| Pteropus | |
|---|---|
_in_flight_Taveuni.jpg) | |
| Polynesian flying fox Pteropus tonganus, Taveuni, Fiji | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Chiroptera |
| Family: | Pteropodidae |
| Tribe: | Pteropodini |
| Genus: | Pteropus Brisson, 1762 |
| Type species | |
| Vespertilio vampyrus niger[2] Kerr, 1792 | |
 | |
| Worldwide distribution of flying foxes | |
Pteropus (suborderYinpterochiroptera) is agenus ofmegabats which are among the largest bats in the world. They are commonly known asfruit bats orflying foxes, among other colloquial names. They live inSouth Asia,Southeast Asia,Australia,East Africa, and some oceanic islands in the Indian and Pacific Oceans.[3] There are at least 60extant species in the genus.[4]
Flying foxes eat fruit and other plant matter, and occasionally consume insects as well. They locate resources with their keen sense of smell.Most, but not all, arenocturnal. They navigate with keen eyesight, as they cannotecholocate.They havelong life spans and low reproductive outputs, with females of most species producing only one offspring per year. Their slow life history makes their populations vulnerable to threats such asoverhunting,culling, and natural disasters. Six flying fox species have been madeextinct in modern times by overhunting. Flying foxes are often persecuted for their real or perceived role indamaging crops. They are ecologically beneficial by assisting in the regeneration of forests viaseed dispersal. They benefit ecosystems and human interests bypollinating plants.
Like other bats, flying foxes are relevant to humans as a source of disease, as they are thereservoirs of rare but fatal disease agents includingAustralian bat lyssavirus, which causesrabies, andHendra virus; seven known human deaths have resulted from these two diseases.Nipah virus is also transmitted by flying foxes—it affects more people, with over 100 attributed fatalities. They have cultural significance to indigenous people, with appearances in traditional art, folklore, and weaponry. Their fur and teeth were used as currency in the past. Some cultures still use their teeth as currency today.
The genus namePteropus, fromAncient Greek 'πτερόν' (pterón), meaning "wing", and 'πούς' (poús), meaning "foot", was coined by French zoologistMathurin Jacques Brisson in 1762.[5]Prior to 1998, genus authority was sometimes given to German naturalistJohann Christian Polycarp Erxleben.[6] Although the Brisson publication (1762) predated the Erxleben publication (1777), thus giving him preference under thePrinciple of Priority, some authors gave preference to Erxleben as genus authority because Brisson's publication did not consistently usebinomial nomenclature.[7] In 1998, theInternational Commission on Zoological Nomenclature (ICZN) decided that Brisson's 1762 publication was a "rejected work" for nomenclatural purposes. Despite rejecting the majority of the publication, the ICZN decided to conserve a dozen generic names from the work and retain Brisson as authority, includingPteropus.[2]
Thetype species of the genus is theMauritian flying fox,Pteropus niger (described asVespertilio vampyrus niger byRobert Kerr in 1792).[8]The decision to designateP. niger as the type species was made by the ICZN through theirplenary powers over biological nomenclature.[7] The phrase "flying fox" has been used to refer toPteropus bats since at least 1759.[9]
| Phylogeny ofPteropus based on mitochondrialcytochrome b and rRNA12S genes. Species without enough data are excluded.[10] |
Flying fox species vary in body weight, ranging from 120–1,600 g (0.26–3.53 lb). Across all species, males are usually larger than females.[11]Thelarge flying fox has the longest forearm length and reported wingspan of any bat species,[3] but some bat species exceed it in weight. Its wingspan is up to 1.5 m (4 ft 11 in), and it can weigh up to 1.1 kg (2+1⁄2 lb).[12] TheIndian andgreat flying foxes are heavier, at1.6 and 1.45 kg (3+1⁄2 and3+1⁄4 lb), respectively.[3][13] Outside this genus, thegiant golden-crowned flying fox (genusAcerodon) is the only bat with similar dimensions.[3]
Most flying fox species are considerably smaller and generally weigh less than 600 g (21 oz).[14] Smaller species such as themasked,Temminck's,Guam, anddwarf flying foxes all weigh less than 170 g (6 oz).[14]
