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bat

 
Dictionary: bat2   (băt) pronunciation
n.

Any of various nocturnal flying mammals of the order Chiroptera, having membranous wings that extend from the forelimbs to the hind limbs or tail and anatomical adaptations for echolocation, by which they navigate and hunt prey.

idiom:

have bats in (one's) belfry

  1. To behave in an eccentric, bizarre manner.

[Alteration of Middle English bakke, of Scandinavian origin.]


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Animal Classification: Chiroptera
Top

I: Pteropus
II: All Other Genera
Family: Mouse-Tailed Bats
Family: Sac-Winged Bats, Sheath-Tailed Bats, and Ghost Bats
Family: Kitti's Hog-Nosed Bats
Family: Slit-Faced Bats
Family: False Vampire Bats
Family: Horseshoe Bats
Family: Old World Leaf-Nosed Bats
Family: American Leaf-Nosed Bats
Family: Moustached Bats
Family: Bulldog Bats
Family: New Zealand Short-Tailed Bats
Family: Funnel-Eared Bats
Family: Smoky Bats
Family: Disk-Winged Bats
Family: Old World Sucker-Footed Bats
Family: Free-Tailed Bats and Mastiff Bats
I: Vespertilioninae
II: Other Subfamilies

(Bats)

Class: Mammalia

Order: Chiroptera

Number of families: 19 living families (18 recognized by some researchers)

Number of genera, species: 192 genera; 1,057 species

Introduction

Bats are nocturnal, coming out at night. They are the only mammals capable of true (meaning, flapping) flight, because the other so-called flying mammals (for example, squirrels, lemurs, and sugar gliders) glide, they do not fly. Today, the diversity of bats is astonishing, with more than 1,000 species making them second only to rodents as the most diverse group of mammals. Although some bats have remarkable faces and behavior, wings are the most conspicuous features of the flying bats. Upon landing, bats immediately fold their wings so they appear to shrink in size. Small size is another distinctive feature of bats. While a few species weigh more than 3.5 oz (100 g) as adults, most weigh less than 1.7 oz (less than 50 g), and the majority less than 0.9 oz (less than 25 g). The smallest bats in the world (hog-nosed bats, Craseonycteris thong-longyai, family Craseonycteridae from Thailand and Myanmar) weigh 0.07 oz (2 g) as adults. The largest, the Indian flying foxes (Pteropus giganteus) from India, Pakistan, and Southeast Asia, weigh 52.9 oz (1,500 g).

Chiroptera means hand (cheiro) and wing (ptera). Bat wings are folds of skin supported by elongated arm, hand, and finger bones, and attached to the sides of the body. In most cases, bats' thumbs are relatively free of the wing membranes and bear claws, which are absent from the fingers. Flying foxes and their allies (family Pteropodidae) usually have claws on their second fingers, but some species (dawn bats, genus Eonycteris, and naked-backed fruit bats, genus Dobsonia) lack these claws. Second fingers with claws occur in some fossil bats.

Measurements made with Doppler radar indicate that bats fly about 6.5–49.2 ft (2–15 m) per second. Bats use nine pairs of muscles to power flight. Muscles that power the down-stroke are located in the chest, and those responsible for the upstroke are located in the back. Although some bats have quite muscular forearms, their wing bones tend to be lightly muscled. In most bats, the folds of skin (wings) enclose some connective tissue, nerves, and blood vessels. Some free-tailed bats (Molossidae) also have sheets of muscle in the wing membranes. In mechanics and aerodynamics, the flight of bats is very similar to that of birds. The passage of air over the airfoil section of the wings generates lift. Movements of the wing tips generate propulsive thrust.

Bats show considerable variation in wing shape and flying abilities. In many species, the wings are relatively broad, providing good lift. Shorter-winged species tend to be more maneuverable than longer-winged ones. Many species of flower-visiting bats and some species that take animal prey from the ground can hover. While some species of bats can take off from the ground, those with longer, narrower wings cannot.

Although both can fly, bats differ from birds. While living birds such as ostriches, emus, and penguins, and fossils like elephant birds have lost the ability to fly, there are no living or fossil flightless bats. Bats have teeth, while living birds do not. Bats give birth to live young, while birds lay eggs. Since teeth are heavy, having them at the front end of a flying animal could create aerodynamic problems. Additionally, laying eggs could be more efficient and less costly for a flying animal than bearing live young. The diversity of birds (more than 8,000 species) suggests that their approach is more successful than that of bats (1,000 species).

In birds, the wings do not involve the hind limbs as they do in bats. The hind limbs of bats tend to be spindly and poorly muscled, and many bats are not mobile on the ground. Most birds are much more mobile on the ground, and their robust hind legs reflect this reality. Mobility in the air, on the ground, and beyond (as for penguins) may partly account for differences in diversity between bats and birds.

In addition to the obvious (i.e., bird wings are made of feathers, while bat wings are folds of skin), there are other differences between these animals. In bats, the division of power generation across nine pairs of muscles means that they are thin in profile through the chest. In birds, two pairs of muscles power flight: one the down-stroke, the other the up-stroke. Both sets of muscles are located on birds' chests and the upstroke muscles operate by a pulley system. A thin profile through the chest allows bats to squeeze into narrow cracks and crevices that serve as places to spend the day (day roosts). While a bird typically has a prominent keel on its breastbone (sternum), this feature is absent in most bats and never as well developed as it is in birds. Birds have wishbones (furcula), bats do not.

In most bats, the thumbs are free of the wings, appearing there as claws. In some bats, notably thumbless ones (family Furipteridae) and some ghost bats (genus Diclidurus, family Emballonuridae), the thumbs are greatly reduced in size and may lack claws. At the other extreme are the very long thumbs of vampire bats (Desmodus rotundus). Vampire bats' thumbs act like "throwing sticks," giving the bats extra leverage for taking off from the ground.

Bats' wing membranes usually join along the side of the body, but in two groups they meet in mid-back. The naked-backed bats belong to species in two families, Old World fruit bats (genus Dobsonia, family Pteropodidae) and naked-backed moustached bats (two species in the genus Pteronotus, family Mormoopidae). The function of the naked back remains unknown.

Wing membranes may attach to the bats' hind legs, extending as far down as the fifth toe of the hind feet. In other species, they attach higher up, at the ankle or knee. Carnivorous bats typically have an interfemoral membrane (between the hind legs) that encloses all or part of the tail. On the tail side, the calcar, a cartilaginous structure protruding from the ankle, supports the back edge of the interfemoral membrane. In flight, the interfemoral membrane acts as a rudder and also reduces oscillations of the body through each wing-beat cycle. But interfemoral membranes are not essential to bats: some plant-visiting and blood-feeding species have very narrow interfemoral membranes or lack them completely.

Most bats have tails. But while tails of some (e.g., mouse-tailed bats, Rhinopomatidae, and some Pteropodidae) are long and slender, others (e.g., free-tailed bats, Molossidae) are short and thick. Tails may or may not extend to the end of the interfemoral membrane. Some bats lack obvious tails.

The diversity of bats is reflected by the variety of trophic (ecological) roles they fill in ecosystems. While most species are mainly insectivorous, others eat plant products (fruit, leaves, seeds, nectar, or pollen). Other bats eat animals such as fish, frogs, birds, and even other bats. The most infamous of bats are the blood-feeding vampires, arguably the most remarkable of mammals. The ecological diversity of bats is reflected in their anatomy and behavior. The cheek teeth (molars and premolars) of carnivorous bats are quite different to those of frugivorous (fruit-eating) bats. Nectar-and pollen-feeding bats have teeth more specialized for crushing food, while the vampires have scalpel-sharp razors.

The facial features of bats reflect their remarkable diversity. Bats also are diverse in their selection of roosts, places they spend the day, and by the social systems that develop in these places.

Evolution and systematics

In spite of their small and delicate skeletons, bats have a long fossil record, something that was not obvious to biologists even 50 years ago. By the Eocene, there were species in at least 10 families of bats, four now extinct. Eocene bats are known from the United States, Germany, and Australia, as well as Pakistan.

It is assumed that bats evolved from nocturnal, arboreal, insectivorous animals that lived in forests. The combination of their small size, delicate skeletons, and the forest conditions make the ancestors of bats unlikely candidates for fossilization. There are no fossils of animals that are part bat, part something else, but it is speculated that a shrew-like animal would be a good candidate as a remote ancestor of bats.

The fact that bats appear fully formed and diverse in the Eocene means that it is not known when they first appeared. The very first bats could have shared the skies with the last of the pterosaurs, overlapping in time with the last dinosaurs. Furthermore, although the fossil record suggests a high level of variety, there are relatively few fossil bats and, for most living families, there is no fossil record.

Living species of bats are classified in two suborders: the Megachiroptera (flying foxes and their relatives, family Pteropodidae), which are the fruit-and flower-visiting bats of the Old World tropics, and the Microchiroptera, which include all of the other bats. The two groups are easy to distinguish. The Pteropodidae have dog-like faces, simple ears, and most have claws on their second fingers. Microchiroptera (18 families) lack claws on their second fingers, do not look like dogs, and their ears (and related structures) are more complex. The teeth of megachiropterans tend to be more specialized than those of microchiropterans (excepting vampire bats). Microchiropteran specializations for flight, particularly in the shoulder girdles, are more complex than those of megachiropterans. While the flying foxes and their relatives use flight to get from one place to another, many microchiropteran species feed on the wing and require higher levels of agility and maneuverability.

From the late nineteenth century, some biologists have questioned the closeness of the relationship between Megachiroptera and Microchiroptera. Two theories appeared. The monophyletic theory holds that the two suborders of Chiroptera are more closely related to one another than either is to any other group of mammals. The diphyletic theory proposes that the Megachiroptera are more closely related to some other group of mammals than they are to Microchiroptera. The neural details of how their eyes connect to their brains indicated that while megachiropterans were like primates, the microchiropterans were like all other mammals. Additional evidence about morphology and genetics has been presented. By the year 2000, the monophyletic theory was more accepted than the diphyletic one. New information could reopen and extend the debate.

Physical characteristics

In general anatomy and physiology, bats are like other mammals. Wings make bats distinct and flight imposes some physiological constraints that make them different in degree from other mammals. For example, the hearts of bats are larger than those of other mammals of comparable size. This difference reflects the higher capacity of the circulatory system associated with flight.

Bats are warm-blooded and, like other animals in this category (birds and mammals), expend energy to maintain body temperatures higher than ambient (surroundings). Bats face a challenge with respect to heat and energy, reflecting the realities of flight and small size. Flying bats shed excess heat generated by contractions of flight muscles, while roosting bats often conserve heat. In flying bats, wings act like radiators because direct connections between small arteries and small veins facilitate shedding heat. To conserve heat, bats roost in places that are at least warm if not hot, saving them the costs of thermoregulation, for example, shivering to keep warm. In temperate areas in summer, bats often use the warmest available roost sites, for example, in attics or tree hollows exposed to direct sunlight for much of the day, or heated rock crevices around hot springs.

