Bats of the United States and Canada
Publication Year: 2011
Published by: The Johns Hopkins University Press
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This book is an updated and expanded version of our 1999 booklet “Bats of the United States,” published by the Arkansas Game and Fish Commission in cooperation with the Asheville (North Carolina) Field Office of the U.S. Fish and Wildlife Service. Thousands of copies of that publication have been distributed. The primary goal of this (and that) publication is to provide readers with an accurate and concise source of information concerning life histories...
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We thank our respective universities (MJH, Tennessee Technological University; JSA, the University of New Mexico; TLB, Auburn University) for aid in making this publication possible. We are especially grateful to Robert R. Currie, U.S. Fish and Wildlife Service, and Keith B. Sutton, Arkansas Game and Fish Commission, for their financial and editorial help in making our 1999 publication...
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Bats are among the most misunderstood animals in the United States and Canada, as well as worldwide, although as consumers of enormous numbers of insects, they rank among the most beneficial. In other parts of the world, in addition to controlling insects, bats are extremely beneficial in dispersal of seeds and pollination of plants; numerous plants depend entirely on bats for these services...
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All bats have both a common name and a scientific designation (species name). Like all animals that have been named and described by scientists, bats are assigned to obligate taxonomic categories: kingdom, phylum, class, order, family, genus, and species. Bats are in the kingdom Animalia, phylum Chordata, class Mammalia...
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Bats, like humans, are mammals: they have hair, give birth to live young, and feed their young on milk from mammary glands of the mother. In southeastern Asia, males of one species of bat (Dayak fruit bat, Pteropus spadiceus) actually provide milk for their young. This is the only one of the more than 5,700 species of mammals in which males provide milk...
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Although bats have relatively good eyesight, most depend on their superbly developed echolocation system (sonar) to navigate and capture insects in the dark. Bats emit pulses of high-frequency sound (usually inaudible to humans) at a rate of a few to 200 per second. Bats can capture tiny flying insects...
Benefits of Insectivorous Bats
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Nearly all species of bats in the United States and Canada, and 70% of species worldwide, feed almost exclusively on insects and are thus extremely beneficial to humans. In fact, bats are the only major predators of night-flying insects. Although bats typically eat more than 50% of their body weight in insects each night, a nursing female may consume enough prey nightly to equal...
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Some bats forage within about 1–2 kilometers (0.6–1.2 miles) of their day roost, while other species may travel more than 50 kilometers (30 miles) each way in search of food every night. Some of the huge colonies of Mexican free-tailed bats, Tadarida brasiliensis mexicana, that leave caves in the southwestern United States each evening in summer are so large that their movements...
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While insect-eating bats may often catch flying insects in their mouths, they also capture insects on the wing by scooping them into their tail or wing membranes. The bat then reaches down and takes the insect into its mouth. This results in the erratic flight most people are familiar with when they observe...
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While most species of bats in the United States and Canada are insectivorous, bats in other parts of the world feed on a variety of items in addition to insects. Many species, including the large flying foxes, feed primarily on fruit, while others feed on nectar and pollen. Several types consume leaf material and sap. Much of the fruit consumed by fruit-eating species is overly ripe...
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Most famous (or infamous) among bats are the three species of vampire bats of Mexico, Central America, and South America, which feed on blood of warm-blooded animals. Vampire bats obtain blood by biting their victims with their sharp incisor teeth and then lapping (not sucking) blood as it flows from the wound. The common vampire bat...
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Bat droppings or “guano” make excellent fertilizer. Certain caves are mined for this valuable material, and some reportedly once contained thousands of tons of guano until much of it was removed for use as fertilizer. More than 90 million kilograms (100,000 tons) of guano were mined from Carlsbad Cavern in New Mexico in the early 1900s...
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During summer, bats in the United States and Canada occupy a variety of habitats. They may congregate in caves, mines, trees, or manmade structures such as bat houses. They may also roost in buildings or under bridges. Many species segregate into maternity and bachelor colonies. Maternity colonies may be huge. For example, 20 million, mostly female, Mexican free-tailed...
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Many species of cave-dwelling bats arrive at their hibernacula in preparation for mating and hibernation as early as late July. Upon arrival, the bats “swarm.” During swarming, large numbers of bats fly in, out, and around openings of caves from dusk to dawn, although a few roost in the caves during daytime. Swarming continues for several weeks, usually through at least mid-October...
