Open main menu

Wikipedia β

Bats are mammals of the order Chiroptera[a] whose forelimbs form webbed wings; they are the only mammals naturally capable of true and sustained flight. Other mammals said to fly, such as flying squirrels, gliding possums, and colugos, can only glide for short distances. Bats are less efficient flyers than birds, but are more manoeuvrable, using their very long spread-out digits which are covered with a thin membrane or patagium.

Bat
Temporal range: EocenePresent
Common vampire batHorseshoe batGreater short-nosed fruit batEgyptian fruit batMexican free-tailed batGreater mouse-eared batWikipedia-Bats-001-v01.jpg
About this image
Clockwise from top right: Egyptian fruit bat (Rousettus aegyptiacus), mass of Mexican free-tailed bats (Tadarida brasiliensis), greater mouse-eared bat (Myotis myotis), greater short-nosed fruit bat (Cynopterus sphinx), horseshoe bat (Rhinolophus ferrumequinum), common vampire bat (Desmodus rotundus).
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Clade: Scrotifera
Order: Chiroptera
Blumenbach, 1779
Suborders
Bat range.png
Worldwide distribution of bat species

Bats are the second largest order of mammals (after the rodents), and comprise about 20% of all classified mammal species worldwide, with about 1,240 bat species divided into two suborders: the less specialised and largely fruit-eating megabats, including flying foxes, and the highly specialised and echolocating microbats. About 70% of bat species are insectivores, and most of the rest are frugivores (fruit-eaters). A few species feed on animals other than insects; the vampire bats feed on blood. Almost all bats are nocturnal, and many roost in caves or other refuges; zoologists wonder whether bats have these behaviours to escape predators, but the evidence remains equivocal.

Bats are present throughout most of the world, with the exception of extremely cold regions. They perform the vital ecological roles of pollinating flowers and dispersing fruit seeds; many tropical plant species depend entirely on bats for the distribution of their seeds. Bats are economically important, as they consume insect pests, reducing the need for pesticides. The smallest bat, and arguably the smallest extant mammal, is Kitti's hog-nosed bat, which is 29–34 mm (1.14–1.34 in) in length, 15 cm (5.91 in) across the wings and 2–2.6 g (0.07–0.09 oz) in mass. The largest bats are a few species of Pteropus (fruit bats or flying foxes) and the giant golden-crowned flying fox, Acerodon jubatus, with weights of up to 1.6 kg (4 lb) and wingspan up to 1.7 m (5 ft 7 in).

Bat dung has been mined as guano from caves and used as fertiliser. Bats are natural reservoirs of many pathogens including those of rabies; since they are highly mobile, social, and long-lived, they can readily spread diseases. They are sometimes numerous enough to serve as tourist attractions, and are used as food across Asia and the Pacific Rim. In many cultures, bats are popularly associated with darkness, death, witchcraft and malevolence.

Contents

Etymology

An older English name for bats is flittermouse, which matches their name in other Germanic languages (for example German Fledermaus and Swedish fladdermus), related to the fluttering of wings. Middle English had bakke, most likely cognate with Old Swedish natbakka ("night-bat"), which may have undergone a shift from -k- to -t- (to Modern English bat) influenced by Latin blatta, "moth, nocturnal insect".[2][3] The name "Chiroptera" derives from Ancient Greek: χείρcheir, "hand"[4] and πτερόν – pteron, "wing".[1][5]

Taxonomy and evolution

Classification

Bats are placental mammals. After rodents, they are the largest order of mammals, and make up about 20% of mammal species.[6] There are 1,240 bat species, traditionally classified as two suborders: Megachiroptera (megabats), and the Microchiroptera (microbats/echolocating bats).[7] Not all megabats are larger than microbats.[8] Microbats use echolocation, but megabats do not, apart from the genus Rousettus.[9] Megabats have a claw on the second finger of the forelimb.[10][11] The external ears of microbats do not close to form a ring; the edges are separated from each other at the base of the ear.[11] Megabats eat fruit, nectar, or pollen. Most microbats eat insects; others may feed on fruit, nectar, pollen, fish, frogs, small mammals, or the blood of animals. Megabats have well-developed visual cortices and good visual acuity, while microbats rely on echolocation for navigation and finding prey.[7] They were formerly grouped in the superorder Archonta, along with the treeshrews (Scandentia), colugos (Dermoptera), and primates.[12]

 
"Chiroptera" from Ernst Haeckel's Kunstformen der Natur, 1904
 
The early Eocene fossil microchiropteran Icaronycteris, from the Green River Formation

Fossil and molecular evidence

The delicate skeletons of bats do not fossilise well, and only an estimated 12% of the bat fossil record is complete at the genus level.[14] Most of the oldest known bat fossils were already very similar to modern microbats. Archaeopteropus, formerly classified as the earliest known megachiropteran, is now considered to be a microchiropteran.[15] The extinct bats Palaeochiropteryx tupaiodon and Hassianycteris kumari are the first fossil mammals whose coloration has been discovered: both were reddish-brown.[16][17]

Modern genetic evidence places bats in the superorder Laurasiatheria, with its sister taxon as Fereuungulata, which includes carnivorans, pangolins, odd-toed ungulates, even-toed ungulates, and cetaceans.[18][19][20][21][22] One study places Chiroptera as a sister taxon to odd-toed ungulates (Perissodactyla).[23]

Boreoeutheria
Laurasiatheria

 Eulipotyphla (hedgehogs, shrews, moles, solenodons) 


Scrotifera

 Chiroptera (bats)  


Fereuungulata
Ferae

 Pholidota (pangolins)  



 Carnivora (cats, hyenas, dogs, bears, seals)     



Euungulata

 Perissodactyla (horses, tapirs, rhinos)  



 Cetartiodactyla (camels, ruminants, whales)    







 Euarchontoglires (primates, colugos, treeshrews, rodents, rabbits)  



Cladogram showing Chiroptera within Laurasiatheria, with Fereuungulata as its sister taxon according to a 2013 study[22]

Genetic evidence indicates that megabats originated during the early Eocene, and should be placed within the four major lines of microbats.[22] Two new suborders have been proposed; Yinpterochiroptera includes the Pteropodidae, or megabat family, as well as the families Rhinolophidae, Hipposideridae, Craseonycteridae, Megadermatidae, and Rhinopomatidae.[24] Yangochiroptera includes the other families of bats (all of which use laryngeal echolocation), a conclusion supported by a 15-base-pair deletion in BRCA1 and a seven-base-pair deletion in PLCB4 present in all Yangochiroptera and absent in all Yinpterochiroptera.[24] One phylogenomic study showed that the two new proposed suborders were supported by analyses of thousands of genes.[22]

Chiroptera

Megachiroptera

Pteropodidae (megabats)  




Microchiroptera

Rhinolophoidea

Megadermatidae (false vampire bats)  





Craseonycteridae (Kitti's hog-nosed bat)  



Rhinopomatidae (mouse-tailed bats)  





Hipposideridae (Old World leaf-nosed bats)  



Rhinolophidae (horseshoe bats)  







Yangochiroptera




Miniopteridae (long winged bat)  







Noctilionidae (fisherman bats)  



Mormoopidae (Pteronotus)  







Mystacinidae (New Zealand short-tailed bats)  



Thyropteridae (disc-winged bats)





Furipteridae  



Mormoopidae (Mormoops)  





Phyllostomidae (New World leaf-nosed bats)  








Molossidae (free-tailed bats)  



Emballonuridae (sac-winged bats)  






Myzopodidae



Emballonuridae (Taphozous)  





Natalidae (funnel-eared bats)  



Vespertilionidae (vesper bats)  












Internal relationships of the Chiroptera, excluding Nycteridae and Cistugidae according to a 2011 study[13]

The phylogenetic relationships of the different groups of bats have been the subject of much debate. The traditional subdivision into Megachiroptera and Microchiroptera reflected the view that these groups of bats had evolved independently of each other for a long time, from a common ancestor already capable of flight. This hypothesis recognised differences between microbats and megabats and acknowledged that flight has only evolved once in mammals. Most molecular biological evidence supports the view that bats form a single or monophyletic group.[15]

In the 1980s, a hypothesis based on morphological evidence stated the Megachiroptera evolved flight separately from the Microchiroptera. The flying primate hypothesis proposed that, when adaptations to flight are removed, the Megachiroptera are allied to primates by anatomical features not shared with Microchiroptera. For example, the brains of megabats have advanced characteristics. Although recent genetic studies strongly support the monophyly of bats,[15] debate continues about the meaning of the genetic and morphological evidence.[25]

The 2003 discovery of an intermediate fossil bat from the 52 million year old Green River Formation, Onychonycteris finneyi, indicates that flight evolved before echolocative abilities.[26][27] Onychonycteris had claws on all five of its fingers, whereas modern bats have at most two claws 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 short, broad 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 probably alternated between flaps and glides in the air.[15] This suggests that this bat did not fly as much as modern bats, but flew from tree to tree and spent most of its time climbing or hanging on branches.[28] The distinctive features of the Onychonycteris fossil also support the hypothesis that mammalian flight most likely evolved in arboreal locomotors, rather than terrestrial runners. This model of flight development, commonly known as the "trees-down" theory, holds that bats first flew by taking advantage of height and gravity to drop down on to prey, rather than running fast enough for a ground-level take off.[29][30]

The molecular phylogeny is controversial, as it points to a microbat paraphyly, which implies that some seemingly unlikely transformations occurred. The first is that laryngeal echolocation evolved twice in bats, once in Yangochiroptera and once in the rhinolophoids.[31] The second is that laryngeal echolocation had a single origin in Chiroptera, was subsequently lost in the family Pteropodidae (all megabats), and later evolved as a system of tongue-clicking in the genus Rousettus.[32] Analyses of the sequence of the vocalization gene FoxP2 were inconclusive on whether laryngeal echolocation was lost in the pteropodids or gained in the echolocating lineages.[33] Echolocation probably first derived in bats from communicative calls. The Eocene bats Icaronycteris and Palaeochiropteryx had cranial adaptations suggesting an ability to detect ultrasound. This may have been used at first mainly for communicative purposes or to map out their surroundings in their gliding phase, only being used to forage on the ground for insects or among vegetation. After the adaptation of flight was established, it may have been refined to target flying prey by echolocation.[28] Bats may have evolved echolocation through a shared common ancestor, in which case it was then lost in the Old World fruit bats, only to be regained in the horseshoe bats; or, echolocation evolved independently in both the Yinpterochiroptera and Yangochiroptera lineages.[34] Analyses of the hearing gene Prestin seem to favour the idea that echolocation developed independently at least twice, rather than being lost secondarily in the pteropodids.[35]

Anatomy and physiology

Slow-motion and normal speed of Egyptian fruit bats flying

Flight

Bats are the only mammals that can truly fly, as opposed to gliding mammals such as the flying squirrel.[36] The fastest bat, the Mexican free-tailed bat (Tadarida brasiliensis), can achieve a ground speed of 160 kilometres per hour (99 mph).[37]

Bones

 
A preserved fruit bat showing how the skeleton fits inside its skin

The finger bones of bats are much more flexible than those of other mammals, owing to their flattened cross-section and to low levels of calcium near their tips. The elongation of bat digits, a key feature required for wing development, is due to the upregulation of bone morphogenetic proteins (Bmps). During embryonic development, the gene controlling Bmp signalling, Bmp2, is subjected to increased expression in bat forelimbs—resulting in the extension of the manual digits. This crucial genetic alteration helps create the specialised limbs required for powered flight. The relative proportion of extant bat forelimb digits compared with those of Eocene fossil bats have no significant differences, suggesting that bat wing morphology has been conserved for over 50 million years.[38] During flight, the bones undergo bending and shearing stress; the bending stresses felt are smaller than in terrestrial mammals, but the shearing stress is larger. The wing bones of bats have a slightly lower breaking stress point than those of birds.[39]

As in other mammals, and unlike in birds, the radius is the main component of the forearm. Bats have five elongated digits, which all radiate around the wrist. The thumb points forward and supports the leading edge, and the other digits support the tension held in the wing membrane. The second and third digits go along the wing tip, allowing the wing to be pulled forward against aerodynamic drag, without having to be thick as in pterosaur wings. The fourth and fifth digits go from the wrist to the trailing edge, and repel the bending force caused by air pushing up against the stiff membrane.[40] Due to their flexible joints, bats are more manoeuvrable and more dexterous than gliding mammals.[41]

