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Megabats constitute the
family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
Pteropodidae of the
order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...
Chiroptera ( bats). They are also called fruit bats, Old World fruit bats, or—especially the
genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial ...
'' Acerodon'' and '' Pteropus''— flying foxes. They are the only member of the superfamily Pteropodoidea, which is one of two superfamilies in the suborder Yinpterochiroptera. Internal divisions of Pteropodidae have varied since
subfamilies In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...
were first proposed in 1917. From three subfamilies in the 1917 classification, six are now recognized, along with various
tribes The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide usage of the term in English is in the discipline of anthropology. This definition is contested, in part due to confl ...
. As of 2018, 197
species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...
of megabat had been described. The leading theory of the evolution of megabats has been determined primarily by genetic data, as the
fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
record for this family is the most fragmented of all bats. They likely evolved in
Australasia Australasia is a region that comprises Australia, New Zealand and some neighbouring islands in the Pacific Ocean. The term is used in a number of different contexts, including geopolitically, physiogeographically, philologically, and ecolo ...
, with the common ancestor of all living pteropodids existing approximately 31 million years ago. Many of their lineages probably originated in
Melanesia Melanesia (, ) is a subregion of Oceania in the southwestern Pacific Ocean. It extends from Indonesia's New Guinea in the west to Fiji in the east, and includes the Arafura Sea. The region includes the four independent countries of Fiji, ...
, then dispersed over time to mainland Asia, the
Mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on th ...
, and
Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
. Today, they are found in tropical and subtropical areas of Eurasia, Africa, and
Oceania Oceania (, , ) is a region, geographical region that includes Australasia, Melanesia, Micronesia, and Polynesia. Spanning the Eastern Hemisphere, Eastern and Western Hemisphere, Western hemispheres, Oceania is estimated to have a land area of ...
. The megabat family contains the largest bat species, with individuals of some species weighing up to and having wingspans up to . Not all megabats are large-bodied; nearly a third of all species weigh less than . They can be differentiated from other bats due to their dog-like faces, clawed second digits, and reduced uropatagium. Only members of one genus, '' Notopteris'', have tails. Megabats have several adaptations for flight, including rapid oxygen consumption, the ability to sustain
heart rate Heart rate (or pulse rate) is the frequency of the heartbeat measured by the number of contractions (beats) of the heart per minute (bpm). The heart rate can vary according to the body's physical needs, including the need to absorb oxygen and e ...
s of more than 700 beats per minute, and large lung volumes. Most megabats are
nocturnal Nocturnality is an ethology, animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatures generally have ...
or
crepuscular In zoology, a crepuscular animal is one that is active primarily during the twilight period, being matutinal, vespertine, or both. This is distinguished from diurnal and nocturnal behavior, where an animal is active during the hours of dayli ...
, although a few species are active during the daytime. During the period of inactivity, they roost in trees or caves. Members of some species roost alone, while others form colonies of up to a million individuals. During the period of activity, they use
flight Flight or flying is the process by which an object moves through a space without contacting any planetary surface, either within an atmosphere (i.e. air flight or aviation) or through the vacuum of outer space (i.e. spaceflight). This can b ...
to travel to food resources. With few exceptions, they are unable to echolocate, relying instead on keen senses of sight and smell to navigate and locate food. Most species are primarily
frugivorous A frugivore is an animal that thrives mostly on raw fruits or succulent fruit-like produce of plants such as roots, shoots, nuts and seeds. Approximately 20% of mammalian herbivores eat fruit. Frugivores are highly dependent on the abundance an ...
and several are nectarivorous. Other less common food resources include leaves, pollen, twigs, and bark. They reach sexual maturity slowly and have a low reproductive output. Most species have one offspring at a time after a pregnancy of four to six months. This low reproductive output means that after a population loss their numbers are slow to rebound. A quarter of all species are listed as
threatened Threatened species are any species (including animals, plants and fungi) which are vulnerable to endangerment in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of ''critical depensa ...
, mainly due to
habitat destruction Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...
and
overhunting Overexploitation, also called overharvesting, refers to harvesting a renewable resource to the point of diminishing returns. Continued overexploitation can lead to the destruction of the resource, as it will be unable to replenish. The term app ...
. Megabats are a popular food source in some areas, leading to population declines and extinction. They are also of interest to those involved in
public health Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals". Analyzing the det ...
as they are
natural reservoir In infectious disease ecology and epidemiology, a natural reservoir, also known as a disease reservoir or a reservoir of infection, is the population of organisms or the specific environment in which an infectious pathogen naturally lives and re ...
s of several viruses that can affect humans.