The pelage is long and silky with a dense underfur.[3] In many species, individuals have a "mantle" of contrasting fur color on the back of their head, the shoulders, and the upper back.[15] They lack tails. As the common name "flying fox" suggests, their heads resemble that of a small fox because of their small ears and large eyes. Females have one pair ofmammae located in the chest region. Their ears are long and pointed at the tip and lacktragi, the outer margin of each ear forming an unbroken ring.[3][15] The toes have sharp, curved claws. Whilemicrobats only have a claw on each thumb of their forelimbs, flying foxes additionally have a claw on each index finger.[3]
The skulls ofPteropus species are composed of 24 bones, thesnout is made of 7, thecranium of 16 and themandible is a single bone. It has a large and bulbousbraincase. Like all mammals, flying foxes have threemiddle ear ossicles which assist in transmitting sound to the brain. Flying fox skulls continue to develop after they are born. Compared to adults, young flying foxes have very short snouts; as they reach maturity, themaxilla elongates, gaining bone between thezygomatic processes and thecanine teeth.[16]
Based on thegrey-headed flying fox's development, pups are born with somemilk teeth already erupted: canines andincisors. By 9 days old, all the milk teeth have emerged, with adental formula of2.1.2.02.1.2.0 and a total of 20 teeth. By 140 days old (4.6 months), all the milk teeth have fallen and been replaced bypermanent teeth. The canines are usually replaced first, followed by thepremolars, incisors, and thenmolars.[17] The adult dental formula is2.1.3.22.1.3.3 for a total of 34 teeth. Theocclusal surface of the molars is generally smooth but with longitudinal furrows.[3]
Flying foxes have large hearts and a relatively fastheart rate: resting individuals have a heart rate of 100–400 beats per minute.[18]
Flying foxes have simpledigestive tracts;[3] the time between ingestion and excretion is as short as 12 minutes. They lack both acecum and anappendix.[19] The stomach has markedcardiac and fundic regions.[15]
The megabats, including flying foxes, have the greatestencephalization quotient (brain size relative to body size) of any bat family at 1.20.[20] This value is equivalent to that of domestic dogs.[21] Flying foxes display behaviors that indicate a reliance on long-term information storage. Though they have wide-ranging movements and cover thousands of square kilometers annually, they are consistently able to locate the same resource patches and roosts. They will visit these resource patches consistently in a strategy known astrap-lining. They can also beconditioned to perform behaviors, such as one study wherespectacled flying foxes were trained to pull a lever using juice as areinforcement. In a follow-up to the initial study, individuals who had learned to pull the lever to receive juice still did so 3.5 years later.[22]
Flying foxes rely heavily on their sense of smell.They have largeolfactory bulbs to process scents. They use scent to locate food, for mothers to locate their pups, and for mates to locate each other.[15] Males have enlargedandrogen-sensitivesebaceous glands on their shoulders that they use forscent-marking their territories, particularly during the mating season. The secretions of these glands vary by species—of the 65 chemical compounds identified from the glands of four species, no compound was found in all species.[23] Males also engage in "urine washing", meaning that they coat themselves in their own urine.[23][24]
Flying foxes do notecholocate, and therefore rely on sight to navigate. Their eyes are relatively large and positioned on the front of their heads, giving thembinocular vision.[25]Like most mammals, though notprimates, they aredichromatic.[26] They have bothrods andcones; they have "blue" cones that detect short-wavelength light and "green" cones that detect medium-to-long-wavelengths. The rods greatly outnumber the cones, however, as cones comprise only 0.5% of photoreceptors. Flying foxes are adapted toseeing in low-light conditions.[27]
| Phylogeny of Pteropodidae[28] |
Flying foxes are poorly represented in the fossil record. Relative to the current number of extant species, the Pteropodidae has one of the most incomplete fossil records of any bat group.[29] As of 2014, no flying fox fossils are known from before theHolocene.[10]Many flying foxes live in thetropics, where conditions for fossilization are poor.[29] Based onmolecular evolution, flying foxes diverged from a common ancestor withRousettus 28–18 million years ago[30] and from theirsister taxaNeopteryx andAcerodon 6.6–10.6 million years ago.[10]Neopteryx,Acerodon,Desmalopex,Melonycteris,Mirimiri,Pteralopex, andStyloctenium are all relatively closely related to the flying foxes, as they are the other members of itssubfamilyPteropodinae.