Heterothermy, the ability of a warm-blooded animal to let its body temperature follow the ambient across some range, is another way that some bats conserve energy. Many species of plain-nosed (Vespertilionidae), horseshoe (Rhinolophidae), and free-tailed (Molossidae) bats are heterothermic, while other bats are not (e.g., slit-faced bats, Nycteridae; Old World leaf-nosed bats, Hipposideridae; and false vampire bats, Megadermatidae). The ability to hibernate (body temperatures measuring below 50°F [10°C] to freezing for a prolonged period) is extreme heterothermy. Heterothermy excuses bats from paying the costs of maintaining their body temperatures above ambient. Heterothermy allows bats (and other animals) to wait out periods of inclement weather (short-term torpor) or to hibernate (long-term torpor).

Distribution

Absent only from very remote oceanic islands, the high Arctic, and the Antarctic, bats are extremely widespread. For the most part, heterothermic species are the bats of temperate regions.

Some species of bats migrate hundreds of miles (kilometers) to avoid inclement seasons, but there is detailed knowledge in only a few cases. Schreiber's long-fingered bats (Miniopterus schreibersi) in Australia, noctules (Nyctalus noctula) in Europe, or Brazilian free-tailed bats (Tadarida brasiliensis) in parts of the New World are species whose seasonal movements have been documented by band recoveries. Seasonal appearances and disappearances of straw-colored fruit bats (Eidolon helvum) at different locations in Africa suggest migrations, and the same patterns have been used to support the proposal that red bats (Lasiurus borealis), hoary bats (Lasiurus cinereus), and silver-haired bats (Lasionycteris noctivagans) migrate in North America. In many other species, the seasonality of captures suggest migrations, but there are not documented movements of individuals (e.g., wrinkle-faced bats, Centurio senex).

The migrations of Brazilian free-tailed bats, like those of many insectivorous birds, allow individuals to remain active year-round because they follow their food supply (insects). Migrations of other bats (e.g., little brown bats [Myotis lucifugus],

Indiana bat [Myotis sodalis], gray myotis [Myotis grisescens], and Daubenton's bats [Myotis daubentonii]) are from summer habitats to hibernation sites. Underground sites (caves or abandoned mines) often are used for hibernation because they provide consistent above-freezing temperatures, often combined with high relative humidity. There are differences in hibernation site requirements (temperature, relative humidity) between species. In temperate areas, other species of bats (e.g., big brown bats, Eptesicus fuscus) use hibernation sites that are close to their summer roosts. Species like noctules hibernate in hollow trees.

Habitat

Bats can be found in virtually every habitat available from rainforests to deserts, montane forests to seasides. Bats have two basic habitat requirements: roosts, or places to spend the day or hibernate, and places to feed. The actual selection of roosting or foraging habitat depends on the species and the time of year.

Roosts of bats can be divided into four broad categories: hollows, crevices, foliage, and "other." Hollows, situations where the roosting bat hangs free by its hind feet, may be inside trees, rocks (caves, mines), buildings, or even birds' nests. An unexpected discovery was of round-eared bats (genus Tonatia, family Phyllostomidae) roosting in hollows in the bases of arboreal termite nests. Crevices and cracks, situations where the bats' venter is against one surface (and its back may be close to the other), occur in rocks, trees (under bark or in wood), and buildings. Bats roosting in foliage may hang from branches of trees, or among or under leaves. The "other" category includes bats roosting in unfurled leaves or in tents.

In the New World, three species of disk-winged bats (genus Thyroptera) roost in unfurled leaves of plants like heliconia or bananas. These roosts are available for about a day, because as the leaves grow they unfurl, obliging the bats to move regularly to new leaves. Suction disks on the wrists and ankles allow the bats to move about on the smooth leaf surfaces. In Africa, rufous mouse-eared bats (Myotis bocagei) and African banana bats (Pipistrellus nanus) roost in unfurled banana leaves. These bats lack suction disks.

In the Neotropics, India, and Southeast Asia, a number of species of bats roost in tents. Tents, usually leaves modified by biting, shelter bats from direct sunlight and rain. One or two species of short-nosed fruit bats (genus Cynopterus, family Pteropodidae), one species of plain-nosed bat (a yellow bat, genus Scotophilus), and about 18 species of New World leaf-nosed bats (family Phyllostomidae) use tent roosts. In the New World tropics, individual tents can last for several months and be occupied by a succession of bats. There is relatively little information about how bats build tents. In India, male lesser short-nosed fruit bats (Cynopterus brachyotis) build tents that are occupied by the tent-builder and groups of females and their dependent young.

Flattened skulls are examples of morphological specializations associated with roosting in narrow spaces or in roosts with small entrances. Good examples occur among free-tailed bats (genera Platymops, Sauromys, and Neoplatymops) that roost under rocks. Bamboo bats (plain-nosed bats, genus Tylonycteris) roost inside the hollows of bamboo stems. They enter these roosts through small holes made by bruchid beetles. These bats have very flattened skulls. Bats roosting on rough surfaces (e.g., under stones) may have wart-like projections on the forearms (e.g., Platymops, Neoplatymops). Species roosting on very smooth surfaces can have suction disks that are best developed in disk-winged bats, either from the New World (family Thyropteridae) or in Madagascar (family Myzopodidae).

Roosting bats readily exploit artificial structures as roosts. People may find bats roosting in their homes. Around buildings, bats can be found roosting in attics or eaves, behind shutters, even among the folds of rolled up patio umbrellas. Bats also roost in the expansion cracks of bridges, a famous example being the Congress Avenue Bridge in downtown Austin, Texas, United States. Bats frequently roost in abandoned mines and in active underground water conduit systems. Today, it is common for people to erect bat houses or bat boxes to provide additional roosting opportunities. Some bat houses have resident bats, while others do not. It remains to be determined if bat populations are limited in size by the availability of roosts.

Behavior

Among mammals, flight is a behavior unique to bats. Two other behaviors, echolocating and hanging upside down, are associated with bats, but not characteristic of them. Not all bats echolocate and not all bats use echolocation the same way. Furthermore, the echolocation calls of many species of bats are ultrasonic, which, by definition, is beyond the range of human hearing. But many species of bats echolocate with sounds readily audible to people.

Bats also use vocalizations in many social situations, and their social calls are often quite audible to people. Male fruit bats in Africa (African epauletted bats [genus Epomops]; epauletted fruit bats [genus Epomophorus]; hammer-headed fruit bats [Hypsignathus monstrosus]) call to attract females. Pipistrelles (Pipistrellus pipistrellus) use harsh-sounding calls to discourage others from feeding in small patches of insects. Greater spear-nosed bats (Phyllostomus hastatus) have group-specific screech calls that keep group members together. Researchers are only just beginning to explore the many ways in which bats use vocalizations.

When roosting, many bats hang upside down. This distinctive behavior makes take-off very easy: the bat just lets go, drops, and starts to fly. Hanging upside down may reflect specialization of the forelimbs as wings and attachments of wing membranes to the hind legs. Many other species of bats roost horizontally, their abdomens against the substrate. These bats, notably some species of free-tailed bats, are quite mobile on the ground, readily running or crawling. Compared to bats that probably never operate on the ground (e.g., some horseshoe bats), free-tailed bats have robust hind limbs, particularly thighbones (femora). Still other bats, for example, Spix's disk-winged bats (Thyroptera tricolor, family Thyropteridae), roost head-up.

Roosting upside down could present problems for hygiene. To relieve themselves (urinate or defecate), bats hanging upside down turn head up to minimize the chances of soiling themselves. Bats are very clean animals, spending time every day grooming. Grooming bats use their tongues, teeth, and toe claws. The claws are used to comb fur and teeth to remove groomed materials from the claws. Bats regularly lick their wings, reaching both sides by turning the wings inside out. Grooming bats also lick their fur. Bats roosting in groups may groom one another. Grooming also maintains coat condition in bats. Combing with the claws of the hind feet also may dislodge ectoparasites such as bat flies (families Streblidae, Nycteribiidae, order Diptera), fleas (order Siphonaptera), bedbugs (order Hemiptera), or lice (order Mallophaga). It is not clear if combing or licking affects mites, which can also be common ectoparasites of bats.

The level of behavioral interactions among roosting bats depends on the situation and the setting. Although a hibernaculum may harbor tens of thousands of individuals, the atmosphere is very quiet as the bats are asleep. This contrasts sharply with the levels of activity in other situations where many bats roost together. These roosts resound with vocalizations as neighbors jostle one another or vie for position. Some bats roost in large aggregations, for example, the several million Brazilian free-tailed bats roosting in Frio Cave in Texas. Many other bats roost alone or in small groups. Red and hoary bats roost alone or in small groups (a female and her dependent young), while Spix's disk-winged bats may roost alone or in groups of up to 10. It is not known where many of the 1,000 or so species of bats roost and there is no information about the social settings in which they operate.

Large aggregations of bats often attract predators because the small size of each bat is more than balanced by their large numbers. In many parts of the world, it is common to see birds of prey hunting among groups of bats emerging from (or returning to) roosts. The aerial chases are obvious, but on the ground other predators also exploit the rich patches of prey presented by large numbers of bats. The list includes mammals such as raccoons, skunks, foxes, civets, house cats, and even a variety of snakes. Although many predators take bats when the opportunity presents itself, few specialize on bats. Bat hawks (Macheirhamphus alcinus) are exceptions. These birds occur in Africa and Southeast Asia and feed heavily on bats. The same may be true of some bat-eating bats, but these are little-studied and details are lacking about the role bats play in their diets.

In many tropical species of bats, reproduction is an organizing influence in roosts. Typically, groups include a single adult male with a group of females and their young. In species forming larger colonies, for example, gray-headed flying foxes (Pteropus poliocephalus), males may be in contact with females only during the period of mating. In tropical species, groups of bachelor males, individuals not holding a territory suitable for breeding, are common (e.g., greater spear-nosed bats). In many temperate species, there is general isolation of males and females in summer, with the latter forming large nursery colonies, sites where they bear and raise young.

Feeding ecology and diet

The combination of small size and high metabolic rates means that bats consume enormous quantities of food. The heart of a flying little brown bat beats about 1,200 times a minute, reflecting the rate at which it burns energy. The same bat, having landed, has a heartbeat rate of less than 300 per minute. During seasons when they are active, little brown bats (like other bats) eat about half their weight in food every night. Nightly, fruit-eating bats may handle three times their weight in food. Lactating females have higher energy demands and nightly eat more than their weight in food.

Consumption of large amounts of food often means that bats eat a variety of prey species, whether insects or fruit. While some insectivorous bats may eat more soft (e.g., moths, flies) than hard (beetles, bugs) prey, there is little evidence of specialization by prey species. Insectivorous bats should not be thought of as consumers of mosquitoes. However, some smaller species, for example, Bodenheimer's pipistrelle (Pipistrellus bodenheimeri) from the Middle East, are known to regularly eat mosquitoes.

Bats normally do not eat food they find distasteful. The list of such prey includes at least arrowhead frogs and insects (like tiger moths) protected by unpleasant chemicals. While insectivorous and frugivorous bats learn to avoid food that has made them sick, this taste aversion does not occur in vampire bats. Whatever their food, bats have ways of avoiding ingesting indigestible materials. From insects, they typically bite off and drop wings and legs, from bats and birds, the wings, or cellulose fibers from leaves and fruit. Insects pass quickly through the digestive tracts of bats, 20–30 minutes for little brown bats. Weight reduction translates into lower costs of flight. There is no evidence that bat populations are limited in size by the availability of food.