Bats are adapted to roosting, hanging upside down from their feet.[42] The femurs are attached at the hips in a way that allows them to bend outward and upward in flight. The ankle joint can flex to allow the trailing edge of the wings to bend downwards. This does not permit many movements other than hanging or clambering up trees.[40] Most megabats roost with the head tucked towards the belly, whereas most microbats roost with the neck curled towards the back. This difference is reflected in the structure of the cervical vertebrae in the two groups, which are clearly distinct.[42] Tendons allow bats to lock their feet closed when hanging from a roost. Muscular power is needed to let go, but not to grasp a perch or when holding on.[43]

Wings

The wings of bats are much thinner and consist of more bones than the wings of birds, allowing bats to manoeuvre more accurately than the latter, and fly with more lift and less drag.[44] By folding the wings in toward their bodies on the upstroke, they save 35 percent energy during flight.[45] Bats save energy by drawing in their wings on the upstroke. The membranes are delicate, tearing easily,[46] but can regrow, and small tears heal quickly.[46][47] The surface of the wings is equipped with touch-sensitive receptors on small bumps called Merkel cells, also found on human fingertips. These sensitive areas are different in bats, as each bump has a tiny hair in the centre, making it even more sensitive and allowing the bat to detect and adapt to changing airflow; the primary use is to judge the most efficient speed to fly at, and possibly also to avoid stalls.[48] Insectivorous bats may also use tactile hairs to help perform complex manoeuvres to capture prey in flight.[41]

 
Wing membranes (patagia) of Townsend's big-eared bat, Corynorhinus townsendii

The patagium is the wing membrane; it is stretched between the arm and finger bones, and down the side of the body to the hind limbs and tail.[49] This skin membrane consists of connective tissue, elastic fibres, nerves, muscles, and blood vessels. The muscles keep the membrane taut during flight.[49] The skin on the body of the bat, which has one layer of epidermis and dermis, as well as hair follicles, sweat glands and a fatty subcutaneous layer, is very different from the skin of the wing membrane. The patagium is an extremely thin double layer of epidermis; these layers are separated by a connective tissue centre, rich with collagen and elastic fibres. The membrane has no hair follicles or sweat glands, except between the fingers.[48][50] For bat embryos, apoptosis only affects the hindlimbs, while the forelimbs retain webbing between the digits that forms into the wing membranes.[51] Unlike birds, whose stiff wings deliver bending and torsional stress to the shoulders, bats have a flexible wing membrane which can only resist tension. To achieve flight, a bat exerts force inwards at the points where the membrane meets the skeleton, so that an opposing force balances it on the wing edges perpendicular to the wing surface. This adaptation does not permit bats to reduce their wingspan as birds do, which means they cannot travel over long distances as birds can.[40]

Nectar- and pollen-eating bats can hover, in a similar way to hummingbirds. The sharp leading edges of the wings can create vortices which provide lift. The vortex may be stabilised by the animal changing its wing curvatures.[52]

Gas exchange

With its extremely thin membranous tissue, a bat's wing can significantly contribute to the organism's total gas exchange efficiency.[50] Because of the high energy demand of flight, the bat's body meets those demands by exchanging gas through the patagium of the wing. When the bat has its wings spread it allows for an increase in surface area to volume ratio. The surface area of the wings is about 85% of the total body surface area, suggesting the possibility of a useful degree of gas exchange.[50] The subcutaneous vessels in the membrane lie very close to the surface and allow for the diffusion of oxygen and carbon dioxide.[53]

Internal systems

Bats have an efficient circulatory system. They seem to make use of particularly strong venomotion, a rhythmic contraction of venous wall muscles. In most mammals, the walls of the veins provide mainly passive resistance, maintaining their shape as deoxygenated blood flows through them, but in bats they appear to actively support blood flow back to the heart with this pumping action.[54][55] Since their bodies are relatively small and lightweight, bats are not at risk of blood flow rushing to their heads when roosting.[56]

Bats possess highly adapted lung systems to cope with the demands of powered flight, an energetically taxing activity which requires a large throughput of oxygen to be sustained. In bats, the relative alveolar surface area and pulmonary capillary blood volume are larger than in most other small quadrupedal mammals.[57] Because of the restraints of the mammalian lungs, bats cannot maintain high-altitude flight.[40]

The digestive system of bats has varying adaptations depending on the species of bat and its diet. As in other flying animals, food is processed quickly and effectively to keep up with the energy demand. Insectivorous bats may have certain digestive enzymes to better process insects, such as chitinase to break down chitin, which is a large component of insects.[58] Vampire bats, probably due to their diet of blood, are the only vertebrates that do not have the enzyme maltase, which breaks down malt sugar, in their intestinal tract. Nectivorous and frugivorous bats have more maltase and sucrase enzymes than insectivorous, to cope with the higher sugar contents of their diet.[59]

The adaptations of the kidneys of bats vary between diets. Carnivorous bats consume large amounts of protein and can output concentrated urine, whereas frugivorous bats lack that ability and instead have kidneys adapted for electrolyte-retention due to their low-electrolyte diet.[59]

Senses

Echolocation

Bats emit ultrasonic sounds to produce echoes. By comparing the outgoing pulse with the returning echoes, the brain and auditory nervous system can produce detailed images of the bat's surroundings. This allows bats to detect, localise, and classify their prey in darkness. Bat calls are some of the loudest airborne animal sounds, and can range in intensity from 60 to 140 decibels.[60][61] Microbats use their larynx to create ultrasound, and emit it through the mouth and sometimes the nose. The latter is most pronounced in the horseshoe bats (Rhinolophus spp.). Microbat calls range in frequency from 14,000 to well over 100,000 Hz, extending beyond the range of human hearing (between 20 and 20,000 Hz).[62]

 
Principle of bat echolocation: orange is the call and green is the echo

In low-duty cycle echolocation, bats can separate their calls and returning echoes by time. They have to time their short calls to finish before echoes return. Bats contract their middle ear muscles when emitting a call, so they can avoid deafening themselves. The time interval between the call and echo allows them to relax these muscles, so they can hear the returning echo.[63] The delay of the returning echoes allows the bat to estimate the range to their prey.[62]

In high-duty cycle echolocation, bats emit a continuous call and separate pulse and echo in frequency. The ears of these bats are sharply tuned to a specific frequency range. They emit calls outside this range to avoid deafening themselves. They then receive echoes back at the finely tuned frequency range by taking advantage of the Doppler shift of their motion in flight. The Doppler shift of the returning echoes yields information relating to the motion and location of the bat's prey. These bats must deal with changes in the Doppler shift due to changes in their flight speed. They have adapted to change their pulse emission frequency in relation to their flight speed so echoes still return in the optimal hearing range.[64]

In addition to echolocating prey, bat ears are sensitive to the fluttering of moth wings, the sounds produced by tymbalate insects, and the movement of ground-dwelling prey, such as centipedes and earwigs. The complex geometry of ridges on the inner surface of bat ears helps to sharply focus echolocation signals, and to passively listen for any other sound produced by the prey. These ridges can be regarded as the acoustic equivalent of a Fresnel lens, and exist in a large variety of unrelated animals, such as the aye-aye, lesser galago, bat-eared fox, mouse lemur, and others.[65][66][67] Bats can estimate the elevation of their target using the interference patterns from the echoes reflecting from the tragus, a flap of skin in the external ear.[62]

 
The tiger moth (Bertholdia trigona) can jam bat echolocation[68][69]

By repeated scanning, bats can mentally construct an accurate image of the environment in which they are moving and of their prey.[70] Some species of moth have exploited this, such as the tiger moths which produces aposematic ultrasound signals to warn bats that they are chemically protected.[68][69] Other moth species can produce signals to jam bat echolocation. Many moth species 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.[71][72][73]

Vision

The eyes of most microbat species are small and poorly developed, leading to poor visual acuity, but no species is blind.[74] Most microbats have mesopic vision, meaning that they can only detect light in low levels, whereas other mammals have photopic vision, which allows colour vision. Microbats may use their vision for orientation and while travelling between their roosting grounds and feeding grounds, as echolocation is only effective over short distances. Some species can detect ultraviolet (UV). As the bodies of some microbats have distinct coloration, they may be able to discriminate colours.[36][75][76][77]

Megabat species often have eyesight as good as, if not better than, human vision. Their eyesight is adapted to both night and daylight vision, including some colour vision.[77]

Magnetic field

Microbats possess magnetoreception, in that they have a high sensitivity to Earth's magnetic field, similar to birds. Microbats use a polarity-based compass, meaning that they differentiate north from south, unlike birds which use the strength of the magnetic field to differentiate latitudes, which may be used in long-distance travel. Since microbats generally have poor eyesight, it is thought they use a magnetite-based method for orientation.[78][79]

Thermoregulation

 
Thermographic image of a bat using trapped air as insulation

Most bats are homeothermic, the exception being the Vespertilionidae, the Rhinolophidae and the Miniopteridae which extensively use heterothermy. Compared to other mammals, bats have a high thermal conductivity. The wings are filled with blood vessels, and lose body heat when extended. At rest, they may wrap their wings around themselves to trap a layer of warm air. Smaller bats generally have a higher metabolic rate than larger bats, and so need to consume more food in order to maintain homeothermy.[80]

Bats may avoid flying during the day to prevent overheating in the sun, since their dark wing-membranes absorb solar radiation. Bats may not be able to dissipate heat if the ambient temperature is too high.[81] Unlike birds which have air sacs or other mammals which have sweat glands, bats have no means to cool themselves by evaporation, though they may use saliva to cool themselves in an emergency.[40]

Bats also possess a system of sphincter valves on the arterial side of the vascular network that runs along the edge of their wings. When fully open, these allow oxygenated blood to flow through the capillary network across the wing membrane; when contracted, they shunt flow directly to the veins, bypassing the wing capillaries. This allows bats to control how much heat is exchanged through the flight membrane, allowing them to release heat during flight. Many other mammals use the capillary network in oversized ears for the same purpose.[82]

Torpor

 
A tricoloured bat (Perimyotis subflavus) in torpor

Torpor is especially useful for microbats, as they use a large amount of energy while active, depend upon an unreliable food source, and have a limited ability to store fat. They generally drop their body temperature in this state to 6–30 °C (43–86 °F), and may reduce their energy expenditure by 50 to 99%. Around 97% of all microbats use torpor,[83] including tropical bats which may use it to avoid predation.[84] Megabats were generally believed to be homeothermic, but three species of small megabats, with a mass of about 50 grams (1.8 oz), have been known to use torpor: the common blossom bat (Syconycteris australis), the long-tongued nectar bat (Macroglossus minimus), and the eastern tube-nosed bat (Nyctimene robinsoni). Torpid states last longer in the summer for megabats than in the winter.[85]

During hibernation, bats enter a torpid state and decrease their body temperature for 99.6% of their hibernation period; even during periods of arousal, when they return their body temperature to normal, they sometimes enter a shallow torpid state, known as "heterothermic arousal".[86] Some bats aestivate to keep cool in the summer months.[87]

Heterothermic bats during long migrations may fly at night and go into a torpid state roosting in the daytime. Unlike migratory birds which fly during the day and feed during the night, nocturnal bats have a conflict between travelling and eating. The energy saved reduces their need to feed, and also decreases the duration of migration, which may prevent them from spending too much time in unfamiliar places, and decrease predation. In some species pregnant individuals may not use torpor.[88][89]

Size

The smallest bat is Kitti's hog-nosed bat, which is 29–34 millimetres (1.1–1.3 in) long with a 15 centimetres (5.9 in) wingspan and weighs 2–2.6 grams (0.071–0.092 oz).[90][91] It is also arguably the smallest extant species of mammal, next to the Etruscan shrew.[92] The largest bats are a few species of Pteropus megabats and the giant golden-crowned flying fox which can weigh 1.6 kilograms (3.5 lb) with a wingspan of 1.7 metres (5.6 ft).[93] Larger bats tend to use lower frequencies and smaller bats higher for echolocation; high-frequency echolocation is better at detecting smaller prey. Small prey may be absent in the diets of large bats as they are unable to detect them.[94] The adaptations of a particular bat species can directly influence what kinds of prey are available to it.[95]

Ecology

 
Tent-making bats (Uroderma bilobatum) in Costa Rica

Flight has enabled bats to become one of the most widely distributed groups of mammals.[96] Apart from the high Arctic, the Antarctic and a few isolated oceanic islands, bats exist in almost every habitat on Earth.[97] Tropical areas tend to have more species than temperate ones.[98] Different species select different habitats during different seasons, ranging from seasides to mountains and deserts, but they require suitable roosts. Bat roosts can be found in hollows, crevices, foliage, and even human-made structures, and include "tents" the bats construct by biting leaves.[99] Most microbats are nocturnal[100] and megabats are typically diurnal or crepuscular.[101][102]

