The family Mormoopidae contains bats known generally as mustached bats, ghost-faced bats, and naked-backed bats. They are found in the Americas from the Southwestern United States to Southeastern Brazil. Mormoopid bats roost in caves and tunnels in huge colonies that may include hundreds of thousands of members, producing enough guano to allow commercial mining. They do not hibernate as some other bats do since they live in the tropics. They feed on insects found close to, or on, bodies of water.