Taxonomy and evolution


Taxonomic history

The family Pteropodidae was first described in 1821 by British zoologist
John Edward Gray John Edward Gray, Fellow of the Royal Society, FRS (12 February 1800 – 7 March 1875) was a British zoology, zoologist. He was the elder brother of zoologist George Robert Gray and son of the pharmacologist and botanist Samuel Frederick Gray ...
. He named the family "Pteropidae" (after the genus '' Pteropus'') and placed it within the now-defunct order Fructivorae. Fructivorae contained one other family, the now-defunct Cephalotidae, containing one genus, ''Cephalotes'' (now recognized as a synonym of '' Dobsonia''). Gray's spelling was possibly based on a misunderstanding of the suffix of "''Pteropus''". "''Pteropus''" comes from
Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ...
"''pterón''" meaning "wing" and "''poús''" meaning "foot". The Greek word ''pous'' of ''Pteropus'' is from the stem word ''pod-''; therefore, Latinizing ''Pteropus'' correctly results in the prefix "''Pteropod-''". French biologist
Charles Lucien Bonaparte Charles Lucien Jules Laurent Bonaparte, 2nd Prince of Canino and Musignano (24 May 1803 – 29 July 1857), was a French naturalist and ornithologist. Lucien and his wife had twelve children, including Cardinal Lucien Bonaparte. Life and career ...
was the first to use the corrected spelling Pteropodidae in 1838. In 1875, the zoologist
George Edward Dobson George Edward Dobson FRS FLS FZS (4 September 1848 at Edgeworthstown, County Longford, Ireland – 26 November 1895) was an Irish zoologist, photographer and army surgeon. He took a special interest in bats, describing many new species, and so ...
was the first to split the order Chiroptera (bats) into two suborders: Megachiroptera (sometimes listed as Macrochiroptera) and Microchiroptera, which are commonly abbreviated to megabats and microbats. Dobson selected these names to allude to the body size differences of the two groups, with many fruit-eating bats being larger than insect-eating bats. Pteropodidae was the only family he included within Megachiroptera. A 2001 study found that the dichotomy of megabats and microbats did not accurately reflect their evolutionary relationships. Instead of Megachiroptera and Microchiroptera, the study's authors proposed the new suborders Yinpterochiroptera and Yangochiroptera. This classification scheme has been verified several times subsequently and remains widely supported as of 2019. Since 2005, this suborder has alternatively been called "Pteropodiformes". Yinpterochiroptera contained species formerly included in Megachiroptera (all of Pteropodidae), as well as several families formerly included in Microchiroptera: Megadermatidae, Rhinolophidae, Nycteridae, Craseonycteridae, and Rhinopomatidae. Two superfamilies comprise Yinpterochiroptera: Rhinolophoidea—containing the above families formerly in Microchiroptera—and Pteropodoidea, which only contains Pteropodidae. In 1917, Danish mammalogist Knud Andersen divided Pteropodidae into three subfamilies: Macroglossinae, Pteropinae (corrected to Pteropodinae), and Harpyionycterinae. A 1995 study found that Macroglossinae as previously defined, containing the genera ''
Eonycteris ''Eonycteris'' ("dawn bat") is a genus of megabats found in Asia. They are the only members of the tribe Eonycterini. Species within this genus are: * Greater nectar bat, ''Eonycteris major'' *Cave nectar bat The cave nectar bat, dawn bat, co ...