Insect-eating is a recurring lifestyle in bats, from tropical South America to Alaska, northern Scandinavia to tropical Africa, Malaysia to Tasmania. While most species of insectivorous bats hunt flying insects and use echolocation to detect, track, and assess their targets, others (gleaners) take prey from surfaces such as foliage or the ground. Some bats such as New Zealand lesser short-tailed bats (Mystacina tuberculata) show great mobility on the ground where they search for food. Their menu includes animals as well as nectar and pollen.

Gleaning bats eat more than flying insects, consuming a wider range of prey, including walking insects and arthropods that do not fly. Larger gleaning bats take a wider range of prey by size than smaller ones. Gleaners such as pallid bats (Antrozous pallidus) from western North America eat large scorpions and centipedes, Jerusalem crickets, and even small pocket mice (genus Perognathus). Larger gleaning bats like the Australian false vampire bat (Macroderma gigas), spectral bat (Vampyrum spectrum), and large slit-faced bats (Nycteris grandis) also eat birds and even other bats.

Aerial-feeding bats tend to take smaller prey than gleaning bats. Among bats, it is rare to find aerial-feeding species taking vertebrate prey. The only known exception is the greater noctule (Nyctalus lasiopterus) from southern Europe. For at least part of the year, this 1.7 oz (50 g) bat preys on migrating birds.

Many species of animal-eating bats hunt along the water's surface. Called "trawlers," these bats (often in the family Vespertilionidae, the plain-nosed bats) have enlarged hind feet with which they gaff small fish. Mexican fishing bats (Myotis vivesi) from Baja California, and Rickett's big-footed bat (My-otis rickettii) from southern China are two examples. The best-known fishing bat is the greater bulldog bat (Noctilio leporinus, family Noctilionidae) from Central America, South America, and the West Indies. Other trawling bats do not have such large hind feet, but still take the occasional fish and even mosquito larvae. This list includes Daubenton's bat, pond bats (Myotis dasycneme), long-fingered bats (Myotis capaccinii), and large-footed myotis (Myotis adversus). Fish eating has been documented in two other bats, large slit-faced bats from Africa and greater false vampire bats (Megaderma lyra) from India and Southeast Asia. These bats do not have enlarged hind feet and are thought to catch their fish directly in their mouths—but to date, they have never been observed fishing.

Other bats eat frogs. Most is known about the fringe-lipped bat (Trachops cirrhosus, family Phyllostomidae) of the New World tropics. This bat listens for the songs male frogs use when courting females, and uses them to find prey. Fringe-lipped bats grab singing frogs directly in their mouths and eat all of them, starting from the head. In south-central Africa, large slit-faced bats prey heavily on frogs, but there is no indication of their using the frogs' songs to find their prey. The same is true of heart-nosed bats (Cardioderma cor) that occur further north in Africa, or of greater false vampire bats in India. Large slit-faced bats also eat frogs from the head down, invariably leaving one leg from the ankle, and the toes of the other foot.

Throughout the tropics, some species of bats get food from plants. Included on the menu are fruits, seeds, leaves, nectar, and pollen. In the Neotropics, the plant-visiting bats belong to the family Phyllostomidae. In the Old World tropics, the bats are in the family Pteropodidae. The two families show remarkable convergence in structure and behavior.

When eating fruit or leaves, bats typically chew their food thoroughly, all the while using their tongues to rub mashed food against prominent ridges on the roofs of their mouths (palates). During this process, the bats suck vigorously, removing the digestible parts of fruit and leaves before spitting out pellets of indigestible fibers.

Flower-visiting bats obtain sugars from nectar and proteins from pollen. Some Neotropical bat flowers have ultrasonic reflectors that guide nectar-feeding bats to nectar and pollen. By drinking their own urine, nectar-feeding bats create acidic conditions in their stomachs, ideal for digesting pollen. Some flower bats also obtain protein from insects.

The most infamous of bats are the blood-feeding vampires. There are three species: vampire bats, hairy-legged vampires (Diphylla ecaudata), and white-winged vampires (Diaemus youngii), all in the family Phyllostomidae. These bats only eat blood they obtain by making shallow bites on a prey's skin. The bites do not penetrate large blood vessels such as arteries or veins. Vampire bats use razor-sharp upper incisor teeth to remove a 0.2-in (5-mm) diameter divot of skin, creating a wound that bleeds readily. The bats enhance bleeding by the actions of their tongues and saliva. The saliva of vampire bats contains chemicals that inhibit the body's defenses against bleeding, including anticoagulants, anti-agglutinants, and chemicals that inhibit local vasoconstriction. Each vampire species appears to be a "one-stop shopper," getting each blood meal from one prey. The bats ingest about 2 tablespoonfuls (25 ml) of blood. Blood represents less than 10% of the mass of a bird or mammal, meaning that only victims larger than 4.4 lb (2 kg) are suitable hosts for vampire bats. Within two minutes of beginning to feed, vampire bats start to urinate. The urine consists mainly of the plasma from the current blood meal; therefore, it is very dilute. This is the bat's way of ridding itself of indigestible material.

Reproductive biology

In their life histories, bats are long-lived with low reproductive output. In the wild, individually marked bats (little brown bats and greater horseshoe bats [Rhinolophus ferrumequinum]) have survived more than 30 years, and females have the capacity to produce one young per year. In Britain, greater horseshoe females appear to have young only every second or third year. Furthermore, 70% of these bats born in any year do not survive their first winter. The litter size in bats is typically one, though a few species bear twins at least some of the time, and another few, notably red bats, may have litters of even three or four.

During birth, female bats turn heads-up to allow gravity to assist with the birth process. The ligaments holding the two halves of the pelvic girdle together are capable of great flexibility to allow birth. Young are born back-end first. Newborn bats are huge compared to their mothers: single young are 25–30% of their mother's postpartum mass. Young consume their own weight in milk every day and grow quickly. In some bats, for example, little brown bats (0.3 oz [8 g]) from North America, young reach adult size (forearm length) by about age 18 days. By then, their milk teeth have been replaced by adult dentition, they have started to fly, and insects first appear in their diets. Big brown bats (0.5 oz [15 g]) take about 28 days to reach this stage, and young vampire bats continue to nurse until they are six months old.

Young bats have huge appetites for milk, which is expensive to produce. Female bats roosting in nurseries with hundreds or even thousands of others use a combination of spatial memory, voice, and odor to recognize their own young. This ensures that her young receives enough milk and maximizes its chances of survival. The challenge of recognizing her young depends upon the female's situation. A red bat roosting only with her own young, has a different task than the Daubenton's bat roosting with tens of other Daubenton's bats. Female Brazilian free-tailed bats with nurseries numbering in the millions have a huge challenge in this regard—one they regularly meet and overcome.

Gestation periods in bats range from 60–100 days, and in most bats, fertilization follows copulation. Most species of bats are monestrus, with females having one reproductive event per year. Some tropical species are diestrus, have two reproductive events per year, and females in a few species (e.g., lesser-crested mastiff bats, Chaerephon pumila) may bear up to five young per year (one per estrous cycle).

Some species of bats extend the time between mating (typically polygynous) and birth. Sometimes fertilization follows copulation, but development or implantation of the fertilized egg is delayed, extending the gestation period. This occurs in some New World leaf-nosed bats (e.g., California leaf-nosed bats, Macrotus californicus) and plain-nosed bats (some populations of Schreiber's long-fingered bats). The other approach, known from plain-nosed bats and horseshoe bats, is to delay fertilization. In this case, females store sperm in the uterus after copulation. Storage can last from less than 20 days in some tropical species, to almost 200 days for north temperate forms. Delayed fertilization does not extend the gestation period. Extension of the time between mating and birth ensures that young are born at the most productive (in terms of food) time of the year.

Conservation

There are three categories of threats to the survival of bats: the general threat of habitat destruction, specific threats to habitats or habitat features important to bats, and threats to bats themselves.

General loss of habitat is the most pressing threat to the survival of most species of bats. Habitat loss typically reflects human population density either directly (urban sprawl) or indirectly (harvesting of resources that generates habitat destruction or disruption). Most species of bats occur in tropical areas, often those with rapidly increasing human populations. Extensive harvesting of rainforests occurs in many parts of the world, no doubt affecting the survival of bats. Detailed information is lacking about the distribution of many species of bats, and there is no accurate information about the sizes of their populations. Nor is it known which habitats or habitat features are vital to bats. This level of ignorance means that specific data cannot be provided about the impact of habitat loss on most of the world's bat species.

Some habitat disruption, specifically forestry or other operations that remove roosts used by bats, can imperil their survival. In other cases, programs to close caves or old mines in the interest of human safety can deprive bats of vital roost sites. In still other cases, habitat connections such as hedgerows are vital for bats like lesser horseshoe bats (Rhinolophus hipposideros) so that agricultural and other land-use practices can threaten the survival of some bats. In the United States, species of bats listed as Endangered experienced population declines as the result of disturbance in their cave roosts. For gray myotis, disturbances were to both nursery and hibernating colonies. For Indiana bats, disturbances were to hibernating animals. Bats are known to survive hibernation by going long periods without arousing. In little brown bats, each arousal from hibernation costs the energy that would support 60 days of hibernation. Survival of bat species that regularly hibernate depends on protecting them in their hibernacula.

Public perception can jeopardize bats. The association of bats with blood-feeding and diseases like rabies can make them the objects of persecution. Continued access to roosts for bats using buildings depends on human attitudes. When bats are perceived as dangerous, human occupants of their building roosts are more likely to take steps to evict them. If bats have moved into buildings in the wake of loss of natural roosts, then eviction may be tantamount to a death sentence. The level of protection accorded bats varies considerably. In the United Kingdom and much of Europe, bats enjoy considerable protection. In the United States and Canada, protection is not nearly as effective. In these countries, bats have more often been associated with rabies, coloring their status with respect to protection, people, and public health. In too many countries, bats have little practical or effective protection.

Their small size means that bats are rarely hunted by people, although in some parts of the world, bats are regular components of people's diets. On some South Pacific islands, hunting pressure has driven some species of bats to extinction. The situation in Guam, for example, demonstrates how the use of bats as festive food affected neighboring populations. After bat populations in Guam had been hunted to very low levels or to extinction, bats were then imported from as far away as the Philippines and New Guinea.

Significance to humans

For the most part, bats interact little with people although many species exploit human structures as roosts or feed in rich patches of food people create. But bat-people interactions are not entirely benign. Bats are commonly associated with two diseases that can afflict humans, histoplasmosis and rabies.

Histoplasmosis, a fungus disease of the lungs, can be contracted when people inhale the spores of the fungus Histo-plasma capsulatum. In warmer parts of the world, these spores are often associated with bat droppings. Their occurrence in bird droppings, including those of pigeons and chickens, is much more widespread. Although histoplasmosis typically gives flu-like symptoms, it can cause severe illness and even death. By wearing a mask that filters out particles larger than 10 microns (0.0004 in), people working in areas where they could encounter the spores of H. capsulatum can avoid exposure.

