THE BRAZILIAN (MEXICAN) FREE-TAILED BAT – Tadarida brasiliensis
Pronunciation: ta-dare-a-dah bra-zill-ee-en-sis
The Brazilian Free-Tailed Bat or Mexican Free-Tailed bat (Tadarida brasiliensis) is a medium sized bat. Their fur is reddish to dark brown or gray in color. They have broad, black, forward pointing ears, and wrinkled lips. Their tails extend more than one third beyond the tail membranes; most other bats have tails that are completely enclosed within the tail membranes. Their wings are long and narrow.
“Most of these bats migrate south to Central America and Mexico during the winter.”
Mexican free-tailed bats occupy a wide variety of habitats, ranging from desert communities through pinion-juniper woodland and pine-oak forests at elevations from sea level to 9,000 feet or more. The largest U.S. populations of free-tailed bats live in the West, with the densest concentrations found in Texas where they form maternity colonies numbering in the millions. They are found throughout Mexico and most of the western and southern U.S. The largest maternity colonies are formed in limestone caves, abandoned mines, under bridges, and in buildings, but smaller colonies also have been found in hollow trees. It is estimated that 100-million Mexican free-tailed bats come to Central Texas each year to raise their young. Nursing females require large quantities of insects that are high in fat, which they obtain by consuming egg-laden moths.
“Free-tail bats consume enormous amounts of moths and other insects. Some roosts are known to contain millions of bats. In those colonies it is estimated that 250 tons of insects can be consumed every night.”
The 100 million free-tailed bats living in Central Texas caves consume approximately 1,000 tons of insects nightly, a large proportion of which are agricultural pests. Researchers using Doppler weather radar watch emerging bats ascend to altitudes of 1,000-10,000 feet to feed on migrating cotton boll worm moths, army cut-worm moths, and other costly agricultural pests that migrate north from Mexico. These migratory moths hopscotch across the country each year, reaching rich agricultural land as far north as the Canadian border. The cotton boll-worm moth (a.k.a. corn ear-worm moth) alone, costs American farmers a billion dollars annually. Although the ecological and economic impacts of large colonies are most obvious, even small colonies of bats can significantly impact local insect populations. Mexican free- tailed bats also consume enormous quantities of insects over woodlands and forests, likely including many additional pests.
List Of Bats In The US And Canada
Thanks to Bat Conservation International for our bat images and much of our bat information.