Ozark Big-eared Bat

Corynorhinus townsendii ingens

ListedNovember 30, 1979
FamilyVespertilionidae (Bats)
DescriptionLarge-eared, medium-sized, red bat.

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HabitatCaves in mature hardwood forests.
ReproductionOne or two young every season.
ThreatsHabitat disturbance
RangeArkansas, Missouri, Oklahoma


The Ozark big-eared bat, Corynorhinus townsendii ingens, is a subspecies that Townsend"s big-eared bat. Adults sweet from 0.2-0.5 oz (5-13 g) and also have influential ears, 1 in (2.5 cm) long, connected throughout the forehead. The bat has actually mitten-shaped glands top top the muzzle and elongated nostril openings.

Townsend"s big-eared bats resemble the east big-eared bat (Plecotus rafinesquii ), yet can be differentiated by color. The brown-backed Townsend"s has tan underparts in comparison to the whitish underparts and gray earlier of the eastern big-eared bat. The Ozark big-eared bat deserve to be differentiated from its close to relative, the Rocky Mountain form (Plecotus townsendii pallescens ), through its reddish color and larger average size.

The types is likewise classified together Plecotus townsendii ingens.


Townsend"s big-eared bat is fairly sedentary, migrating no an ext than 40 mi (64 km) in between hibernation and maternity caves. It return to the exact same roosts year after ~ year, and also caves are offered year round. The bat normally hibernates near cave entrances just past the twilight zone, however during a hefty winter may move deeper within the cave.

Bats hibernate singly and in clusters. Solitary bats hang upside under by one or both feet through wings wrapped approximately the body and interlocked. Wing of clustered bats space usually folded against the body, and also the ears might be coiled tightly against extreme cold.

Ozark bats feeding principally top top moths and other insects. Some have been observed gleaning insects from pipeline while perched, but most feed while in flight, locating insects through echolocation.

These bats monitor a mating routine that contains vocalization and also head-nuzzling. Breeding begins in autumn and also peaks in November. Young females girlfriend in their first year. The male"s sperm is stored in the reproductive tracts the females till spring, once fertilization take away place. Gestation takes from 56 come 100 days.

Townsend"s bats space born hairless v their huge ears draped down over unopened eyes because that the first few days. Young bats are capable of trip at three weeks and are totally weaned at six weeks.


Ozark big-eared bats inhabit caves commonly located in limestone karst regions dominated by mature hardwood forests of hickory, beech, maple, and also hemlock trees. Females bear and also care for young in maternity caves. This caves space usually closer to food resources than the hibernation caves, which are better protected indigenous the cold and wind.


Non-endangered subspecies that Townsend"s big-eared bat, consisting of P. T. Townsendii, P. T. Pallescens, and P. T. Australis, are found throughout lot of western north American native British Columbia south through California into Mexico, and east native the shore to a line prolonging from the black color Hills of southern Dakota south through western Texas. A 4th subspecies, Virginia big-eared bat (P. T. Virginianus ), is federally listed as Endangered.

Once fairly common, the Ozark big-eared bat is now limited to a couple of isolated populaces in Arkansas, Missouri, and Oklahoma.

In 1986 a survey of 71 potentially habitable caves in Arkansas and also Oklahoma situated only 4 maternity caves that still harbored viable breeding colonies the the Ozark big-eared bat. These were Blue Heaven cavern in Marion County, Arkansas, and three unnamed caves in Adair County, Oklahoma. In addition, hibernation swarms were located in four caves in Marion and Washington counties, Arkansas, and also Adair County, Oklahoma.

A census the the populaces of the maternity caves was performed again in 1987, resulting in a minimum count of 450 Ozark big-eared bats, a slight boost over the vault year. In addition, biologists discovered a new maternity cavern in Adair County that housed 260 bats, the largest known reproduction colony. None of the recognized hibernation caves support much more than 100 bats.

Seventeen caves in Adair, Cherokee, Delaware, and also Sequoyah counties, Oklahoma, have been discovered to support a couple of solitary bats. Three caves in Marion and also Washington counties, Arkansas, and also four caves in stone and Barry counties, Missouri, likewise sheltered diverted individuals. By 1992, the total population numbers were assumed to be much less than 1,000 individuals.


Not all determinants limiting the Ozark big-eared bats room known. Although some predation occurs, ns of habitat does no seem to be a factor. A number of apparently an ideal caves remain unoccupied. The most significant cause the this subspecies" overall decline is most likely increased human intrusion right into bat caves. Typically, bats only store sufficient calories to make it through the winter, and, once aroused indigenous hibernation, castle burn up these reserves. Disturbed bats frequently starve or are required to leaving hibernation prematurely in search of food. Bats additionally tend come abandon cave sites that are disturbed frequently.

Conservation and also Recovery

Gates have actually been constructed at the gates of some caves to store out people and predators. The results have actually been mixed. Part gated caves seem to have minimal bats" access to the caves, and populations actually decreased as a result. Gates have newly been redesigned come protect cavern entrances without limiting bat egress. Participating agreements have been got to with owners of some caves to restrict person intrusion.

In 1988, lightweight radio transmitters were attached to female Ozark big-eared bats in Oklahoma to recognize the feasibility of utilizing telemetry in recovery efforts. If the bats appeared unencumbered, the short selection of the radios used in the experiments minimal the practicality the this initiative to determine bats" reproductive activities.

In 1991, the U. S. Fish and Wildlife Service listed funds for bat cavern protection in ~ Devil"s Den State Park, a major wintering residence to the bats. The park"s popularity through visitors—a half-a-million a year—made cave protection difficult. Accumulation were offered to download a customized alarm mechanism to ward off intruders; though gating is the preferred habitat security tool for such caves, the uneven, irregular form of the see made together a barrier solution impractical in ~ Devil"s Den.

Another significant recovery effort in recent years was the deliver of a 255-acre (103.2-hectare) street of Farmer"s Home administration property include caves and also land vital to the recovery of the Ozark big-eared bat come the Oklahoma Bat Caves national Wildlife Refuge. An agreement was negotiated through the Cherokee country to protect 120 acre (48.6 hectares) of defect lands because that the advantage of these endangered bats.


U.S. Fish and Wildlife Service local Office, department of Endangered types P.O. Crate 1306 Albuquerque, new Mexico 87103 http://southwest.fws.gov/

U.S. Fish and Wildlife Service local Office, department of Endangered types Federal building Ft. Snelling twin Cities, Minnesota 55111 http://midwest.fws.gov/

U.S. Fish and Wildlife Service regional Office, department of Endangered varieties 1875 Century Blvd., Suite 200 Atlanta, Georgia 30345 http://southeast.fws.gov/


Harnish, H.E. 1992. "Protecting the Bats of Devil"s Den." BATS Magazine, 10(2): 13-18.

Harvey, M. J., et al. 1981. "Endangered Bats the Arkansas: Distribution, Status, Ecology, Management." ecological Research Center, Memphis State University, Memphis.

Jacobs, J., and F. Bagley. 1984. "1983 Rangewide inspection of Ozark and Virginia Big-Eared Bat Maternity Colonies." U.S. Fish and also Wildlife Service, Atlanta.

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U.S. Fish and also Wildlife Service. 1984. "A Recovery arrangement for the Ozark Big-Eared Bat and also the Virginia Big-Eared Bat." U.S. Fish and also Wildlife Service, Newton Corner, Massachusetts.