Rabies, a disease of the nervous system, is caused by a lyssavirus. Normally associated with mammals, rabies is usually fatal. Rabies virus tends to accumulate in the saliva of infected animals. Transmission usually occurs by biting when saliva with virus enters a wound. Today, rabies is an uncommon disease in the developed world. Elsewhere, rabies is usually associated with dogs and some other Carnivora and annually accounts for 30,000–70,000 human deaths.

Using molecular techniques, strains of rabies occurring in bats can be distinguished from those in other mammals. Human deaths from bat strains of rabies have been reported in the New World (27 cases in the United States and Canada between 1980 and 2000) and in Europe. In Australia, at least one human death was caused by another lyssavirus reported from bats. Biting appears to be the main route of infection, and strains of bat rabies have been found in other mammals. People bitten by bats should obtain post-exposure rabies vaccinations as soon as possible after the incident.

Images of bats abound in some human cultures, from depictions in Chinese art, on military emblems, and on coats of-arms. Bats may be positive or negative symbols, but often people do not know what they represent. It is obvious that at least some people have a long fascination with bats.

In China, the "wu fu" (five bats) is commonly portrayed on dishes and robes. In this case, the bats are arranged in a circle facing inward and they depict the five blessings: good health, long life, wealth, love of virtue, and a peaceful death. Chinese bats are often shown in red, the color of joy, and they may carry other positive symbols such as blossoms or fruit. Bats carrying swastikas are jarring images for those unfamiliar with the underlying symbolism. In some Chinese dialects, the word for swastika sounds the same as the word for 10,000. The bat image symbolizes a blessing, but the swastika image it carries turns it into 10,000 blessings.

The Maya god of the underworld, Zotz has the head of a vampire bat on a human body. Zotz usually carries a bleeding heart. Other Mayan portrayals of bats reflect knowledge of different species, from leaf-nosed bats (family Phyllostomidae) to ghost-faced bats (genus Mormoops, family Mormoopidae). The significance of these other bats to the Maya remains unclear, but the Maya unmistakably associated vampire bats with blood and the underworld. Further south in the area that today is northern Colombia and Venezuela, the Taironan people associated vampire bats with human fertility. A woman who had "been bitten by the bat" had started to menstruate. The connection here was to the fertility of women. In some areas of New Guinea, long penises make bats symbols of male fertility.

The connection between bats and blood is strong and recurring, but things are not what they seem in the area of vampires, bats, and blood. In the late nineteenth century, when he was writing Dracula, Bram Stoker wrote bats into the book, perhaps because blood-feeding bats were in the news. European explorers and naturalists had long been intrigued by blood-feeding bats and called them vampires. Indeed, many bats that eat fruit or animals are called vampyressa, vampyrops, or vampyrum, reflecting this fascination. In Africa, India, Southeast Asia, and Australia, there are false vampire bats.

In human folklore, vampires are people who come back from the dead to feed on the blood of living people. Folklore about vampires is widespread in parts of the world where it typically has nothing to do with bats. Vampire bats occur only in the New World tropics (parts of Central and South America). For Europeans, the name vampire goes from human folklore to the bat, not the other way around. Vampire bats, the blood-feeders, do not occur in Transylvania, Africa, India, or Australia.

Modern military units with bats on their emblems are often those associated with electronic warfare. The parallel is with bats and echolocation (or biosonar). At least one British unit has a tiger moth on its emblem, reflecting the defensive behavior of these moths: some tiger moths use acoustic signals to thwart the attacks of bats. The most famous bat in the world, the Bacardi bat, also has a military connection. This bat comes from Spain where it was associated with a victory of the Spanish over the Moors. On the eve of the battle, the bat that flew into the tent of James I of Aragon proved to be a good omen. The bat was then placed on the city of Valencia's coat of arms. This story trail ends up with a bat symbol on a bottle of rum.

But most of the 1,000 or so species of bats have little to do with people and vice versa. A few fruit-eating bats impact economically as pests of commercial crops, and vampire bats may be responsible for spreading rabies among livestock. On balance, other bats pollinate plants that are ecologically (and sometimes economically) important, while still others disperse seeds and play a vital role in reforestation. Insect-eating bats consume vast quantities of insects every year, including some agricultural pests.

Although bats are occasionally harvested as human food, and may be important economically as pollinators or agents of reforestation, they are rarely exploited economically. One important exception is the harvesting of bat guano, an activity that may disturb bats. In many parts of the world, there is a long tradition of harvesting bat guano for fertilizer. Today in Canada, some garden stores sell bat guano from the Philippines. In the past, bat guano has been a source of saltpeter for gunpowder. During the War of 1812, American forces depended upon bat guano for some of their gunpowder. Later, during the Civil War in the United States, Confederate forces were likewise partly dependent upon bats.

Resources

Books:

Allen, G. M. Bats. Cambridge: Harvard University Press, 1939

Altringham, J. D. Bats: Biology and Behaviour. London: Oxford University Press, 1996.

Barber, P. Vampires, Burial, and Death: Folklore and Reality. New Haven: Yale University Press, 1998.

Bates, P. J. J., and D. L. Harrison. Bats of the Indian Subcontinent, Sevenoaks, England: Harrison Zoological Museum, 1997.

Bonaccorso, F. J. Bats of Papua New Guinea. Washington: Conservation International, 1998.

Brosset, A. La Biologie des Cchiroptères. Paris: Masson et Cie, 1966.

Fenton, M. B. Communication in the Chiroptera. Bloomington: Indiana University Press, 1985. ——. Bats: Revised Edition. New York: Facts On File Inc., 2001.

Findley, J. S. Bats: A Community Perspective. Cambridge: Cambridge University Press, 1993.

Fleming, T. H., and A. Valiente-Banuet, eds. Columnar Cacti and Their Mutualists. Tucson: University of Arizona Press, 2002.

Greenhall, A. M., and U. Schmidt, eds. The Natural History of Vampire Bats. Boca Raton: CRC Press, 1988.

Griffin, D. R. Listening in the Dark. New Haven: Yale University Press, 1958.

Hill, J. E., and J. D. Smith. Bats: A Natural History. London: British Museum of Natural History, 1984.

Hutson, A. M., S. P. Mickelburgh, and P. A. Racey. Microchiropteran Bats—Global Status Survey and Conservation Action Plan. Gland, Switzerland: IUCN, 2001.

Jackson, A. C., and W. H. Wunner, eds. Rabies. New York: Academic Press, 2002.

Kunz, T. H., ed. Ecology of Bats. New York: Plenum Press, 1982.

Kunz, T. H., and M. B. Fenton, eds. Bat Ecology. Chicago: University of Chicago Press, 2003.

Marshall, A. G. The Ecology of Ectoparasitic Insects. London: Academic Press, 1981.

Neuweiler, G. Biology of Bats. Oxford: Oxford University Press, 2000.

Norberg, U. M. Vertebrate Flight, Mechanics, Physiology, Morphology, Ecology and Evolution. Berlin: Springer-Verlag, 1989.

Nowak, R. M. Walker's Mammals of the World, 6th edition. Baltimore: Johns Hopkins Press, 1999.

Popper, A. N., and R. R. Fay, eds. Hearing by Bats. New York: Springer-Verlag, 1995.

Ransome, R. D. The Natural History of Hibernating Bats. London: Christopher Helm, 1990.

Reid, F. A. A Field Guide to the Mammals of Central America and Southeast Mexico. New York: Oxford University Press, 1997.

Roeder, K. D. Nerve Cells and Insect Behavior, Revised Edition. Cambridge: Harvard University Press, 1967.

Schober, W., and E. Grimmberger. The Bats of Europe and North America. Neptune City, FL: TFH Publications Inc., 1997.

Taylor, P. J. Bats of Southern Africa. Pietermaritzberg, South Africa: University of Natal Press, 2000.

Tupinier, D. La Chauve-souris et l'Homme. Paris: Editions L'Harmattan, 1989.

Tuttle, M. D. America's Neighborhood Bats. Austin: University of Texas Press, 1988.

Wimsatt, W. A., ed. Biology of Bats, Volume 1. New York: Academic Press, 1970. ——, ed. Biology of Bats, Volume 2. New York: Academic Press, 1970. ——, ed. Biology of Bats, Volume 3. New York: Academic Press, 1977.

Periodicals:

Simmons, N. B., and J. H. Geisler. "Phylogenetic Relationships of Icaronycteris, Archaeonycteris, Hassianycteris, and Palaeochiropteryx with Comments on the Evolution of Echolocation and Foraging Strategies in Microchiroptera." Bulletin of the American Museum of Natural History 235 (1998): 1–182.

[Article by: Melville Brockett Fenton, PhD]


Any member of more than 1,100 species (order Chiroptera) of the only mammals to have evolved true flight. Their wings are evolutionary modification of the forelimbs, with greatly elongated fingers joined by a membrane that extends down the side of the body. Most bats use echolocation to orient themselves and find prey. Found worldwide, they are particularly abundant in the tropics. Wingspreads vary among species from 6 in. (15 cm) to 5 ft (1.5 m). Nearly all species roost during the day (in caves, crevices, burrows, building, or trees) and feed at night. Most are insectivores, consuming enough insects to affect the balance of insect populations. Others feed on fruit, pollen, nectar, or blood (vampire bats). Some may live more than 20 years. The guano of bats has long been used for agricultural fertilizer. See also free-tailed bat, fruit bat.

For more information on bat, visit Britannica.com.

Architecture: bat
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1. A piece of brick with one undamaged end; also called a “brickbat.”
2. A unit of batt insulation.
3. A piece of wood used as a brace.
4. A batten.

bat, 1


 
bat, winged mammal of the order Chiroptera, which includes 900-1,000 species classified in about 200 genera and 17 families. Bats range in size from a wingspread of over 5 ft (150 cm) to a wingspread of less than 2 in. (5 cm). They are found in nearly all parts of the world but are most numerous in the tropics; there are about 39 species in the United States. Most bats are economically valuable because of the large number of insects they consume.

The body of the bat is mouselike and usually covered with fine fur. The face varies greatly from one species to another; many species have complex appendages on the snout and projections, or false ears, in front of the true ears; the ears themselves are often very large and elaborately convoluted. These facial structures are part of the sensory apparatus that emits and receives sound vibrations.

Some bats are solitary, living in caves, crevices, hollow trees, or attics; other species are communal, with thousands or even millions of bats roosting together in a cave or on branches in a section of forest. In some species of communal bats, the entire colony leaves the roost together in the evening and returns together in the morning; in others, individuals come and go at different times. Bats of northern regions migrate, hibernate, or both in winter.

In most species, males and females do not associate except during the mating season. Females of most species bear a single young in the summer of each year. The young are then carried by the mothers for a few days, after which they are left in the roost when not nursing; they begin to fly in a few weeks. The life span of some bats is 20 years in captivity.

Special Characteristics

Bat Flight

Bats are the only mammals capable of true flight, that is, flight powered by muscular movement as distinct from gliding. The wing is a double membrane of skin stretched between the enormously elongated bones of four fingers and extending along the body from the forelimbs to the hind limbs and from there to the tail. The thumb is small, clawed, and free from the membrane. The hind limbs are small and may be rotated in such a way that the knees bend backward rather than forward, as in other mammals; this is presumably an adaptation for takeoff and flight. Bats at rest hang head down, grasping a twig or crevice with their clawed feet; they take off into flight from this position.