'', '' Notopteris'', ''
Macroglossus ''Macroglossus'' (nectar bat) is a genus of megabats (family Pteropodidae) found in Indonesia and Southeast Asia. It has two species: * Long-tongued nectar bat, ''Macroglossus minimus'' *Long-tongued fruit bat The long-tongued fruit bat (''M ...
'', ''
Syconycteris ''Syconycteris'' (blossom bat) is a genus of megabat in the family Pteropodidae. There are three described species at present, with more likely to be added. Members of this genus are found in Indonesia, New Guinea and Australia. Their diet mainly ...
'', '' Melonycteris'', and ''
Megaloglossus ''Megaloglossus'' is a genus of bats in the family Pteropodidae. It is native to Africa. It contains two species, '' Megaloglossus azagnyi'' and '' Megaloglossus woermanni''. Prior to 2012, it was considered a monotypic genus. In 2012, however, ...
'', was
paraphyletic In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...
, meaning that the subfamily did not group all the descendants of a common ancestor. Subsequent publications consider Macroglossini as a tribe within Pteropodinae that contains only ''Macroglossus'' and ''Syconycteris''. ''Eonycteris'' and ''Melonycteris'' are within other tribes in Pteropodinae, ''Megaloglossus'' was placed in the tribe Myonycterini of the subfamily Rousettinae, and ''Notopteris'' is of uncertain placement. Other subfamilies and tribes within Pteropodidae have also undergone changes since Andersen's 1917 publication. In 1997, the pteropodids were classified into six subfamilies and nine tribes based on their morphology, or physical characteristics. A 2011 genetic study concluded that some of these subfamilies were paraphyletic and therefore they did not accurately depict the relationships among megabat species. Three of the subfamilies proposed in 1997 based on morphology received support: Cynopterinae, Harpyionycterinae, and Nyctimeninae. The other three clades recovered in this study consisted of Macroglossini, Epomophorinae + Rousettini, and Pteropodini + ''Melonycteris''. A 2016 genetic study focused only on African pteropodids (Harpyionycterinae, Rousettinae, and Epomophorinae) also challenged the 1997 classification. All species formerly included in Epomophorinae were moved to Rousettinae, which was subdivided into additional tribes. The genus '' Eidolon'', formerly in the tribe Rousettini of Rousettinae, was moved to its own subfamily, Eidolinae. In 1984, an additional pteropodid subfamily, Propottininae, was proposed, representing one extinct species described from a fossil discovered in Africa, ''
Propotto leakeyi ''Propotto'' is an extinct, monotypic genus of early strepsirrhine primate from the early Miocene of Kenya. It contains one described species, ''Propotto leakeyi''. Although long considered a pteropodid fruit-eating bat after spending a brief soj ...
''. In 2018 the fossils were reexamined and determined to represent a
lemur Lemurs ( ) (from Latin ''lemures'' – ghosts or spirits) are wet-nosed primates of the superfamily Lemuroidea (), divided into 8 families and consisting of 15 genera and around 100 existing species. They are endemic to the island of Madaga ...
. As of 2018, there were 197 described species of megabat, around a third of which are flying foxes of the genus ''Pteropus''.


