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The big brown bat (''Eptesicus fuscus'') is a species of
vesper bat Vespertilionidae is a family of microbats, of the order Chiroptera, flying, insect-eating mammals variously described as the common, vesper, or simple nosed bats. The vespertilionid family is the most diverse and widely distributed of bat famili ...
distributed widely throughout North America, the Caribbean, and the northern portion of South America. It was first described as a species in 1796. Compared to other microbats, the big brown bat is relatively large, weighing and possessing a wingspan of . Big brown bats are insectivorous, consuming a diverse array of insects, particularly night-flying insects, but especially
beetle Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...
s. Some of the beetles it consumes are serious agricultural pests, including
cucumber beetle Cucumber beetle is a common name given to members of two genera of beetles, ''Diabrotica'' and ''Acalymma'', both in the family Chrysomelidae. The adults can be found on cucurbits such as cucumbers and a variety of other plants. Many are no ...
s. They are nocturnal, foraging for prey at night and roosting in sheltered areas during the day such as caves, tunnels, tree cavities, and human structures. Their breeding season is in the fall, shortly before their annual hibernation. After hibernation ends in the spring, females form maternity colonies for giving birth to young. Oftentimes only one offspring is produced per litter, though twins are common in the Eastern US. Lifespans of 6.5 years are considered average. The big brown bat occurs widely throughout the US, Canada, Central America, and the Caribbean. Its range extends into parts of South America, found as far south as Colombia and Venezuela. It is adaptable to many habitats and is considered a
generalist species A generalist species is able to thrive in a wide variety of environmental conditions and can make use of a variety of different natural resource, resources (for example, a heterotroph with a varied diet (nutrition), diet). A specialist species can ...
. The big brown bat is not considered at risk for extinction, and is evaluated as the lowest conservation priority by the
International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of nat ...
(IUCN). While some other bat species in its range have experienced dramatic population declines due to the fungal disease
white-nose syndrome White-nose syndrome (WNS) is a fungal disease in North American bats which has resulted in the dramatic decrease of the bat population in the United States and Canada, reportedly killing millions as of 2018. The condition is named for a distincti ...
, the big brown bat is relatively resistant to the effects of the disease, and some populations have even increased since the syndrome arrived in North America. Like all bats in the US, the big brown bat can be impacted by
rabies Rabies is a viral disease that causes encephalitis in humans and other mammals. Early symptoms can include fever and tingling at the site of exposure. These symptoms are followed by one or more of the following symptoms: nausea, vomiting, ...
, though some individuals have immunity against the virus. Even though sick bats are more likely to be submitted for testing, in 2011, only 3.8% of submitted big brown bats were positive for the rabies virus. Bat boxes are sometimes used to attract them as they are an agriculturally valuable species.


