Brazilian Free-Tailed Bat

Photo of the Brazilian Free-tailed Bat, Murci��lago de Cola Libre

Brazilian Free-tailed Bat, House Bat (Eng.), Murciago de Cola Libre (Sp.), Tadarida brasiliensis (Sci.), Native; North, South and Central America, Greater and Lesser Antilles Islands (to St. Lucia).

Photo Merlin D. Tuttle/Bat Conservation International. Information compiled by Alan Mowbray, Interpretive Media Writer, EYNF/LEF

General Information

The insectivorous Brazilian Free-tailed Bat (Tadarida brasiliensis) is of the Order Chiroptera; Family Molossidae. Members of this family have tails extending well beyond the edge of the tail membrane. All have short, dense fur and give off a musky odor. Primarily cave bats, Free-tailed bats are known from the lower Oligocene period in the fossil record.


Tadarida brasiliensis is a medium-sized bat with broad ears and large feet. The terminal half of its tail is free from its tail membranes, hence the name free-tail. It has broad ears which extend to the tip of its snout when laid forward, that appear to unite across its forehead. Its feet have white bristles on each side of the outer and inner toes. Its pelage (furry coat) is short and velvety. Its upper body parts vary from reddish to black while the underbody is slightly more pale, and its ears are blackish. Tadarida brasiliensis average total length is 3.7 inches (95 millimeters), its tail measures 1.5 inches (38 millimeters). Its foot is 0.4 inches (10 millimeters), ear 0.7 inches (19 millimeters) and its forearm is 1.6 inches (42 millimeters) in length. The Brazilian Free-tailed Bat Weighs between 0.02 and 0.03 ounces (11-14 grams.).


The Brazilian Free-tailed Bat is an opportunistic insectivore; its diet includes moths, flying ants, beetles, bugs and other insects. It often preys on swarming insects and may fly considerable distances to favorite feeding areas. It breeds in March or early April; gestation lasts for 2.5 to 3.5 months. Births occur from early June to mid-July. Litters are usually limited to one, although a female may contain two embryos. Young nurse for about 45 days and first fly at 6-7 weeks. Females can become pregnant at 1 year, while males become sexually mature at 18-22 months. It roosts in dry, dark areas (caves, old buildings, hollow trees) where a dozen or more animals can hang-up together and have enough space below to drop-down when taking wing. They fly as a group to begin foraging several minutes before dark.


Tadarida brasiliensis roosts in caves and old buildings in Puerto Rico, and also has been known to occupy hollow trees. It usually roosts about 10 feet (3 meters) above the ground to allow for free fall necessary to achieve flight.

Where to look for this animal in the EYNF

Since this animal is dormant during the day (nocturnal), emerging to forage at night, it is typically encountered only on night-time guided nature trail walks.