Evolutionary history


Fossil record and divergence times

The fossil record for pteropodid bats is the most incomplete of any bat family. Although the poor skeletal record of Chiroptera is probably from how fragile bat skeletons are, Pteropodidae still have the most incomplete despite generally having the biggest and most sturdy skeletons. It is also surprising that Pteropodidae are the least represented because they were the first major group to diverge. Several factors could explain why so few pteropodid fossils have been discovered: tropical regions where their fossils might be found are under-sampled relative to Europe and North America; conditions for fossilization are poor in the tropics, which could lead to fewer fossils overall; and even when fossils are formed, they may be destroyed by subsequent geological activity. It is estimated that more than 98% of pteropodid fossil history is missing. Even without fossils, the age and divergence times of the family can still be estimated by using
computational phylogenetics Computational phylogenetics is the application of computational algorithms, methods, and programs to phylogenetic "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary hist ...
. Pteropodidae split from the superfamily
Rhinolophoidea Rhinolophoidea is a superfamily of bats. It contains the following families: Craseonycteridae, Hipposideridae, Megadermatidae, Rhinolophidae, Rhinonycteridae, and Rhinopomatidae. It is one of two superfamilies that comprise the suborder Yinpte ...
(which contains all the other families of the suborder Yinpterochiroptera) approximately 58 Mya (million years ago). The ancestor of the
crown group In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. ...
of Pteropodidae, or all living species, lived approximately 31 Mya.


Biogeography

The family Pteropodidae likely originated in
Australasia Australasia is a region that comprises Australia, New Zealand and some neighbouring islands in the Pacific Ocean. The term is used in a number of different contexts, including geopolitically, physiogeographically, philologically, and ecolo ...
based on biogeographic reconstructions. Other biogeographic analyses have suggested that the
Melanesia Melanesia (, ) is a subregion of Oceania in the southwestern Pacific Ocean. It extends from Indonesia's New Guinea in the west to Fiji in the east, and includes the Arafura Sea. The region includes the four independent countries of Fiji, ...
n Islands, including
New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; id, Papua, or , historically ) is the world's second-largest island with an area of . Located in Oceania in the southwestern Pacific Ocean, the island is separated from Australia by the wide Torr ...
, are a plausible candidate for the origin of most megabat subfamilies, with the exception of Cynopterinae; the cynopterines likely originated on the
Sunda Shelf Geologically, the Sunda Shelf is a south-eastern extension of the continental shelf of Mainland Southeast Asia. Major landmasses on the shelf include the Bali, Borneo, Java, Madura, and Sumatra, as well as their surrounding smaller island ...
based on results of a Weighted Ancestral Area Analysis of six nuclear and mitochondrial genes. From these regions, pteropodids colonized other areas, including continental Asia and Africa. Megabats reached Africa in at least four distinct events. The four proposed events are represented by (1) '' Scotonycteris'', (2) '' Rousettus'', (3) Scotonycterini, and (4) the "endemic Africa clade", which includes Stenonycterini, Plerotini, Myonycterini, and Epomophorini, according to a 2016 study. It is unknown when megabats reached Africa, but several tribes (Scotonycterini, Stenonycterini, Plerotini, Myonycterini, and Epomophorini) were present by the
Late Miocene The Late Miocene (also known as Upper Miocene) is a sub-epoch of the Miocene Epoch made up of two stages. The Tortonian and Messinian stages comprise the Late Miocene sub-epoch, which lasted from 11.63 Ma (million years ago) to 5.333 Ma. The ...
. How megabats reached Africa is also unknown. It has been proposed that they could have arrived via the
Middle East The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabia (including the Arabian Peninsula and Bahrain), Asia Minor (Asian part of Turkey except Hatay Province), East Thrace (Europ ...
before it became more arid at the end of the Miocene. Conversely, they could have reached the continent via the
Gomphotherium land bridge The ''Gomphotherium land bridge'' was a land bridge that connected Eurasia to Afro-Arabia between approximately 19 Mya (million years ago) and 15 Mya. Significance Passage of fauna between Eurasia and the Arabian Plate and thus Africa was largely ...
, which connected Africa and the Arabian Peninsula to
Eurasia Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelag ...
. The genus ''Pteropus'' (flying foxes), which is not found on mainland Africa, is proposed to have dispersed from Melanesia via island hopping across the
Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by ...
; this is less likely for other megabat genera, which have smaller body sizes and thus have more limited flight capabilities.