Phylogenetic analysis indicates that flying foxes diversified rapidly in an explosiveevolutionary radiation, creating many taxa in a relatively short time frame.[31] Most flying fox lineages emerged after theZanclean, with two majorclades created: one consisting of theIndian Ocean species and the other of theMelanesian,Micronesian, Australian, and insularSoutheast Asian species. Flying foxes likely originated on mainland Asia; molecular data suggests that there were at least threecolonization events into the Indian Ocean. One event resulted inLivingstone's fruit bat and thePemba flying fox, which are the westernmost flying foxes. A second colonization event resulted in theRodrigues flying fox toRodrigues Island; while a third event resulted in several species diverging toMauritius, theSeychelles,Madagascar, andAldabra.[32]
With one possible exception - the masked flying fox (P. personatus), flying foxes are likelymonophyletic. There are over 60 extant species of flying fox.[10] Flying foxes are now present from the western Indian Ocean midway through thePacific Ocean as far east as theCook Islands.[32][10] They are found in tropical and subtropical climates.[32]
Many species of flying fox arepolygynandrous, meaning that each individual will mate with several other individuals.[33] TheSamoa flying fox is a notable exception because it ismonogamous.[34] Flying fox sexual behaviors include oral sex in addition to intercourse, withfellatio andcunnilingus observed between opposite sexes, as well as homosexual fellatio in at least one species, theBonin flying fox.[35][36] Opposite-sex oral sex is associated with increased duration of intercourse, while same-sex fellatio is hypothesized to encourage colony formation of otherwise-antagonistic males in colder climates.[35][36]
Flying foxgestation length varies among species; gestation length is 140–190 days (4.6–6.3 months).Females have alitter size of one young at a time, called a pup.[37]Twins have been occasionally documented in some species, however. Twins can befraternal,identical, or the result ofsuperfetation.[38] Pups arealtricial and sparsely furred at birth, thereby dependent on their mothers for care.[37] Pups are relatively small at birth, weighing approximately 12% of the mother's weight. Bats in other genera can have pups that weigh as much as 30% of the mother's weight at birth.[39][40] They cling to their mothers' abdomens, gripping her fur with their thumb claws and teeth; females carry the pups for the first several weeks of life. After this, the females may leave the pups behind at the roost at night while they forage.[37] As with nearly all bat species, males do not assist females in parental care.[41] While male flying foxes of at least one species, theBismarck masked flying fox, canlactate, it is unclear if the lactation is functional and males actually nurse pups or if it is a result ofstress ormalnutrition.[42] Pupsfledge beginning at 3 months old, but may not beweaned until 4–6 months old. Pups may stay with their mothers until age one. Flying foxes do not reachsexual maturity until 1.5–2 years old. Females can have up to two litters annually, though one is the norm due to the long weaning period. Most flying foxes areseasonal breeders and give birth in thespring, though theMariana fruit bat seems to have aseasonal breeding with new pups documented throughout the year.[37] Females remainfertile with no decrease in reproductive capability for at least the first 12 or 13 years of life.[43]
Flying foxes, like all bats, are long-lived relative to their size.[44] In the wild, average lifespans are likely 15 years.[45] However, individuals part of populations that face excessivedisturbance may have lifespans as short as 7.1 years.[46] In captivity, individuals can live approximately 20–28 years.[45] The longest-lived flying fox was an Indian flying fox named Statler, who was a resident at Bat World Sanctuary for his last few years. He was born at a zoo in 1987, and was 34 years old at the time of his death.[3]
Most flying fox species aregregarious and form large aggregations of individuals calledcolonies or "camps." The large flying fox forms colonies of up to 15,000 individuals,[47][48] while thelittle red flying fox forms colonies of up to 100,000 individuals.[37] A few species and subspecies, such asOrii's flying fox (P. dasymallus inopinatus) and theCeram fruit bat, are solitary.[49][50]
Colony size varies throughout the year in response to biological needs. The grey-headed flying fox formsharems during the breeding season consisting of one male and up to six females. These colonies break up after the breeding season is over.[51] In the Bonin flying fox, colony formation is based on both the sex and age of individuals, as well as the season. In the winter breeding season, adult females will form colonies that include a few adult males (likely harems). Adult males who do not roost with females will form colonies with other adult andsubadult males. Subadults will form mixed-sex "subadult groups" with each other. In the summer, however, individuals are solitary, with the exception ofnursing females, who roost with their pups.[34]