Taxonomy and etymology

The big brown bat was described in 1796 by French naturalist
Palisot de Beauvois Ambroise Marie François Joseph Palisot, Baron de Beauvois (27 July 1752, in Arras – 21 January 1820, in Paris) was a French naturalist and zoologist. Palisot collected insects in Oware, Benin, Saint Domingue, and the United States, from 17 ...
. Palisot described the species based on specimens in the museum of
Charles Willson Peale Charles Willson Peale (April 15, 1741 – February 22, 1827) was an American Painting, painter, soldier, scientist, inventor, politician and naturalist. He is best remembered for his portrait paintings of leading figures of the American Revolu ...
, 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 In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...
"'' fuscus''" is
Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
in origin, meaning "brown". The big brown bat is the
type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specime ...
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 Lajos Méhelÿ (August 24, 1862 – February 4, 1953) was a Hungarian zoologist, herpetologist, professor, and prolific author. He is one of the greatest, but also one of the most controversial, personalities in the history of Hungarian zoology ...
. 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 The Integrated Taxonomic Information System (ITIS) is an American partnership of federal agencies designed to provide consistent and reliable information on the taxonomy of biological species. ITIS was originally formed in 1996 as an interagenc ...
(ITIS) as of 2019. In the US state of
Colorado Colorado (, other variants) is a state in the Mountain states, Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the wes ...
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. As the genus ''
Eptesicus ''Eptesicus'' is a genus of bats, commonly called house bats or serotine bats, in the family Vespertilionidae. The genus name is likely derived from the Greek words ''ptetikos'' 'able to fly' or ''petomai'' 'house flier', although this is not ce ...
'' is fairly speciose, it is further divided into morphologically similar " species-groups". The big brown bat belongs to the ''serotinus'' group, which is defined by having a large, elongate skull, flat braincase, and a long snout. In a study of the evolutionary relationships of some ''Eptesicus'' species, the big brown bat was most closely related to the two other species from the Americas: the Argentine brown bat and the diminutive serotine. The ''serotinus'' group also includes: * Little black serotine, ''E. andinus'' * Botta's serotine, ''E. bottae'' *
Brazilian brown bat The Brazilian brown bat (''Eptesicus brasiliensis''), is a bat species from South and Central America Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States ...
, ''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 The Lagos serotine (''Eptesicus platyops'') is a species of vesper bat. It is found in Equatorial Guinea, Nigeria, and possibly Senegal Senegal,; Wolof: ''Senegaal''; Pulaar: 𞤅𞤫𞤲𞤫𞤺𞤢𞥄𞤤𞤭 (Senegaali); Arabic: ال� ...
, ''E. platyops'' *
Serotine bat The serotine bat (''Eptesicus serotinus''), also known as the common serotine bat, big brown bat, or silky bat, is a fairly large Eurasian bat with quite large ears. It has a wingspan of around and often hunts in woodland. It sometimes roosts ...
, ''E. serotinus'' * Sombre bat, ''E. tatei''


Description

It is a relatively large
microbat Microbats constitute the suborder Microchiroptera within the order Chiroptera ( bats). Bats have long been differentiated into Megachiroptera (megabats) and Microchiroptera, based on their size, the use of echolocation by the Microchiroptera an ...
, weighing . Adult body length is . Its forearm is usually longer than . Its wingspan is . Its
dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal c ...
fur is reddish brown and glossy in appearance; its
ventral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...
fur is lighter brown. Its snout,
uropatagium The patagium (plural: patagia) is a membranous body part that assists an animal in obtaining lift when gliding or flight. The structure is found in extant and extinct groups of flying and gliding animals including bats, birds, some dromaeosau ...
(flight membrane between the hind limbs), and wing membranes are black and hairless. Its ears are also black; they are relatively short with rounded tips. The tragi (cartilage flaps in front of the ear canal) also have rounded tips. It has a robust
skull The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, th ...
; the greatest length of the skull is approximately . The snout has a rounded and somewhat flattened appearance. The braincase has a breadth of approximately and the
mandible In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...
(jawbone) has a length of approximately . The upper incisors are large, with the inner pair more prominent than the outer pair. The inner pair of upper incisors also has a distinctive secondary cusp. The crowns of the lower incisors are trifid, or have three cusps. Its
dental formula Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiolog ...
is , for a total of 32 teeth.


