Discover Life | All Living Things | IDnature guides | Mammalia | Vespertilionidae | Myotis | sodalis

Species Description

• Adult total length: 2 3/4 - 3 3/4 in. (69 - 95 mm)

• Tail: 1 - 1 3/4 in. (25 - 45 mm)

• Hind foot: 1/4 - 3/8 in. (7 - 9 mm)

• Weight: 1/7 - 1/4 oz. (4 - 8 g)

• Physical Characteristics: Bats are unique among mammals because their forelimbs are specialized for true flight. Flight membranes, which are actually extensions of the skin of the back and belly, connect the body with the wings, legs, and tail. Unlike birds, bats use both legs and wings during flight. Other modifications for flight include greatly elongated fingers to provide support for the wing membrane, a keeled sternum for the attachment of the enlarged flight muscles, and fusion of some vertebrae. The membrane extending from the tail to the hind legs is known as the interfemoral membrane. The dorsal pelage of the Indiana bat differs from that of the other three species of Myotis in being somewhat tricolored. Each hair is black at its base, grayish in the middle, and has a cinnamon-brown tip. The belly hairs are grayish tinged with cinnamon-brown. Overall color is dull chestnut-gray above and pinkish-white beneath. The ear reaches the nostril when laid forward. Hairs on the toes barely reach the base of the claws.

left lateral view of skull and mandible	dorsal view of skull	ventral view of skull

Index

Photographs

Myotis sodalis	Myotis sodalis

Index

Phylogeny

The Indiana bat originally inhabited the eastern United States from central Vermont south along the Appalachian chain to northwestern Florida and west to southwestern Wisconsin and northeastern Oklahoma. However, this species has shown a drastic population decrease since 1950, and it is scarce in some parts of its range. Harvey et al. (1999) stated: "The present total population of this endangered species is fewer than 360,000, with more than 85 percent hibernating at only nine locations, making them extremely vulnerable to destruction. "

• Range Maps

  North America	Great Smokies

• Great Smoky Mountains National Park: The Indiana bat was first recorded at park headquarters in 1937. In 1950, 2,242 individuals were counted in Blowhole Cave in Whiteoak Sink. In 1972, approximately 20,000 bats were observed; in 1975, 6,050 were present; in 1987, 10,760 bats were counted; in 1991, 5,383 bats were counted; and in 1993, 3,900 bats were present in the same cave. This represents the largest known population of this species in the state of Tennessee. Harvey (1992) noted that approximately 8,500 bats hibernate in Blowhole Cave and a small colony of approximately 200 Indiana bats hibernate in Bull Cave. These are the only records for the park.
  • Blount Co.: Blowhole Cave; Bull Cave; Scott Gap Cave (Wallace, 1984).

  • Sevier Co.: Park headquarters.

All of the park's caves provide critically important habitats for bats. During the summer, these bats are usually found in buildings, towers, hollow trees, beneath the loose bark of trees, in crevices of cliffs, and beneath bridges. During winter, these colonial bats move into caves where they form dense masses containing 300-450 individuals per square foot on the ceilings and walls (Cope, 1999). They prefer sections of caves where temperatures average 3 - 6°C (38 - 43°F) and with relative humidities of 66 - 95% (Harvey et al., 1999).

Index

Natural History

• Reproduction
  

• Longevity
  

• Terrestrial Ecology
  The senses of sight and hearing are well developed in bats. Since most bats become active near dusk and are active much of the night, sight is of little importance in navigation and in the capture of prey. Instead, they use echolocation, a system somewhat similar to radar. They emit ultrasonic calls far above the range of human hearing that are reflected from objects ahead of them. They hear the echoes and are able to avoid obstacles and find food in total darkness. Different species can be distinguished by differences in the structure of their echolocation calls (Fenton and Bell, 1981).

  During feeding maneuvers, the tail and wing membranes are used to capture and restrain prey. Some insects are captured by the tail membrane, which forms a pouch-like compartment. The bat must bend its head forward in order to grasp the insect with its teeth and take it into its mouth. Sometimes the bat may use its mouth to capture an insect from its wing.

  Eleven species of bats have been recorded in the park and all feed exclusively on insects. During the colder months when flying insects are unavailable, bats must either hibernate or migrate to warmer areas. Eight of our bats are known to hibernate. Only three - the red bat, hoary bat, and the silver-haired bat - are migratory. Bats have been seen flying over the park during every month of the year. When

• Predators and Defense
  No predators recorded from the park.

• Parasites
  None recorded from the park.

• Transmittable Diseases
  Bats are capable of transmitting two diseases to humans - rabies and histoplasmosis. Histoplasmosis is a disease caused by inhaling dust that contains contaminated spores. Tuttle ( 1988) stated: "Less than a half of 1 percent of bats contract rabies, a frequency no higher than that seen in many other animals. Like others, they die quickly, but unlike even dogs and cats, rabid bats seldom become aggressive." Bats do not attack when they get rabies; they just lie in one place. Although it is rare for humans to contract rabies from infected bats, persons handling them should be aware of this possibility.

• University of Michigan, Museum of Zoology
• eNature

Index

Acknowledgements

• Text
  • Dr. Donald W. Linzey, Wytheville Community College - wclinzd@wcc.vccs.edu
  • Christy Brecht, Wytheville Community College - wcbrecc@wcc.vccs.edu

• Photographs
  • Roger Barbour

• Map development
  • Richard Schulz, Great Smoky Mountains National Park - richard_schulz@nps.gov

• Web page design & coding
  • Denise Lim, University of Georgia, Athens
  • John Pickering, University of Georgia, Athens

• Barbour, R.W. and W. H. Davis. 1969. Bats of America. Lexington: The University Press of Kentucky.

• Cope, J. B. 1999. Indiana bat. Pages 97-98. In: D. E. Wilson and S. Ruff (eds.). The Smithsonian Book of North American Mammals. Washington, D. C.: Smithsonian Institution Press.

• Fenton, M.B., and G.P. Bell. 1981. Recognition of insectivorous bats by their echolocation calls. Journal of Mammalogy 62 (2): 233-243.

• Harvey, M.J. 1992. Bats of the eastern United States. Little Rock: Arkansas Game and Fish Commission.

• Harvey, M.J., J.S. Altenbach, and T.L. Best. 1999. Bats of the United States. Little Rock: Arkansas game and Fish Commission.

• Linzey, D. W. 1995a. Mammals of Great Smoky Mountains National Park. The McDonald & Woodward Publishing Company, Inc., Blacksburg, Virginia.

• Linzey, D. W. 1995b. Mammals of Great Smoky Mountains National Park-1995 Update. Journal of the Elisha Mitchell Scientific Society 111(1):1-81.

• Linzey, D. W. 1998. The Mammals of Virginia. Blacksburg, Virginia: The McDonald & Woodward Publishing Company, Inc

• Wallace, R. L. 1984. Biological survey report of Great Smoky Mountains National Park caves. Typewritten in GSMNP library.

• Tuttle, M.D. 1988. America's Neighborhood Bats. Austin: University of Texas Press.