Flying foxes consume 25–35% of their body weight daily.[52] They aregeneralists that will consume a variety of items to meet their nutritional needs. Food items include fruit, flowers, nectar, and leaves.[53][54] They will sometimes deliberately consume insects such ascicadas as well.[55]In Australia,eucalypt blossoms and pollen are preferred food sources, followed byMelaleuca andBanksia flowers[56] They feed on a wide variety ofcrops as well, causing conflicts with farmers. Crops eaten by flying foxes includesisal,cashew,pineapple,areca,breadfruit,jackfruit,neem,papaya,citrus,fig,mango,banana,avocado,guava,sugar cane,tamarind,grapes, and more.[57]
In captivity, the recommended diet for flying foxes consists of two-thirds hard fruits like pears and apples and one-third soft fruits. Bananas and other high-fiber fruits should only be offered occasionally, as flying foxes are not adapted to high-fiber diets. Protein supplements are recommended for captive flying foxes; other supplements such asvitamin C,calcium,chondroitin sulfate, andglucosamine can be recommended periodically.[52]
The majority of flying fox species arenocturnal and forage at night. A few island species and subspecies arediurnal, however, hypothesized as a response to a lack of predators. Diurnal taxa includeP. melanotus natalis, the Mauritian flying fox, theCaroline flying fox,P. p. insularis, and theSeychelles fruit bat. Foraging resources are often far from roosts, with individuals traveling up to 40–60 km (25–37 mi) to reach them.[37] Flying foxes can travel at 6 m/s (13 mph) for three hours or more, and can reach top speeds of 8.6 m/s (19 mph).[58] Some colonial species will forage in groups, especially when resources are abundant. Less social species will forage alone.[37] When they land on a tree with food, they will hang onto the branch with their clawed hind feet and use their clawed thumbs to pull branches bearing flowers or fruits towards them.[22] As they forage on fruit, flying foxes will compress the fruit against thepalate with the tongue to squeeze out and consume the juices. The rest of the fruit is then discarded in "ejecta pellets."[59]
Flying foxes have important roles asseed dispersers andpollinators. They help spread the seeds in the fruit they eat by discarding them in ejecta pellets or through theirguano. In Madagascar, fig seeds have better germination success if they have passed through the gut of a flying fox, which is important because fig trees are a vitalpioneer species in regenerating lost forest. Even though flying foxes can have a gut transit time as fast as 12 minutes, seeds can be retained in the gut for as long as 20 hours. As the flying foxes travel large distances, seeds can be deposited up to 20 km (12 mi) from the parent tree. They are particularly important in fragmented forests, as many other frugivores are terrestrial and often confined to forest fragments.Flying foxes have the capability to spread seeds beyond the forest fragments through flight.[60]
Flying foxes pollinate a variety of plants, including the economically valuabledurian. They forage on its nectar in such a way that the flowers (and eventual fruit production) are not usually harmed. Flying fox pollination has a positive effect on durian reproductive success, suggesting that both flying foxes and durian treesbenefit from this relationship.[61]
Of the 62 flying fox species evaluated by theIUCN as of 2018, 3 are consideredcritically endangered: theAru flying fox, Livingstone's fruit bat, and theVanikoro flying fox. Another 7 species are listed asendangered; 20 are listed asvulnerable, 6 asnear threatened, 14 asleast concern, and 8 asdata deficient. A further 4 are listed asextinct: thedusky flying fox, thelarge Palau flying fox, thesmall Mauritian flying fox, and the Guam flying fox.[62] Over half of the species are threatened today with extinction, and in particular in the Pacific, a number of species have died out as a result of hunting, deforestation, and predation by invasive species.[45] Six flying fox species are believed to have gone extinct from 1864 to 2014: the Guam, large Palau, small Mauritian, dusky,large Samoan, and thesmall Samoan flying foxes.[10]
All species ofPteropus are placed onAppendix II ofCITES and 10 onAppendix I, which restricts international trade.[63] Individual species have different legal protections from hunting and domestic trade that reflect the environmental laws of the countries where they are found.[64]
In some countries such as Bangladesh, Sri Lanka, and Thailand, flying foxes are absolutely protected from harm under the Wildlife Preservation and Security Act of 2012, Fauna and Flora Protection Ordinance of 1937, and Wildlife Protection and Reservation Act of 1992, respectively.[64] However, in Thailand, flying fox poaching and the illegal bushmeat trade still occurs outside ofprotected areas. The large flying fox and the small flying fox are particularly prone to poaching and roost disturbance.[64]