Echolocation

Nearly all bats are nocturnal and many live in caves; although they see well, they rely primarily on their highly developed hearing, using echolocation (sonar) to avoid collisions and to capture insects in flight. The bat emits high-pitched sounds (up to 100,000 hertz) that echo from objects it encounters; the echo provides the bat with information about the size, shape, and distance of the object. The rate at which bats emit these squeaks is sometimes as high as 200 per second. Blinded bats easily find their way through complex obstacle courses, but deafness leaves them helpless.

Types of Bats

The bat order is divided on anatomical grounds into two major divisions, or suborders: the Megachiroptera, or fruit bats, found only in the Old World tropics, and the Microchiroptera, or insect-eating bats, with a worldwide distribution. The fruit bats include the largest species of bat, the flying foxes, which may weigh 2 or 3 lbs (.9 to 1.4 kg). Their diet is confined almost entirely to fruit, nectar, and pollen. The insect-eating bats include the smallest bat species. Despite the name, some of these bats live wholly or largely on fruit; a large number eat insects and, in some cases, larger animals. Members of several species catch fish as they skim over water, and the South American vampire bats feed exclusively on blood.

The most common bats of the temperate Northern Hemisphere are the Old World horseshoe bats (Rhinolophus), characterized by one or two horseshoe-shaped facial appendages, the cosmopolitan little brown bats (Myotis), big brown bats, or serotines (Eptesicus), and pipistrelles (Pipistrellus). The last three, all represented by species in North America, belong to the plain-nosed bat family (Vespertilionidae), characterized by a lack of appendages on the snout.

There are over a dozen species of Myotis in North America; the common little brown bat, M. lucifugus, is distributed over the entire continent from Alaska and Labrador to the S United States. A colonial bat, it is found in many habitats, including houses. It is about 21/2 in. (6.3 cm) long without the tail and weighs about 1/4 oz (7 grams). The North American big brown bat, Eptesicus fuscus, of similar distribution, is about three times as heavy, with a wingspread of 12 in. (30 cm). Large, solitary North American bats of wide distribution are the hoary bat, Lasiurus cinereus, yellow-brown with silver frosting, and the red bat, L. borealis, which is a striking brick-red color. Both have soft, thick fur and roost in trees.

The freetail bats (family Molossidae) are a cosmopolitan group of communal bats characterized by a long tail extending well beyond the end of the tail membrane. Among them are the guano bats (Tadarida), which live in enormous colonies. Their excrement, called guano, accumulates in great quantities in their roosting places and is commercially valuable as fertilizer. Most New World freetail bats are tropical, but several are found in the S United States. One of these, the Mexican freetail bat (Tadarida brasiliensis), is noted for its colonies in the Carlsbad Caverns of New Mexico, numbering an estimated 250,000 to 500,000 individuals. When these bats leave the caves together it takes about 20 min for the entire column to make its exit. This family also includes the mastiff bats (Eumops), largest of the North American bats, with a wingspread of 18 in. (46 cm).

Classification

Bats are classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Chiroptera.

Bibliography

See R. W. Barbour and W. H. Davis, Bats of America (1969); W. A. Wimsatt, ed., Biology of Bats (2 vol., 1970).


There is an Oriental belief that the bat is specially adapted to occult uses. In the Tyrol, there is a folklore belief that the man who wears the left eye of a bat may become invisible, and in Hesse, he who wears the heart of a bat tied to his arm with red thread will always be lucky at cards.

Word Tutor: bat
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pronunciation

IN BRIEF: A small furry animal that flies. Also: A stout solid stick.

pronunciation We watched as the bat swooped down to eat the bugs just above the water.

Tutor's tip: A "bat" is a flying rodent. "Batt" refers to the matted cotton inside a quilt.

Wikipedia: Bat
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Bats
Fossil range: 52–0 Ma
Late Paleocene – Recent
Townsend's big-eared bat, Corynorhinus townsendii
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Infraclass: Eutheria
Superorder: Laurasiatheria[1]
Order: Chiroptera
Blumenbach, 1779
Suborders

See article

Bats are flying mammals in the order Chiroptera (pronounced /kaɪˈrɒptərə/). The forelimbs of bats are webbed and developed as wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums and colugos, glide rather than fly, and only for short distances. Bats do not flap their entire forelimbs, like birds, but instead flap their spread out digits[2], which are very long and covered with a thin membrane or patagium. Chiroptera comes from two Greek words, cheir (χειρ) "hand" and pteron (πτερον) "wing."

There are about 1,100 bat species worldwide, which represent about 20 percent of all classified mammal species.[3] About 70 percent of bats are insectivores. Most of the rest are frugivores, or fruit eaters. A few species feed from animals other than insects. Bats are present throughout most of the world and perform vital ecological roles such as pollinating flowers and dispersing fruit seeds. Many tropical plants depend entirely on bats for the distribution of their seeds.

Bats range in size from Kitti's Hog-nosed Bat measuring 29–33 mm (1.14–1.30 in) in length and 2 g (0.07 oz) in mass,[4] to the Giant Golden-crowned Flying-fox which has a wing span of 1.5 m (4 ft 11 in) and weighs approximately 1.2 kg (3 lb).

Contents

Fossil bats

There are few fossilized remains of bats as they are terrestrial and light-boned. An Eocene bat, Onychonycteris finneyi, was found in the 52-million-year-old Green River Formation in South Dakota (US) in 2004 and was added as a new genus and placed in a new family when published in Nature in 2008.[5] It had characteristics indicating that it could fly, yet the well-preserved skeleton showed that the cochlea of the inner ear lacked development needed to support the greater hearing abilities of modern bats. This provided evidence that flight in bats developed well before echolocation. The team that found the remains of this species, named Onychonycteris finneyi, recognized that it lacked ear and throat features present not only in echolocating bats today, but also in other known prehistoric species.

Fossil remains of another Eocene bat, Icaronycteris, were found in 1960.

The appearance and flight movement of bats 52.5 million years ago were different from those of bats today. Onychonycteris had claws on all five of its fingers, whereas modern bats have at most two claws appearing on two digits of each hand. It also had longer hind legs and shorter forearms, similar to climbing mammals that hang under branches such as sloths and gibbons. This palm-sized bat had broad, short wings suggesting that it could not fly as fast or as far as later bat species. Instead of flapping its wings continuously while flying, Onychonycteris likely alternated between flaps and glides while in the air. Such physical characteristics suggest that this bat did not fly as much as modern bats do, rather flying from tree to tree and spending most of its waking day climbing or hanging on the branches of trees.[6]

Classification and evolution

Bats are mammals. Sometimes they are mistakenly called "flying rodents" or "flying rats". And they can also be mistaken for insects and birds. There are two suborders of bats:

Not all megabats are larger than microbats. The major distinctions between the two suborders are:

  • Microbats use echolocation: megabats do not with the exception of Rousettus and relatives.
  • Microbats lack the claw at the second toe of the forelimb.
  • The ears of microbats do not close to form a ring: the edges are separated from each other at the base of the ear.
  • Microbats lack underfur: they are either naked or have guard hairs.

Megabats eat fruit, nectar or pollen while most microbats eat insects; others may feed on the blood of animals, small mammals, fish, fruit, pollen or nectar. Megabats have a well-developed visual cortex and show good visual acuity, while microbats rely on echolocation for navigation and finding prey.

The phylogenetic relationships of the different groups of bats have been the subject of much debate. The traditional subdivision between Megachiroptera and Microchiroptera reflects the view that these groups of bats have evolved independently of each other for a long time, from a common ancestor that was already capable of flight. This hypothesis recognised differences between microbats and megabats and acknowledged that flight has just evolved only in one order of mammals. Most molecular biological evidence supports the view that bats form a single or monophyletic group.[7]

Common Pipistrelle, Pipistrellus pipistrellus

Researchers have proposed alternate views of chiropteran phylogeny and classification, but more research is needed.

Genetic evidence indicates that megabats originated during the early Eocene and should be placed within the four major lines of microbats.

Consequently, two new suborders have been proposed. The new suborder Yinpterochiroptera includes the Pteropodidae or megabat family as well as the Rhinolophidae, Megadermatidae, and Rhinopomatidae families. The new suborder Yangochiroptera includes all the remaining families of bats. This relationship combines echolocating and non-echolocating bats, and it is not clear whether the ancestor of bats possessed laryngeal echolocation which the bats of Pteropodiae subsequently lost or if this ability evolved twice.[8]

In addition to Yinpterochiroptera and Yangochiroptera, the names Pteropodiformes and Vespertilioniformes have also been proposed for these suborders.[9][10] Under this new proposed nomenclature, the suborder Pteropodiformes includes all extant bat families more closely related to the genus Pteropus than the genus Vespertilio, while the suborder Vespertilioniformes includes all extant bat families more closely related to the genus Vespertilio than to the genus Pteropus.

In the 1980s, a hypothesis based on morphological evidence was offered which stated that the Megachiroptera evolved flight separately from the Microchiroptera. The so-called flying primates theory proposed that when adaptations to flight are removed, the Megachiroptera are allied to primates by anatomical features that are not shared with Microchiroptera. One example is that the brains of megabats show a number of advanced characteristics which link them to primates. Although recent genetic studies support the monophyly of bats[11], debate continues as to the meaning of available genetic and morphological evidence.[citation needed].

Little fossil evidence is available to help map the evolution of bats, since their small, delicate skeletons do not fossilize very well. However a Late Cretaceous tooth from South America resembles that of an early Microchiropteran bat. The oldest known definitely identified bat fossils, such as Icaronycteris, Archaeonycteris, Palaeochiropteryx and Hassianycteris, are from the early Eocene period, 52.5 million years ago[7]. These fossil bats were already very similar to modern microbats. Archaeopteropus, formerly classified as the earliest known megachiropteran, is now classified as a microchiropteran.

Bats were formerly grouped in the superorder Archonta along with the treeshrews (Scandentia), colugos (Dermoptera), and the primates, because of the apparent similarities between Megachiroptera and such mammals. Genetic studies have now placed bats in the superorder Laurasiatheria along with carnivorans, pangolins, odd-toed ungulates, even-toed ungulates, and cetaceans[1].

"Chiroptera" from Ernst Haeckel's Kunstformen der Natur, 1904

The traditional classification of bats is:

Megabats primarily eat fruit or nectar. In New Guinea, they are likely to have evolved for some time in the absence of microbats. This has resulted in some smaller megabats of the genus Nyctimene becoming (partly) insectivorous to fill the vacant microbat ecological niche. Furthermore, there is some evidence that the fruit bat genus Pteralopex from the Solomon Islands, and its close relative Mirimiri from Fiji, have evolved to fill some niches that were open because there are no nonvolant or non-flying mammals in those islands.

Anatomy

Skeleton of a Greater Mouse-eared Bat (Myotis myotis))

Echolocation

In emitting high-pitched sounds and listening to resultant echoes, the process used in sonar technology, bats are able to locate prey and nearby objects. This is known as echolocation, an ability they share with dolphins and whales.