Winter Habitat and Hibernation
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Because insects are not available as food during winter, temperate-zone bats survive by either migrating to warmer regions, where insects are available, or by hibernating. Most bats that do not migrate hibernate in caves or abandoned mines. Hibernation is a state of torpor during which normal metabolic activities are greatly reduced...
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Most cave bats in the United States and Canada spend winter hibernating in caves (or mines) and move to trees or man-made structures during summer. A few species reside in caves year-round. Tree bats seldom enter caves. Most roost in trees in summer and migrate to warmer regions during winter...
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Homing ability, defined as the ability to return home after being displaced into unfamiliar territory, has been demonstrated to occur in diverse groups of animals, among them, birds, rodents, turtles, frogs, fish, and bats. The homing ability of pigeons is well known. During the 1950s and 1960s, numerous homing studies were conducted to determine if bats exhibited homing ability...
Reproduction and Longevity
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Most female bats in the United States and Canada produce only one offspring per year, although some species give birth to two, three, or four babies at a time. Most breed in autumn, with females storing sperm until the following spring when fertilization takes place (delayed fertilization); other species breed in spring....
Bats as Food
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In some locations, especially parts of Asia and Africa and islands in the Pacific, many species, particularly the large fruit bats, are used as food by humans. For example, on the island of Guam, many native people consider Mariana fruit bats (Pteropus mariannus) to be a delicacy. Prior to government regulations to protect the bats from overharvesting, people sometimes paid exorbitant prices...
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One of the most interesting stories about bats concerns a plan to use them as weapons during World War II. Project X-Ray, conceived by Lytle S. Adams, a Pennsylvania dental surgeon, was to be carried out by the U.S. Navy. The plan entailed using thousands of Mexican freetailed bats...
Mines and Bridges
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Bats often occupy abandoned mines where they raise their young during summer and hibernate in winter. Many of the largest remaining populations of bats in the United States and Canada roost in mines. Many bats use areas beneath bridges and joints between structural components of bridges as sites for maternity and day roosts...
Controlling “Nuisance” Bats
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The news media are often guilty of sensationalizing stories about rabid bats or colonies of bats in buildings and exaggerating the dangers involved. Even some well-respected magazines have published ridiculous bat-scare stories. One such article, “The Nightmare House,” described the experiences of a family that didn’t know “there was another presence in the house ‘strange and ominous’ that was soon...
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Several attempts have been made to attract bats to large wooden “municipal bat roosts.” One such roost was constructed in 1918 near San Antonio, Texas. This “bat tower” was designed by Charles A. R. Campbell, a physician in San Antonio, Texas. He hoped that bats would occupy the structure and eradicate mosquitoes and thus malaria, as well as supply guano for fertilizer. But relatively few bats used the structure...
Threats to Bats
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In the United States and Canada, several animals, including owls, hawks, raccoons, skunks, feral cats, and snakes prey on bats. But relatively few animals consume bats as a regular part of their diet. Humans seem to be the only animal having a significant impact on populations of bats. Adverse impacts from humans include habitat destruction, direct killing, vandalism, disturbance...
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Bats, like many other mammals, can contract and transmit the deadly rabies virus as well as other diseases. Although rabies has been detected at one time or another in many species of bats in the United States and Canada, it is relatively uncommon. However, reports of rabid bats often make the headlines. Fear of rabid bats is widespread, but even rabid bats are seldom aggressive...
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Histoplasmosis is a fungal infection that, in humans, primarily affects the lungs, but other organs may also be affected. The fungus that causes this disease, Histoplasma capsulatum, occurs throughout the world, where it grows in soil and in deposits of bat guano, in poultry-house litter, and in droppings beneath roosts used by birds...
Bats and Wind Power
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Wind turbines are an effective means of increasing energy production and cause significantly less damage to our environment than conventional methods such as strip mining, oil and gas extraction, and damming rivers for hydroelectric plants. Towers supporting turbines are typically 60–90 meters (200–300 feet) tall. Most support turbines with three blades...
