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Gray Bat

[AR T&E Species Home]

Find out more about White-nose Syndrome (WNS) at:

White-nose Syndrome.org

F&W Service WNS FAQ

Fort Collins Science Center WNS Info

WNS Decontamination Guidelines

Learn more about gray bat recovery in the Gray Bat 5-year Review.

To learn more about the karst environment, visit our Caves and Karst page.

Gray Bat (Myotis grisescens)
Status: Endangered
Listed: April 28, 1976

For questions regarding the Gray Bat in Arkansas, please contact Tommy Inebnit at thomas_inebnit@fws.gov or 501-513-4483.

Species Facts:
The gray bat is 3-4 inches in length and weighs 7-16 grams (1/4 to 1/2 an ounce).  Its fur is gray, but may have a slight reddish cast in the summer.  The gray bat is the only Myotis with the wing membrane attached to the ankle (instead of at the base of the toe), and the only bat in its range with dorsal (back) hair that is uniform in color from base to tip. Individuals forage along river or shoreline up to 12 miles from their roosts. Foraging is generally parallel to streams, over the water at heights of 6.5 to 9.8 feet where they feed mostly on flying insects, including mayflies and beetles. Adult females sometimes feed continuously for seven or more hours per night

Bats are the only major predator of night flying insects; a single bat can consume between 600 - 1200 mosquitoes and other insects in just one hour. A nursing female can eat more than her body weight in insects in one night—up to 4,500 mosquitoes and other insects. Bats also consume pests such as the cucumber beetle and corn earworm moth, both of which can cause millions of dollars in crop damage each year. Other species of bats are important pollinators and seed dispersers.

Habitat Summary:
Gray bat roost sites are nearly exclusively restricted to caves in limestone karst areas throughout the year. Colonies occupy a home range that often contains several roosting caves scattered along as much as 43 miles of river or reservoir borders. Gray bats have specific roost requirements and few caves meet these. Winter roosts are in deep vertical caves with domed halls. Winter cave temperatures range from 42- 51° F The species selects hibernation sites where there are multiple entrances and good air flow.  Summer cave temperatures range from 57-75 °F, trap warm air, provide restricted rooms or domed ceilings, and are nearly always located within a mile of a river or reservoir. Maternity caves often have a stream flowing through them. There are occasional reports of storm sewers, mines, and buildings being used as roost sites.

Forested areas along the banks of streams and lakes provide important protection for adults and young. Young often feed and take shelter in forest areas near the entrance to cave roosts. They do not feed in areas along rivers or reservoirs where the forest has been cleared.

Why is it Endangered?

Threats to the gray bat include human disturbance of the cave habitat, including habitat loss and degredation, cave commercialization, and improper cave gating.  Since large numbers of gray bats are found in only a few caves year round, the species is very vulnerable to human presence.  Human presence in caves causes bats within range of any light or sound to at least partially arouse from hibernation, which depletes the energy reserves meant to sustain the bat through winter. The construction of dams has flooded many former bat caves, and human surface activities such as deforestation and pesticide use can also greatly affect the survival of the gray bat. The fungal disease of white-nose syndrome was detected in Arkansas in 2014 and may affect the gray bat population as well. Check the links in the sidebar for more information about white-nose syndrome.

Recovery:

Many private and public caves have been closed to public access to reduce stress and/or damage to bats and their habitats and to prevent the further spread of WNS in Arkansas. Cave gates that limit human disturbance of the bats and/or their habitat are a good way to protect these animals. The Partners for Fish and Wildlife program can help provide funding and expertise if you are interested in protecting your property from trespassing and vandalism with a gate over the cave mouth. Contact Joe Krystofik at joe_krystofik@fws.gov or 501-513-4478 for more information about cave gates and cave protection.

Efforts are also being made to educate people about WNS and WNS decontamination procedures to reduce the risk of transmission of the the fungus to other bats and/or habitats. You can find the full decontamination guidelines here.

You can learn more about gray bat recovery in the Gray Bat 5-year Review.

Range in Arkansas:

Arkansas Field Office
110 S. Amity Road
Suite 300
Conway, AR 72032

501/513 4470 (v)
501/513 4480 (f)

Last Updated: October 17, 2018

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