In other countries, such as Australia, Japan, and the United States, some species of conservation concern are protected under national environmental legislation, while others are not. In Australia, two flying foxes are listed under theEnvironment Protection and Biodiversity Conservation Act of 1999: the grey-headed and spectacled flying foxes are listed as "vulnerable."[65] Farmers can apply for permits to kill flying foxes when they are causing crop damage.[66]
Several flying fox species occur in Japan. The Bonin flying fox has been aNatural Monument of Japan since 1969, which means that it is illegal to capture or disturb them without appropriate permits.[67] Two subspecies of the Ryukyu flying fox (P. d. dasymallus andP. d. daitoensis) are also listed as Natural Monuments.[68]Flying foxes are not designated game species in Japan, and therefore cannot be legally hunted per the Wildlife Protection and Hunting Law.[69] The Bonin flying fox andP. d. daitoensis are also listed as National Endangered Species, meaning that they cannot be killed or harmed; furthermore, the sale or transfer of live or dead individuals in whole or part is also prohibited without permits.[69][70]
Despite not occurring in the continental United States, several species and subspecies are listed under itsEndangered Species Act of 1973.Pteropus mariannus mariannus—a subspecies of the Mariana fruit bat—is listed asthreatened while the Rodrigues flying fox and Guam flying fox are listed asendangered.[71] Additionally, the U. S. government has been petitioned to list the Aru flying fox and Bonin flying fox as threatened or endangered.[72]
In such countries as India and Pakistan, flying foxes explicitly have no legal protection. In India, they are listed as "vermin" under theWildlife Protection Act of 1972.[73] Pakistan's only flying fox, the Indian flying fox, is listed under Schedule 4 of the Punjab Wildlife (Protection, Preservation, Conservation and Management) Act of 1974, meaning that it has no legal protections and can be hunted.[64]In Mauritius, flying foxes were formerly protected but are now legally culled at a large scale. In 2015, the Mauritian government passed the Native Terrestrial Biodiversity And National Parks Act, which legalized culling of the Mauritian flying fox. In Mauritius, over 40,000 Mauritian flying foxes were culled in a two-year period, reducing its population by an estimated 45%.[45] This decision was viewed with controversy, with researchers stating "Because they spread seeds and pollinate flowers, flying foxes are vital for regenerating lost forests."[74]
Legal protection can vary within a country as well, such as inMalaysia. Under the 1990 Protection of Wild Life Amendment Order, flying foxes can be hunted with a permit; each permit is good for killing up to 50 flying foxes. Permits cost U.S.$8 each. However, under the Protection of WildLife Act of 1972, flying foxes can be killed without permits if they are causing damage or if there is "reason to believe that it is about to cause serious damage" to crops.[64] In 2012, the Malaysian state ofTerengganu issued a moratorium on hunting flying foxes.[64]InSarawak, all bat species are listed as "Protected" and hunting them is not legal.[64]
Flying foxes species are declining or going extinct as a result of severalhuman impacts to their environments, in addition to natural phenomena.[37] Their populations are especially vulnerable to threats because the litter size is usually only individual and females generally only have one litter per year. Even when nearly every female (90%) successfully produces and raises young, if a population'smortality rate exceeds 22% annually, then it will steadily decline.[43]
Invasive species, such as thebrown tree snake, can seriously affect populations; the brown tree snake consumes so many pups that it reduced therecruitment of theGuam population of the Mariana fruit bat to essentially zero.[75]
Many flying fox species are threatened by overhunting. While they have long been a dietary component of indigenous people,expanding human population and more efficient weapons have resulted in population declines,local extinctions, and extinctions. Overhunting is believed to be the primary cause of extinction for the small Mauritian flying fox and the Guam flying fox.[37]
Flying foxes are also threatened with excessive culling due to conflict with farmers. They are shot, beaten to death, or poisoned to reduce their populations. Mortality also occurs via accidental entanglement intonetting used to prevent the bats from eating fruit.[76] Culling can dramatically reduce flying fox populations.In Mauritius, over 40,000 Mauritian flying foxes were culled in a two-year period, reducing its population by an estimated 45%.[45] Flying foxes are also killed by electrocution. In one Australian orchard, it is estimated that over 21,000 bats were electrocuted to death in an 8-week period.[43] Farmers construct electrified grids over their fruit trees to kill flying foxes before they can consume their crop. The grids are questionably effective at preventing crop loss, with one farmer who operated such a grid estimating that they still lost 100–120 tonnes (110–130 short tons) of fruit to flying foxes in a year.[77] Some electrocution deaths are also accidental, such as when bats fly intooverhead power lines.[78]
