There are around 100 species in this family of small to large bats. They are found in from the mid United States south to Central and South America. They are also found in Europe and Africa.
They have long, external tails; large, sometimes uniquely-shaped, ears that are joined by a membrane at the base; small eyes; long, narrow wings; and well-developed legs that they use for walking. They have short black or brown fur and thick lips and snouts.
They are found in caves, old buildings, and hollow trees. Most species roost in colonies. They eat flying insects.