Biology


Diet

Big brown bats are insectivorous, eating many kinds of insects including beetles,
flies Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced m ...
, stone flies,
mayflies Mayflies (also known as shadflies or fishflies in Canada and the upper Midwestern United States, as Canadian soldiers in the American Great Lakes region, and as up-winged flies in the United Kingdom) are aquatic insects belonging to the order ...
,
true bugs Hemiptera (; ) is an order (biology), order of insects, commonly called true bugs, comprising over 80,000 species within groups such as the cicadas, aphids, planthoppers, leafhoppers, Reduviidae, assassin bugs, Cimex, bed bugs, and shield bugs. ...
, net-winged insects,
scorpionflies Mecoptera (from the Greek language, Greek: ''mecos'' = "long", ''ptera'' = "wings") is an Order (biology), order of insects in the superorder Endopterygota with about six hundred species in nine Family (biology), families worldwide. Mecopterans ...
,
caddisflies The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which can be divided into the suborders Integripalpia and Annulipalpia on the ...
, and
cockroaches Cockroaches (or roaches) are a paraphyletic group of insects belonging to Blattodea, containing all members of the group except termites. About 30 cockroach species out of 4,600 are associated with human habitats. Some species are well-known a ...
. It will forage in cities around street lamps. As the big brown bat is such a widespread species, it has regional variation in its diet, though it is generally considered a beetle specialist. Populations in
Indiana Indiana () is a U.S. state in the Midwestern United States. It is the 38th-largest by area and the 17th-most populous of the 50 States. Its capital and largest city is Indianapolis. Indiana was admitted to the United States as the 19th s ...
and
Illinois Illinois ( ) is a state in the Midwestern United States. Its largest metropolitan areas include the Chicago metropolitan area, and the Metro East section, of Greater St. Louis. Other smaller metropolitan areas include, Peoria and Rockf ...
have particularly high consumption of
scarab beetles The family Scarabaeidae, as currently defined, consists of over 30,000 species of beetles worldwide; they are often called scarabs or scarab beetles. The classification of this family has undergone significant change in recent years. Several sub ...
, cucumber beetles,
ground beetles Ground beetles are a large, cosmopolitan family of beetles, the Carabidae, with more than 40,000 species worldwide, around 2,000 of which are found in North America and 2,700 in Europe. As of 2015, it is one of the 10 most species-rich animal fam ...
and
shield bugs The Pentatomoidea are a superfamily of insects in the Heteroptera suborder of the Hemiptera order. As Hemiptera, they share a common arrangement of sucking mouthparts. The roughly 7000 species under Pentatomoidea are divided into 21 families (16 ...
. In
Oregon Oregon () is a state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington, while the Snake River delineates much of its eastern boundary with Idaho. T ...
, primary prey items include moths in addition to scarab beetles and ground beetles. In
British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...
, large proportions of caddisflies are consumed, with flies as a secondary prey source. A study in
Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central C ...
compared fecal samples of big brown bats with the abundance of insects collected in passive traps. The result was a strong preference for beetles as prey. Lepidoptera were the most common insect order collected but beetles were present in 99.2% of fecal samples. When being rehabilitated, big brown bats are often fed
mealworm Mealworms are the larval form of the yellow mealworm beetle, ''Tenebrio molitor'', a species of darkling beetle. Like all holometabolic insects, they go through four life stages: egg, larva, pupa, and adult. Larvae typically measure about or ...
s which have been supplemented with necessary vitamins and minerals. 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 The family Scarabaeidae, as currently defined, consists of over 30,000 species of beetles worldwide; they are often called scarabs or scarab beetles. The classification of this family has undergone significant change in recent years. Several sub ...
, 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. They generally roost in cavities, though they can sometimes be found under exfoliating bark. 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 Philopatry is the tendency of an organism to stay in or habitually return to a particular area. The causes of philopatry are numerous, but natal philopatry, where animals return to their birthplace to breed, may be the most common. The term derive ...
("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. Like many other species of microbats, the big brown bat often uses echolocation to navigate. This means that the species emits a call out into its environment and listens to the echoes of those calls that return from various objects near them. 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
insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three ...
s (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 Seasonal breeders are animal species that successfully mate only during certain times of the year. These times of year allow for the optimization of survival of young due to factors such as ambient temperature, food and water availability, and ch ...
is in the fall. After the breeding season, pregnant females separate into maternity colonies around April. Maternity colonies range in size from 5-700 individuals, though in the eastern US and Canada, they are frequently 25-75 adults. Historically, maternity colonies were probably in tree cavities. In modern, human-dominated landscapes, however, many maternity colonies are in buildings. In the eastern United States, twins are commonly born sometime between May and July; in western North America, females give birth to only one pup each year. A dissected female was once found with four embryos; had the female given birth, though, it is unlikely that all four would have survived. Like most species of bat, 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. The pup nurses from its mother for approximately one month. Mothers leave their pups behind at the roost while they forage at night. Pups fledge, or begin flying, at three to five weeks old. A 2011 study of a population in Colorado found that their average life expectancy was a little over 6.5 years; 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.


