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Evening Bat

Overview

The evening bat (Nycticeius humeralis) is the only bat in the Nycticelus genus in the United States. The Latin Origin of the genus name means “belongs to the night,” as all bats are nocturnal.

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(Photo courtesy of Organization for Bat Conservation - click to view)

Description

This medium-sized brown bat looks like a smaller version of the big brown bat. and is often misidentified as one. The hair on its back is a bronze-brown, whereas the hair on its underside is slightly lighter. The muzzle is hairless and black. The forearm of an evening bat measures 38 mm or less, whereas a big brown bat’s forearm measures 44 mm or more. Additionally, evening bats have one upper incisor on each side of its mouth and big brown bats and Myotis species have two.

Reproduction

Details about the reproductive behavior of evening bats are not well known. When females ovulate and when fertilization takes place are not known, but it is thought that mating takes place before winter. Two pups are usually born in between mid-May and early July. Newborn pups are hairless and pink, but their eyes open and their body color darkens within 12-30 hours. They begin to fly at around three weeks and start flying outdoors around four weeks. Some evidence suggests that females will nurse only their own pups for two weeks after their birth, but after that, they will nurse any young who approaches them. Females live in groups of about 30 in the summer where they raise their pups. Mothers use the scent and call of their pups in order to distinguish them from the rest of the pups in the roost site.

Habitat & Behavior

Diet studies have shown that evening bats eat beetles, moths, and leafhoppers. They also consume many insect pests such as the spotted cucumber beetle and stinkbugs. Evening bats are migratory tree bats and can be found in Ohio, although it is rarely encountered. They roost in buildings and tree hollows in summer.

Migratory tree bat species travel north in the summer and back south in the winter. They migrate varying distances using landmarks and magnetic cues to direct themselves. Evening bats have not been observed hibernating in caves but have been documented in other areas hibernating in hollow trees and leaf litter.