Climate change causes flying fox mortality and a source of concern for species persistence. Extreme heat waves in Australia have been responsible for thedeaths of more than 30,000 Australian flying foxes from 1994 to 2008. Females and young bats are most susceptible to extreme heat, which affects a population's ability to recover.[79] Flying foxes are threatened by sea level rise associated with climate change, as several taxa are endemic to low-lyingatolls.[80]
Because many species are endemic to a single island, they are vulnerable to random events such astyphoons. A 1979 typhoon halved the remaining population of the Rodrigues flying fox. Typhoons result in indirect mortality as well: Because they defoliate the trees, flying foxes are more visible and easily hunted by humans. Food resources for the bats become scarce after major storms, and flying foxes resort to riskier foraging strategies such as consuming fallen fruit off the ground. There, they are more vulnerable to depredation by domestic cats, dogs, and pigs.[37]
Flying foxes are also threatened by disease such astick paralysis. Tick paralysis affects the spectacled flying fox, and is responsible for an estimated 1% of its annual mortality.[81]
Several species of endangered flying fox are bred in captivity to augment their population sizes. Critically endangered Livingstone's fruit bats were taken from the wild starting in 1995 to create acaptive breeding program. All captive individuals remain the property of theComorian government.[82] 17 individuals were collected from the wild; with breeding, there are 71 in captivity as of 2017. Individuals are held at theJersey Zoo and theBristol Zoo.[83] Though the program has been successful in increasing the population, caretakers of the captive population have had to deal withhusbandry issues such asobesity andcardiomyopathy.[84] Relative to their wild counterparts, captive bats have a higher percentage of body fat and a lower percentage of muscle mass. The problem is pronounced indominant males, which are the mostsedentary. Addressing these concerns involves increasing flight space so that the animals can exercise adequately.[85] Keepers are also exploring ways of distributing food within enclosures to encourage exercise.[84]
The endangered Rodrigues flying fox has been bred in captivity with great success. By 1979, only 70–100 individuals were left in the world. In 1976, 25 individuals were removed from the wild byDurrell Wildlife Conservation Trust to begin a breeding program.[86] In 1988, the breeding program was called "undoubtedly the most important chiropteran breeding project now in operation."[87] By 2016, there were 180 individuals in 16 zoos across the United States alone.[86] Worldwide, 46 zoos participate in the Rodrigues flying fox breeding program as of 2017.[88]
Many flying foxes species are killed forbushmeat. The bushmeat harvest is often unsustainable, often resulting in severe population decline orlocal extinction. Flying foxes are killed and sold for bushmeat in several countries in Southeast Asia,South Asia, andOceania, includingIndonesia, Malaysia,Papua New Guinea, thePhilippines, Bangladesh, China,[89]Fiji, and Guam.[90] Flying fox consumption is particularly common in countries with lowfood security and lack of environmental regulation.[91] In some cultures in the region, however, eating flying fox meat istaboo. InNamoluk, locals are repulsed by the idea of eating flying foxes because the flying foxes urinate on themselves.[80] In predominatelyMuslim regions such as much of Indonesia, flying foxes are rarely consumed because ofhalal dietary restrictions.[91]
North Sulawesi has the greatest demand for flying fox bushmeat. Despite being in Muslim-majority Indonesia, North Sulawesi is predominatelyChristian; therefore, many locals do not follow halal guidelines prohibiting flying fox consumption. InManado, most local people consume flying fox meat at least once a month. The frequency of flying fox consumption increases tenfold around holidays.Locals believe that "unique meat" from undomesticated animals should be served on special occasions to "enliven the atmosphere." Suggestions to make the flying fox bushmeat trade more sustainable include enforcing a quota system for harvesting, encouraging hunters to release female and juvenile individuals, and providing economic alternatives to those who make a living selling flying fox bushmeat.[91]
In Guam and theCommonwealth of the Northern Mariana Islands, consumption of the Mariana fruit bat exposes locals to theneurotoxinbeta-Methylamino-L-alanine (BMAA) which may later lead toneurodegenerative diseases. BMAA may becomebiomagnified in humans who consume flying foxes; flying foxes are exposed to BMAA by eatingcycad fruits.[92][93][94]
