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Mexican free-tailed bats (Tadarida brasiliensis) are perhaps the most social mammals in the world, at least in terms of numbers, clustering together in vast colonies numbering millions of individuals. Unlike some species of bat, they don’t seem to be in any danger at the moment, with populations stable throughout most of the extensive range.
Mexican free-tailed bats, also known as Brazilian free-tailed bats, take their common names from their distinctive tails. These tails are unusually long for a bat, growing to nearly the length of the body, and extend past the tail membrane. The tail membrane is the webbing stretched between a bat’s hind legs and tail, which aids flight. A portion of the Mexican free-tailed bat’s tail sticks past this.
Geographical Distribution and Habitat
The Mexican free-tailed bat is indeed found in Mexico, and also much of the rest of the Americas, being abundant in North, South and Central America, although its range doesn’t extend into Canada. The habitat is equally varied, with this bat occupying a variety of different types of forest, agricultural land and even desert. The main requirements are somewhere to roost, usually large caves, and a large supply of insects.
These bats are insectivores, devouring a staggering number of insects, including significant agricultural pests such as corn earworm moths. A colony of millions of bats consumes billions of insects over the course of a year and even much smaller colonies have a substantial impact on insect populations, according to Bat Conservation International. This makes them a definite economic asset to farming communities.
There might be billions of people on this planet, but millions of us don’t usually collect together in the same room to sleep. These bats do, which means they have evolved a range of complex social behaviors, using scent marking and vocalizations to communicate with each other. They use a different set of sounds for echolocation to navigate and find food.
The main natural predators of Mexican free-tailed bats are birds of prey, such as hawks and owls, when they are flying and small carnivorous mammals and snakes when they are roosting. Humans don’t hunt them, at least not often, but people do cause other damage, for example by destroying their caves, killing off the food supply or inadvertently poisoning them. The main threats appear to be cave mining and the widespread use of agricultural pesticides. Although this species is nowhere near endangered, some populations have been extirpated, sometimes on purpose. For example, the International Union for the Conservation of Nature reports that several populations have been deliberately exterminated in Uruguay.