Brazilian Free-tailed Bat
- Scientific Name: Tadarida brasiliensis
- Weight: 11-15 grams
- Wingspan: 29-35 centimeters
- Distribution: The southern United States and southward through Mexico and Central America into northern South America.
- Ecology and Behavior: Habitat of Brazilian free-tailed bats differs in various parts of the United States. In the southwestern United States, they primarily are cave bats migrating to Mexico to winter. About 20,000,000 bats of this species occur in one cave near San Antonio, Texas; this is the largest concentration of mammals in the world. In the eastern United States, this species does not occur in caves, it is present in only man-made structures, it does not migrate long distances, and few colonies larger than a few hundred individuals are known. These bats often select hot attics as roosts, and young seem to be able to tolerate higher temperatures than adults. High temperatures in roosts are essential for the rapid growth of young bats; apparently, the larger the colony, the less energy expenditure per bat to maintain a given temperature.
- Food Habits: This species feeds almost exclusively on small moths.
- Reproduction: One young is born in late spring or early summer. Birth occurs with the mother hanging head downwards. Passage of the young through the birth canal requires about 90 seconds. Newborns are hairless, but have all their milk teeth. Mothers usually are able to locate their own young among the thousands of other babies in a cave.
- Status of Populations: Common throughout most of its range, but only locally common in much of the southeastern United States.
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were compiled by Bat Conservation International using data from state natural heritage programs, published literature, unpublished reports, museum collections, and personal communications from university, Federal, State, and local biologists.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.