- Scientific Name: Myotis grisescens
- Weight: 8-11 grams
- Wingspan: 27-30centimeters
- Distribution: Cave regions of Arkansas, Missouri, Kentucky, Tennessee, and Alabama, with occasional colonies found in adjacent states.
- Ecology and Behavior: Gray bats are cave residents year-round, but different caves usually are occupied in summer and winter. Few have been found roosting outside of caves. They hibernate primarily in deep vertical caves with large rooms acting as cold- air traps (42-52*F). In summer, females form maternity colonies of a few hundred to many thousands of individuals, often in large caves containing streams. Maternity colonies occur in caves that, because of their configuration trap warm air (58-77* F) or provide restricted rooms or domed ceilings capable of trapping combined body heat from clustered individuals. Because of their specific habitat requirements fewer than 5% of available caves are suitable for gray bats. Males and non-reproductive females form bachelor colonies in the summer. Gray bats primarily forage over water of rivers and lakes.
- Food Habits: Mayflies are important in the diet, but gray bats also consume a variety of other insects.
- Reproduction: Mating occurs in September and October, and females enter hibernation immediately after mating. Females sore sperm throughout the winter and become pregnant after emerging from hibernation. One young is born in late May or early June, and begins to fly within 20-25 days after birth. The lifespan of gray bats may exceed 15 years.
- Status of Populations: Endangered. About 95% of these bats hibernate in only eight caves making them extremely vulnerable to destruction.
The presence of species in particular counties is based on both summer and winter occurrence records compiled by the TNBWG, an unshaded county does not represent the absence of a particular species from that county, only the lack of an occurrence record. These maps are intended for educational and general information purposes only and are not intended for use in consultation with US Fish and Wildlife Service (USFWS) or any other state or federal agencies. Project proponents should contact USFWS and the Tennessee Wildlife Resources Agency for the most up to date ranges for bat species in Tennessee.
Range Map Data Sources
National bat ranges - Layer downloaded from nationalatlas.gov. The data were compiled by Bat Conservation International using data from state natural heritage programs, published literature, unpublished reports, museum collections, and personal communications from university, Federal, State, and local biologists.
TN county occurrence data - TWRA Scientific Collection Permit data compiled from 2000-2013, TWRA Wildlife Diversity database, published literature [Graves and Harvey 1974. (Journal of the Tennessee Academy of Sciences 49:106-109)], personal communications from university, Federal, State, local biologists, and TNBWG members.