Flying foxes are killed for use in traditional medicine. The Indian flying fox, for example, has many perceived medical uses.Some believe that its fat is a treatment forrheumatism.[3] Tribes in theAttappadi region of India eat the cooked flesh of the Indian flying fox to treat asthma and chest pain.[95] Healers of the Kanda tribe of Bangladesh use hair from Indian flying foxes to create treatments for "fever with shivering."[96]
Flying foxes are thenatural reservoirs of several viruses, some of which can betransmitted to humans. Notably, flying foxes can transmitlyssaviruses, which causerabies. In Australia therabies virus is not naturally present;Australian bat lyssavirus is the only lyssavirus present. Australian bat lyssavirus was first identified in 1996; it is very rarely transmitted to humans. Transmission occurs from the bite or scratch of an infected animal, but can also occur from getting the infected animal's saliva in amucous membrane or an openwound. Exposure to flying fox blood, urine, or feces is not a risk of exposure to Australian bat lyssavirus.Since 1994, there have been three records of people getting infected with it—all three were inQueensland and each case was fatal.[97]
Flying foxes are also reservoirs ofhenipaviruses such asHendra virus andNipah virus. Hendra virus was first identified in 1994; it also rarely occurs humans. From 1994 to 2013, there have been seven reported cases of Hendra virus affecting people, four of which were fatal. The hypothesized primary route of human infection is via contact withhorses that have come into contact with flying foxurine.[98]There are no documented instances of direct transmission between flying foxes and humans.[99] As of 2012, there is avaccine available for horses to decrease the likelihood of infection and transmission.[100]
Nipah virus was first identified in 1998 in Malaysia. Since 1998, there have been several Nipah outbreaks in Malaysia,Singapore,India, and Bangladesh, resulting in over 100 casualties. A 2018 outbreak inKerala, India resulted in 19 humans infected, of which 17 died.[101] The overall fatality rate is 40–75%. Humans can contract Nipah virus from direct contact with flying foxes or their fluids, through exposure to an intermediatehost such asdomestic pigs, or from contact with an infected person.[102] A 2014 study of the Indian flying fox and Nipah virus found that while Nipah virus outbreaks are more likely in areas preferred by flying foxes, "the presence of bats in and of itself is not considered a risk factor for Nipah virus infection." Rather, the consumption ofdate palm sap is a significant route of transmission. The practice of date palm sap collection involves placing collecting pots at date palm trees. Indian flying foxes have been observed licking the sap as it flows into the pots, as well as defecating and urinating in proximity to the pots. In this way, humans who drink the palm sap can be exposed to the bats' viruses.[103] The use of bamboo skirts on collecting pots lowers the risk of contamination from bat fluids.[104]
Flying foxes can transmit several non-lethal diseases as well, such asMenangle virus[105] andNelson Bay virus.[106] These viruses rarely affect humans and few cases have been reported.[105][106] While other bat species have been suspected or implicated as the reservoir of diseases such asSARS andEbola, flying foxes are not suspected as hosts for either causative virus.[107]
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Flying foxes are often consideredpests due to the damage they cause toorchard crops. Flying foxes have been cited as particularly destructive toalmonds,guavas, andmangoes in the Maldives;lychee in Mauritius;areca in India; andstone fruits in Australia. Orchard damages from other animals are often misattributed to flying foxes, though, and economic damage can be difficult to quantify or exaggerated.[57] To prevent fruit damage, farmers may legally or illegally cull flying foxes. In the 1800s, the Australian government paid farmersbounties to kill flying foxes, though the practice has since been discontinued.[108]Alternatives to culling include placing barriers between the bats and fruit trees, such as netting, or harvesting fruit in a timely manner to avoid attracting as many flying foxes.[109] Netting is the most effective way to prevent crop loss, though some farmers find it cost prohibitive. It costs US$4,400–44,000 to net 1 ha (2.5 acres) of crops.[64] Other methods of preventing fruit loss may also involve the use of scare guns, chemical deterrents, or night-time lights. Alternatively, plantingSingapore cherry trees and otherdecoy crops next to an orchard can be effective, as flying foxes are much more attracted to their fruits than many other orchard crops.[110]
The location of flying fox camps can be a disturbance to humans. InBatemans Bay, Australia, locals report being so disturbed by flying fox vocalizations in the morning that they lose sleep. Flying foxes can fly into power lines and cause electricity outages. Their guano and body odor are also unpleasant to smell.[111] The presence of flying fox colonies can cause nearby property values to decline.[112]
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Flying foxes are featured in many indigenous cultures and traditions.