Food and feeding

 
Mexican long-tongued bat (Choeronycteris mexicana) drinking from a cactus

Different bat species have different diets including insects, nectar, pollen, fruit and even vertebrates.[103] Megabats are mostly fruit, nectar and pollen eaters.[101] Due to their small size, high-metabolism and rapid burning of energy through flight, bats must consume large amounts of food for their size. Insectivorous bats may eat over 120 percent of their body weight while frugivorous bats may eat over twice their weight.[104] Predatory bats typically hunt at night, reducing competition with birds, and minimising contact with certain predators. They can travel large distances, up to 800 kilometres (500 mi), in search of food.[36] Bats use a variety of hunting strategies.[94] The bite force of small bats is generated through mechanical advantage, allowing them to bite through the hardened armour of insects or the skin of fruit.[105] Bats get most of their water from the food they eat; many species also drink from water sources like lakes and streams, flying over the surface and dipping their tongues into the water.[106]

The Chiroptera as a whole are in the process of losing the ability to synthesise vitamin C: most have lost it completely.[107] In a test of 34 bat species from six major families of bats, including major insect- and fruit-eating bat families, all were found to have lost the ability to synthesise it, and this loss may derive from a common bat ancestor, as a single mutation.[108][b] At least two species of bat, the frugivorous bat (Rousettus leschenaultii) and the insectivorous bat (Hipposideros armiger), have retained their ability to produce vitamin C.[109]

Insects

Most microbats, especially in temperate areas, prey on insects.[103] The diet of an insectivorous bat may span many species,[110] including flies, beetles, moths, grasshoppers, crickets, termites, bees, wasps, mayflies and caddisflies.[111] Large numbers of Mexican free-tailed bats (Tadarida brasiliensis) fly hundreds of metres above the ground in central Texas to feed on migrating moths.[112] Species that hunt insects in flight, like the little brown bat (Myotis lucifugus), may catch an insect in mid-air with the mouth, and eat it in the air or use their tail membranes or wings to scoop up the insect and carry it to the mouth.[113][114] The bat may also take the insect back to its roost and eat it there.[115] Slower moving bat species such as the brown long-eared bat (Plecotus auritus) and many horseshoe bat species, may take or glean insects from vegetation or hunt them from perches.[111] Insectivorous bats living at high latitudes have to consume prey with higher energetic value than tropical bats.[116]

Fruit and nectar

 
An Egyptian fruit bat (Rousettus aegyptiacus) carrying a fig

Fruit eating, or frugivory, is found in both major suborders. Bats prefer ripe fruit, pulling it off the trees with their teeth. They fly back to their roosts to eat the fruit, sucking out the juice and spitting the seeds and pulp out onto the ground. This helps disperse the seeds of these fruit trees, which may take root and grow where the bats have left them, and many species of plants depend on bats for seed dispersal.[117][118] The Jamaican fruit bat (Artibeus jamaicensis) has been recorded carrying fruits weighing 3–14 g (0.11–0.49 oz) or even as much as 50 g (1.8 oz).[119]

Nectar-eating bats have acquired specialised adaptations. These bats possess long muzzles and long, extensible tongues covered in fine bristles that aid them in feeding on particular flowers and plants.[118][120] The tube-lipped nectar bat (Anoura fistulata) 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 the tongue retracts, it coils up inside the rib cage.[120] Because of these features, nectar-feeding bats cannot easily turn to other food sources in times of scarcity, making them more prone to extinction than other types of bat.[121][122] Nectar feeding also aids a variety of plants, since these bats serve as pollinators, as pollen gets attached to their fur while they are feeding. Around 500 species of flowering plant rely on bat pollination and thus tend to open their flowers at night.[118] Many rainforest plants depend on bat pollination.[123]

Vertebrates

 
The greater noctule bat (Nyctalus lasiopterus) uses its large teeth to catch birds.[124]

Some bats prey on other vertebrates, such as fish, frogs, lizards, birds and mammals.[111][125] The fringe-lipped bat (Trachops cirrhosus,) for example, is skilled at catching frogs. These bats locate large groups of frogs by tracking their mating calls, then plucking them from the surface of the water with their sharp canine teeth.[126] The greater noctule bat can catch birds in flight.[124] Some species, like the greater bulldog bat (Noctilio leporinus) hunt fish. They use echolocation to detect small ripples on the water's surface, swoop down and use specially enlarged claws on their hind feet to grab the fish, then take their prey to a feeding roost and consume it.[127] At least two species of bat are known to feed on other bats: the spectral bat, also known as the American false vampire bat, and the ghost bat of Australia.[128]

Blood

 
The common vampire bat (Desmodus rotundus) feeds on blood (hematophagy).

A few species, specifically the common, white-winged, and hairy-legged vampire bats, only feed on animal blood (hematophagy). The common vampire bat typically feeds on large mammals such as cattle; the hairy-legged and white-winged vampires feed on birds.[129] Vampire bats target sleeping prey and can detect deep breathing.[130] Heat sensors in the nose help them to detect blood vessels near the surface of the skin.[131] They pierce the animal's skin with their teeth, biting away a small flap,[132] and lap up the blood with their tongues, which have lateral grooves adapted to this purpose.[133] The blood is kept from clotting by an anticoagulant in the saliva.[132]

Predators, parasites, and diseases

Bats are subject to predation from birds of prey such as owls, hawks, and falcons, and at roosts also from terrestrial predators able to climb, such as cats.[134] Twenty species of tropical New World snakes are known to capture bats, often waiting at the entrances of refuges such as caves for bats to fly past.[135] J. Rydell and J. R. Speakman argue that bats today are almost entirely nocturnal because they evolved this behaviour during the early and middle Eocene period to avoid predators.[134] The evidence is thought by some zoologists to be equivocal so far.[136]

Among ectoparasites, bats carry fleas and mites, as well as specific parasites such as bat bugs and bat flies (Nycteribiidae and Streblidae).[137][138] Bats are among the few non-aquatic mammalian orders that do not host lice, possibly due to competition from more specialised parasites which occupy the same niche.[138]

White nose syndrome is a condition associated with the deaths of millions of bats in the Eastern United States and Canada.[139] The disease is named after a white fungus, Pseudogymnoascus destructans, found growing on the muzzles, ears, and wings of afflicted bats. The fungus is mostly spread from bat to bat, and causes the disease.[140] The fungus was first discovered in central New York State in 2006 and spread quickly to the entire Eastern US north of Florida; mortality rates of 90–100% have been observed in most caves.[141] New England and the mid-Atlantic states have, since 2006, witnessed entire species completely extirpated and others with numbers that have gone from the hundreds of thousands, even millions, to a few hundred or less.[142] Nova Scotia, Quebec, Ontario, and New Brunswick have witnessed identical die offs, with the Canadian government making preparations to protect all remaining bat populations in its territory.[143] Scientific evidence suggests that longer winters where the fungus has a longer period to infect bats result in greater mortality.[144][145][146] In 2014, infection crossed the Mississippi River,[147] and in 2017, it was found on bats in Texas.[148]

Bats are natural reservoirs for a large number of zoonotic pathogens,[149] including rabies, endemic in many bat populations,[150][151][152] histoplasmosis both directly and in guano,[153] Nipah Hendra viruses,[154] and possibly the ebola virus.[155][156] Their high mobility, broad distribution, long life spans, substantial sympatry, and social behaviour make bats favourable hosts and vectors of disease. Compared to rodents, bats carry more zoonotic viruses per species, and each virus is shared with more species.[157] They seem to be highly resistant to many of the pathogens they carry, suggesting a degree of adaptation to their immune systems.[157][158][159] Their interactions with livestock and pets, including predation by vampire bats, accidental encounters, and the scavenging of bat carcasses, compound the risk of zoonotic transmission.[151] Bats are implicated in the emergence of severe acute respiratory syndrome (SARS) in China, since they serve as natural hosts for Coronaviruses, several from a single cave in Yunnan, one of which developed into the SARS virus.[160][153][161]

Social behaviour

Social structure

Bracken Bat Cave, home to 20 million Mexican free-tailed bats

Some bats lead solitary lives, while others live in colonies of more than a million.[162] Living in large colonies lessens the risk to an individual of predation.[111] Temperate bat species may swarm at hibernation sites as autumn approaches. This may serve to introduce young to hibernation sites, signal reproduction in adults and allow adults to breed with those from other groups.[163]

Several species have a fission-fusion social structure, where large numbers of bats congregate in one roosting area, along with breaking up and mixing of subgroups. Within these societies, bats are able to maintain long term relationships.[164] Some of these relationships consist of matrilineally related females and their dependent offspring.[165] Food sharing and mutual grooming may occur in certain species, such as the common vampire bat (Desmodus rotundus), and these strengthen social bonds.[166][167]

 
Mexican free-tailed bats on their long aerial migration between Oregon and Mexico

In temperate areas, some bats migrate hundreds of kilometres to winter hibernation dens;[168] others pass into torpor in cold weather, rousing and feeding when warm weather allows insects to be active.[169] Others retreat to caves for winter and hibernate for as much as six months.[169] Microbats rarely fly in rain; it interferes with their echolocation, and they are unable to hunt.[170] A few species such as the New Zealand short-tailed bat and the common vampire bat are agile on the ground.[171]

Communication

 
Acoustics of the songs of Mexican free-tailed bats[172]

Bats are among the most vocal of mammals and produce calls to attract mates, find roost partners and defend resources. These calls are typically low-frequency and can travel long distances.[111][173] Mexican free-tailed bats are one of the few species to "sing" like birds. Males sing to attract females. Songs have three phrases: chirps, trills and buzzes, the former having "A" and "B" syllables. Bat songs are highly stereotypical but with variation in syllable number, phrase order, and phrase repetitions between individuals.[172] Among greater spear-nosed bats (Phyllostomus hastatus), females produce loud, broadband calls among their roost mates to form group cohesion. Calls differ between roosting groups and may arise from vocal learning.[174]

In captive Egyptian fruit bats, 70% of the directed calls could be identified as to which bat made it, and 60% could be categorised into four contexts: squabbling over food, jostling over position in their sleeping cluster, protesting over mating attempts and arguing when perched in close proximity to each other. The animals made slightly different sounds when communicating with different individual bats, especially those of the opposite sex.[175] In the highly sexually dimorphic hammer-headed bat (Hypsignathus monstrosus), males produce deep, resonating, monotonous calls to attract females. Bats in flight make vocal signals for traffic control. Greater bulldog bats honk when on a collision course with each other.[173]

Bats also communicate by other means. Male little yellow-shouldered bats (Sturnira lilium) have shoulder glands which produce a spicy odour during the breeding season. Like many other species, they have hair specialised for retaining and dispersing secretions. Such hair forms a conspicuous collar around the necks of the some Old World megabat males. Male greater sac-winged bats (Saccopteryx bilineata) have sacs in their wings in which they mix body secretions like saliva and urine to create a perfume which they sprinkle on roost sites, a behaviour known as "salting". Salting may be accompanied by singing.[173]

Reproduction and life history

 
Group of polygynous vampire bats

Strategies

Most bat species are polygynous, where males mate with multiple females. Male pipistrelle, noctule and vampire bats may claim and defend resources that attract females, such as roost sites, and mate with those females. Males unable to claim a site are forced to live on the periphery where they have less reproductive success.[176][111] Promiscuity, where both sexes mate with multiple partners, exists in species like the Mexican free-tailed bat and the little brown bat.[177][178] There appears to be bias towards certain males among females in these bats.[111] In a few species, such as the yellow-winged bat and spectral bat, adult males and females form monogamous pairs.[111][179] Lek mating, where males aggregate and compete for female choice through display, is rare in bats[180] but occurs in the hammerheaded bat.[181]

Mating

For temperate living bats, mating takes place in late summer and early autumn.[182] Tropical bats may mate during the dry season.[183] After copulation, the male may leave behind a mating plug to ensure his paternity. In hibernating species, males are known to mate with females in torpor.[111] 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 fertilisation, in which sperm is stored in the reproductive tract for several months after mating. Mating occurs in the autumn but fertilisation does not occur until the following spring. Other species exhibit delayed implantation, in which the egg is fertilised after mating, but remains free in the reproductive tract until external conditions become favourable for giving birth and caring for the offspring.[184] In another strategy, fertilisation and implantation both occur, but development of the foetus is delayed until good conditions prevail. During the delayed development the mother keeps the fertilised egg alive with nutrients. This process can go on for a long period, because of the advanced gas exchange system.[185]

