Bio. 226: Biological Diversity 2003
Earlham College

M. sodalis emerging from a tree roost. Image courtesy of Bat Conservation International

Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Chiroptera
Family: Vespertilioninae
Subfamily: Vespertilionidae
Genus: Myotis
Species: Myotis sodalis

M. sodalis image courtesy of Bat Conservation International

Conservation Organizations

Bat Conservation International
A site, based in Austin, Texas, devoted to the protection and restoration of bats and their habatats world wide.

IUCN Red List of Threatened Species
This assesses the conservation status of species in order to highlight taxa threatened with extinction and promote their conservation.

DNR Division of Fish and Wildlife Nongame and Endangered Wildlife Program
Indiana government site providing information on endangered wildlife. (go to the site index and look under "i" for the Indiana Bat site.)

New York State Department of Environmental Conservation
Information on conservation issues and programs in New York - Includes a page on M. sodalis

Kingston Telemetry Project
A project locating M. sodalis maternity sites for conservation purposes.


Image courtesy of New York State Department of Environmental Conservation

Image of hibernating bats courtesy of Indiana Bats. Image is a link to a larger photo.

Female Myotis sodalis. Image courtesy of Kingston Telemetry Project
















Note: PDF Files require Acrobat Reader. Free downloads of the Reader are available here.

Myotis sodalis - the Indiana, or Social, Bat


The Indiana Bat, Myotis sodalis, is a small, brownish insectivorous bat that was first described in Indiana in 1928 (Green Mountain National Forest: Forest Factsheet). It is currently endangered, due to human disturbances in the caves where this bat hibernates in the winter and habitat loss. In Indiana its conservation is the responsibility of the DNR Division of Fish and Wildlife Nongame and Endangered Wildlife Program.

Introduction - Data

Myotis sodalis occurs in the Midwest and eastern United States, including Alabama, Arkansas, Georgia, Iowa, Illinois, Indiana, Kansas, Kentucky, Maryland, Michigan, Missouri, Mississippi, North Carolina, New Jersey, New York, Ohio, Oklahoma, Pennsylvania, South Carolina, Tennessee, Virginia, Vermont, and West Virginia (according to the U.S. Fish and Wildlife Service, and the University of Michigan Museum of Zoology).

Myotis sodalis lives in cavernous limestone areas. In the winter the bats live in caves, where humans frequently disturb them. In the summer the females’ nest in trees and the male's roost locations are not known (University of Michigan).

Physical Characteristics:
Male bats are typically 7.1g, while the females are slightly heavier; 7.5g. They have dark (black to light brown) dorsal fur and lighter ventral fur. Distinguishing features are a keeled calcar (a cartilaginous projection from the foot) and short sparse hairs on the toes. The fur appears bicolored (USDA Forest Survice, a pdf file).

Myotis sodalis eats flying insects, feeding after sunset over water, or around canopy level. These bats mate in the fall and the females become pregnant in the spring (New York State Department of Environmental Conservation).

They normally have only one pup a year (Green Mountain National Forest: Forest Factsheet). They mate in the fall before entering the cave for hibernation and the females become pregnant in the spring. Young are raised under loose tree bark (University of Michigan).

Myotis sodalis swarms at cave mouths, mates, and enters hibernation in the early fall, forming clusters in the cooler parts of the cave. They leave hibernation between April and June and disperse hundreds of miles(New York State Department of Environmental Conservation). The few female summer roosts that have been found are near water.

Conservation Status

Myotis sodalis is listed as EN A1c in the IUCN Red List of Threatened Species, indicating that it is endangered. This is due to a population drop of 50% in the last 10 years caused by habitat loss.

Conservation Issues

The Indiana bat, Myotis sodalis, is listed as an endangered species within its entire range, and has been given the code En A1c (IUCN list). This code signifies that the population of the species has dropped over 50% in the last ten years. The main cause of the decline in M. sodalis population is the human destruction of their habitat. There are a number of ways that humans have directly and indirectly ruined these bats’ habitat. The caves that the bats use for shelter, hibernation, breeding grounds, and for socializing are being turned into tourist sites and are being industrialized, making them unsuitable for the bats’ survival. Destruction of even a small number of caves is a very serious threat to the species, as thousands and thousands of bats can inhabit a single cave.

Fig. 1: Range of M. Sodalis in America. This map links to the enlarged version. Image courtesy of Bat Conservation International

All bats thrive when their roosting caves are left undisturbed, and they suffer when they are intruded upon. The main factor in the decline of the M. sodalis population is the intrusion into their caves by people. Cave tours, spelunkers, vandals, and researchers all take a toll on these sensitive animals (eNature). Cave commercialization has a number of negative effects on bat habitats. For example, the improper gating of cave entrances and construction for cave commercialization have altered cave environments, rendering some caves unsuitable for Indiana bat hibernation (Clawson).

One serious problem is human disturbance of hibernating bats. Once in hibernation, a bat must conserve its body fat supplies until spring or face starvation. When aroused from hibernation, they can expend 10 to 30 days of these limited reserves, leaving them without the proper fat reserves (University of Michigan).

Vandalism and direct destruction of roosting bats have also been documented. Other human-related factors that have been implicated in the decline of the species include habitat changes such as stream channelization and bank modification, forest clearing and alteration, agricultural development and indiscriminate collecting. Although pesticide poisoning of M. sodalis has not been documented, other North American bats in agricultural habitats have declined due to the effects of pesticides, and it is likely that the species suffers at least some level of contamination (University of Michigan).