Hibernation

Big brown bats enter into hibernation around November, often in a location less than away from their summer roosts. Big brown bats often hibernate by themselves, or in small groups. While some big brown bats hibernate in subterranean locations such as caves and underground mines, most can be found in warm man-made structures. Big brown bats tolerate cold weather fairly well, although they can be negatively affected by major changes in temperature. It is fairly common for some hibernating big brown bats to awaken temporarily and seek warmer shelter, locate water, and even mate. Big brown bats come out of hibernation in the spring.


Predators, parasites, and disease

The big brown bat has few natural predators. Depredation occurs opportunistically, with
common grackle The common grackle (''Quiscalus quiscula'') is a species of large icterid bird found in large numbers through much of North America. First described in 1758 by Carl Linnaeus, the common grackle has three subspecies. Adult common grackles have a ...
s,
American kestrel The American kestrel (''Falco sparverius''), also called the sparrow hawk, is the smallest and most common falcon in North America. It has a roughly two-to-one range in size over subspecies and sex, varying in size from about the weight of ...
s, owls,
long-tailed weasel The long-tailed weasel (''Neogale frenata''), also known as the bridled weasel, masked ermine, or big stoat, is a species of mustelid distributed from southern Canada throughout all the United States and Mexico, southward through all of Central A ...
s, and American bullfrogs as known predators. It is affected by a number of ectoparasites (external parasites) and
endoparasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...
s (internal parasites). Insect ectoparasites include '' Basilia'' (flies), ''
Cimex ''Cimex'' is a genus of insects in the family Cimicidae. ''Cimex'' species are ectoparasites that typically feed on the blood of birds and mammals. Two species, '' Cimex lectularius'' and ''Cimex hemipterus'', are known as bed bugs and frequen ...
'' (true bugs), and '' Myodopsylla'' (fleas). Several
mite Mites are small arachnids (eight-legged arthropods). Mites span two large orders of arachnids, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari, but genetic analysis does not show clear e ...
s are ectoparasites as well, including '' Acanthopthirius'', '' Cheletonella'', '' Euschoengastia'', ''
Leptotrombidium ''Leptotrombidium'' () is a genus of mites in the family Trombiculidae, that are able to infect humans with scrub typhus (''Orientia tsutsugamushi'' infection) through their bite. The larval form (called chiggers) feeds on rodents, but also occa ...
'', '' Macronyssus'', '' Neospeleognathopsis'', ''
Neotrombicula ''Neotrombicula'' is a genus of mites in the family Trombiculidae Trombiculidae (); commonly referred to in North America as chiggers and in Britain as harvest mites, but also known as berry bugs, bush-mites, red bugs or scrub-itch mites, are ...
'', '' Olabidocarpus'', ''
Ornithodoros ''Ornithodoros'' is a genus in the soft-bodied tick family, Argasidae. Physiology The opening between the midgut and hindgut has been lost, making the ticks unable to pass digestive waste products out of their bodies. Taxonomy The Linnean nam ...
'', '' Parasecia'', '' Perissopalla'', and '' Spinturnix''. Endoparasites include nematodes, cestodes, and
trematode Trematoda is a class of flatworms known as flukes. They are obligate internal parasites with a complex life cycle requiring at least two hosts. The intermediate host, in which asexual reproduction occurs, is usually a snail. The definitive h ...
s. Like all bats in the United States, big brown bats can be affected by
rabies Rabies is a viral disease that causes encephalitis in humans and other mammals. Early symptoms can include fever and tingling at the site of exposure. These symptoms are followed by one or more of the following symptoms: nausea, vomiting, ...
. The
incubation period Incubation period (also known as the latent period or latency period) is the time elapsed between exposure to a pathogenic organism, a chemical, or radiation, and when symptoms and signs are first apparent. In a typical infectious disease, the in ...
for rabies in this species can exceed four weeks, though the mean incubation period is 24 days. 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 An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the ...
