Mexican Free-tailed Bat
Scientific Name: Tadarida brasiliensis
As their name suggests, the Mexican (or Brazilian) free-tailed bats may be most easily identified by their free-tail, which extend out beyond the membrane, unlike other NC bat species. They are medium-sized bats with large ears, short snouts, wrinkled upper lips, and wings that are great for quick, direct flight. They typically weigh between 7 to 12 grams with an average wingspan of 280 mm. Their tails are almost half the length of their bodies, which range between 79 and 98 mm for adults.
Mexican free-tailed bats are found in caves, attics, hollow trees, and under bridges throughout most the US, Mexico, Central and South America. However, their population numbers have declined in the last 50 years due to habitat loss, pesticides, and damage to roosting sites.
Ecology and Behavior.
Mexican free-tailed bats have the highest flight altitude of any bat species and can also fly long distances. They are a social bat species, forming some of the largest colonies of any animal.
Food and Feeding.
Mexican free-tailed bats mostly eat flies, beetles, moths, dragonflies, wasps, bees, and ants but this diet can vary depending on geographic location, weather, prey availability, metabolic needs, and even moon patterns.
Reproduction and Development.
Mexican free-tailed bats form maternity roosts in caves, trees, buildings, and bridges, their location depending on the size of the maternity colony. Males are aggressive during mating and sometimes mate with multiple females. Female offspring only take about nine months to mature while males reach maturity at about two years old. Mexican free-tailed bats grow quickly compared to other species because their milk has the highest fat content of any bat species. Females only have one pup and give birth upside down in about 90 seconds. Females identify their pup through calls and the pup’s odor, which is used to locate the pup among all the offspring of the maternity colony since the mother roosts separately.
Mexican free-tailed bats are labeled as “near threatened” due to their population decrease in the last century. Their declining numbers are due to habitat destruction and disturbance to roosting sites, as well as indirect pesticide poisoning. In NC they have recently expanded their range to nearly statewide.
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