Big brown bat

The big brown bat was described in 1796 by French naturalist Palisot de Beauvois. Palisot described the species based on specimens in the Philadelphia Museum of Charles Willson Peale, an American naturalist, giving it the name Vespertila fuscus. The genus name, Eptesicus, is likely derived from the Greek words ptetikos ("able to fly") or petomai ("house flier"), and the species name "fuscus" is Latin in origin, meaning "brown". The big brown bat is the type species for the genus Eptesicus, which was established in 1820 by French-American naturalist Constantine Samuel Rafinesque. Though Rafinesque designated the type species as Eptesicus melanops, this was later determined to be a synonym of Eptesicus fuscus. The first use of the current name combination Eptesicus fuscus was in 1900 by Hungarian zoologist Lajos Méhelÿ. Recognized subspecies number eleven or twelve: E. f. lynni has sometimes been considered a full species, though was listed as a subspecies by the American Society of Mammalogists and the Integrated Taxonomic Information System (ITIS) as of 2019. In the US state of Colorado where two subspecies were hypothesized to overlap (E. f. fuscus and E. f. pallidus), morphological features did not agree with genetic lineages, and thus were not reliable in distinguishing the two subspecies. Individuals with eastern and western US genetic lineages co-occurred in the same colonies, however. The serotinus group also includes: • Little black serotine, E. andinus • Botta's serotine, E. bottae • Brazilian brown bat, E. brasiliensis • Diminutive serotine, E. diminutus • Argentine brown bat, E. furinalis • Long-tailed house bat, E. hottentotus • Harmless serotine, E. innoxius • Meridional serotine, E. isabellinus • Lagos serotine, E. platyops • Serotine bat, E. serotinus • Sombre bat, E. tatei ==Description==

It is a relatively large microbat, weighing . Adult body length is . Its wingspan is . Its dorsal fur is reddish brown and glossy in appearance; its ventral fur is lighter brown. Its snout, uropatagium (flight membrane between the hind limbs), and wing membranes are black and hairless. Its ears ( It has a robust skull; The snout has a rounded and somewhat flattened appearance. ==Biology==

Diet . Big brown bats are insectivorous, eating many kinds of insects including beetles, flies, stone flies, mayflies, true bugs, net-winged insects, scorpionflies, caddisflies, and cockroaches. Big brown bats are significant predators of agricultural pests. A 1995 study found that, per year, a colony of 150 big brown bats in Indiana or Illinois consumes 600,000 cucumber beetles, 194,000 scarab beetles, 158,000 leafhoppers, and 335,000 shield bugsall of which cause serious agricultural damage. Behavior The big brown bat is nocturnal, roosting in sheltered places during the day. It will utilize a wide variety of structures for roosts, including mines, caves, tunnels, buildings, bat boxes, tree cavities, storm drains, wood piles, and rock crevices. Both solitary males and solitary, non-pregnant/non-lactating females have been found roosting under bark. In the summer, males are most often solitary, though they may form small, all-male colonies. Males will also sometimes roost with adult females. Females exhibit philopatry ("love of place"), with 10-30% of female offspring returning to their natal roost the following year and up to 72% of adult females using the same roost in subsequent years. Using echolocation, big brown bats can determine how far away an object is, the objects size, shape and density, and the direction (if any) that an object is moving. Their use of echolocation allows them to occupy a niche where there are often many insects (that come out at night since there are fewer predators then), less competition for food, and fewer species that may prey on the big brown bat itself. Reproduction and life expectancy Big brown bat mating season is in the fall. After the breeding season, pregnant females separate into maternity colonies around April. the big brown bat only has two nipples. At birth, pups are blind, helpless, and only , though they grow quickly, gaining up to per day. according to a 2008 report, some banded big brown bats have lived up to 20 years, although some experts have hypothesized that the bats might be "capable of living much longer." In general, males live longer than females. Big brown bats often hibernate by themselves, or in small groups. Big brown bats tolerate cold weather fairly well, although they can be negatively affected by major changes in temperature. The big brown bat has large deposits of brown fat, which provides the bats with a source of energy to rapidly increase body temperature upon arousal from hibernation. In the summer, big brown bats substantially reduce their brown fat deposits, which are less than half of their winter size. Predators, parasites, and disease The big brown bat has few natural predators. Predation occurs opportunistically, with common grackles, American kestrels, owls, long-tailed weasels, and American bullfrogs as known predators. Rabid big brown bats will bite each other, which is the primary method of transmission from individual to individual. However, not all individuals will develop rabies after exposure to the virus. Some individuals have been observed with a sufficiently high rabies antibody concentration to confer immunity. Rabies immunity can be passed from mother to pup via passive immunity or from exposure to the bite of a rabid individual. Overall, a low proportion of big brown bats become infected with rabies. Populations of big brown bats in the Eastern United States have a different strain of rabies than the populations in the Western United States. In one study, only 10% of big brown bats were shedding the rabies virus through their saliva before exhibiting clinical symptoms of the disease; symptoms of rabies in big brown bats include acute weight loss, paralysis, ataxia (inability to coordinate muscle movement), paresis (weakness of voluntary movement), and unusual vocalizations. ==Range and habitat==

The big brown bat is encountered widely throughout North America in present times. It is found from southern Canada and Alaska to as far south as Colombia and Venezuela. It has also been documented in the Caribbean in both the Greater and Lesser Antilles, including Cuba, Hispaniola, Dominica, Barbados, and the Bahamas. The big brown bat has been documented from above sea level. It has been called "the most widespread Pleistocene bat in North America", as it is more represented in the fossil record of that time than any other bat species. Its extensive fossil record is known from more than thirty sites, including fourteen US states, Puerto Rico, Mexico, and the Bahamas. ==Conservation==

The big brown bat is evaluated at the lowest conservation priority by the IUCN—least concern. It meets the criteria for this designation because it has a wide geographic distribution, a large population size, occurrence in protected areas, and tolerance to habitat modification by humans. ==Relationship to people==

The big brown bat is the official state mammal of the District of Columbia. Economic value Big brown bats are a species that will use bat houses for their roosts. Landowners will purchase or construct bat houses and install them, hoping to attract big brown bats, largely due to their being an "agriculturally valuable species". In particular, the big brown bat feeds on cucumber beetles, which can decimate corn; this makes the species quite beneficial to farmers in the Corn Belt. As disease vectors Big brown bats can be of concern to public health as a rabies vector, as they commonly roost in buildings and thus have a higher chance of encountering humans. Big brown bats infrequently test positive for the rabies virus; of the 8,273 individuals submitted for testing across the United States in 2011, 314 (3.8%) tested positive for the virus. There is a known bias in testing, however, as healthy bats rarely come into contact with humans, and therefore sick bats are more likely to be tested. In the US, human rabies cases from exposure to bats more frequently come from other bat species. Of the twenty-four human rabies cases from bats from 1993 to 2000, seventeen cases (71%) were a rabies variant associated with the silver-haired bat (Lasionycteris noctivagans) while one case (4%) was associated with the rabies variant found in big brown bats. Histoplasma capsulatum, the fungus that causes the disease histoplasmosis, is occasionally found in its guano. The big brown bat may also be a vector of the Saint Louis encephalitis virus, a mosquito-born virus that can affect humans. ==See also==