concentration to confer
immunity Immunity may refer to: Medicine * Immunity (medical), resistance of an organism to infection or disease * ''Immunity'' (journal), a scientific journal published by Cell Press Biology * Immune system Engineering * Radiofrequence immunity desc ...
. Rabies immunity can be passed from mother to pup via
passive immunity Passive immunity is the transfer of active humoral immunity of ready-made antibodies. Passive immunity can occur naturally, when maternal antibodies are transferred to the fetus through the placenta, and it can also be induced artificially, when ...
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 Ataxia is a neurological sign consisting of lack of voluntary coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in eye movements. Ataxia is a clinical manifestation indicating dysfunction of ...
(inability to coordinate muscle movement),
paresis In medicine, paresis () is a condition typified by a weakness of voluntary movement, or by partial loss of voluntary movement or by impaired movement. When used without qualifiers, it usually refers to the limbs, but it can also be used to desc ...
(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 The Lesser Antilles ( es, link=no, Antillas Menores; french: link=no, Petites Antilles; pap, Antias Menor; nl, Kleine Antillen) are a group of islands in the Caribbean Sea. Most of them are part of a long, partially volcanic island arc bet ...
, including
Cuba Cuba ( , ), officially the Republic of Cuba ( es, República de Cuba, links=no ), is an island country comprising the island of Cuba, as well as Isla de la Juventud and several minor archipelagos. Cuba is located where the northern Caribbea ...
, Hispaniola, Dominica,
Barbados Barbados is an island country in the Lesser Antilles of the West Indies, in the Caribbean region of the Americas, and the most easterly of the Caribbean Islands. It occupies an area of and has a population of about 287,000 (2019 estimate) ...
, and the
Bahamas The Bahamas (), officially the Commonwealth of The Bahamas, is an island country within the Lucayan Archipelago of the West Indies in the North Atlantic. It takes up 97% of the Lucayan Archipelago's land area and is home to 88% of the ar ...
. The big brown bat has been documented from above sea level. It is a
generalist A generalist is a person with a wide array of knowledge on a variety of subjects, useful or not. It may also refer to: Occupations * a physician who provides general health care, as opposed to a medical specialist; see also: ** General pract ...
, capable of living in urban, suburban, or rural environments. It has been called "the most widespread
Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in ...
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 A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...
. 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. While other bat species in the Eastern United States have experienced significant population declines (up to 98% loss) due to
white-nose syndrome White-nose syndrome (WNS) is a fungal disease in North American bats which has resulted in the dramatic decrease of the bat population in the United States and Canada, reportedly killing millions as of 2018. The condition is named for a distincti ...
, the big brown bat is relatively resistant to its effects. Even in caves harboring ''
Pseudogymnoascus destructans ''Pseudogymnoascus destructans'' (formerly known as ''Geomyces destructans'') is a psychrophilic (cold-loving) fungus that causes white-nose syndrome (WNS), a fatal disease that has devastated bat populations in parts of the United States and Ca ...
'', the fungus that causes white-nose syndrome, big brown bats maintain normal
torpor Torpor is a state of decreased physiological activity in an animal, usually marked by a reduced body temperature and metabolic rate. Torpor enables animals to survive periods of reduced food availability. The term "torpor" can refer to the time ...
patterns. Unlike in other species more affected by white-nose syndrome, big brown bats are able to retain more of their body fat throughout hibernation. In fact, some regions of the eastern United States have seen an increase in big brown bat populations since the arrival of white-nose syndrome.