Life cycle

 
Newborn common pipistrelle, Pipistrellus pipistrellus

For temperate living bats, births typically take place in May or June in the northern hemisphere; births in the southern hemisphere occur in November and December. Tropical species give birth at the beginning of the rainy season.[186] In most bat species, females carry and give birth to a single pup per litter.[187] At birth, a bat pup can be up to 40 percent of the mother's weight,[111] and the pelvic girdle of the female can expand during birth as the two halves are connected by a flexible ligament.[188] Females typically give birth in a head-up or horizontal position, using gravity to make birthing easier. The young emerges rear-first, possibly to prevent the wings from getting tangled, and the female cradles it in her wing and tail membranes. In many species, females give birth and raise their young in maternity colonies and may assist each other in birthing.[189][190][188]

Most of the care for a young bat comes from the mother. In monogamous species, the father plays a role. Allo-suckling, where a female suckles another mother's young, occurs in several species. This may serve to increase colony size in species where females return to their natal colony to breed.[111] A young bat's ability to fly coincides with the development of an adult body and forelimb length. For the little brown bat, this occurs about eighteen days after birth. Weaning of young for most species takes place in under eighty days. The common vampire bat nurses its offspring beyond that and young vampire bats achieve independence later in life than other species. This is probably due to the species' blood-based diet which is difficult to obtain on a nightly basis.[191]

Life expectancy

The maximum lifespan of bats is three-and-a-half times longer than other mammals of similar size. Five species have been recorded to live over 30 years in the wild: the brown long-eared bat (Plecotus auritus), the little brown bat (Myotis lucifugus), Brandt's bat (Myotis brandti), the lesser mouse-eared bat (Myotis blythii) and the greater horseshoe bat (Rhinolophus ferrumequinum). One hypothesis consistent with the rate-of-living theory links this to the fact that they slow down their metabolic rate while hibernating; bats that hibernate, on average, have a longer lifespan than bats that do not.[192][193] Another hypothesis is that flying has reduced their mortality rate, which would also be true for birds and gliding mammals. Bat species which give birth to multiple pups generally have a shorter lifespan than species that give birth to only a single pup. Cave-roosting species may have a longer lifespan than non-roosting species because of the decreased predation in caves. The oldest recorded bat is a 41-year-old male Brandt's bat.[193][194]

Interactions with humans

 
Bat roost in San Antonio, Texas, 1915

Conservation

Groups such as the Organization for Bat Conservation[195] and Bat Conservation International[196] aim to increase awareness of bats' ecological roles and the environmental threats they face. In the United Kingdom, all bats are protected under the Wildlife and Countryside Acts, and disturbing a bat or its roost can be punished with a heavy fine.[197] In Sarawak, Malaysia, "all bats"[198] are protected under the Wildlife Protection Ordinance 1998,[198] but species such as the hairless bat (Cheiromeles torquatus) are still eaten by the local communities.[199] 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. About 100,000 tourists a year visit the bridge at twilight to watch the bats leave the roost.[200]

Many people put up bat houses to attract bats.[201] The 1991 University of Florida bat house is the largest occupied artificial roost in the world, with around 300,000 residents.[202][203] In Britain, thickwalled and partly underground World War II pillboxes have been converted to make roosts for bats,[204][205] and purpose-built bat houses are occasionally built to mitigate damage to habitat from road or other developments.[206][207] Cave gates are sometimes installed to limit human entry into caves with sensitive or endangered bat species. The gates are designed not to limit the airflow, and thus to maintain the cave's micro-ecosystem.[208]

 
Francisco Goya, The Sleep of Reason Produces Monsters, 1797

Bats are eaten in countries across Asia and the Pacific Rim. In some cases, such as in Guam, flying foxes have become endangered through being hunted for food.[209] There is evidence that wind turbines create sufficient barotrauma (pressure damage) to kill bats.[210] Bats have typical mammalian lungs, which are thought to be more sensitive to sudden air pressure changes than the lungs of birds, making them more liable to fatal rupture.[211][212][213][214][215] Bats may be attracted to these structures, perhaps seeking roosts, increasing the death rate.[211] Acoustic deterrents may help to reduce bat mortality at wind farms.[216]

Cultural significance

In many cultures, including in Europe, bats are associated with darkness, death, witchcraft, and malevolence.[217] Because bats are mammals, yet can fly, they are liminal beings in many traditions.[218] Among Native Americans such as the Creek, Cherokee and Apache, the bat is a trickster spirit. In Tanzania, a winged bat cryptid known as Popobawa is believed to be a shapeshifting evil spirit that assaults and sodomises its victims.[219] In Aztec mythology, bats symbolised the land of the dead, destruction, and decay.[220][221][222][223] An East Nigerian tale tells that the bat developed its nocturnal habits after causing the death of his partner, the bush-rat, and now hides by day to avoid arrest.[224]

More positive depictions of bats exist in some cultures. In China, bats have been associated with happiness, joy and good fortune. Five bats are used to symbolise the "Five Blessings": longevity, wealth, health, love of virtue and peaceful death.[225] The bat is sacred in Tonga and is often considered the physical manifestation of a separable soul.[226] In the Zapotec civilisation of Mesoamerica, the bat god presided over corn and fertility.[227]

 
Zapotec bat god, Oaxaca, 350–500 AD

The Weird Sisters in Shakespeare's Macbeth used the fur of a bat in their brew.[228] 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, such as Count Dracula, and heroes, such as Batman.[229][230] Kenneth Oppel's Silverwing novels narrate the adventures of a young bat,[231] based on the silver-haired bat of North America.[232]

The bat is sometimes used as a heraldic symbol in Spain and France, appearing in the coats of arms of the towns of Valencia, Palma de Mallorca, Fraga, Albacete, and Montchauvet.[233][234][235] Three US states have an official state bat. Texas and Oklahoma are represented by the Mexican free-tailed bat, and Virginia is represented by the Virginia big-eared bat.[236]

Bat dung, a type of guano, is rich in nitrates and is mined from caves for use as fertiliser.[237] During the US Civil War, saltpetre was collected from caves to make gunpowder; it used to be thought that this was bat guano, but most of the nitrate comes from nitrifying bacteria.[238]

See also

Notes

  1. ^ Pronounced /kˈrɒptərə/; from the Ancient Greek: χείρcheir, "hand" and πτερόν – pteron, "wing".[1]
  2. ^ Earlier reports that only fruit bats were deficient were based on smaller samples.[109]