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Between 2006 and 2010, well over a million bats died in the eastern United States and Canada from a mysterious ailment called whitenose syndrome, first reported from a cave in New York in February 2006. At least eight species of bats that hibernate in caves have been infected, with more likely to be infected. The disease has spread rapidly across the eastern United States and into Canada...
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Numerous federal, state, provincial, and nongovernmental organizations are engaged in the bat conservation effort. Many private landowners and other individuals also are involved. The U.S. Fish and Wildlife Service, Canadian Wildlife Service, as well as other federal, state, and provincial agencies and organizations consider several species of bats to be “endangered”...
Status of Bats in the United States and Canada
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Of the 47 species of bats in the United States and Canada, 6 are wholly (species and subspecies) or partially (certain subspecies) considered endangered by the U.S. Fish and Wildlife Service under the Endangered Species Act of 1973. The Canadian Wildlife Service and the Committee on the Status of Endangered Wildlife in Canada...
Endangered Species and Subspecies
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The Indiana bat was listed as endangered throughout its range in the United States by the U.S. Fish and Wildlife Service in March 1967 under the Endangered Species Preservation Act of 1966 and is currently listed as endangered under the Endangered Species Act of 1973. A recovery plan for this species was approved (on an interim basis) in June 1976 and a final plan was approved...
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Before threatened or endangered species and their critical habitats can be protected, studies must be conducted to obtain pertinent data concerning distribution, status, and ecology of these and other species. Studies have been initiated by federal, state, and provincial agencies. Primary objectives are to determine distribution and status of species that are endangered, threatened...
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Techniques to inventory bats include searching caves known to have been inhabited by bats and attempting to locate additional caves occupied by bats. Estimates of populations are made by actually counting the number of bats hibernating in caves or mines, or by estimating numbers emerging to forage. For bats that cluster together during hibernation, estimates are made by multiplying...
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Because bats are endothermic (warm blooded), digital-thermalimaging techniques can be used to estimate the number of bats emerging from caves. A night-vision camera is used because emergences occur under low-light conditions and illumination in the visible light band may alter the behavior of bats. The technique is based on using a change-detection procedure to detect and track bats flying through the field of view of the camera and evaluating...
Nets and Traps
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Outside caves or mines (or sometimes at openings of caves and mines), sampling for the presence of bats is done by setting up mist nets or by using harp traps at locations where bats would likely fly. Mist nets are large (up to 3 by 18 meters [10 by 60 feet]) and made of very fine thread. They are used to capture flying bats, which become entangled in the nets...
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Use of bands to mark bats for later identification has provided researchers with a wealth of information concerning migration, movements, homing ability, longevity, size of populations, survival, sex ratios, age of individuals, rates of growth, and so on. From 1932 to 1972, a bat-banding program was administrated, coordinated, and maintained by the U.S. Bureau of Biological Survey in the Department of Agriculture...
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Some bats are fitted with tiny radiotransmitters and their movements are tracked with directional antennae and radio receivers. These transmitters should weigh no more than 5%–10% of the weight of the bat. Unfortunately, because of their small size and short battery life, transmitters only have a range of a few kilometers...
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Acoustic identification equipment, such as the AnaBat Bat Detector, can be used to identify bats to species. This bat-detector system renders ultrasonic calls made by bats audible to humans. Recordings of the search-phase calls of free-flying bats produce sonograms, which vary among species....
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Night-vision (or starlight) scopes and ultrasonic detectors are used to observe bats at night. Bats may also be fitted with small vials containing a chemical light substance (Cyalume) so researchers can observe their flight behavior, determine foraging habitat, and track movements. Environmental conditions in roost sites are monitored with electronic data loggers to determine microclimate factors such as temperature and humidity...
Mexican Long-tongued Bat, Choeronycteris mexicana
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Weight is 10–25 grams (0.4–0.9 ounce); wingspan is 33–36 centimeters (13–14 inches); distribution includes the southwestern United States, most of Mexico, and Central America. It is a rather large bat with a long, slender nose. This species occupies a variety of vegetative habitats ranging from arid thorn shrub...
Mexican Long-nosed Bat, Leptonycteris nivalis
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Weight is 23–25 grams (0.8–0.9 ounce); wingspan is 40–42 centimeters (16–17 inches); distribution extends from the Big Bend region of Texas, southward across most of Mexico to central Guatemala. It is a colonial cave dweller that usually inhabits deep caverns but also occurs in mines, culverts, hollow trees, and unoccupied buildings. This bat occupies a variety of habitats from high-elevation, pine-oak woodlands to sparsely vegetated deserts...