Relationship to people


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 The Corn Belt is a region of the Midwestern United States that, since the 1850s, has dominated corn production in the United States. In the United States, ''corn'' is the common word for maize. More generally, the concept of the Corn Belt con ...
.


As disease vectors

Big brown bats can be of concern to
public health Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals". Analyzing the det ...
as a rabies vector, as they commonly roost in buildings and thus have a higher chance of encountering humans. Because they are often found in proximity to humans, the big brown bat and the not-closely related
little brown bat The little brown bat or little brown myotis (''Myotis lucifugus'') is an endangered species of mouse-eared microbat found in North America. It has a small body size and glossy brown fur. It is similar in appearance to several other mouse-ea ...
are the two bat species most frequently submitted for rabies testing in the United States. 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 The silver-haired bat (''Lasionycteris noctivagans'') is a solitary migratory species of vesper bat in the family Vespertilionidae and the only member of the genus ''Lasionycteris''. Etymology The species name translates as night-wandering, ref ...
(''Lasionycteris noctivagans'') while one case (4%) was associated with the rabies variant found in big brown bats. ''
Histoplasma capsulatum ''Histoplasma capsulatum'' is a species of dimorphic fungus. Its sexual form is called ''Ajellomyces capsulatus''. It can cause pulmonary and disseminated histoplasmosis. ''H. capsulatum'' is "distributed worldwide, except in Antarctica, but m ...
'', the fungus that causes the disease
histoplasmosis Histoplasmosis is a fungal infection caused by '' Histoplasma capsulatum''. Symptoms of this infection vary greatly, but the disease affects primarily the lungs. Occasionally, other organs are affected; called disseminated histoplasmosis, it can ...
, is occasionally found in its guano. The big brown bat may also be a vector of the Saint Louis encephalitis virus, a
mosquito Mosquitoes (or mosquitos) are members of a group of almost 3,600 species of small flies within the family Culicidae (from the Latin ''culex'' meaning " gnat"). The word "mosquito" (formed by ''mosca'' and diminutive ''-ito'') is Spanish for "li ...
-born virus that can affect humans. Individuals have also tested positive for ''
West Nile virus West Nile virus (WNV) is a single-stranded RNA virus that causes West Nile fever. It is a member of the family '' Flaviviridae'', from the genus '' Flavivirus'', which also contains the Zika virus, dengue virus, and yellow fever virus. The v ...
'', which can also be transferred to humans via mosquitoes.


See also

*
Bats of Canada There are eighteen indigenous species of bats in Canada, which are found in many parts of the country. They are insectivores, and are prey to falcons, hawks, owls, snakes, cats, and raccoons.Health Canada Species The little brown bat is the mos ...
*
Bats of the United States Most of the many bat species found in the United States are insectivorous except for three flower eating species that migrate from Mexico and one that inhabits the Florida Keys. __TOC__ Species Bats belong to the biological order of Chiropt ...
*
Little brown bat The little brown bat or little brown myotis (''Myotis lucifugus'') is an endangered species of mouse-eared microbat found in North America. It has a small body size and glossy brown fur. It is similar in appearance to several other mouse-ea ...
, a similarly named bat belonging to the ''
Myotis The mouse-eared bats or myotises are a diverse and widespread genus (''Myotis'') of bats within the family Vespertilionidae. The noun "''myotis''" itself is a New Latin construction, from the Greek "''muós'' (meaning "mouse") and "''oûs''" (me ...
''
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...


Notes


References


External links

* {{Taxonbar, from=Q301254 Articles containing video clips Big Brown Big Brown Big Brown Eptesicus Mammals described in 1796 Mammals of Colombia Mammals of the Dominican Republic Taxa named by Palisot de Beauvois