Bats are among the most fascinating animals and they are also the least understood, myth and ignorance have caused many people to fear or hate them. For example, bats are not blind; in fact, they have good eyesight. Bats are actually very clean animals and don't get caught in people's hair, nor do they eat through house attics or chew holes. No bat species prey on humans. There are no vampire bats in the United States. They are the only true flying mammal. Bats have been known to migrate at cruising altitudes of 10,000 feet, much higher than most birds. Of the 43 species of bats that live in the U.S., more than half are considered rare or uncommon. Nine insect-eating species of bats, including one classified as rare, live in Michigan. All are nocturnal (active at night), and feed exclusively on flying insects, including moths, beetles, and mosquitoes.
The big brown bat is reddish to dark brown in color, and sports a wingspan ranging from 12 1/2 to 13 1/2 inches. Its slow, steady flight, and large size make it fairly easy to identify. They are late-dusk fliers that often swoop low to the ground. A colonizing species, big browns roost in buildings and under bridges in summer and hibernate in caves, mines, houses, hollow trees, and even storm sewers in winter. Efficient feeders, the species often roosts for a short nap after gorging itself. Porches, garages, and breezeways are good places to find them. The female gives birth to only one pup per year.
The little brown bat is especially abundant throughout the state and is the most common species. A light brown to dark brown in color, little browns are fairly small in size with a wingspan of 8 1/2 to 11 1/2 inches. In summer, colonies of them live in hot attics and under shingles and siding; in winter, they hibernate in caves, houses, hollow trees, or mines. Females form nursery colonies away from the males. Little brown bats like to feed on aquatic insects such as mosquitoes and can eat up to 600 to a 1,000 an hour. They frequently are seen dipping and diving over water but will also forage over lawns and pastures, among trees, and under street lights.