Brazilian Free-tailed Bat
Tadarida brasilienus
These bats, which are regarded as one of the most abundant mammals in North America, are named because their naked tails extend well beyond the edge of their interfemoral (tail) membrane. This species is known from only one record in Tennessee; it was found in a building in Montgomery County.
Description: A medium-sized bat with a distinctive tail, which extends about ½ of its length beyond the back edge of the tail membrane. The short, dense fur is dark brown to grayish brown with the underside slightly paler. The wings are long and narrow. Ears are broad and the tragus (membrane inside ear) is small and blunt. Eyes are relatively large compared to other bats. Long hairs protrude from the toes.
Length: 3.5 - 4.5 inches
Tail: 1.1 - 1.9 inches
Ears: 0.5 - 0.8 inches
Weight: 0.25 - 0.50 ounces
Similar Species: None.
Habitat: These bats occur in caves in the southwestern U.S., but occur only in man-made structures in the eastern U.S. They prefer buildings and attics, especially hot attics. The high temperatures are essential for the rapid growth of young bats.
Diet: Feeds on small moths almost exclusively, but also flying ants, beetles, leafhoppers, and other flying insects, which it captures in the tail membrane.
Breeding information: Unlike most of Tennessee's bat species, Brazilian Free-tailed Bats breed during late winter, usually in February or March. A single young is born in late spring or early summer after a gestation period of 11-12 weeks. Females returning to the nursery will nurse any of the young. The young will begin flying at about 5 weeks old.
Status in Tennessee: Though common throughout most of its range, the status of this bat in Tennessee is unknown.
Fun Facts:
- Brazilian Free-tailed Bats are one of the most ecologically and economically important animals in North America, consuming astounding numbers of insects nightly, many of which are agricultural pests.
- They can live up to 11 years in the wild.
Best places to see in Tennessee: Probably attics of buildings in southern counties.
For more information:
Tennessee Bat Working Group Species Account
Sources:
Schwartz, C.W. and E.R. Schwartz. 2001. The Wild Mammals of Missouri, 2nd Edition. University of Missouri Press and Missouri Department of Conservation, Columbia, MO.