Lesser Long-nosed Bat, Leptonycteris yerbabuenae
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Weight is 15–25 grams (0.5–0.9 ounce); wingspan is 37–38 centimeters (15 inches); distribution is from the southwestern United States to Honduras. A resident of desert-scrub country, it is colonial, occupying mines and caves at the base of mountains where the alluvial fan supports agaves, yuccas, saguaros, and organ pipe cacti. It hangs with its feet so close together that it can turn nearly 360° to watch for predators....
California Leaf-nosed Bat, Macrotus californicus
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Weight is 8–17 grams (0.3–0.6 ounce); wingspan is 33–35 centimeters (13–14 inches); distribution is the southwestern United States, western and southern Mexico, and northern Central America. This rather large bat is a resident of lowland desert habitat. Its favored daytime retreat is abandoned mine tunnels, which provide protection from the heat and the drying effects of the desert climate...
Jamaican Fruit-eating Bat, Artibeus jamaicensis
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Weight is 42–44 grams (1.5 ounces); wingspan is 44–46 centimeters (17–18 inches). This fruit-eating bat is widely distributed from northern Sinaloa, Mexico, and from the Florida Keys southward through the Caribbean and northern South America. The Jamaican fruit-eating bat forages in small groups. Captured individuals may produce distress calls, which induce mobbing behavior by other members of the group...
Peter’s Ghost-faced Bat, Mormoops megalophylla
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Weight is 13–19 grams (0.5–0.6 ounce); wingspan is 36–38 centimeters (14–15 inches). Distribution is southeastern Arizona and across southern Texas, throughout most of Mexico (except northwestern region), then southward into Central America. Peter’s ghost-faced bats usually occur in lowland areas, especially desert scrub and riverine habitats, where they often roost in caves, tunnels, and mine shafts...
Florida Bonneted Bat, Eumops floridanus
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Weight is 30–55 grams (1.1–1.9 ounces) in pregnant females; wingspan is 49–51 centimeters (20 inches). The Florida bonneted bat occurs only in southern Florida. Although these bats occur in cities as well as in forested areas, precise foraging and roosting habits and long-term requirements are unknown...
Greater Bonneted Bat, Eumops perotis
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Weight is 60–70 grams (2.1–2.5 ounces); wingspan is 53–57 centimeters (21–22 inches); distribution is central California to central Mexico and northern South America to northern Argentina. It is capable of fast and prolonged flight; the wings are long and slender and the flight membranes are tough and leathery. These bats live in high, dry places...
Underwood’s Bonneted Bat, Eumops underwoodi
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Weight is 50–60 grams (1.8–2.1 ounces); wingspan is 50–54 centimeters (20–21 inches); distribution is in south-central Arizona, then along the western coast of Mexico into Central America. Among bats of the United States, this species is second in size only to the greater bonneted bat. Its long, narrow wings are adapted for rapid, longdistance flight in open habitats...
Pallas’ Mastiff Bat, Molossus molossus
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Weight is 13–15 grams (0.5 ounce); wingspan is 29–31 centimeters (11–12 inches). This species is widely distributed from northern Mexico and from the Florida Keys southward through the Caribbean and northern South America to northern Argentina. Throughout its broad range, this species commonly is associated with human dwellings; it also roosts in hollow trees...
Pocketed Free-tailed Bat, Nyctinomops femorosaccus
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Weight is 10–14 grams (0.4–0.5 ounce); wingspan is 34–35 centimeters (13–14 inches); distribution is from the southwestern United States to southcentral Mexico. The common and scientific names refer to a shallow fold of skin that forms a pocketlike structure on the underside of the interfemoral membrane near the knee. The pocketed free-tailed bat occurs in arid lowlands...
Big Free-tailed Bat, Nyctinomops macrotis
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Weight is 25–30 grams (0.9–1.1 ounces); wingspan is 42–44 centimeters (17 inches); distribution is in the southwestern United States, Caribbean, and Central America through northern South America. The big free-tailed bat inhabits rocky country, where it roosts in crevices high up on cliff faces. It has been known to roost in buildings. This bat leaves its roost...