References

  1. ^ a b   "Chiroptera". Encyclopædia Britannica. 6 (11th ed.). 1911. pp. 239–247. 
  2. ^ "Bat". Dictionary.com. Retrieved 9 September 2017. 
  3. ^ "Bat, noun 2". Online Etymology Dictionary. Retrieved 24 June 2013. 
  4. ^ "χείρ". Perseus Digital Library. Retrieved 9 September 2017. 
  5. ^ "πτερόν". Perseus Digital Library. Retrieved 9 September 2017. 
  6. ^ Lei, M.; Dong, D. (2016). "Phylogenomic analyses of bat subordinal relationships based on transcriptome data". Scientific Reports. 6: 27726. Bibcode:2016NatSR...627726L. doi:10.1038/srep27726. 
  7. ^ a b Prothero, D. R. (2017). "Laurasiatheria: Chiroptera". The Princeton Field Guide to Prehistoric Mammals. Princeton University Press. pp. 112–116. ISBN 978-0-691-15682-8. 
  8. ^ Hutcheon, J. M.; Garland, T. (2004). "Are Megabats Big?". Journal of Mammalian Evolution. 11 (3/4): 257. doi:10.1023/B:JOMM.0000047340.25620.89. 
  9. ^ Holland, R. A. (2004). "Echolocation signal structure in the Megachiropteran bat Rousettus aegyptiacus Geoffroy 1810". Journal of Experimental Biology. 207 (25): 4361–4369. doi:10.1242/jeb.01288. PMID 15557022. 
  10. ^ Brown, W. M. (2001). "Natural selection of mammalian brain components". Trends in Ecology and Evolution. 16 (9): 471–473. doi:10.1016/S0169-5347(01)02246-7. 
  11. ^ a b Stephen, J.; Olney, P. (1994). Creative Conservation: Interactive Management of Wild and Captive Animals. Springer. p. 352. ISBN 978-0412495700. 
  12. ^ Van de Bussche, R. A.; Hoofer, S. R. (2004). "Phylogenetic relationships among recent chiropteran families and the importance of choosing appropriate out-group taxa". Journal of Mammalogy. 85 (2): 321–330. doi:10.1644/1545-1542(2004)085<0321:Prarcf>2.0.Co;2. 
  13. ^ a b Agnarsson, I.; Zambrana-Torrelio, C. M.; Flores-Saldana, N. P.; May-Collado, L. J. (2011). "A time-calibrated species-level phylogeny of bats (Chiroptera, Mammalia)". PLoS Currents. 3: RRN1212. doi:10.1371/currents.RRN1212. PMC 3038382 . PMID 21327164. 
  14. ^ Eiting, T. P.; Gunnell, G. F. (2009). "Global completeness of the bat fossil record". Journal of Mammalian Evolution. 16 (3): 151–173. doi:10.1007/s10914-009-9118-x. 
  15. ^ a b c d Simmons, N. B.; Seymour, K. L.; Habersetzer, J.; Gunnell, G. F. (2008). "Primitive Early Eocene bat from Wyoming and the evolution of flight and echolocation". Nature. 451 (7180): 818–21. Bibcode:2008Natur.451..818S. doi:10.1038/nature06549. PMID 18270539. 
  16. ^ "Paleontologists Determine Original Color of Extinct Bats". SciNews. 29 September 2015. Retrieved 10 September 2017. 
  17. ^ Collearya, C.; Dolocanc, A.; Gardnerd, J.; Singha, Suresh; Wuttkee, M. (2015). "Chemical, experimental, and morphological evidence for diagenetically altered melanin in exceptionally preserved fossils". Proceedings of the National Academy of Sciences of the United States of America. 112 (41): 12592–12597. Bibcode:2015PNAS..11212592C. doi:10.1073/pnas.1509831112. PMC 4611652 . 
  18. ^ Smith, D. "Chiroptera: Systematics". University of California Museum of Paleontology. Retrieved 9 September 2017. 
  19. ^ Eick, G. N.; Jacobs, D. S.; Matthee, C. A. (2005). "A Nuclear DNA Phylogenetic Perspective on the Evolution of Echolocation and Historical Biogeography of Extant Bats (Chiroptera)". Molecular Biology and Evolution. 22 (9): 1869–1886. doi:10.1093/molbev/msi180. PMID 15930153. Several molecular studies have shown that Chiroptera belong to the Laurasiatheria (represented by carnivores, pangolins, cetartiodactyls, eulipotyphlans, and perissodactyls) and are only distantly related to dermopterans, scandentians, and primates (Nikaido et al. 2000; Lin and Penny 2001; Madsen et al. 2001; Murphy et al. 2001a, 2001b; Van Den Bussche and Hoofer 2004) 
  20. ^ Pumo, D. E.; et al. (1998). "Complete Mitochondrial Genome of a Neotropical Fruit Bat, Artibeus jamaicensis, and a New Hypothesis of the Relationships of Bats to Other Eutherian Mammals". Journal of Molecular Evolution. 47 (6): 709–717. Bibcode:1998JMolE..47..709P. doi:10.1007/PL00006430. PMID 9847413. 
  21. ^ Zhou, X.; et al. (2011). "Phylogenomic Analysis Resolves the Interordinal Relationships and Rapid Diversification of the Laurasiatherian Mammals". Systematic Biology. 61 (1): 150–164. doi:10.1093/sysbio/syr089. PMC 3243735 . PMID 21900649. 
  22. ^ a b c d Tsagkogeorga, G.; Parker, J.; Stupka, E.; Cotton, J. A.; Rossiter, S. J. (2013). "Phylogenomic analyses elucidate the evolutionary relationships of bats (Chiroptera)". Current Biology. 23 (22): 2262–2267. doi:10.1016/j.cub.2013.09.014. PMID 24184098. 
  23. ^ Zhang, G.; Cowled, C.; Shi, Z.; Huang, Z.; Bishop-Lilly, K. A.; Fang, X.; Wynne, J. W.; Xiong, Z.; Baker, M. L.; Zhao, W.; Tachedjian, M.; Zhu, Y.; Zhou, P.; Jiang, X.; Ng, J.; Yang, L.; Wu, L.; Xiao, J.; Feng, Y.; Chen, Y.; Sun, X.; Zhang, Y.; Marsh, G. A.; Crameri, G.; Broder, C. C.; Frey, K. G.; Wang, L.-F.; Wang, J. (2012). "Comparative Analysis of Bat Genomes Provides Insight into the Evolution of Flight and Immunity". Science. 339 (6118): 456–460. Bibcode:2013Sci...339..456Z. doi:10.1126/science.1230835. PMID 23258410. 
  24. ^ a b Teeling, E.C.; Springer, M. S.; Madsen, O.; Bates, P.; O'Brien, S. J.; Murphy, W. J. (2005). "A Molecular Phylogeny for Bats Illuminates Biogeography and the Fossil Record". Science. 307 (5709): 580–584. Bibcode:2005Sci...307..580T. doi:10.1126/science.1105113. PMID 15681385. 
  25. ^ Pettigrew, J. D.; Maseko, B. C.; Manger, P. R. (2008). "Primate-like retinotectal decussation in an echolocating megabat, Rousettus aegyptiacus". Neuroscience. 153 (1): 226–31. doi:10.1016/j.neuroscience.2008.02.019. PMID 18367343. 
  26. ^ Simmons, N. B.; Seymour, K. L.; Habersetzer, J.; Gunnell, G. F. (2008). "Primitive early Eocene bat from Wyoming and the evolution of flight and echolocation". Nature. 451 (7180): 818–816. Bibcode:2008Natur.451..818S. doi:10.1038/nature06549. PMID 18270539. 
  27. ^ "Bat fossil solves evolution poser". BBC News. 13 February 2008. 
  28. ^ a b Norberg, U. M. (1994). Wainwright, P. C.; Reilly, S. M., eds. "Ecological Morphology: Integrative Organismal Biology". University of Chicago Press: 206–208. ISBN 978-0-226-86995-7. 
  29. ^ Bishop, K. L. (2008). "The Evolution of Flight in Bats: Narrowing the Field of Plausible Hypotheses". The Quarterly Review of Biology. 83 (2): 153–169. doi:10.1086/587825. PMID 18605533. 
  30. ^ Kaplan, Matt (2011). "Ancient bats got in a flap over food". Nature. doi:10.1038/nature.2011.9304. 
  31. ^ Teeling; Teeling, E. C.; Scally, M.; Kao, D. J.; Romagnoli, M. L.; Springer, M. S. (2000). "Molecular evidence regarding the origin of echolocation and flight in bats". Nature. 403 (6766): 188–192. Bibcode:2000Natur.403..188T. doi:10.1038/35003188. PMID 10646602. 
  32. ^ Teeling, E. C.; Madsen, O.; Stanhope, M. J.; De Jong, W. W. (2001). "Integrated fossil and molecular data reconstruct bat echolocation". Proceedings of the National Academy of Sciences. 98 (11): 6241–6246. Bibcode:2001PNAS...98.6241S. doi:10.1073/pnas.111551998. PMC 33452 . PMID 11353869.  Missing |last1= in Authors list (help)
  33. ^ L., G.; Wang, J.; Rossiter, S. J.; Jones, G.; Zhang, S. (2007). "Accelerated FoxP2 evolution in echolocating bats". PLoS One. 2 (19): e900. Bibcode:2007PLoSO...2..900L. doi:10.1371/journal.pone.0000900. PMC 1976393 . 
  34. ^ DesRoche, K.; Fenton, M. B.; Lancaster, W. C. (2007). "Echolocation and the thoracic skeletons of bats: a comparative morphological study". Acta Chiropterologica. 9 (2): 483–494. doi:10.3161/1733-5329(2007)9[483:EATTSO]2.0.CO;2. 
  35. ^ Li, G.; Wang, J.; Rossiter, S. J.; Jones, G.; Cotton, J. A.; Zhang, S. (2008). "The hearing gene Prestin reunites the echolocating bats". Proceedings of the National Academy of Sciences of the United States of America. 105 (37): 13959–13964. Bibcode:2008PNAS..10513959L. doi:10.1073/pnas.0802097105. PMC 2544561 . 
  36. ^ a b c Hunter, P. (2007). "The nature of flight: The molecules and mechanics of flight in animals". Science and Society. 8 (9): 811–813. doi:10.1038/sj.embor.7401050. PMC 1973956 . PMID 17767190. 
  37. ^ McCracken, G. F.; Safi, K.; Kunz, T. H.; Dechmann, D. K. N.; Swartz, S. M.; Wikelski, M. (9 November 2016). "Airplane tracking documents the fastest flight speeds recorded for bats". Royal Society Open Science. 3 (11): 160398. Bibcode:2016RSOS....360398M. doi:10.1098/rsos.160398. PMID 28018618. 
  38. ^ Sears, K. E.; Behringer, R. R.; Rasweiler, J. J.; Niswander, L. A. (2006). "Development of bat flight: Morphologic and molecular evolution of bat wing digits". Proceedings of the National Academy of Sciences. 103 (17): 6581–6586. Bibcode:2006PNAS..103.6581S. doi:10.1073/pnas.0509716103. PMC 1458926 . PMID 16618938. 
  39. ^ Kirkpatrick, S. J. (1994). "Scale effects on the stresses and safety factors in the wing bones of birds and bats". Journal of Experimental Biology. 190: 195–215. PMID 7964391. 
  40. ^ a b c d e Pennycuick, C. J. (2008). "Bats". Modelling the Flying Bird. Elsevier. pp. 136–143. ISBN 978-0-12-374299-5. 
  41. ^ a b Marshall, K. L.; Chadha, M.; deSouza, L. A.; Sterbing-D'Angelo, S. J.; Moss, C. F.; Lumpkin, E. A. (2015). "Somatosensory substrates of flight control in bats". Cell Reports. 11 (6): 851–858. doi:10.1016/j.celrep.2015.04.001. PMC 4643944 . PMID 25937277. 
  42. ^ a b Fenton, M. B.; Crerar, L. M. (1984). "Cervical Vertebrae in Relation to Roosting Posture in Bats". Journal of Mammalology. 65 (3): 395–403. doi:10.2307/1381085. 
  43. ^ Fenton & Simmons 2015, p. 78.
  44. ^ Brown University (2007). "Bats In Flight Reveal Unexpected Aerodynamics". ScienceDaily. Retrieved 31 October 2017. 
  45. ^ Riskin, D. K.; Bergou, A.; Breuer, K. S.; Swartz, S. M. (2012). "Upstroke wing flexion and the inertial cost of bat flight". roceedings of the Royal Society B: Biological Sciences. 279 (1740). doi:10.1098/rspb.2012.0346. 
  46. ^ a b Roberts, W. C. (2006). "Facts and ideas from anywhere". Proceedings (Baylor University. Medical Center). 19 (4): 425–434. PMC 1618737 . PMID 17106509. 
  47. ^ Irwin, N. (1997). "Wanted DNA samples from Nyctimene or Paranyctimene Bats" (PDF). The New Guinea Tropical Ecology and Biodiversity Digest. 3: 10. 
  48. ^ a b Sterbing-D'Angelo, S.; Chadha, M.; Chiu, C.; Falk, B.; Xian, W.; Barcelo, J.; Zook, J. M.; Moss, C. F. (2011). "Bat wing sensors support flight control". Proceedings of the National Academy of Sciences of the United States of America. 108 (27): 11291–11296. Bibcode:2011PNAS..10811291S. doi:10.1073/pnas.1018740108. PMC 3131348 . 
  49. ^ a b Mehlhorn, H. (2013). Bats (Chiroptera) as Vectors of Diseases and Parasites: Facts and Myths. Springer. pp. 2–27. ISBN 3642393330. 
  50. ^ a b c Makanya, A. N.; Mortola, J. P. (2017). "The structural design of the bat wing web and its possible role in gas exchange". Journal of Anatomy. 211 (6): 687–697. doi:10.1111/j.1469-7580.2007.00817.x. PMC 2375846 . PMID 17971117. 
