The short, sparse hair is medium to dark brown. Evening Bats average 87 mm (3.4 in) in total length. A nondescript bat that is often confused with the Big Brown Bat, Eptesicus fuscus and members of the common genus Myotis, or Mouse-eared Bats.
Mating takes place in the fall and females give birth to a single young the following spring, in late May or early June. The young grow rapidly and is capable of flight within three weeks, they are weaned between 6 - 9 weeks of age. Females carry the young on foraging flights for a period of one week to 10 days after birth. Pregnant females form nursery colonies of a few to several hundred individuals.
Evening Bats are a woodland species that roosts behind loose bark, in hollow trees, in clumps of Spanish moss, beneath palm fronds, under bridges, and in buildings. They like to forage along streams in bottomlands and lakes or ponds, in a slow steady flight. Foraging takes place at two peaks during the night, the first is about one hour after dark and the second peak occurring just before dawn. Evening Bats in northern latitudes accumulate fat deposits in the fall and may hibernate in unknown locations. In one instance it has been shown that movements of up to 523 km (325 mi) have been made in the fall. It has been suggested that increases in the number of winter roosting bats in Florida may demonstrate fall migrations to southern climes to overwinter. Evening Bats feed on beetles, bugs, flying ants, various flies, and moths. Natural predators include owls, hawks, Raccoons (Procyon lotor), Black Rat Snakes (Elaphe obsoleta), and feral cats. The reported lifespan in this species is about five years, but is probably longer. Evening Bats are known to share roosts with other species of bats, like the Big Brown Bat (Eptesicus fuscus) and the Brazilian Free-tailed Bat (Tadarida brasiliensis).
Evening Bats range from Pennsylvania west to southeastern Nebraska south to eastern and southern Texas and east Florida. In Georgia they can be found throughout the state.
Considered abundant throughout most of its range in appropriate habitats.
Evening bats are smaller than the Big Brown Bat (Eptesicus fuscus), and can be distinguished from members of the genus Myotis by having a tragus that is blunt and curved forward, rather than long and pointed.