AfolkloreDreamtime story from theNew South Wales North Coast in Australia features an impatient flying fox wanting the Great Spirit to teach him how to be a bird, only to be hung upside down on a branch.[113] They were also featured in Aboriginal cave art, as evinced by several surviving examples.[18]
InTonga, flying foxes are considered sacred. All flying foxes are the property of the king, meaning non-royal persons cannot harm them in any way. Tongan legend states that a colony of flying foxes atKolovai are the descendants of a pair of flying foxes gifted to the King of Tonga by the Princess of Samoa.[114]
In the Indian village of Puliangulam, a colony of Indian flying foxes roosts in aBanyan tree. Villagers believe that the flying foxes are under the protection ofMuni, and do not harm the bats. A shrine to Muni is beneath the tree.If locals believe that they have offended Muni by failing to protect the bats, they will pray and performpuja after offering sweet rice, coconut, and bananas to those attending the ceremony.[115]
Flying foxes are also featured in folk stories from Papua New Guinea. Stories with flying foxes include a legend about acockatoo stealing feathers from the flying fox, resulting in it becoming nocturnal. Another story features a flying fox that could transform into a young man; the flying fox stole a woman away from her husband to take as his wife. Another legend states that a flying fox-man was responsible for introducingyams to their people.[116]
Indigenous societies in Oceania used parts of flying foxes for functional and ceremonial weapons. In the Solomon Islands, people created barbs out of their bones for use in spears.[117] In New Caledonia,ceremonial axes made ofjade were decorated with braids of flying fox fur.[118] Flying fox wings were depicted on the war shields of theAsmat people of Indonesia; they believed that the wings offered protection to their warriors.[119]
There are modern and historical references to flying fox byproducts used as currency. In New Caledonia, braided flying fox fur was once used as currency.[117] On the island ofMakira, which is part of the Solomon Islands, indigenous peoples still hunt flying foxes for their teeth as well as for bushmeat. Thecanine teeth are strung together on necklaces that are used ascurrency.[120] Teeth of theinsular flying fox are particularly prized, as they are usually large enough to drill holes in. TheMakira flying fox is also hunted, though, despite its smaller teeth. Deterring local peoples from using flying fox teeth as currency may be detrimental to the species, with Lavery and Fasi noting, "Species that provide an important cultural resource can be highly treasured." Emphasizingsustainable hunting of flying foxes to preserve cultural currency may be more effective than encouraging the abandonment of cultural currency. Even if flying foxes were no longer hunted for their teeth, they would still be killed for bushmeat; therefore, retaining their cultural value may encourage sustainable hunting practices.[121] Lavery stated, "It’s a positive, not a negative, that their teeth are so culturally valuable. The practice of hunting bats shouldn’t necessarily be stopped, it needs to be managed sustainably."[120]
Flying foxes and other bat species in Southeast Asia are often killed and sold as "mummies". The mummified bodies or skeletons of these bats are often shipped to the United States where they are sold in souvenir or curiosity shops or online through vendors such asEtsy oreBay. From 2000 to 2013, over 100,000 dead bats were imported to the United States. Bat conservationistMerlin Tuttle wrote, "I've seen huge losses, mostly due to various kinds of over-harvesting, especially at cave entrances, either for food or for sale as mummies." Despite sometimes being advertised as "sustainable," the practice could lead to overharvesting and depletion of flying fox species, with Tuttle saying, "It is a virtual certainty that the bats you've seen advertised are not sustainably harvested."[122]
[Pteropus vampyrus is] heavily hunted in some areas, where its large size makes it a useful food item
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