They forage low over the ground, flying fairly straight courses. Vampire bats, like those New World bats known to feed on fruit, emit pulses having only about one-thousandth of the sound energy of those used by bats that feed on flying insects or fish. Some other species of the Phyllostomidae also roost in dark areas, whereas still others shelter in fairly well-illuminated places. Some members of this family are gregarious, others associate in small groups, and some roost singly. American leaf-nosed bats are often associated with other species of bats in their retreats, which may be caves, culverts, trees, buildings, or animal burrows.
Several species form their own shelters by modifying leaves.
Indirect evidence indicates that those species found in the southwestern United States migrate to a warmer climate for the winter. American leaf-nosed bats fly with their mouth closed, transmitting sounds through their nostrils. Except in the insectivorous forms, the soft impulses emitted by the members of this family are a complex and changing mixture of high frequencies of short duration. Some species aid in seed dissemination, and those that seek nectar, pollen, or insects from flowers pollinate the flowers. The scientific names of certain genera suggest that they drink blood, but their food habits are actually much like those of most other phyllostomids.