Two groups of moths exploit a bat sense to echolocate: tiger moths produce ultrasonic signals to warn the bats of that moths are chemically-protective or aposematic. This was once thought to be the biological equivalent of "radar jamming", but this theory has yet to be confirmed. The moths Noctuidae have a hearing organ called a tympanum which responds to an incoming bat signal by causing the moth's flight muscles to twitch erratically, sending the moth into random evasive manoeuvres.

Eyes

Although the eyes of most microbat species are small and poorly developed, leading to poor visual acuity, none of them are blind. Vision is used to navigate microbats especially for long distances when beyond the range of echolocation. It has even been discovered that some species are able to detect ultraviolet light. They also have a high quality sense of smell and hearing. Bats hunt at night to avoid competition with birds, and travel large distances at most 800 km, in their search for food.[2]

Wings

Thermographic image of a bat using trapped air as insulation.

The finger bones of bats are much more flexible than those of other mammals. One reason is that the cartilage in their fingers lacks calcium and other minerals nearer the tips, increasing their ability to bend without splintering. The cross-section of the finger bone is also flattened compared to circular cross section of human finger bone have, and is very flexible. The skin on their wing membranes has more elasticity and so can stretch much more than other mammals.

The wings of bats are much thinner than those of birds, so bats can manoeuvre more quickly and more accurately than birds. It is also delicate, ripping easily.[12] However the tissue of the bat's membrane is able to regrow, such that small tears can heal quickly.[12][13] The surface of their wings is equipped with touch-sensitive receptors on small bumps called Merkel cells, found in most mammals including humans, similarly found on our finger tips. These sensitive areas are different in bats as each bump has a tiny hair in the center,[14] making it even more sensitive and allowing the bat to detect and collect information about the air flowing over its wings, thereby providing feedback to the bat to change its shape of its wing to fly more efficiently.[14] Some bats like the little brown bat can use this dexterious ability where it is able to drink in mid air.[15] Other bats such as the flying fox or fruit bat gently skim the water's surface, then land nearby to lick water from their chest fur.[16] An additional kind of receptor cell is found in the wing membrane of species that use their wings to catch prey. This receptor cell is sensitive to the stretching of the membrane.[14] The cells are concentrated in areas of the membrane where insects hit the wings when the bats capture them.

Other

The teeth of microbats resemble insectivorans. They are very sharp to bite through the hardened armor of insects or the skin of fruit. Mammals have one-way valves in veins to prevent the blood from flowing backwards, but bats also have one-way valves in arteries.

One species of bat has the longest tongue of any mammal relative to its body size. This is beneficial to them in terms of pollination and feeding their long narrow tongues can reach deep into the long cup shape of some flowers. When their tongue retracts, it coils up inside their rib cage.[17]

Reproduction

Newborn Common Pipistrelle, Pipistrellus pipistrellus
Colony of Mouse-eared bats, Myotis myotis

Most bats have a breeding season, which is in the spring for species living in a temperate climate. Bats may have one to three litters in a season, depending on the species and on environmental conditions such as the availability of food and roost sites. Females generally have one offspring at a time, this is maybe a result of the mother's need to fly to feed while pregnant. Female bats nurse their youngster until it has grown nearly to adult size, this is because a young bat cannot forage on its own until its wings are fully developed.

Female bats use a variety of strategies to control the timing of pregnancy and the birth of young, to make delivery coincide with maximum food ability and other ecological factors. Females of some species have delayed fertilization, in which sperm are stored in the reproductive tract for several months after mating. In many such cases, mating occurs in the fall, and fertilization does not occur until the following spring. Other species exhibit delayed implantation, in which the egg is fertilized after mating, but remains free in the reproductive tract until external conditions become favorable for giving birth and caring for the offspring. In yet another strategy, fertilization and implantation both occur but development of the fetus is delayed until favorable conditions prevail. All of these adaptations result in the pup being born during a time of high local production of fruit or insects.

At birth wings are too small to be used for flight. Young microbats become independent at the age of 6 to 8 weeks, megabats do not until they are four months old.

A single bat can live over 20 years, but the bat population growth is limited by the slow birth rate.[18]

Behaviour

Most microbats are nocturnal and are active at twilight. A large portion of bats migrate hundreds of kilometres to winter hibernation dens[19], some pass into torpor in cold weather, rousing and feeding when warm weather allows for insects to be active[20]. Others retreat to caves for winter and hibernate for six months.[20] Bats rarely fly in rain as the rain interferes with their echo location, and they are unable to locate their food.

The social structure of bats varies, with some bats leading a solitary life and others living in caves colonized by more than a million bats[21]. The fission-fusion social structure is seen among several species of bats. The term "fusion" refers to a large numbers of bats that congregate together in one roosting area and "fission" refers to breaking up and the mixing of subgroups, where individual bats switching roosts with others and often ending up in different trees and with different roostmates.

Studies also show that bats make all kinds of sounds to communicate with others. Scientists in the field have listened to bats and have been able to identify some sounds with some behaviour bats will make after the sounds are made[21].

70% of bat species are insectivorous, locating their prey by means of echolocation. Of the remainder, most feed on fruits[22]. Only three species sustain themselves with blood. Some species even prey on vertebrates: these are the leaf-nosed bats (Phyllostomidae) of Central America and South America, and the two bulldog bat (Noctilionidae) species, which feed on fish. At least two species of bat are known to feed on bats: the Spectral Bat, also known as the American False Vampire bat, and the Ghost Bat of Australia[22]. One species, the Greater Noctule bat, catches and eats small birds in the air.

Threats

A little brown bat with white nose syndrome.

White nose syndrome

White nose syndrome is a condition associated with the deaths of more than a million bats in the Northeastern United States.[23] The disease is named after a white fungus found growing on the muzzles, ears, and wings of some afflicted bats, but it is not known if the fungus is the primary cause of the disease or is merely an opportunistic infection.[24] Mortality rates of 90-100% have been observed in some caves.[24] At least six species of hibernating bats are affected, including the endangered Indiana bat.[25] Because the affected species have a long lifespan and a low birth rate of only about one offspring per year, it is not expected that populations will recover quickly.[25]

Wind turbines

The lungs of bats are typical mammalian lungs, and unlike the lungs of birds it has been hypothesized they are more sensitive to sudden air pressure changes in their immediate vicinity such as wind turbines, and are more liable to rupture them to explain their apparent higher rate of mortality rate with such devices.[26] Bats suffer a higher death rate than birds in the neighborhood of wind turbines[27][28][29] ; since there are no signs of external trauma, the cause has been hypothesized to be a greater sensitivity to sudden pressure fluctuations in the mammalian lung than in that of birds.[30] In addition, it has been suggested that bats are attracted to these structures, perhaps seeking roosts, and thereby increasing the death rate.[26]

Role in the transmission of pathogens

A big brown bat (Eptesicus fuscus) approaches a wax moth (Galleria mellonella), which serves as the control species for the studies of the tiger moths. The moth is only "semi-tethered," allowing it to fly evasively.

Bats are natural reservoir for a large number of zoonotic pathogens[31] including rabies,[32] severe acute respiratory syndrome (SARS),[33] Henipavirus (ie. Nipah virus and Hendra virus)[34] and possibly ebola virus[35].[36] Their high mobility, broad distribution, and social behaviour (communal roosting, fission-fusion social structure) make bats favourable hosts and vectors of disease. Many species also appear to have a high tolerance for harbouring pathogens and often do not develop disease while infected.

In regions where rabies is endemic, only 0.5% of bats carry the disease. However, of the few cases of rabies reported in the United States every year not caused by dogs, most are caused by bat bites.[37] Those that are rabid may be clumsy, disoriented, and unable to fly, which makes it more likely that they will come into contact with humans. Although one should not have an unreasonable fear of bats, one should avoid handling them or having them in one's living space, as with any wild animal. If a bat is found in living quarters near a child, mentally handicapped person, intoxicated person, sleeping person, or pet, the person or pet should receive immediate medical attention for rabies. Bats have very small teeth and can bite a sleeping person without being felt. There is evidence that it is possible for the bat rabies virus to infect victims purely through airborne transmission, without direct physical contact of the victim with the bat itself.[38][39]

If a bat is found in a house and the possibility of exposure cannot be ruled out, the bat should be sequestered and an animal control officer called immediately, so that the bat can be analysed. This also applies if the bat is found dead. If it is certain that nobody has been exposed to the bat, it should be removed from the house. The best way to do this is to close all the doors and windows to the room except one to the outside. The bat should soon leave.

Due to the risk of rabies and also due to health problems related to their faecal droppings (guano), bats should be excluded from inhabited parts of houses. The Center for Disease Control and Prevention provides full detailed information on all aspects of bat management, including how to capture a bat, what to do in case of exposure, and how to bat-proof a house humanely.[40] In certain countries, such as the United Kingdom, it is illegal to handle bats without a license.

Where rabies is not endemic, as throughout most of Western Europe, small bats can be considered harmless. Larger bats can give a nasty bite. They should be treated with the respect due to any wild animal.

The bat in heraldry

Valencia city's arms.
Palma de Mallorca's arms.
Fraga coat of arms.
Burgee of the Royal Valencia Yacht Club.

The bat is sometimes used as a heraldic symbol. The coats of arms of certain cities in eastern Spain, like Valencia, Palma de Mallorca and Fraga have the bat over the shield. Formerly the Barcelona city coat of arms also had a bat crowning it, but the bat has been removed in the present-day versions.

The heraldic use of the bat in Valencia, Catalonia and the Balearic Islands has its origins in a winged dragon (vibra or vibria) which featured in King James I of Aragon's helmet or cimera reial. This is the most widely accepted theory, although there is also a legend that says that due to the intervention of a bat, King James was able to win a crucial battle against the Saracens that allowed him to win Valencia for his kingdom.

The use of the bat as a heraldic symbol is prevalent in the territories of the former Crown of Aragon and it is little used elsewhere. However, it can be found in a few places, as in the coats of arms of the city of Albacete, in Spain, as well as the town of Montchauvet (Yvelines), in France.

Certain Spanish soccer clubs including Valencia CF and Levante UD use bats in their badges.

The Burgee of the Royal Valencia Yacht Club (Reial Club Nàutic de València) displays a bat on a golden field in its center.

Cultural aspects

The bat is sacred in Tonga and is often considered the physical manifestation of a separable soul[citation needed]. Bats are closely associated with vampires, who are said to be able to shapeshift into bats, fog, or wolves. Bats are also a symbol of ghosts, death, and disease. Among some Native Americans, such as the Creek, Cherokee and Apache, the bat is a trickster spirit.

Bat. Moche Culture 100 A.D. Larco Museum Lima, Peru.

Chinese lore claims the bat is a symbol of longevity and happiness, and is similarly lucky in Poland and geographical Macedonia and among the Kwakiutl and Arabs. The bat is also a heraldic animal of the Spanish autonomous community of Valencia.

