Bats in New Mexico

Bazilian Free-tailed Bat

BRAZILIAN FREE-TAILED BAT - Tadarida brasiliensis

Weight: 11-15 grams.

Wingspan: 29-35 centimeters.

Distribution: Southern United States and southward through Mexico and Central America into north­ern South America. It also occurs on islands of the Caribbean.

Ecology and Behavior: Habitat of Brazilian free-tailed bats differs in various parts of the United States. In the Southwest, 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 Southeast, this species does not occur in caves, it is pre­sent only in man-made structures, it does not migrate great distances (if at all), and few colonies larger than a few hundred individuals are known. This species often selects hot attics and caves as roosts; young bats seem to be able to tolerate high­er temperatures than adults. High temperatures in roosts are essential for rapid growth of young bats; apparently, the larger the colony, the less the energy expenditure per bat to maintain a given temperature.

Food Habits: This species usually feeds on small moths and beetles.

Reproduction: One baby is born in late spring or early summer. Birth occurs with the mother hang­ing head downward. Passage of the baby bat through the birth canal requires about 90 seconds. Newborn are hairless, but have all their milk teeth. Mothers usually are able to locate their own baby among the thousands of babies in a colony.

Status of Populations: Common throughout most of its range.

Thanks to T. L. Best, J. S. Altenbach, and M. J. Harvey for permission to reprint portions of Bats of the Western United States, 1998.

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