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.They are distinguished by the presence of a leaf-like projection from their lips, instead of the nose-leaf found in many other bat species. In some species, the wing membranes join over the animal's back, making it appear hairless.