Brazilian Free-tailed Bat, Tadarida brasiliensis
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Weight is 11–15 grams (0.4–0.5 ounce); wingspan is 29–35 centimeters (11–14 inches); distribution is in the southern United States and southward through Mexico and Central America into northern South America. It also occurs on islands of the Caribbean. Habitat of Brazilian free-tailed bats differs in various parts of the United States...
Big Brown Bat, Eptesicus fuscus
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Weight is 14–21 grams (0.5–0.7 ounce); wingspan is 32–39 centimeters (13–15 inches). Distribution is from southern Canada through southern North America into South America, including many islands in the Caribbean. These bats are closely associated with humans and more people in the United States are familiar with this bat than with any other species of bat. Most summer roosts are located in attics, barns, bridges, or other man-made structures, where colonies of a few to several hundred individuals gather to form maternity colonies...
Western Red Bat, Lasiurus blossevillii
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Weight is 10–15 grams (0.4–0.5 ounce); wingspan is 29–30 centimeters (11–12 inches); distribution is western Canada, western United States, western Mexico, and Central America. This solitary species roosts in the foliage of large shrubs and trees in habitats bordering forests, rivers...
Eastern Red Bat, Lasiurus borealis
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Weight is 9–15 grams (0.3–0.5 ounce); wingspan is 28–33 centimeters (11–13 inches). Distribution includes southern Canada, the eastern United States (except the Florida peninsula), and northeastern Mexico. Eastern red bats spend daylight hours hanging in foliage of trees. They usually hang by one foot, giving them the appearance of dead leaves...
Hoary Bat, Lasiurus cinereus
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Weight is 25–30 grams (0.9–1.1 ounces); wingspan is 34–41 centimeters (13–16 inches). This is the most widespread bat in the Americas, occurring in most of southern Canada and southward through most of South America. It also occurs in Hawaii (where it is the only native terrestrial mammal), Iceland, Bermuda, and the Dominican Republic...
Southern Yellow Bat, Lasiurus ega
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Weight is 10–15 grams (0.4–0.5 ounce); wingspan is 34–36 centimeters (13–14 inches); distribution is from southern Texas through eastern Mexico and Central America into southern South America. Like other members of the genus Lasiurus, the southern yellow bat is a tree-roosting species; it often roosts...
Northern Yellow Bat, Lasiurus intermedius
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Weight is 14–31 grams (0.5–1.1 ounces); wingspan is 35–39 centimeters (14–15 inches). Distribution includes the coastal regions of the southeastern United States, eastern Texas, Cuba, and southward into Central America. These bats typically inhabit wooded areas in the vicinity of permanent water. In the southeastern United States, the distribution of northern yellow...
Seminole Bat, Lasiurus seminolus
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Weight is 9–14 grams (0.3–0.5 ounce); wingspan is 29–31 centimeters (11–12 inches). Distribution is the southeastern United States; extralimital records include New York, Pennsylvania, southern Texas, Bermuda, and Veracruz, Mexico. The distribution of Seminole bats nearly...
Western Yellow Bat, Lasiurus xanthinus
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Weight is 10–15 grams (0.4–0.5 ounce); wingspan is 33–36 centimeters (13–14 inches). Distribution is from the southwestern United States across the Mexican Plateau to southern Mexico. Little is known regarding its habitat, but like other lasiurine bats, it roosts in leafy vegetation...
Evening Bat, Nycticeius humeralis
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Weight is 7–14 grams (0.2–0.5 ounce); wingspan is 26–28 centimeters (10–11 inches); distribution is most of the eastern United States and northeastern Mexico. This species usually inhabits tree cavities or buildings in summer. In the Southeast, it may share roosts with the Brazilian free-tailed bat. It almost never enters caves, although it sometimes joins the bats swarming about certain cave openings in late summer...
Canyon Bat, Parastrellus hesperus
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Weight is 3–6 grams (0.1–0.2 ounce); wingspan is 19–22 centimeters (7–9 inches); distribution is from southern Washington to southern Mexico. The genus of this bat recently was changed from Pipistrellus to Parastrellus. There is no bat in the genus Pipistrellus in the United States or Canada (there were 2), but there are 29 species of Pipistrellus elsewhere in the world...
