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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).

Indiana Bat
Indiana Bat
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 are found.

  • 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. Hibernia Mine entranceRepeated disturbances may force them to use up too much of their fat reserves and cause them to starve to death before warm spring weather arrives.

  • 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) Hibernating bat cluster 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 in color.

  • 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.
Ways 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 ( to obtain plans for building your own bat house or click on their catalog to purchase one.
Conserve Wildlife license plate
Order a 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.
Additional Sources of Information

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Copyright © State of New Jersey, 1996-2004
Department of Environmental Protection
P. O. Box 402
Trenton, NJ 08625-0402

Last Updated: October 7, 2004