Echolocation

Megabats are the only family of bats incapable of laryngeal echolocation. It is unclear whether the common ancestor of all bats was capable of echolocation, and thus echolocation was lost in the megabat lineage, or multiple bat lineages independently evolved the ability to echolocate (the superfamily
Rhinolophoidea Rhinolophoidea is a superfamily of bats. It contains the following families: Craseonycteridae, Hipposideridae, Megadermatidae, Rhinolophidae, Rhinonycteridae, and Rhinopomatidae. It is one of two superfamilies that comprise the suborder Yinpte ...
and the suborder Yangochiroptera). This unknown element of bat evolution has been called a "grand challenge in biology". A 2017 study of bat
ontogeny Ontogeny (also ontogenesis) is the origination and development of an organism (both physical and psychological, e.g., moral development), usually from the time of fertilization of the egg to adult. The term can also be used to refer to the stu ...
(embryonic development) found evidence that megabat embryos at first have large, developed
cochlea The cochlea is the part of the inner ear involved in hearing. It is a spiral-shaped cavity in the bony labyrinth, in humans making 2.75 turns around its axis, the modiolus. A core component of the cochlea is the Organ of Corti, the sensory org ...
similar to echolocating microbats, though at birth they have small cochlea similar to non-echolocating mammals. This evidence supports that laryngeal echolocation evolved once among bats, and was lost in pteropodids, rather than evolving twice independently. Megabats in the genus ''Rousettus'' are capable of primitive echolocation through clicking their tongues. Some species—the cave nectar bat (''Eonycteris spelaea''),
lesser short-nosed fruit bat The lesser short-nosed fruit bat (''Cynopterus brachyotis'') is a species of megabat within the family Pteropodidae. It is a small bat that lives in South Asia and Southeast Asia. It weighs between , and measures . It occurs in many types of habit ...
(''Cynopterus brachyotis''), and the long-tongued fruit bat (''Macroglossus sobrinus'')— have been shown to create clicks similar to those of echolocating bats using their wings. Both echolocation and
flight Flight or flying is the process by which an object moves through a space without contacting any planetary surface, either within an atmosphere (i.e. air flight or aviation) or through the vacuum of outer space (i.e. spaceflight). This can b ...
are energetically expensive processes. Echolocating bats couple sound production with the mechanisms engaged for flight, allowing them to reduce the additional energy burden of echolocation. Instead of pressurizing a bolus of air for the production of sound, laryngeally echolocating bats likely use the force of the downbeat of their wings to pressurize the air, cutting energetic costs by synchronizing wingbeats and echolocation. The loss of echolocation (or conversely, the lack of its evolution) may be due to the uncoupling of flight and echolocation in megabats. The larger average body size of megabats compared to echolocating bats suggests a larger body size disrupts the flight-echolocation coupling and made echolocation too energetically expensive to be conserved in megabats.