Tri-colored Bat, Perimyotis subflavus
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Weight is 6–8 grams (0.2–0.3 ounce); wingspan is 21–26 centimeters (8–10 inches). Distribution includes eastern Canada, most of the eastern United States, and southward through eastern Mexico to Central America. The genus of this species recently was changed from Pipistrellus to Perimyotis...
Rafinesque’s Big-eared Bat, Corynorhinus rafinesquii
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Weight is 8–14 grams (0.3–0.5 ounce); wingspan is 26–30 centimeters (10–12 inches); distribution is the southeastern United States. Rafinesque’s big-eared bats occur in nearly every type of forested habitat within their range. Roosts include partially lighted, abandoned buildings, hand-dug wells, cisterns, grain silos, attics of occupied houses, highway...
Townsend’s Big-eared Bat, Corynorhinus townsendii
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(0.3–0.5 ounce); wingspan is 30–32 centimeters (12–13 inches). Distribution includes western Canada, the western United States to southern Mexico, and a few isolated populations in the eastern United States. These bats hibernate in caves or mines where the temperature is 12°C (54°F) or less, but usually above freezing...
Spotted Bat, Euderma maculatum
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Weight is 16–20 grams (0.6–0.7 ounce); wingspan is 34–36 centimeters (13–14 inches); distribution is from south-central British Columbia to southern Mexico. This spectacularly colored bat is white underneath and has black fur on its back with three large white spots. The spotted bat occurs in a wide range of habitats in the western regions of the continent, most often in rough, rocky, semiarid, or arid terrain, varying from ponderosa pine forest to scrub country and open desert. The day roosts often are situated on...
Allen’s Big-eared Bat, Idionycteris phyllotis
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Weight is 8-16 grams (0.3–0.6 ounce); wingspan is 31–35 centimeters (12–14 inches); distribution is the southwestern United States to central Mexico. This is a rather large bat with enormous ears and a unique pair of lappets projecting from the median bases of the ears over the top of the snout. When this bat is at rest, the huge ears lie along the back, often curled into the shape of a ram’s horn. Allen’s big-eared bat usually inhabits forested areas of the mountainous Southwest and is relatively common in pine-oak forested canyons...
Pallid Bat, Antrozous pallidus
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Weight is 20–35 grams (0.7–1.2 ounces); wingspan is 37–39 centimeters (15 inches); distribution is south-central British Columbia to central Mexico. It is common in arid regions with rocky outcroppings, particularly near water. This gregarious species usually roosts in small colonies of 20 or more individuals in rock crevices and buildings...
Silver-haired Bat, Lasionycteris noctivagans
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Weight is 8–11 grams (0.3–0.4 ounce); wingspan is 27–31 centimeters (11–12 inches); distribution is southern Alaska across southern Canada and southward through much of the United States to northeastern Mexico. A typical day roost is under loose tree bark, but these bats also have been found in woodpecker holes and bird nests. Although they may appear in any kind of building...
Southwestern Bat, Myotis auriculus
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Weight is 5–8 grams (0.2–0.3 ounce); wingspan is 26–28 centimeters (10–11 inches). Distribution is from Arizona and New Mexico to southern Mexico, but the winter range is unknown. The southwestern bat often occurs in ponderosa pine forests. It is also present from mesquite and chaparral through the oak forests into pinyon-juniper habitats and seems to reach its greatest abundance in areas of extensive rocky cliffs where water...
Southeastern Bat, Myotis austroriparius
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Weight is 5–8 grams (0.2–0.3 ounce); wingspan is 24–27 centimeters (9–11 inches). Distribution includes the southeastern United States from southern Illinois and Indiana to northeastern Texas and northern Florida. Caves are favorite roosting sites, although buildings and other shelters sometimes are used. Maternity colonies composed of thousands of individuals inhabit caves. Throughout much of the South...
California Bat, Myotis californicus
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Weight is 3–5 grams (0.1–0.2 ounce); wingspan is 22–23 centimeters (9 inches); distribution is from southern Alaska and western Canada southward through most of Mexico. It is one of the smallest bats in the United States. It occupies a variety of habitats in the Pacific Northwest and southern and western British Columbia, from the humid coastal forest to semidesert, and from sea level to about 1,800 meters (5,900 feet) elevation...