  51. ^ Fenton & Simmons 2015, pp. 166–167.
  52. ^ "Leading Edge Vortex Allows Bats to Stay Aloft, Aerospace Professor Reports". USC Viterbi School of Engineering. 29 February 2008. 
  53. ^ Holbrook, K. A.; Odland, G. F. (1978). "A collagen and elastic network in the wing of the bat". Journal of Anatomy. 126 (Pt 1): 21–36. PMC 1235709 . PMID 649500. 
  54. ^ Jones, T. W. (1852). "Discovery That the Veins of the Bat's Wing (Which are Furnished with Valves) are Endowed with Rythmical Contractility, and That the Onward Flow of Blood is Accelerated by Each Contraction". Philosophical Transactions of the Royal Society of London. 142: 131–136. doi:10.1098/rstl.1852.0011. JSTOR 108539. 
  55. ^ Dongaonkar, R. M.; Quick, C. M.; Vo, J. C.; Meisner, J. K.; Laine, G. A.; Davis, M. J.; Stewart, R. H. (15 June 2012). "Blood flow augmentation by intrinsic venular contraction in vivo". American Journal of Physiology. Regulatory, Integrative and Comparative Physiology. 302 (12): R1436–R1442. doi:10.1152/ajpregu.00635.2011. PMC 3378342 . PMID 22513742. 
  56. ^ Langley, L. (29 August 2015). "Bats and Sloths Don't Get Dizzy Hanging Upside Down—Here's Why". news.nationalgeographic.com. Retrieved 10 June 2017. 
  57. ^ Maina, J. N. (2000). "What it takes to fly: the structural and functional respiratory refinements in birds and bats". Journal of Experimental Biology. 203 (20): 3045–3064. PMID 11003817. 
  58. ^ Strobel, S.; Roswag, A.; Becker, N. I.; Trenczek, T. E.; Encarnação, J. A. (2013). "Insectivorous Bats Digest Chitin in the Stomach Using Acidic Mammalian Chitinase". PLoS One. 8 (9). doi:10.1371/journal.pone.0072770. PMC 3760910 . 
  59. ^ a b Schondube, J. E.; Herrera-M, L. G.; Martínez del Rio, C. (2001). "Diet and the evolution of digestion and renal function in phyllostomid bats" (PDF). Zoology. 104: 59–73. doi:10.1078/0944-2006-00007. PMID 16351819. 
  60. ^ Jones, K. E.; Bininda-Emonds , O. R. P.; Gittleman, J. L. (2005). "Bats, clocks, and rocks: diversification patterns in chiroptera". Evolution. 59 (10): 2243–2255. doi:10.1554/04-635.1. PMID 16405167. 
  61. ^ Surlykke, A.; Elisabeth, K. V. (2008). "Echolocating bats Cry Out Loud to Detect Their Prey". PLoS ONE. 3 (4): e2036. Bibcode:2008PLoSO...3.2036S. doi:10.1371/journal.pone.0002036. PMC 2323577 . 
  62. ^ a b c Muller, R. (2004). "A numerical study of the role of the tragus in the big brown bat". JASA. 116 (6): 3701–3712. Bibcode:2004ASAJ..116.3701M. doi:10.1121/1.1815133. 
  63. ^ Teeling, E. C. (2009). "Hear, hear: the convergent evolution of echolocation in bats?". Trends in Ecology & Evolution. 24 (7): 351–354. doi:10.1016/J.Tree.2009.02.012. PMID 19482373. 
  64. ^ Jones, G.; Holderied, M. W. (2007). "Bat echolocation calls: adaptation and convergent evolution". Proceedings of the Royal Society B: Biological Sciences. 274 (1612): 905–912. doi:10.1098/Rspb.2006.0200. PMC 1919403 . PMID 17251105. 
  65. ^ Pavey, C. R.; Burwell, C. J. (1998). "Bat Predation on Eared Moths: A Test of the Allotonic Frequency Hypothesis". Oikos. 81 (1): 143–151. doi:10.2307/3546476. JSTOR 3546476. 
  66. ^ "The Bat's Ear as a Diffraction Grating". Oai.dtic.mil. 
  67. ^ K., Roman (2009). "Model predicts bat pinna ridges focus high frequencies to form narrow sensitivity beams". J. Acoust. Soc. Am. 125 (5): 3454–9. Bibcode:2009ASAJ..125.3454K. doi:10.1121/1.3097500. PMID 19425684. 
  68. ^ a b Corcoran, A. J.; Barber, J. R.; Conner, W. E. (2009). "Tiger moth jams bat sonar". Science. 325 (5938): 325–327. Bibcode:2009Sci...325..325C. doi:10.1126/science.1174096. PMID 19608920. 
  69. ^ a b Hristov, N. I.; Conner, W. E. (2005). "Sound strategy: acoustic aposematism in the bat–tiger moth arms race". Naturwissenschaften. 92 (4): 164–169. Bibcode:2005NW.....92..164H. doi:10.1007/s00114-005-0611-7. PMID 15772807. 
  70. ^ Surlykke, A.; Ghose, K.; Moss, C. F. (2009). "Acoustic scanning of natural scenes by echolocation in the big brown bat, Eptesicus fuscus". Journal of Experimental Biology. 212 (Pt 7): 1011–20. doi:10.1242/jeb.024620. PMC 2726860 . PMID 19282498. 
  71. ^ Strauß, J.; Lakes-Harlan, R. (2014). "Evolutionary and Phylogenetic Origins of Tympanal Hearing Organs in Insects". In Hedwig, B. Insect Hearing and Acoustic Communication. Springer. pp. 5–26. doi:10.1007/978-3-642-40462-7_2. ISBN 978-3-642-40462-7. 
  72. ^ Fullard, J. H. (1998). "Moth Ears and Bat Calls: Coevolution or Coincidence?". In Hoy, R. R.; Fay, R. R.; Popper, A. N. Comparative Hearing: Insects. Springer Handbook of Auditory Research. Springer. ISBN 978-1-4612-6828-4. 
  73. ^ Takanashi, Takuma; Nakano, Ryo; Surlykke, A.; Tatsuta, H.; Tabata, J.; Ishikawa, Y.; Skals, N. (2010). "Variation in Courtship Ultrasounds of Three Ostrinia Moths with Different Sex Pheromones". Plos One. 5 (10): e13144. Bibcode:2010PLoSO...513144T. doi:10.1371/journal.pone.0013144. PMID 20957230. 
  74. ^ Sophasarun, N. "Experts debunk bats' bad rap". Online extra. National Geographic. Retrieved 14 November 2017. 
  75. ^ Müller, B.; Glösmann, M.; Peichl, L.; Knop, G. C.; Hagemann, C.; Ammermüller, J. (2009). "Bat Eyes Have Ultraviolet-Sensitive Cone Photoreceptors". PLoS One. 4 (7): e6390. Bibcode:2009PLoSO...4.6390M. doi:10.1371/journal.pone.0006390. PMC 2712075 . PMID 19636375. 
  76. ^ Shen, Y.-Y.; Liu, J.; Irwin, D. M.; Zhang, Y.-P. (2010). "Parallel and Convergent Evolution of the Dim-Light Vision Gene RH1 in Bats (Order: Chiroptera)". PLoS One. 5 (1): e8838. Bibcode:2010PLoSO...5.8838S. doi:10.1371/journal.pone.0008838. PMC 2809114 . PMID 20098620. 
  77. ^ a b Wang, D.; Oakley, T.; Mower, J.; Shimmin, L. C.; Yim, S.; Honeycutt, R. L.; Tsao, H.; Li, W. H. (2004). "Molecular evolution of bat color vision genes". Molecular Biology and Evolution. 21 (2): 295–302. doi:10.1093/molbev/msh015. PMID 14660703. 
  78. ^ Wang, Y.; Pan, Y.; Parsons, S.; Walker, M.; Zhang, S. (2007). "Bats Respond to Polarity of a Magnetic Field". Proceedings of the Royal Society B: Biological Sciences. 274 (1627): 2901–2905. doi:10.1098/rspb.2007.0904. PMC 2288691 . 
  79. ^ Tian, L.-X.; Pan, Y.-X.; Metzner, W.; Zhang, J.-S.; Zhang, B.-F. (2015). "Bats Respond to Very Weak Magnetic Fields". PLoS One. 10 (4): e0123205. Bibcode:2015PLoSO..1023205T. doi:10.1371/journal.pone.0123205. PMC 4414586 . PMID 25922944. 
  80. ^ Altringham 2011, pp. 99–100.
  81. ^ Voigt, C. C.; Lewanzik, D. (2011). "Trapped in the darkness of the night: thermal and energetic constraints of daylight flight in bats". Proceedings of the Royal Society B: Biological Sciences. 278 (1716): 2311–2317. doi:10.1098/rspb.2010.2290. PMC 3119008 . 
  82. ^ Neuweiler, Gerhard (2000). "The Circulatory and Respiratory Systems". The Biology of Bats. Oxford University Press. pp. 43–62. ISBN 978-0-1950-9951-5. 
  83. ^ Geiser, F.; Stawski, C. (2011). "Hibernation and Torpor in Tropical and Subtropical Bats in Relation to Energetics, Extinctions, and the Evolution of Endothermy". Integrative and Comparative Biology. 51 (3): 337–338. doi:10.1093/icb/icr042. PMID 21700575. 
  84. ^ Stawski, C.; Geiser, F. (2010). "Fat and Fed: Frequent Use of Summer Torpor in a Subtropical Bat". Naturwissenschaften. 97 (1): 29–35. Bibcode:2010NW.....97...29S. doi:10.1007/s00114-009-0606-x. PMID 19756460. 
  85. ^ Zubaid, A.; McCracken, G. F.; Kunz, T. (2006). Functional and Evolutionary Ecology of Bats. Oxford University Press. pp. 14–16. ISBN 978-0-19-515472-6. 
  86. ^ Knight, K. (2012). "Bats Use Torpor to Minimise Costs". Journal of Experimental Biology. 215 (12): iii. doi:10.1242/jeb.074823. 
  87. ^ Bondarenco, A.; Körtner, G.; Geiser, F. (2016). "How to Keep Cool in a Hot Desert: Torpor in Two Species of Free-Ranging Bats in Summer". Temperature. 6 (3): 476–483. doi:10.1080/23328940.2016.1214334. PMC 5079220 . 
  88. ^ McGuire, L. P.; Jonassen, K. A.; Guglielmo, C. G. (2014). "Bats on a Budget: Torpor-Assisted Migration Saves Time and Energy". PLoS One. 9 (12): e115724. Bibcode:2014PLoSO...9k5724M. doi:10.1371/journal.pone.0115724. PMC 4281203 . PMID 25551615. 
  89. ^ Hamilton, I. M.; Barclay, R. M. R. (1994). "Patterns of daily torpor and day-roost selection by male and female big brown bats (Eptesicus fuscus)". Canadian Journal of Zoology. 72 (4): 744. doi:10.1139/z94-100. 
  90. ^ "Kitti's Hog-Nosed Bat: Craseonycteridae – Physical Characteristics – Bats, Bumblebee, Species, Inches, Brown, and Tips". JRank. Retrieved 14 June 2013. 
  91. ^ "Bumblebee bat (Craseonycteris thonglongyai)". EDGE Species. Retrieved 10 April 2008. 
  92. ^ "Kitti's Hog-Nosed Bat Is World's Smallest Mammal". SciTechDaily. 3 December 2012. Retrieved 1 November 2017. 
  93. ^ Nowak, R. M., editor (1999). Walker's Mammals of the World. Vol. 1. 6th edition. Pp. 264–271. ISBN 0-8018-5789-9
  94. ^ a b Gonsalves, L.; Bicknell, B.; Law, B.; Webb, C.; Monamy, V. (2013). "Mosquito Consumption by Insectivorous Bats: Does Size Matter?". PLoS One. 8 (10): e77183. Bibcode:2013PLoSO...877183G. doi:10.1371/journal.pone.0077183. PMC 3795000 . PMID 24130851. 
  95. ^ Dechmann, D. K. N.; Safi, K.; Vonhof, M. J. (2006). "Matching Morphology and Diet in the Disc-Winged Bat Thyroptera tricolor (Chiroptera)". Journal of Mammalogy. 87 (5): 1013–1019. doi:10.1644/05-MAMM-A-424R2.1. 
  96. ^ Thomas, S. P.; Suthers, R. A. (1972). "Physiology and energetics of bat flight" (PDF). Journal of Experimental Biology. 57: 317–335. 
  97. ^ "Bats of the World". Bat Conservation Trust. Archived from the original on 5 January 2011. Retrieved 16 January 2011. 
  98. ^ Fenton & Simmons 2015, pp. 32.
  99. ^ Grzimek's Animal Life Encyclopedia: Vol 13 Mammals II (2nd ed.). 2003. p. 311. ISBN 0-7876-5362-4. 
  100. ^ "Smithsonian Institution". Si.edu. 7 December 2010. 
  101. ^ a b Schwab, I. R.; Pettigrew, J. (2005). "A choroidal sleight of hand". British Journal of Ophthalmology. 89 (11): 1398. doi:10.1136/bjo.2005.077966. 
  102. ^ Alexander, D. E. (2015). On the Wing: Insects, Pterosaurs, Birds, Bats and the Evolution of Animal Flight. Oxford University Press. p. 137. ISBN 978-0199996773. 
  103. ^ a b Fenton & Simmons 2015, pp. 104–107.
  104. ^ Fenton & Simmons 2015, p. 116.
  105. ^ Senawi, J.; Schmieder, D.; Siemers, B.; Kingston, T. (2015). "Beyond size – morphological predictors of bite force in a diverse insectivorous bat assemblage from Malaysia". Functional Ecology. 29 (11): 1411–1420. doi:10.1111/1365-2435.12447. 
  106. ^ Fenton & Simmons 2015, pp. 76.
  107. ^ Cui, J.; Yuan, X.; Wang, L.; Jones, G.; Zhang, S. (2011). "Recent loss of vitamin C biosynthesis ability in bats". PLoS ONE. 6 (11): e27114. Bibcode:2011PLoSO...627114C. doi:10.1371/journal.pone.0027114. PMC 3206078 . PMID 22069493. 
  108. ^ Jenness, R.; Birney, E.; Ayaz, K. (1980). "Variation of L-gulonolactone oxidase activity in placental mammals". Comparative Biochemistry and Physiology Part B. 67: 195–204. 
