GENERAL INFORMATION

Bats are our only true flying mammals. They are also one of the most numerous, second only to rodents, and comprise almost one-fourth of all mammal species. Worldwide there are over 900 species with 42 native to the United States and 16 species recorded in North Carolina.

DESCRIPTION

The Big Brown Bat is relatively large in size, from about 4 to 5 inches in length and weighing 1/2 to 5/8 ounce. The fur is moderately long, and shiny brown. The wing membranes, ears, feet, and face are dark brown to blackish in color. Several other species closely resemble the big brown bat in appearance but most are much smaller in size.

HABITS AND HABITATS

Big brown bats spend the daylight hours sleeping in dark secluded areas such as hollow trees, beneath loose tree bark, or in the crevices of rocks. Big brown bats will often roost in man-made structures as well, such as attics, barns, old buildings, under eaves and behind window shutters, particularly during the summer months. Like other bats, the big brown is nocturnal, becoming active just before dark. Bats navigate through the night skies by use of echolocation, a method by which ultrasonic sounds emitted through the mouth or nose of the bat are bounced off objects in the bat's flight path. By analyzing the returning echoes, a bat can tell the location, speed, and distance of nearby objects and determine whether the object is food or an obstacle to be avoided. Big brown bats are insectivorous, eating many kinds of night-flying insects including beetles and wasps which they capture on the wing. Individual bats eat many insects and large colonies can consume countless quantities nightly. Big brown bats hibernate during the winter months, often in different locations than their summer roosts. Some winter roosts tend to be in caves and underground mines where temperatures remain stable but it is still unknown where a large majority of big brown bats spend the winter. If the weather warms enough, they may awaken to seek water, defecate, and even breed. Mating among big brown bats occurs sporadically from November through March. After the breeding season, pregnant females separate themselves into maternity colonies. Maternity colonies are most likely to be encountered in the attics of buildings and other similar locations since female bats tend to choose areas with high daytime temperatures in which to raise their young. The young bats, averaging two to a litter, are born in late May or early June. The baby bats are nursed in the roost and then left there in the evenings while the females fly out to feed. When the young are between three and four weeks of age, they begin to leave the roost for their first flights. Big brown bats are a long-lived species, with some specimens having lived for as long as 18 years.

HISTORY

Bats are one of our most misunderstood and feared animals. They have long been associated with evil and doom yet the truth is that they are one of our most beneficial species. Insectivorous bats such as the big brown eat enormous amounts of destructive insects including mosquitoes. Contrary to popular belief, they are extremely shy and non-aggressive. Although known to carry rabies, the incidence of this disease in bats is extremely low. There is a much better chance of encountering a rabid raccoon, fox, skunk, or even a domestic animal such as a cat or dog than a bat with this dreaded disease. Many bats worldwide are in danger of extinction due to senseless slaughter and loss of critical bat habitats. Bats are legally protected as non-game animals and cannot be injured or killed without a special permit. Unwanted bats that take up residence in attics or buildings can be effectively and humanely excluded without lethal means by the use of proper techniques. Many people are now learning about the beneficial qualities of these shy mammals and are constructing artificial bat roosts or boxes to attract bats to their yard and home. For information on deterring bats or attracting them, contact your local zoo, museum, or Nature Center.

INFORMATION LINKS

Bat Conservation International
Chiroptera: Night Fliers

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©2002 WNC Nature Center