Western Small-footed Bat, Myotis ciliolabrum
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Weight is 4–6 grams (0.1–0.2 ounce); wingspan is 21–25 centimeters (8–9 inches); distribution is from southern Alberta and Saskatchewan to northeastern New Mexico and western Kansas. The western small-footed bat is yellowish on its back and nearly white on its underside. (The dark-nosed smallfooted bat...
Long-eared Bat, Myotis evotis
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Weight is 5-8 grams (0.2–0.3 ounce); wingspan is 25–29 centimeters (10–11 inches); distribution includes southwestern Canada, western United States, and Baja California, Mexico. It occurs in a variety of habitats over its range in North America, but mostly in forested areas. In the Pacific Northwest and British Columbia, it occurs from dry forest to subalpine forest, especially where broken rock outcroppings prevail...
Gray Bat, Myotis grisescens
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Weight is 8-11 grams (0.3–0.4 ounce); wingspan is 27–30 centimeters (11–12 inches). Distribution includes cave regions of Arkansas, Missouri, Kentucky, Tennessee, and Alabama, with occasional colonies in adjacent states. Gray bats are cave residents year-round, but different caves usually are occupied in summer and winter. Few have been found roosting outside of caves. They hibernate...
Keen’s Bat, Myotis keenii
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(0.1–0.2 ounce); wingspan is 21–26 centimeters (8–10 inches); The geographic range of Keen’s bat is among the smallest of any bat in North America. The bulk of its range is in British Columbia west of the coastal mountains, extending into southeastern Alaska and northwestern Washington. Keen’s bat is restricted to the dense coastal forest of the Pacific coast. The species is believed to be solitary and to roost in tree cavities...
Eastern Small-footed Bat, Myotis leibii
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Weight is 3–4 grams (0.1 ounce); wingspan is 21–25 centimeters (8–10 inches); distribution is from eastern Canada and New England southward to Alabama and Georgia and westward to Oklahoma. This is one of the smallest bats in the United States and Canada. Eastern small-footed bats hibernate in caves or mines and are among the hardiest of cave bats. They are one of the last to enter caves in autumn and often hibernate near entrances of caves or mines where temperatures...
Little Brown Bat, Myotis lucifugus
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Weight is 7–14 grams (0.2–0.5 ounce); wingspan is 22–27 centimeters (9–11 inches). The species is widely distributed from central Alaska and southern Canada into the southwestern and southeastern United States. The little brown bat usually hibernates in caves and mines. During summer, it often inhabits buildings, usually rather hot attics, where females form nursery colonies of hundreds or even thousands of individuals. Where most males spend summer is unknown, but they likely are solitary and scattered in a variety of roost types...
Dark-nosed Small-footed Bat, Myotis melanorhinus
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Weight is about 4–5 grams (0.1–0.2 ounce); wingspan is 24–25 centimeters (9–10 inches); distribution is from southern British Columbia to central Mexico. The dark-nosed small-footed bat seems to prefer arid habitats, where it is associated with cliffs and talus fields; on prairies it is associated with clay buttes and steep riverbanks. This species roosts in crevices in rock faces and clay banks, may use spaces beneath and between boulders in talus fields, and also has been found roosting...
Arizona Bat, Myotis occultus
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Weight 7–9 grams (0.2–0.3 ounce), wingspan 24–25 centimeters (9–10 inches). The species occurs only in the southwestern United States and Mexico. Habitat is variable, from ponderosa pine and oakpine woodlands near water, to areas with permanent water in riparian forest, to desert areas along rivers. Mines rarely are used in summer, but may be used in winter. It spends daytime hours in crevices in canyon walls, caves, attics, and other safe shelters, emerging shortly before dark...
Northern Long-eared Bat, Myotis septentrionalis
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Weight is 6–9 grams (0.2–0.3 ounce); wingspan is 23–26 centimeters (9–10 inches); and distribution includes southern Canada and the central and eastern United States southward to northern Florida. Northern long-eared bats hibernate in parts of caves and mines that are relatively cool and moist, where the air is still. Hibernation may begin as early as August and may last for 8–9 months in northern latitudes. In summer, these bats roost by day in a variety of shelters, including inside buildings and under tree bark and shutters...