Another habitat of M. sodalis being destroyed are roost sites in trees. The bats make maternity roost sites in dead trees exposed to sunlight, located in upland forests, and near streams. Losses of these sparse sites through streamside deforestation and stream channelization pose threats to the recovery of the species (Drobney, Clawson).

So many caves have been degraded that some 87 percent of the M. sodalis population hibernates in only seven caves (enature). Habitat destruction is thus a huge problem for the species, as huge colonies inhabit a single cave. During hibernation, M. sodalis bats cluster in groups of up to 484 bats per square foot (hence the common name social bat). Because the largest hibernation caves support from 20,000 to 50,000 bats, it is easy to see how a large part of the total population can be affected by a single disturbance (Indiana Bat Factsheet).

Biologists are making an effort is to preserve these caves, and keep people away from them. A number of techniques and plans have been devised to slow and stop the decline in the M. sodalis' population. Bat Conservation International (BCI) has many projects underway to protect the existing roost sites and restore previous habitats to stop the decline of endangered bat populations. Also the North American Bat Conservation Partnership (NABCP) has biologists trying to prevent the extinction of the species. Plans to slow the decreasing populations generally begin with research. Research on M. sodalis can include capturing, observing, tagging, and sampling of hair, blood, or wing tissue. Some BCI biologists have also attached radio receivers to the bats and tracked their progress for a longer period of time, hoping the bats will lead them to their roosting site (Kingston Telemetry Project). A typical recovery plan is illustrated in this document: This plan is to be carried out by the Indiana Bat Recovery Team, biologists working for the US Fish and Wildlife Service.

The US Fish and Wildlife Service has taken measures to insist that M. sodalis be protected during the proposed construction of a new I-70 interchange near the Indianapolis Airport. This involves providing new habitats for the bats to replace the 93.7 acres of their habitat that will be destroyed for the new highway (Final Environmental Assessment and Final Habitat Conservation Plan - pdf file).

Although biologists and environmentalists are hopeful, the revival of the M. sodalis population is not trivial, and it will take time and effort. Since the female M. sodalis bat only produces one young each year, and as their habitats are in grave danger, the odds are against them. However with the help of scientists and researchers from a number of federal and private organizations, the future of the Indiana bat, Myotis sodalis, is uncertain.

Literature Cited:

Bat Conservation International. 2002. BCI-bat species: US species: Myotis sodalis. Accessed 2003 March 29.

Clawson, Richard L .1997. Indiana Bats: Down for the Count. BATS Magazine. Bat Conservation International (BCI), Accessed 2003 March 30.

Drobney, Ronald D. and Clawson, Richard L. (no date) Indiana Bats. Accessed 2003 March 30

eNature. (no date). Indiana Myotis -
. Accessed 2003 March 28.

Green Mountain National Forest. 2002 September 4. Indiana bat. Accessed 2003 March 28.

IUCN 2002. 2002 IUCN Red List of Threatened Species. Downloaded on 29 March 2003. (site specified citation)

Kingston Telemetry Project. 2001. Bat Conservation and Management Telemetry. Accessed 2003 March 30.

New York State Department of Environmental Conservation. 2003 March 1. Indiana Bat Fact Sheet. Accessed 2003 March 29.

University of Michigan - Museum of Zoology - Animal Diversity Web. 1997 Febuary 25. Myotis sodalis (indiana bat): narrative. Accessed 2003 March 29.

USDA Forest Service pdf file. date unknown. Indiana bat - Myotis sodalis. Accessed 2003 March 28.

U.S. Fish and Wildlife Service. (no date) Indiana Bat Fact Sheet Accessed 2003 March 30.

U.S. Fish and Wildlife Service. 2003 March 29. Species profile for indiana bat. Accessed 2003 March 29.

U.S. Fish and Wildlife Service. (no date) Six Points Environmental Assessment. Accessed 2003 March 30.

U.S. Fish and Wildlife Service. 2001 September 19. Habitat Conservation Plan for the Six Points Road Interchange and Associated Development (PDF file). Accessed 2003 March 30.

Author: Alexandra Turnbull and Adam Morris
Creation/revision date: 11 Feb. 2003 / 4April 2003

Biology 226: Biological Diversity Spring 2003:

Attwater's Prairie ChickenAloe VeraAmerican LobsterBacillus anthracisBasilisk LizardBlue-headed WrasseBlue-ringed OctopusBotfliesHyacinth MacawMyotis sodalis (this site) • Leafy Sea DragonLeishmaniaManed SlothPlatypusRafflesiaRing-tailed LemurSpanish DancerSt. Croix Ground LizardTomatoesVampire Squid

Biology 226: Biological Diversity Fall 2001:

Apis melliferaCapybara Chimpanzee Danaus plexippusExciting CephalopodsGreen Sea Turtle (H-R,K)Green Sea Turtle (B,M,C)Green Serpent Star HolothuroideaHyenasLatimeria chalumnaeMudpuppyNorthern Leopard FrogPink Seafan SalamandersScyphozoaTuatara

This website is part of a Biology 226 class project on the conservation of global biodiversity.

Earlham · Biology Department · Biology 226: Biological Diversity

Copyright ©-2001 Earlham College. Revised 16 November 2001. Send corrections or comments to Alexandra Turnbull or Adam Morris