season to learn about bats and explore the world
of the Indiana Bat (Myotis sodalis).
This beneficial species is listed as being endangered
in New Jersey as well as throughout the United States. The Indiana bat
was the October Species of the Month, in honor
of the 30th Anniversary of the New Jersey Endangered Species Conservation
Act and the formation of DEP's Endangered
and Nongame Species Program (ENSP).
Photo courtesy of Dr. J. Scott Altenbach
MD Dept. of Natural Resources
Protecting Habitats for Bats
- Indiana bats occur in the Midwest and eastern
United States, from parts of Oklahoma, to southern Wisconsin,
east to Vermont, and then as far south as northern Florida.
Since 1991, the Indiana bat population has dropped from an estimated
500,000 Indiana bats nationwide to approximately 300,000 today.
- Bats are sometimes mistreated and generally
misunderstood creatures. They do not become tangled in people's
hair and very few incidents of human rabies have been traced
to bat strains of rabies. Instead, they help control populations
of harmful or pesky insects wherever large populations of bats
- Indiana bats hibernate in limestone caves
and open, abandoned mine shafts (not belfries) between October
and April. Temperature and humidity are important factors for
bat habitat and Indiana bats seek out portions of the mines
where conditions are suitable.
- The hibernating Indiana bats form tight
compact clusters with bats of other species, usually on flat
surfaces or ceilings in a cooler part of a cave. The number
of bats at one site can range from 300 - 484 bats per square
foot. They hang by their feet from the ceiling
- During the summer females occupy maternity
roosts of up to 100 females under the loose bark of dead or
dying trees. These roosts have also been located under the loose
bark of living trees and in cavities of dead trees.
- The Indiana bat population is endangered
in New Jersey and nationwide because these hibernation sites
and roosting places used by Indiana bats are often disturbed
or altered by humans. Caves can be altered and used for commercial
purposes or frequented by spelunkers, photographers and hikers
throughout the year. While in winter hibernation, these bats
are most susceptible to disturbance because of lower respiration
rates and body temperature. At this stage they only have enough
energy reserved to last them through the winter. Repeated
disturbances may force them to use up too much of their fat
reserves and cause them to starve to death before warm spring
- Population declines also are believed to
result from home and landowners removing dead or dying trees
from their property. Bats rely on these trees for roosting during
the summer. The removal of these trees is also thought to cause
female bats to abandon their young.
- The Hibernia Mine in Morris County is home
to over 30,000 hibernating bats, including a small number of
Indiana bats. In the mid-1990s a gate was constructed over the
mine entrance. The gate allows bats to access the mine while
keeping people out. Every other year DEP biologists enter this
mine to conduct winter population counts. Over 400 iron mines
were opened in northern New Jersey between 1700 - 1900. Scientists
are inspecting those that are still open in the hope of discovering
new hibernation sites for wintering bat.
Indiana Bats Facts of Interest
- Bats are mammals and are the only true flying mammal
on earth. Just like other mammals, they do not lay eggs but bear live
young and then nurse them. Bats are also covered with fur. The body
of the Indiana bat is about the size of a mouse.
- The wings of a bat are like a webbed hand, which
allows them to fly. The wings have skin membranes that stretch between
each finger. The thumbs are not attached to the membrane allowing them
to climb and hang. Bats use their tails to slow themselves down when
they are flying.
- Bats are not blind. Their vision is thought to
be comparable to that of humans. To navigate at night, they use high
frequency calls (echolocation) that bounce off insects and other objects
and then return to the bat. This
radar-like trait helps the bat locate food sources and prevents them
from flying into other objects. Bats have superb flying abilities.
- The Indiana bat is difficult to distinguish from
other bat species. It closely resembles the common little brown bat
but instead of having black-brown lips it has pink lips. Its fur is
black and gray, instead of brown or bronze, and its underside is pinkish
- Insect-eating bats can consume large quantities
of mosquitoes and other insects. In fact, Indiana bats have been known
to eat more than their own body weight in insects in one night.
- Female Indiana bats give birth to only one young
(rarely, twins) and only once a year. This low birthrate contributes
to the decline of Indiana bat population numbers.
You Can Help
- If a bat is in your house don't try to kill it
- it is illegal for anyone to harm or kill bats. Isolate it in one room
by closing all of the doors then open any exterior doors and windows
in the room so that it can exit on its own. Turn off the lights in the
room, leave the bat alone and have someone stay in the room (standing
against one of the walls) to make sure it finds its way outside by itself.
If you must remove the bat yourself, do not touch it with your bare
hands. Put on gloves, place a box or coffee can over the bat when it
lands, slide a piece of cardboard behind the container to trap the bat
inside of it, then release it outdoors.
As long as a standing tree provides no hazard
to any nearby structures, roads or parking lots, consider letting
the tree remain in place as it may provide critical roosting habitat
for the Indiana bat.
- If you know of a location where bats roost during
the summer (an attic, barn, church, bridge, etc.), participate in DEP's
"Summer Bat Count." Volunteers
who know of such a site must count the bats at the same location twice
during the summer months. Biologists use this documentation to collect
important distribution and status information about New Jersey's bats.
To participate in the Summer Bat Count contact 908-735-9281.
- Put up a bat box in your yard! Bat houses are
becoming available in many garden supply stores. However, bats are specific
about their roosting requirements. After conducting many studies, Bat
Conservation International designed their bat houses to meet those specific
needs and provide the best chance of success in attracting bats to a
bat box. Visit Bat Conservation International (www.batcon.org)
to obtain plans for building your own bat house or click on their catalog
to purchase one.
Conserve Wildlife special interest license plate for your vehicle. It's
tax-deductible, with 80% of the payment benefiting New Jersey's Endangered
and Nongame Species Program.