  109. ^ a b Cui, J.; Pan, Y. H.; Zhang, Y.; Jones, G.; Zhang, S. (2011). "Progressive pseudogenization: vitamin C synthesis and its loss in bats". Mol. Biol. Evol. 28 (2): 1025–31. doi:10.1093/molbev/msq286. PMID 21037206. 
  110. ^ Fenton & Simmons 2015, pp. 108–110.
  111. ^ a b c d e f g h i j k Jones, G. (2001). "Bats". In MacDonald, D. The Encyclopedia of Mammals (2nd ed.). Oxford University Press. pp. 754–75. ISBN 978-0-7607-1969-5. 
  112. ^ McCracken, G. F.; Gillam, E. H.; Westbrook, J. K.; Lee, Y. F.; Jensen, M. L.; Balsley, B. B. (2008). "Brazilian free-tailed bats (Tadarida brasiliensis: Molossidae, Chiroptera) at high altitude: Links to migratory insect populations". Integrative and Comparative Biology. 48 (1): 107–18. doi:10.1093/icb/icn033. PMID 21669777. 
  113. ^ "Little Brown Bat". Penn State University. Retrieved 13 September 2017. 
  114. ^ Fenton & Simmons 2015, p. 120.
  115. ^ Fitt, G. P. (1989). "The ecology of Heliothis species in relation to agro-ecosystems". Annual Review of Entomology. 34: 17–52. doi:10.1146/annurev.ento.34.1.17. 
  116. ^ Boyles, J. G.; McGuire, L. P.; Boyles, E.; Reimer, J. P.; Brooks, C. A.; Rutherford, R. W.; Rutherford, T. A.; Whitaker, J. O., Jr.; McCracken, G. F. (2016). "Physiological and behavioral adaptations in bats living at high latitudes". Physiology and Behavior. 165: 322–327. doi:10.1016/j.physbeh.2016.08.016. 
  117. ^ Simmons, N. B.; Voss, R. S.; Mori, S. A. "Bats as Dispersers of Plants in the Lowland Forests of Central French Guiana". New York Botanical Garden. Retrieved 14 September 2017. 
  118. ^ a b c Fenton & Simmons 2015, p. 115.
  119. ^ Ortega, J.; Castro-Arellano, I. (2001). "Artibeus jamaicensis" (PDF). Mammalian Species. 662: 1–9. doi:10.1644/1545-1410(2001)662<0001:aj>2.0.co;2. 
  120. ^ a b Chamberlain, T. (6 December 2006). "Photo in the News: Bat Has Longest Tongue of Any Mammal". National Geographic News. National Geographic Society. Archived from the original on 6 June 2007. Retrieved 18 June 2007. A. fistulata (shown lapping sugar water from a tube) has the longest tongue, relative to body length, of any mammal—and now scientists think they know why 
  121. ^ Arita, H. T.; Santos-Del-Prado, K.; Arita, H.T. (1999). "Conservation Biology of Nectar-Feeding Bats in Mexico". Journal of Mammalogy. 80 (1): 31–41. doi:10.2307/1383205. 
  122. ^ Gerardo, H.; Hobson, K. A.; Adriana, M. A.; Daniel, E. B.; Sanchez-Corero, V.; German, M. C. (2001). "The Role of Fruits and Insects in the Nutrition of Frugivorous Bats: Evaluating the Use of Stable Isotope Models". Biotropica. 33 (3): 520–528. doi:10.1111/j.1744-7429.2001.tb00206.x. 
  123. ^ Hodgkison, R.; Balding, S. T.; Zuibad, A.; Kunz, T. H. (2003). "Fruit Bats (Chiroptera: Pteropodidae) as Seed Dispersers and Pollinators in a Lowland Malaysian Rain Forest". Biotropica. 35 (4): 491–502. doi:10.1111/j.1744-7429.2003.tb00606.x. 
  124. ^ a b Popa-Lisseanu, A. G.; Delgado-Huertas, A.; Forero, M. G.; Rodríguez, A.; Arlettaz, R.; Ibáñez, C. (2007). "Bats' Conquest of a Formidable Foraging Niche: The Myriads of Nocturnally Migrating Songbirds". PLoS One. 2 (2): e205. Bibcode:2007PLoSO...2..205P. doi:10.1371/journal.pone.0000205. PMC 1784064 . PMID 17299585. 
  125. ^ Fenton & Simmons 2015, p. 107.
  126. ^ Cramer, M. J.; Wilig, M. R.; Jones, C. (2001). "Trachops cirrhosus" (PDF). Mammalian Species. 656: 1–6. 
  127. ^ Schnitzler, H.-U.; Kalko, E. K. V.; Kaipf, I.; Grinnell, A. D. (1994). "Fishing and Echolocation Behavior of the Greater Bulldog Bat, Noctilio leporinus, in the Field". Behavioral Ecology and Sociobiology. 35 (5): 327–345. doi:10.1007/BF00184422. 
  128. ^ Fenton 2001, pp. 4–5.
  129. ^ Greenhall, A. M. (1961). Bats in Agriculture. A Ministry of Agriculture Publication. p. 8. 
  130. ^ Fenton & Simmons 2015, p. 119.
  131. ^ Wilkinson, G. (1990). "Food Sharing in Vampire Bats" (PDF). Scientific American. 262 (21): 76–82. 
  132. ^ a b Nowak, R. M. (1991). Walker's Mammals of the World. Johns Hopkins Press. p. 1629. ISBN 0-8018-3970-X. 
  133. ^ "Vampire Bats – The Good, the Bad, and the Amazing" (PDF). Natural Science Research Laboratory – Texas Tech. Retrieved 14 December 2017. 
  134. ^ a b Rydell, J.; Speakman, J. R. (1995). "Evolution of nocturnality in bats: Potential competitors and predators during their early history". Biological Journal of the Linnean Society. 54 (2): 183–191. doi:10.1111/j.1095-8312.1995.tb01031.x. 
  135. ^ Esbérard, C. E. L.; Vrcibradic, D. (2007). "Snakes preying on bats: new records from Brazil and a review of recorded cases in the Neotropical Region". Revista Brasileira de Zoologia. 24 (3): 848–853. doi:10.1590/S0101-81752007000300036. 
  136. ^ Lima, S. L.; O'Keefe, J. M. (2013). "Do predators influence the behaviour of bats?". Biological Reviews. 88 (3): 626–644. doi:10.1111/brv.12021. 
  137. ^ Klimpel, S.; Mehlhorn, H. (2013). Bats (Chiroptera) as Vectors of Diseases and Parasites: Facts and Myths. Springer. p. 87. ISBN 9783642393334. 
  138. ^ a b Clayton, D. H.; Bush, S. E.; Johnson, K. P. (2015). Coevolution of Life on Hosts: Integrating Ecology and History. University of Chicago Press. p. 28. ISBN 9780226302270. 
  139. ^ "White-Nose Syndrome (WNS)". National Wildlife Health Center, U.S. Geological Survey. Retrieved 3 June 2014. 
  140. ^ "Culprit Identified: Fungus Causes Deadly Bat Disease". United States Geological Survey. 26 October 2011. 
  141. ^ "White-Nose Syndrome – Background". Canadian Cooperative Wildlife Health Centre. Retrieved 3 June 2014. 
  142. ^ Daly, M. (14 November 2013). "Pennsylvania's Bats Nearly Wiped Out". CBS Philadelphia. 
  143. ^ Gutenberg, G. (7 June 2012). "White-nose syndrome killing Canada's bats". Postmedia Network. Retrieved 21 April 2016. 
  144. ^ "Canada : Environment Canada Announces Funding to Fight Threat of White-nose Syndrome to Bats". Mena Report. 6 April 2013. Retrieved 3 June 2014. 
  145. ^ "Social Bats Pay a Price: Fungal Disease, White-Nose Syndrome ... Extinction?". The National Science Foundation. 3 July 2012. Retrieved 3 June 2014. 
  146. ^ Frick, W. F.; Pollock, J. F.; Hicks, A. C.; Langwig, K. E.; Reynolds, D. S.; Turner, G. G.; Butchkoski, C. M.; Kunz, T. H. (2010). "An Emerging Disease Causes Regional Population Collapse of a Common North American Bat Species". Science. 329 (5992): 679–682. Bibcode:2010Sci...329..679F. doi:10.1126/science.1188594. 
  147. ^ "White-Nose Syndrome Confirmed in Illinois Bats: Illinois becomes 20th state in U.S. to confirm deadly disease in bats" (PDF). Illinois Department of Natural Resources. 28 February 2013. 
  148. ^ {{cite web |url=https://tpwd.texas.gov/newsmedia/releases/?req=20170323c |title=Fungus that Causes White-nose Syndrome in Bats Detected in Texas|publisher=Texas Parks and Wildlife |date=23 March 2017 |accessdate=15 December 20147}
  149. ^ Wong, S.; Lau, S.; Woo, P.; Yuen, K.-Y. (October 2006). "Bats as a continuing source of emerging infections in humans". Reviews in Medical Virology. John Wiley & Sons. 17 (2): 67–91. doi:10.1002/rmv.520. PMID 17042030. The currently known viruses that have been found in bats are reviewed and the risks of transmission to humans are highlighted. 
  150. ^ McColl, K. A.; Tordo, N.; Setien Aquilar, A. A. (2000). "Bat lyssavirus infections". Revue scientifique et technique. 19 (1): 177–196. PMID 11189715. Bats, which represent approximately 24% of all known mammalian species, frequently act as vectors of lyssaviruses 
  151. ^ a b Calisher, C. H.; Childs, J. E.; Field, H. E.; Holmes, K. V.; Schountz, T. (2006). "Bats: Important Reservoir Hosts of Emerging Viruses". Clinical Microbiology Reviews. 19 (3): 531–545. doi:10.1128/CMR.00017-06. PMC 1539106 . PMID 16847084. 
  152. ^ Brüssow, H. (2012). "On Viruses, Bats and Men: A Natural History of Food-Borne Viral Infections": 245–267. doi:10.1007/978-94-007-4899-6_12. 
  153. ^ a b "CDC Features – Take Caution When Bats Are Near". Centers for Disease Control and Prevention. 14 April 2014. 
  154. ^ Halpin, K.; Young, P. L.; Field, H. E.; Mackenzie, J. S. (2000). "Isolation of Hendra virus from pteropid bats: a natural reservoir of Hendra virus". Journal of General Virology. 81 (8): 1927–1932. PMID 10900029. In this paper we describe the isolation of HeV from pteropid bats, corroborating our serological and epidemiological evidence that these animals are a natural reservoir host of this virus. 
  155. ^ Leroy, E. M.; Kumulungui, B.; Pourrut, X.; Rouque, P. (2005). "Fruit bats as reservoirs of Ebola virus" (Brief Communication). Nature. 438 (7068): 575–576. Bibcode:2005Natur.438..575L. doi:10.1038/438575a. PMID 16319873. We find evidence of asymptomatic infection by Ebola virus in three species of fruit bat, indicating that these animals may be acting as a reservoir for this deadly virus 
  156. ^ Choi, C. Q. (2006). "Going to Bat". Scientific American. pp. 24, 26. 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 is a lay summary of the various scientific publications cited in the preceding sentence.
  157. ^ a b Castro, J. (6 February 2013). "Bats Host More Than 60 Human-Infecting Viruses". 
  158. ^ Dobson, A. P. (2005). "What Links Bats to Emerging Infectious Diseases?". Science. 310 (5748): 628–629. doi:10.1126/science.1120872. PMID 16254175. 
  159. ^ "Why Do Bats Transmit So Many Diseases?". 
  160. ^ Li, W.; Shi, Z.; Yu, M.; Ren, W. (28 October 2005). "Bats are natural reservoirs of SARS-like coronaviruses". Science. 310 (5748): 676–679. Bibcode:2005Sci...310..676L. doi:10.1126/science.1118391. PMID 16195424. Retrieved 29 December 2007. Lay summaryScience (2005-10-28). The genetic diversity of bat-derived sequences supports the notion that bats are a natural reservoir host of the SARS cluster of coronaviruses 
  161. ^ Drosten, C.; Hu, B.; Zeng, L.-P.; Yang, X.-L.; Ge, Xing-Yi; Zhang, Wei; Li, Bei; Xie, J.-Z.; Shen, X.-R.; Zhang, Yun-Zhi; Wang, N.; Luo, D.-S.; Zheng, X.-S.; Wang, M.-N.; Daszak, P.; Wang, L.-F.; Cui, J.; Shi, Z.-L. (2017). "Discovery of a rich gene pool of bat SARS-related coronaviruses provides new insights into the origin of SARS coronavirus". PLOS Pathogens. 13 (11): e1006698. doi:10.1371/journal.ppat.1006698. ISSN 1553-7374. 
  162. ^ Fenton 2001, pp. 95–107.
  163. ^ Fenton & Simmons 2015, pp. 188–189.
  164. ^ Kerth, G.; Perony, N.; Schweitzer, F. (2011). "Bats are able to maintain long-term social relationships despite the high fission–fusion dynamics of their groups". Proceedings of the Royal Society B: Biological Sciences. 278 (1719): 1719. doi:10.1098/rspb.2010.2718. 
  165. ^ Fornůsková, A,; Petit, E. J.; Bartonička, T.; Kaňuch, P.; Butet, A.; Řehák, Z.; Bryja, J. (2014). "Strong matrilineal structure in common pipistrelle bats (Pipistrellus pipistrellus) is associated with variability in echolocation calls". Biological Journal of the Linnean Society. 113 (4): 1115–1125. doi:10.1111/bij.12381. 