Very large bat house, Tallahassee, Florida, United States

Pre-Columbian cultures associated animals with gods and often displayed them in art. The Moche people depicted bats in their ceramics.[41]

In Western Culture, the bat is often a symbol of the night and its foreboding nature. The bat is a primary animal associated with fictional characters of the night, both villains like Dracula and heroes like Batman. The association of the fear of the night with the animal was treated as a literary challenge by Kenneth Oppel, who created a best selling series of novels, beginning with Silverwing, which feature bats as the central heroic figures much as anthropomorphized rabbits were the central figures to the classic novel Watership Down.

An old wives' tale has it that bats will entangle themselves in people's hair. One likely source of this belief is that insect-eating bats seeking prey may dive erratically toward people, who attract mosquitoes and gnats, leading the squeamish to believe that the bats are trying to get in their hair.

"Nightwing," a work of art by Dale Whistler located in Austin, Texas, United States

In the United Kingdom all bats are protected under the Wildlife and Countryside Acts, and even disturbing a bat or its roost can be punished with a heavy fine.

In Sarawak, Malaysia bats are protected species under the Wildlife Protection Ordinance 1998 (see Malaysian Wildlife Law). The large Naked bat (see Mammals of Borneo) and Greater Nectar bat are consumed by the local communities.

Bats can be a tourist attraction. The Congress Avenue Bridge in Austin, Texas is the summer home to North America's largest urban bat colony, an estimated 1,500,000 Mexican free-tailed bats, which eat an estimated 10,000 to 30,000 pounds of insects each night. An estimated 100,000 tourists per year visit the bridge at twilight to watch the bats leave the roost.

Bats in Mesoamerican mythology

In Mesoamerican mythology during the Classic-Contemporary period, bats symbolized the land of the dead, which was considered to be the underworld[1]. They also symbolized destruction and decay. Bats may have symbolized in this way because they fly only at night and dwell in caves during the daytime and are associated with human skulls and bones by classic Maya ceramists. Central Mexicans sometimes depicted bats having snouts that looked like sacrificial knives and carrying human head in the Postclassic era[42]. Bat images were engraved onto funerary urns and were emphasized with large claws and round ears by Zapotecs. They were commonly associated with death[2]. The depiction of bats on funeral urns and goods took on some the characteristics of the jaguar which was and still is another entity of the night and the underworld. There have also been instances where bats are portrayed next to other unseemly animals including scorpions and other nocturnal animals such as owls.

A gigantic, life-size ceramic bat-man has been discovered and dug up from the Templo Mayor. The Templo Mayor is located in the center of the Mexica capital of Tenochtitlan. Known as a god of death, this statue has the clawed feet and hands of a bat, but the body of a man. The statue's human-like eyes bulged out from the bat-like head, making the Zapotec images very realistic and living. It was said that in the 1930s the Kaqchikel Maya proclaimed that the bat was the Devil’s provider. Kaqchikel would leave the Devil’s underworld home and collect blood from the animals to be used for scrumptious meals to feed the Devil. “In the myths, the beast of prey and the animal that is preyed upon play two significant roles. They represent two aspects of life—the aggressive, killing, conquering, creating aspect of life, and the one that is the matter or, you might say, the subject matter”[43]. In the Devil’s underworld, dead sinners would work off their sins in order to get to heaven, indicating that the bat was too a sinner and worked under the authority of the Devil[44].

In Oaxacan mythology

Oaxacans believe that the jealousy of the bat in wanting birds' feathers that gently fit their bodies led him to become nocturnal. The bat feeling isolated and undesirable spoke to God after that he complained he was extremely cold. God, fair and just turned to birds in the animal kingdom and asked if they would show compassion and donate a feather to the bat so the feathers would keep him warm. The birds all agreed, and began to pluck one feather from their bodies to give to the bat. With all of the feathers, the bat became much magnificent looking than all birds, even able to spread color to the night sky. During daylight, the bat created rainbows that reflected vibrant colors from the sun. The bat soon became overly arrogant and conceited, due having this new and improved look. The birds grew tired of the bat’s self conceitedness and glorification, and so decided to fly up to heaven and speak to God to do something. The birds informed to God of the bat's behaviour, God was surprised and so decided to take a look himself. When on Earth, God called on the bat to show him what he was doing. The bat began to fly across the light blue sky, where one by one each feather began to fall out, uncovering the bat’s natural ugly looking body. The bat became ashamed and distressed of his appearance after all feathers came off, missing the beautiful, plentiful feathers that he had, that he decided to hide in caves during the day. He would only come out during the night, searching high and low for the feathers to avoid embarrassment that he will not be seen during his search.[44]

East Nigerian mythology

According to a particular East Nigerian tale, the bat developed its nocturnal habits after causing the death of his partner the bush-rat. The bat and the bush-rat would share activities such as rummaging through the grass and trees, hunting, talking and bonding during the day. When at night, the bat and the bush-rat would alternate in cooking duties cooking what was caught, and eat together. It appeared to a dedicated partnership, however the bat hated the bush-rat immensely. The bush rat always found the bat’s soup more appetising so when eating dinner one night asked the bat why the soup tasted better than his own and also asked how it was made. The bat agreed to show him how to make it the next day but instead was forming a malicious plan. Next day as bat prepared his soup, the bush-rat came, greeting him and asked if he could be shown what was agreed yesterday. Earlier, the bat has found a pot looking exactly like the one he used usually, but it held warm water and so decided to use this instead. The bat explained to the bush-rat that to make his soup, he had to boil himself prior to serving the soup where sweetness and flavor of the soup came from the flesh. The bat jumped in the pot seemingly excited, with the bush-rat mesmerised. After a few minutes the bat climbed out and while the bush-rat was distracted, switched pots. The bat then served his soup out of the soup pot, both tasted it. Over anxious and eager, the bush-rat, jumped into the pot of warm water. He stayed much longer in the pot dying in the process. When the bush-rat’s wife returned that night to find her husband dead, she wept and ran to the chief of the land's house telling him about what happened and what she was sure what the bat had done. In hearing this, the chief became angry, ordering for the immediate arrest of the bat. It just so happened that the bat was flying over the house and overheard what was just said. He quickly went into hiding high up in a tree. When the chief’s men went looking for the bat, he could not be found. The search to arrest the bat carried on over several days, but still could not be found. The bat needed to eat, so flew out of hiding every night to hunt for food to escape of being arrested. This, according to Eastern Nigeria mythology, is why bats only fly at night.[45].

Artificial roosts

Many people put up bat houses to attract bats just like many people put up birdhouses to attract birds. Reasons for this vary, but mostly center around the fact that bats are the primary nocturnal insectivores in most if not all ecologies. Bat houses can be made from scratch, made from kits, or bought ready made. Plans for bat houses exist on many web sites, as well as guidelines for designing a bat house[46]. Some conservation societies are giving away free bat houses to bat enthusiasts worldwide[citation needed].

A bat house constructed in 1991 at the University of Florida campus next to Lake Alice in Gainesville, Florida has a population of over 100,000 free-tailed bats.[47]

In Britain, British hardened field defences of World War II have been converted to make roosts for bats. Pillboxes that are well dug-in and thick walled are naturally damp and provide a stable thermal environment that is required by bats that would otherwise hibernate in caves. With a few minor modifications, suitable pillboxes can be converted to artificial caves for bats.[48][49]

Again in the UK, purpose-built bat houses are occasionally built when existing roosts are destroyed by developments such as new roads; one such has been built associated with bat bridges on the new (2008) A38 Dobwalls bypass.[citation needed]

See also

References

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  36. ^ Charles Q. Choi (March 2006). "Going to Bat". Scientific American: pp. 24, 26. http://www.sciam.com/article.cfm?id=going-to-bat. Retrieved 2007-12-29. "Long known as vectors for rabies, bats may be the origin of some of the most deadly emerging viruses, including SARS, Ebola, Nipah, Hendra and Marburg."  Note: This could be considered a lay summary of the various scientific publications cited in the preceding sentence.
  37. ^ Gibbons, Robert V.; Charles Rupprecht (2000). "Twelve Common Questions About Human Rabies and Its Prevention" (PDF). Infectious Diseases in Clinical Practice (Lippincott Williams & Wilkins) 9: 202–207. doi:10.1097/00019048-200009050-00005. http://www.cdc.gov/rabies/docs/12_questions_rabies.pdf. Retrieved 2007-12-29. "Excluding dog bites that occurred outside of the country, 22 of the 31 (71%) human cases of rabies in the United States since 1980 have been associated with bat rabies virus variants.".  Note: the 71% figure in the quote would be for the 20 year period from 1980 to c.2000.
  38. ^ Constantine, Denny G. (April 1962). "Rabies transmission by nonbite route" (PDF). Public Health Reports (Public Health Service) 77 (4): 287–289. PMID 13880956. http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1914752&blobtype=pdf. Retrieved 2007-12-29. "These findings support consideration of an airborne medium, such as an aerosol, as the mechanism of rabies transmission in this instance.". 
  39. ^ Messenger, Sharon L.; Jean S. Smith and Charles E. Rupprecht (2002-09-15). "Emerging Epidemiology of Bat-Associated Cryptic Cases of Rabies in Humans in the United States". Clinical Infectious Diseases 35 (6): 738–747. doi:10.1086/342387. PMID 12203172. http://www.journals.uchicago.edu/doi/abs/10.1086/342387. Retrieved 2007-12-29. "Cryptic rabies cases are those in which a clear history of exposure to rabies virus cannot be documented, despite extensive case‐history investigation. Absence of a documented bite history reflects inherent difficulties in obtaining accurate animal‐contact information.... <gap> Thus, absence of bite‐history data does not mean that a bite did not occur.". 
  40. ^ Center for Disease Control's website on bats and rabies
  41. ^ Berrin, Katherine & Larco Museum. The Spirit of Ancient Peru:Treasures from the Museo Arqueológico Rafael Larco Herrera. New York: Thames and Hudson, 1997.
  42. ^ Kay Almere Read and Jason J. Gonzalez. 2000. Mesoamerican Mythology. Oxford University Press. pp. 132
  43. ^ Joseph Cambell and Bill Moyers. 1988. The Power of Myth. Doubleday. pp. 91
  44. ^ a b Kay Almere Read and Jason J. Gonzalez. 2000. Mesoamerican Mythology. Oxford University Press. pp. 132-134
  45. ^ Arnott, Kathleen. 1962. African Myths and Legends. Oxford University Press. Pp. 150-152
  46. ^ http://web.archive.org/web/20020124162143/www.batcon.org/
  47. ^ Nordlie, Tom (2001-10-29). "Backyard Bat Houses Promote Pest Control, Says UF Expert". UF News. University of Florida. pp. 30. Archived from the original on 2001-11-30. http://web.archive.org/web/20011030203049/http://www.napa.ufl.edu/2001news/backyardbats.htm. Retrieved 2007-06-18. "... an example of good bat management. When a large colony of Brazilian free-tailed bats roosting in a campus stadium caused odor problems, university officials installed the massive house, which now holds about 100,000 bats and has become a local landmark." 
  48. ^ "Protecting and managing underground sites for bats (pdf), see section 6.4." (PDF). http://www.eurobats.org/documents/pdf/AC9/Doc_AC9_15_Protecting_underground_sites.pdf. Retrieved 2006-05-18. 
  49. ^ "Pillbox converted to bat retreat, BBC website". http://news.bbc.co.uk/1/hi/england/4885642.stm. Retrieved 2006-05-18. 
General references
  • Greenhall, Arthur H. 1961. Bats in Agriculture. A Ministry of Agriculture Publication. Trinidad and Tobago.
  • Nowak, Ronald M. 1994. " Walker's BATS of the World". The Johns Hopikins University Press, Baltimore and London.
  • John D. Pettigrew's summary on Flying Primate Hypothesis
  • Altringham, J.D. 1998. Bats: Biology and Behaviour. Oxford: Oxford University Press.
  • Dobat, K.; Holle, T.P. 1985. Blüten und Fledermäuse: Bestäubung durch Fledermäuse und Flughunde (Chiropterophilie). Frankfurt am Main: W. Kramer & Co. Druckerei.
  • Fenton, M.B. 1985. Communication in the Chiroptera. Bloomington: Indiana University Press.
  • Findley, J.S. 1995. Bats: a Community Perspective. Cambridge: Press Syndicate of the University of Cambridge.
  • Fleming, T.H. 1988. The Short-Tailed Fruit Bat: a Study in Plant-Animal Interactions. Chicago: The University of Chicago Press.
  • Kunz, T.H. 1982. Ecology of Bats. New York: Plenum Press.
  • Kunz, T.H.; Racey, P.A. 1999. Bat Biology and Conservation. Washington: Smithsonian Institution Press.
  • Kunz, T.H.; Fenton, M.B. 2003. Bat Ecology. Chicago: The University of Chicago Press.
  • Neuweiler, G. 1993. Biologie der Fledermäuse. Stuttgart: Georg Thieme Verlag.
  • Nowak, R.M. 1994. Walker's Bats of the World. Baltimore: The Johns Hopkins University Press.
  • Richarz, K. & Limbruner, A. 1993. The World of Bats. Neptune City: TFH Publications.
  • Twilton, B. 1999. My Life as The Bat. Liverpool Hope University press

