Vespertilionidae
Vespertilionidae is a family of microbats, of the order Chiroptera, flying, insect-eating mammals variously described as the common, vesper, or simple nosed bats. The vespertilionid family is the most diverse and widely distributed of bat families, specialised in many forms to occupy a range of habitats and ecological circumstances, and it is frequently observed or the subject of research. The facial features of the species are often simple, as they mainly rely on vocally emitted echolocation. The tails of the species are enclosed by the lower flight membranes between the legs. Over 300 species are distributed all over the world, on every continent except Antarctica. It owes its name to the genus Vespertilio, which takes its name from a word for bat, vespertilio, derived from the Latin term vesper meaning 'evening'; they are termed "evening bats" and were once referred to as "evening birds". (The term "evening bat" also often refers more specifically to one of the species, Nycticeius humeralis.) They are allied to the suborder Microchiroptera, the families of microbats separated from the flying foxes and fruit bats of the megabat group Megachiroptera. The treatments of bat taxonomy have also included a placement amongst the Vespertilioniformes, or Yangochiroptera, as suborder Vespertilionoidea. Molecular data indicate the Vespertilionidae diverged from the Molossidae in the early Eocene period. The family is thought to have originated somewhere in Laurasia, possibly North America. A recently extinct species, Synemporion keana, is known from the Holocene of Hawaii. All species are carnivorous and most are insectivores, exceptions are bats of genera Myotis and Pizonyx that catch fish and the larger Nyctalus species known to capture small passerine birds in flight. The dentition of the family varies between species; the dental formula of the family is: They rely mainly on echolocation to navigate and obtain food, but they lack the elaborate nose appendages of microbats that focus nasal emitted ultrasound.