Bats, the only mammals that fly, are among nature's least understood and unfairly maligned creatures. They are extremely valuable animals, responsible for consuming huge numbers of insects and pollinating and dispersing the seeds of fruit-bearing plants and trees, especially in the tropics. Yet, superstitions about and fear of these nocturnal creatures have led to their persecution and elimination from many areas, and several species of bats are now threatened with extinction.

There are over 900 species of bats, representing almost a quarter of all mammal species, and they are found on every continent except Antarctica. Most types of bats live in the tropics, and some 40 species are found in the United States and Canada. The largest bats, flying foxes, found on Pacific islands, have wingspreads of five feet (1.5 m). The smallest bats, bamboo bats, are the size of the end of a person's thumb.

Bats commonly feed on mosquitoes...