SUMMARY: Vespertilionidae
Common Name
: No common name, generally just called vespertilionid bats (evening/plain-nosed)
Taxonomy: 42 genera and 355 species. 5 subfamilies
Distribution: Worldwide distribution, absent from remote islands, Polar and near Polar regions
Fossil Record: middle Eocene to Recent in Europe, late Oligocene to Recent in North America, middle Miocene to Recent in Africa and Asia, Pleistocene to Recent in West Indies, South America, and Australia, and Recent over the remainder of the present range
Size Range: Head and body length range from 32 - 105 mm, tail length 25 - 75, and forearm length from 22 - 75 mm
The largest Chiropteran family.

Worldwide distribution, ranging in altitude to the limits of the tree line, in temperate, tropical and arid areas. In temperate zones, vespertilioinids are usually the most common bats.

The family includes many single species genera. The genus
Myotis is the largest genus with 97 species and a global distribution, limited only from the arctic, subarctic, and Antarctic, and some oceanic islands.

Vespertilionids lack any distinctive facial characteristics to characterize the family. The tail is well developed, extending to the rear edge of the tail membrane or slight beyond. The nose is typically unadorned, lacking a nose leaf, and the eyes are small. The ears are of moderate to large size and the tragus is always present but remarkable in it variability.

Many vespertilionids use a diversity of roost site: caves, mines, rock crevices, buildings, trees, old bird nests, and culverts. Many species have proved adaptable to urban roosts. The bats typically hang on a vertical surface rather than freely suspend themselves.

Vespertilionids range from solitary species to large colonies. As well, in temperate regions, some species migrate, whereas others hibernate through the fall and winter. In the temperate zone, reproduction is seasonal, with mating occurring in late summer and fall.

The diet is typically insectivorous, but 1 species is known to eat fish, 2 more are suspected of eating fish and another has demonstrated the ability to eat reptiles.

(from the books "Bats - A Natural History" and from "Walker's Bats of the World")