Further reading

External links

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Translations: Bat
Top

Dansk (Danish)
1.
n. - boldtræ, bat
v. tr. - slå, slå til
v. intr. - være inde

idioms:

  • go to bat for someone    støtte, forsvare
  • off one's own bat    på eget initiativ, på egen hånd
  • right off the bat    på stående fod

2.
n. - flagermus

idioms:

  • have bats in your belfry    have rotter på loftet
  • like a bat out of hell    med ekspresfart, med fanden i hælene
  • old bat    gammel krage

3.
v. tr. - blinke med

idioms:

  • doesn't bat an eyelid    ikke fortrække en mine, ikke så meget som blinke

4.
n. - narrebriks

Nederlands (Dutch)
knuppel, vleermuis, slaghout, kabaal, oplichterij, racket, knuppelen, knip(pe)ren, batten, slaan, bataljon

Français (French)
1.
n. - (Sport, etc) batte, raquette, (fig) initiative, coup
v. tr. - frapper (avec une batte, une raquette, etc), cogner, flanquer un coup à (fam), (US, fig) discuter (à bâtons rompus)
v. intr. - manier la batte, être à la batte

idioms:

  • at bat    à la batte
  • bat about    discuter à bâtons rompus (fam)
  • bat around    discuter à bâtons rompus (fam)
  • bat for    intervenir, intercéder (en faveur de qn)
  • bat something about    discuter de qch à bâtons rompus (fam)
  • bat something around    discuter de qch à bâtons rompus (fam)
  • go to bat for    intervenir en faveur de
  • off one's own bat    de sa propre initiative
  • right off the bat    sur-le-champ

2.
n. - (Zool) chauve-souris

idioms:

  • bats in the belfry    avoir une araignée au plafond
  • like a bat out of hell    s'enfuir comme si l'on avait le diable à ses trousses
  • old bat    vieille bique (fam)

3.
v. tr. - battre (des paupières)

idioms:

  • not bat an eyelid    ne pas sourciller, ne pas broncher

4.
n. - (GB) allure, (US) fête, bombe, bringue (fam)

Deutsch (German)
1.
n. - Schläger
v. - schlagen

idioms:

  • at bat    Schlagmann sein
  • bat about    umherstreifen, debattieren
  • bat around    umherstreifen, debattieren
  • bat for    für jemanden eintreten
  • bat something about    umherstreifen, durchstreifen
  • bat something around    umherstreifen
  • go to bat for    für jemanden eintreten
  • off one's own bat    auf eigene Faust
  • right off the bat    sofort

2.
n. - Fledermaus

idioms:

  • bats in the belfry    einen Dachschaden haben
  • like a bat out of hell    als sei der Teufel hinter ihm her
  • old bat    (abwert) alte Schrulle

3.
v. - blinzeln

idioms:

  • not bat an eyelid    mit den Augenlidern blinzeln od. zwinkern

4.
n. - Sauferei, Einkaufsorgie

Ελληνική (Greek)
n. - νυχτερίδα, ρόπαλο, ρακέτα πινγκ-πονγκ, βάτα, καστόρι, απότομο χτύπημα, γλέντι, ξεφάντωμα, παίκτης με το ρόπαλο (στο κρίκετ)
v. - χτυπώ, κοπανάω (με ρόπαλο), πεταρίζω, παίζω τα βλέφαρα

idioms:

  • doesn't bat an eyelid    μένει ατάραχος
  • go to bat for someone    προστρέχω, σπεύδω σε βοήθεια κάποιου
  • have bats in your belfry    είσαι θεόμουρλος
  • like a bat out of hell    σαν αστραπή, ταχύτατος
  • off one's own bat    από μόνος μου, από δική μου πρωτοβουλία
  • old bat    παλιός παίκτης
  • right off the bat    αμέσως, χωρίς κανένα δισταγμό

Italiano (Italian)
randellare, mazza, pipistrello

idioms:

  • as blind as a bat    cieco come una talpa
  • doesn't bat an eyelid    non batte ciglio
  • go to bat for someone    difendere qualcuno
  • have bats in your belfry    essere strambo
  • like a bat out of hell    come un fulmine
  • off one's own bat    di propria iniziativa
  • right off the bat    di primo acchito

Português (Portuguese)
n. - morcego (m), bastão (m), bebedeira (f), pá (m)
v. - rebater, espancar

idioms:

  • as blind as a bat    cego como um morcego
  • doesn't bat an eyelid    não impressionar-se com algo surpreendente ou desagradável que acontece
  • go to bat for someone    sair em defesa de alguém
  • have bats in your belfry    ser bobo
  • like a bat out of hell    rapidamente (dirigir um veículo)
  • off one's own bat    sem ajuda
  • right off the bat    na primeira tentativa, de cara

Русский (Russian)
ударять битой, бита, летучая мышь, ракетка

idioms:

  • as blind as a bat    слепой как крот
  • doesn't bat an eyelid    и ухом не ведет
  • go to bat for someone    помочь, поддержать, вступиться
  • have bats in your belfry    быть слегка помешанным
  • like a bat out of hell    поспешно, на большой скорости
  • off one's own bat    по собственной инициативе
  • old bat    старуха (оскорбительно)
  • right off the bat    первым делом, немедленно

Español (Spanish)
1.
n. - raqueta, paleta, pala de tenis de mesa
v. tr. - batear, golpear
v. intr. - batear, golpear

idioms:

  • at bat    turno de batear (en el béisbol)
  • bat about    viajar mucho, viajar porque sí
  • bat around    discutir, ponderar
  • bat for    acudir a la ayuda o defensa de alguien, interceder
  • bat something about    discutir por gusto
  • bat something around    discutir o ponderar algo
  • go to bat for    acudir a la ayuda o defensa de alguien, ir en ayuda de
  • off one's own bat    por su cuenta
  • right off the bat    inmediatamente, sin más deliberación

2.
n. - murciélago

idioms:

  • bats in the belfry    estar mal de la azotea
  • like a bat out of hell    muy rápidamente
  • old bat    vieja, arpía

3.
v. tr. - pestañear, parpadear

idioms:

  • not bat an eyelid    no mover ni un párpado

4.
n. - juerga

Svenska (Swedish)
n. - fladdermus, läderlapp, käring, racket, slagträ
v. - slå, (kricket) vara inne (som slagman)

中文(简体)(Chinese (Simplified))
1. 球棒, 短棍, 球拍, 击球, 用球棒打, 击球率达..., 挥打, 成功率达..., 用球棒打球, 轮到击球

idioms:

  • go to bat for someone    为某人辩护
  • off one's own bat    独立地
  • right off the bat    立刻, 马上, 毫不犹豫地, 一下子

2. 蝙蝠

idioms:

  • have bats in your belfry    发痴, 异想天开, 发疯
  • like a bat out of hell    如飞地, 不顾一切地冲出来
  • old bat    老太婆

3. 眨

idioms:

  • doesn't bat an eyelid    没有合眼, 全然不流露感情

4. 外国话

中文(繁體)(Chinese (Traditional))
1.
n. - 外國話

2.
n. - 球棒, 短棍, 球拍, 擊球
v. tr. - 用球棒打, 擊球率達..., 揮打, 成功率達...
v. intr. - 用球棒打球, 輪到擊球

idioms:

  • go to bat for someone    為某人辯護
  • off one's own bat    獨立地
  • right off the bat    立刻, 馬上, 毫不猶豫地, 一下子

3.
v. tr. - 眨

idioms:

  • doesn't bat an eyelid    沒有合眼, 全然不流露感情

4.
n. - 蝙蝠

idioms:

  • have bats in your belfry    發痴, 異想天開, 發瘋
  • like a bat out of hell    如飛地, 不顧一切地衝出來
  • old bat    老太婆

한국어 (Korean)
1.
n. - 배트, 타격[수]
v. tr. - 배트로 ~을 치다, ~의 타율을 기록하다
v. intr. - 공을 치다, 타자가 되다, 돌진하다

idioms:

  • go to bat for someone    변호하다, 지지하다

2.
n. - 박쥐, 매춘부

idioms:

  • have bats in your belfry    지능이 모자라는, 괴짜다
  • like a bat out of hell    굴 밖의 박쥐처럼

3.
v. tr. - 눈을 깜박거리다

4.
n. - 구어, 속어

日本語 (Japanese)
n. - バット, ラケット, 打撃, 強い一撃, 強打, 打者, コウモリ
v. - バットで打つ, 打って進める, 打席に立つ, 打つ, こん棒で殴る, またたかせる

idioms:

  • doesn't bat an eyelid    一睡もしない, 少しも動じない
  • go to bat for someone    人の援助に乗り出す
  • like a bat out of hell    猛スピードで
  • right off the bat    直ちに

العربيه (Arabic)
‏(الاسم) مضرب الكرة, خفاش الليل, وطواط (فعل) يضرب الكرة‏

עברית (Hebrew)
n. - ‮מחבט, מחזיק המחבט, כלי דמוי מחבט להדרכת מטוס במסלול‬
v. tr. - ‮חבט, היכה‬
v. intr. - ‮חבט, היכה‬
n. - ‮עטלף‬
v. tr. - ‮מיצמץ, קרץ‬
n. - ‮הילולה‬


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