Free-Tailed Bat

Free-Tailed Bat, or Mastiff bats, a family that includes about 90 species of bats that are among the fastest flying bats in the world. The long tails of these bats give this family its common name.

Free-tailed bats are found in warm and tropical climates, from the southern United States through Central America to Argentina in South America. They are also found in southern Europe and Africa as well as in southern and Southeast Asia, including Malaysia. Some species migrate great distances—more than 1300 km (800 mi)—between their winter and summer habitats.

Free-tailed bats are covered with short, velvety fur that is brown, gray, or black in color. Two East Asian species, commonly known as naked bats, have such short fur that they appear hairless. Free-tailed bats range in length from 4 to 13 cm (2 to 5 in) and weigh from 8 to 230 g (0.3 to 6 oz), with most species at the smaller end of these ranges. Tail length ranges from 1.5 to 8 cm (0.6 to 3 in), and forearm length ranges from 3 to 9 cm (1 to 4 in). The wings of free-tailed bats are long and narrow, which helps with their rapid flight. They are capable of reaching speeds of up to 55 km/h (34 mph).

Free-tailed bats fly with their mouths open, catching their food in midair while on what are known as feeding flights. All free-tailed bats are insect eaters, feeding on moths, beetles, and flying termites. They are sometimes preyed on by owls, hawks, and snakes, and often they are host to small parasites, such as fleas, ticks, and lice.

Like most bats, free-tailed bats give birth to a single offspring once a year. Some species form huge nursery colonies of females and their offspring. These colonies often number in the tens of thousands. Nursery colonies of the Mexican free-tailed bat can reach 50 million or more individuals. In general, free-tailed bats roost in large groups, using caves, foliage, rock cliffs, hollow trees, and human-made structures, such as buildings and tunnels.

When large colonies of free-tailed bats roost undisturbed in caves for many years, great quantities of their excrement, or guano, build up. Because of its abundance, the guano of free-tailed bats was used as a source of sodium nitrate for gunpowder during the Civil War (1861-1865), and it has also been widely used as a fertilizer. Experiments during World War II (1939-1945) explored the use of these bats—noted for their rapid, direct flights—for carrying small bombs, but the efforts were not successful.

Scientific classification: Free-tailed bats make up their own family, the Molossidae, in the bat order, Chiroptera. The two species of naked bats are classified as Cheiromeles torguatus and Cheiromeles parvidens. The Mexican free-tailed bat is classified as Tadarida brasilienses.