  166. ^ Carter, G. G.; Wilkinson, G. S. D. (2013). "Does food sharing in vampire bats demonstrate reciprocity?". Communicative & Integrative Biology. 6 (6): e25783. doi:10.4161/cib.25783. PMC 3913674 . PMID 24505498. 
  167. ^ Wilkinson, G. S. (1986). "Social Grooming in the Common Vampire Bat, Desmodus rotundus" (PDF). Anim. Behav. 34 (6): 1880–1889. doi:10.1016/s0003-3472(86)80274-3. 
  168. ^ Fenton 2001, pp. 60–62.
  169. ^ a b Fenton 2001, pp. 93–94.
  170. ^ Wolchover, N. (5 May 2011). "Why Bats Hate Rain". LiveScience. 
  171. ^ Riskin, D. K.; Parsons, S.; Schutt, W. A., Jr.; Carter, G. G.; Hermanson, J. W. (2006). "Terrestrial locomotion of the New Zealand short-tailed bat Mystacina tuberculata and the common vampire bat Desmodus rotundus" (PDF). Journal of Experimental Biology. 209 (9): 1725––1736. doi:10.1242/jeb.02186. 
  172. ^ a b Bohn, K. M.; Schmidt-French, Barbara; Schwartz, Christine; Smotherman, Michael; Pollak, George D. (2009). "Versatility and Stereotypy of Free-Tailed Bat Songs". PLoS ONE. 4 (8): e6746. Bibcode:2009PLoSO...4.6746B. doi:10.1371/journal.pone.0006746. PMC 2727915 . 
  173. ^ a b c Fenton & Simmons 2015, pp. 190–194.
  174. ^ Boughman, J. W. (1998). "Vocal learning by greater spear-nosed bats". Proceedings of the Royal Society B: Biological Sciences. 265 (1392): 227–33. doi:10.1098/rspb.1998.0286. 
  175. ^ Prat, Y.; Taub, M.; Yovel, Y. (22 December 2016). "Everyday bat vocalizations contain information about emitter, addressee, context, and behavior". Scientific Reports. 6: 39419. Bibcode:2016NatSR...639419P. doi:10.1038/srep39419. PMC 5178335 . PMID 28005079. 
  176. ^ Wilkinson, G. S. (1985). "The Social Organization of the Common Vampire Bat II: Mating system, genetic structure, and relatedness" (PDF). Behavioral Ecology and Sociobiology. 17 (2): 123–134. 
  177. ^ Thomas, D. W.; Fenton, M. R.; Barclay, R. M. R. (1979). "Social Behavior of the Little Brown Bat, Myotis lucifugus: I. Mating Behavior". Behavioral Ecology and Sociobiology. 6 (2): 129–136. JSTOR 4599268. 
  178. ^ Keeley, A. T. H.; Keeley, B. W. (2004). "The Mating System of Tadarida brasiliensis (Chiroptera: Molossidae) in a Large Highway Bridge Colony". Journal of Mammalogy. 85: 113–119. doi:10.1644/BME-004. 
  179. ^ Fenton & Simmons 2015, p. 197.
  180. ^ Toth, C. A.; Parsons, S. (2013). "Is lek breeding rare in bats?". Journal of Zoology. 291 (1): 3–11. doi:10.1111/jzo.12069. 
  181. ^ Bradbury, J. W. (1977). "Lek Mating Behavior in the Hammer-headed Bat". Zeitschrift für Tierpsychologie. 45 (3): 225–255. doi:10.1111/j.1439-0310.1977.tb02120.x. 
  182. ^ Altringham 2011, p. 105.
  183. ^ Mares, M. A.; Wilson, D. E. (1971). "Bat Reproduction during the Costa Rican Dry Season". BioScience. 21 (10): 471–472+477. doi:10.2307/1295789. JSTOR 1295789. 
  184. ^ Altringham 2011, p. 114–119.
  185. ^ Neuweiler, G. (2000). Biology of Bats. p. 247. ISBN 978-0-19-509950-8. 
  186. ^ Fenton, M. B. (1983). Just Bats. University of Toronto Press. ISBN 9781442655386. 
  187. ^ Kunz, T. H.; Fenton, B. (2005). Bat Ecology. University of Chicago Press. p. 216. ISBN 978-0226462073. 
  188. ^ a b Fenton 2001, p. 166.
  189. ^ Nagorsen, D. W.; Brigham, R. M. Bats of British Columbia. UBC Press. p. 17. ISBN 9780774804820. 
  190. ^ Altringham 2011, p. 119.
  191. ^ Fenton & Simmons 2015, p. 171.
  192. ^ Turbill, C.; Bieber, C.; Ruf, T. (2011). "Hibernation is associated with increased survival and the evolution of slow life histories among mammals". Proceedings of the Royal Society B. 278 (1723): 3355–3363. doi:10.1098/rspb.2011.0190. PMC 3177628 . 
  193. ^ a b Wilkinson, G. S.; South, J. M. (2002). "Life history, ecology and longevity in bats" (PDF). Aging Cell. 1 (2): 124–131. doi:10.1046/j.1474-9728.2002.00020.x. PMID 12882342. 
  194. ^ Gager, Y.; Gimenez, O.; O'Mara, M. T.; Dechmann, D. K. N. (2016). "Group size, survival and surprisingly short lifespan in socially foraging bats". BMC Ecology. 16 (2): 2. doi:10.1186/s12898-016-0056-1. PMC 4714502 . 
  195. ^ "Our Mission". Organization for Bat Conservation. Retrieved 16 November 2017. 
  196. ^ "Mission & Vision". Bat Conservation International. Retrieved 16 November 2017. 
  197. ^ "Bats and the Law". Bat Conservation Trust. Retrieved 16 November 2017. 
  198. ^ a b "Wildlife Protection Ordinance 1998" (PDF). FAO. Retrieved 16 November 2017. 
  199. ^ Leong, T. M.; Teo, S. C.; Lim, K. K. P. (2009). "The Naked Bulldog Bat, Cheiromeles torquatus in Singapore — past and present records, with highlights on its unique morphology (Microchiroptera: Molossidae)". Nature in Singapore. 2: 215–230. 
  200. ^ Fox. "Best time to see the bat colony emerge from Congress Bridge in Downtown Austin". Retrieved 21 August 2016. 
  201. ^ "Bat Conservation International". Web.archive.org. 24 January 2002. Archived from the original on 23 June 2013. 
  202. ^ "UF Bat Colony". Florida Museum of Natural History. Retrieved 21 August 2016. 
  203. ^ Glover, M. "Facts about this colony". UF News. University of Florida. p. 1. Retrieved 16 March 2012. 
  204. ^ "Protecting and managing underground sites for bats (pdf), see section 6.4" (PDF). Archived from the original (PDF) on 12 May 2012. Retrieved 18 May 2006. 
  205. ^ "Pillbox converted to bat retreat, BBC website". BBC News. 6 April 2006. Retrieved 18 May 2006. 
  206. ^ "Bypass wings it with bat bridges". BBC. 4 April 2008. Retrieved 21 August 2016. 
  207. ^ "Bat bridges cost £27k per animal". BBC. 22 October 2009. Retrieved 21 August 2016. 
  208. ^ "Agency Guide to Cave and Mine Gates 2009" (PDF). Batcon.org. Retrieved 1 November 2017. 
  209. ^ Hopkins, J.; Bourdain, A. (2004). Extreme Cuisine: The Weird & Wonderful Foods that People Eat. Periplus. p. 51. ISBN 978-0-7946-0255-0. 
  210. ^ Baerwald, E. F.; D'Amours, G. H.; Klug, B. J.; Barclay, R. M. R. (2008). "Barotrauma is a significant cause of bat fatalities at wind turbines". Current Biology. 18 (16): R695–R696. doi:10.1016/j.cub.2008.06.029. 
  211. ^ a b "B.C. study to help bats survive wind farms", National Wind Watch, 23 September 2008, retrieved 19 April 2015 
  212. ^ "Bats take a battering at wind farms", New Scientist, 12 May 2007
  213. ^ "Caution Regarding Placement of Wind Turbines on Wooded Ridge Tops" (PDF). Bat Conservation International. 4 January 2005. Archived (PDF) from the original on 23 May 2006. Retrieved 21 April 2006. 
  214. ^ Arnett, E. B.; Erickson, W. P.; Kerns, J.; Horn, J. (12 June 2005). "Relationships between Bats and Wind Turbines in Pennsylvania and West Virginia: An Assessment of Fatality Search Protocols, Patterns of Fatality, and Behavioral Interactions with Wind Turbines" (PDF). Bat Conservation International. Archived from the original (PDF) on 10 February 2006. Retrieved 21 April 2006. 
  215. ^ Baerwald, E. F.; D'Amours, G.H.; Klug, Brandon J.; Barclay, R. M. R. (26 August 2008). "Barotrauma is a significant cause of bat fatalities at wind turbines". Current Biology. 18 (16): R695–R696. doi:10.1016/j.cub.2008.06.029. OCLC 252616082. PMID 18727900. 
  216. ^ Johnson, J. B.; Ford, W. M.; Rodrigue, J. L.; Edwards, J. W. (2012). "Effects of Acoustic Deterrents on Foraging Bats". U.S. Department of Agriculture, U.S. Forest Service, Northern Research Station: 1–5. 
  217. ^ Chwalkowski, F. (2016). Symbols in Arts, Religion and Culture: The Soul of Nature. Cambridge Scholars Publishing. p. 523. ISBN 978-1443857284. 
  218. ^ McCracken, G. F. (1993). "Folklore and the Origin of Bats". BATS Magazine. Bats in Folklore. 11 (4). 
  219. ^ Saleh, A. (19 July 2001). "Sex-mad 'ghost' scares Zanzibaris". BBC News. Retrieved 29 December 2014. 
  220. ^ "Aztec Symbols". Aztec-history.net. Retrieved 24 June 2013. 
  221. ^ Read, K. A.; Gonzalez, J. J. (2000). Mesoamerican Mythology. Oxford University Press. pp. 132–134. 
  222. ^ "Artists Inspired by Oaxaca Folklore Myths and Legends". Oaxacanwoodcarving.com. Retrieved 24 June 2013. 
  223. ^ Berrin, Katherine & Larco Museum. The Spirit of Ancient Peru:Treasures from the Museo Arqueológico Rafael Larco Herrera. New York: Thames and Hudson, 1997.
  224. ^ Arnott, K. (1962). African Myths and Legends. Oxford University Press. pp. 150–152. 
  225. ^ "Chinese symbols" (PDF). British Museum. Retrieved 10 September 2017. 
  226. ^ Grant, G. S. "Kingdom of Tonga: Safe Haven for Flying Foxes". Batcon.org. Retrieved 24 June 2013. 
  227. ^ Cartwright, M. (28 October 2013). "Zapotec Civilization". Ancient History Encyclopedia. Retrieved 2 December 2017. 
  228. ^ de Vries, A. (1976). Dictionary of Symbols and Imagery. Amsterdam: North-Holland. p. 36. ISBN 0-7204-8021-3. 
  229. ^ "Bats – nature's most misunderstood animal". The Telegraph. The Daily Telegraph. 25 September 2015. Retrieved 9 September 2017. 
  230. ^ Fleisher, M. L. (1976). The Encyclopedia of Comic Book Heroes Volume 1 Batman. Collier Books. p. 31. ISBN 978-0-02-080090-3. 
  231. ^ "Silverwing by Kenneth Oppel". Kirkus Reviews. 1997. Retrieved 25 September 2017. 
  232. ^ Oppel, K. "The Characters: Shade". Kenneth Oppel. Retrieved 25 September 2017. "Shade is based on a Silver-Haired Bat. I thought they were very dashing-looking creatures. I liked the fact this was a bat that lived in the same part of the world as me (eastern Canada). These are small creatures, with a wing span of a few inches. Their bodies are about the same size as mice. They’re insectivores, which means they eat only insects." – K.O. 
  233. ^ Tramoyeres Blasco, L. "Lo Rat Penat en el escudo de armas de Valencia" [The Rat Penat in the coat of arms of Valencia] (in Spanish). Retrieved 14 November 2014. 
  234. ^ Alomar i Canyelles, A. I. (1998). L'Estendard, la festa nacional més antiga d'Europa [The Banner, the oldest national party in Europe]. Palma. pp. XIII–XXI. 
  235. ^ Emblemata Revista aragonesa de emblematica (PDF) (in Spanish). 6. 2005 https://web.archive.org/web/20170910130155/http://ifc.dpz.es/recursos/publicaciones/25/75/_ebook.pdf. Archived from the original (PDF) on 15 November 2017.  Missing or empty |title= (help)[page needed]
  236. ^ "Official state bats". netstate.com. NSTATE, LLC. Archived from the original on 9 March 2011. Retrieved 13 February 2011. 
  237. ^ Weaver, H. D. (2008). Missouri Caves in History and Legend. University of Missouri Press. pp. 64–69. ISBN 978-0-8262-6645-3. 
  238. ^ Whisonant, R. C. (2001). "Geology and History of Confederate Saltpeter Cave Operations in Western Virginia" (PDF). Virginia Minerals. 47 (4): 33–43. 

Sources

  • Altringham, J. D. (2011). Bats: From Evolution to Conservation. Oxford University Press. ISBN 978-0199207114. 
  • Fenton, M. B. (2001). Bats. Checkmark Books. ISBN 978-0-8160-4358-3. 
  • Fenton, M. B.; Simmons, N. B. (2015). Bats: A World of Science and Mystery. University of Chicago Press. ISBN 978-0226065120. 

External links