The Family Vespertilionidae is the largest family of bats, commonly known as vesper or evening bats, with over 400 species worldwide. Members are insectivorous, using echolocation to navigate and hunt at night. They are generally small to medium-sized, with simple faces, large ears, and tails enclosed in a tail membrane (uropatagium). Vespertilionids occupy diverse habitats, from forests and grasslands to urban areas, roosting in trees, caves, or buildings. They play a vital ecological role by controlling insect populations and contributing to ecosystem balance.