Indiana Bat, Myotis sodalis
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Weight is 7–8 grams (0.2–0.3 ounce); wingspan is 24–27 centimeters (9–11 inches). Its distribution includes cave regions in the eastern United States. Indiana bats usually hibernate in large dense clusters of up to several thousand individuals in sections of the hibernation cave where temperatures average 3–6°C (38–43°F), with a relative humidity of 66%–95%...
Fringed Bat, Myotis thysanodes
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Weight is 5–7 grams (0.2–0.3 ounce); wingspan is 27–30 centimeters (11–12 inches); distribution includes southern British Columbia, Canada, western United States, and most of Mexico. The fringed bat occurs in a variety of habitats from desert-scrub to fir-pine associations...
Cave Bat, Myotis velifer
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Weight is 12–15 grams (0.4–0.5 ounce); wingspan is 28–32 centimeters (11–13 inches); distribution is southern Kansas and western Oklahoma, the southwestern United States, Mexico, and into Central America. This bat occurs in colonies of 2,000–5,000 individuals throughout much of its range. Habitats vary from desert floodplains and rocky canyons to the cave country from central Texas to south-central Kansas. In summer, this species congregates in caves, mines, and less often in buildings...
Long-legged Bat, Myotis volans
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Weight is 6–9 grams (0.2–0.3 ounce); wingspan is 25–27 centimeters (10–11 inches); distribution is southern Alaska and western Canada southward into northern Mexico. The long-legged bat primarily inhabits forested mountainous regions, where it roosts in trees, rock crevices, cracks and crevices in stream banks, and buildings. It may be in streamside and arid habitats in some areas. This bat emerges early in the evening when it is still twilight...
Yuma Bat, Myotis yumanensis
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Weight is 4-6 grams (0.1–0.2 ounce); wingspan is 22–24 centimeters (9 inches); distribution is from southwestern British Columbia, through the western United States, and into central Mexico. From the cottonwood-lined streams of the southwestern deserts to the redwood canyons of the Pacific coast, nearly all habitats of the Yuma bat show a common feature, the presence of open water nearby. It often is in areas without trees...
SPECIES OF ACCIDENTAL OCCURRENCE
Hairy-legged Vampire Bat, Diphylla ecaudata
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Weight is 24–43 grams (0.8–1.5 ounces); wingspan is 37–45 centimeters (15–18 inches). The species is known from only one record in the United States. In 1967, a hairy-legged vampire bat was observed in an abandoned railroad tunnel in Val Verde County, Texas. The species occurs across eastern...
Buffy Flower Bat, Erophylla sezekorni
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Weight is 16–18 grams (0.6 ounce). There is a record of occurrence in the Florida Keys, and the species is present throughout most of the Greater Antilles and associated islands. Large colonies occupy cooler portions of hot (25–28°C [77–82°F]) caves from well-lighted areas near entrances to deep, dark chambers. Individuals may hang alone or in groups on walls or ceilings of caves...
Cuban Flower Bat, Phyllonycteris poeyi
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Weight is about 14 grams (0.5 ounce) and, other than a fossil from the Bahamas and a recent record in the Florida Keys, the species is known only from Cuba and Hispaniola. Pelage of the Cuban flower bat is grayish white; it has a silky texture and silvery reflections under certain light. The head is long and narrow, and the long tongue has many tiny papillae for gathering nectar...
Cuban Fig-eating Bat, Phyllops falcatus
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Weight is 16–23 grams (0.6–0.8 ounce); wingspan is 32–37 centimeters (13–15 inches). This species is known from the United States based on one record at Key West, Florida. The Cuban fig-eating bat is an uncommon species that occurs only in the Caribbean area, especially on the islands of Cuba and Hispaniola, where it occupies lowlands in a variety of forested habitats including evergreen, submontane, pine, and semideciduous...
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Bats are an extremely interesting and highly beneficial segment of our fauna. They should be understood and appreciated, not feared and persecuted. Like many wild animals, they sometimes pose public health problems or become nuisances by residing where they are not wanted. However, their benefit as the only major predator of nightflying insects greatly outweighs any negative aspects...
Appendix: Bats of the United States and Canada (Including Protection Status)
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Page Count: 288
Illustrations: 135 color photos, 47 maps, 2 graphs
Publication Year: 2011