List of genera

The family Pteropodidae is divided into six
subfamilies In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...
represented by 46
genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial ...
: Family Pteropodidae * subfamily Cynopterinae ** genus '' Aethalops'' – pygmy fruit bats ** genus ''
Alionycteris The Mindanao pygmy fruit bat (''Alionycteris paucidentata'') is a species of megabat in the family Pteropodidae. It is the only species within the genus ''Alionycteris''. It is endemic to the Philippines. Its natural habitat is subtropical or ...
'' ** genus '' Balionycteris'' ** genus ''
Chironax The black-capped fruit bat (''Chironax melanocephalus'') is a species of megabat in the monotypic genus ''Chironax''. Distribution Seven specimens of ''C. melanocephalus'' were collected from the lowland forest at Kubah and Lambir, and beach fo ...
'' ** genus '' Cynopterus'' – dog-faced fruit bats or short-nosed fruit bats ** genus ''
Dyacopterus ''Dyacopterus'' is a genus of megabats from south-east Asia. It contains three species, namely: * Dayak fruit bat, ''Dyacopterus spadiceus''
'' – Dayak fruit bats ** genus ''
Haplonycteris The Fischer's pygmy fruit bat or Philippine pygmy fruit bat (''Haplonycteris fischeri'')named after Arthur Frederick Fischer is a species of megabat in the family Pteropodidae. It is monotypic within the genus ''Haplonycteris''. It is endemic to t ...
'' ** genus '' Latidens'' ** genus '' Megaerops'' ** genus ''
Otopteropus The Luzon fruit bat (''Otopteropus cartilagonodus'') is a species of megabat in the family Pteropodidae. It is the only species within the genus ''Otopteropus'' and is endemic to the Philippines. Its natural habitat is subtropical or tropical d ...
'' ** genus '' Penthetor'' ** genus ''
Ptenochirus ''Ptenochirus'' is a genus of bat Bats are mammals of the order Chiroptera.''cheir'', "hand" and πτερόν''pteron'', "wing". With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats ...
'' – musky fruit bats ** genus ''
Sphaerias Blanford's fruit bat (''Sphaerias blanfordi'') is a mountain species of megabat. It is found in several countries in South and Southeast Asia. Taxonomy Blanford's fruit bat was described as a new species in 1891 by English zoologist Oldfield T ...
'' ** genus '' Thoopterus'' * subfamily Eidolinae ** genus '' Eidolon'' – straw-colored fruit bats * subfamily Harpyionycterinae ** genus '' Aproteles'' ** genus '' Boneia'' ** genus '' Dobsonia'' – naked-backed fruit bats ** genus ''
Harpyionycteris ''Harpyionycteris'' is a genus of megabat Megabats constitute the family Pteropodidae of the order Chiroptera (bats). They are also called fruit bats, Old World fruit bats, or—especially the genera ''Acerodon'' and ''Pteropus''—flyi ...
'' * subfamily Nyctimeninae ** genus '' Nyctimene'' – tube-nosed fruit bats ** genus '' Paranyctimene'' * subfamily Pteropodinae *** genus '' Melonycteris'' ** tribe Pteropodini *** genus '' Acerodon'' *** genus '' Pteralopex'' *** genus '' Pteropus'' – flying foxes *** genus '' Styloctenium'' * subfamily Rousettinae ** tribe Eonycterini *** genus ''
Eonycteris ''Eonycteris'' ("dawn bat") is a genus of megabats found in Asia. They are the only members of the tribe Eonycterini. Species within this genus are: * Greater nectar bat, ''Eonycteris major'' *Cave nectar bat The cave nectar bat, dawn bat, co ...
'' – dawn fruit bats ** tribe Epomophorini *** genus '' Epomophorus'' – epauletted fruit bats *** genus '' Epomops'' – epauletted bats *** genus ''
Hypsignathus The hammer-headed bat ('), also known as hammer-headed fruit bat and big-lipped bat, is a megabat widely distributed in West and Central Africa. It is the only member of the genus ''Hypsignathus'', which is part of the tribe Epomophorini along w ...
'' *** genus '' Micropteropus'' – dwarf epauletted bats *** genus ''
Nanonycteris Veldkamp's dwarf epauletted fruit bat (''Nanonycteris veldkampii'') is a species of bat in the family Pteropodidae. It is the only species within the genus ''Nanonycteris''. It is found in Benin, Cameroon, Central African Republic, Ivory Coast, ...
'' ** tribe ''
incertae sedis ' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertain ...
'' ***genus '' Pilonycteris'' **tribe Myonycterini *** genus ''
Megaloglossus ''Megaloglossus'' is a genus of bats in the family Pteropodidae. It is native to Africa. It contains two species, '' Megaloglossus azagnyi'' and '' Megaloglossus woermanni''. Prior to 2012, it was considered a monotypic genus. In 2012, however, ...
'' *** genus '' Myonycteris'' – little collared fruit bats ** tribe Plerotini *** genus ''
Plerotes D'Anchieta's fruit bat or D'Anchieta's epauletted bat (''Plerotes anchietae'') is a species of megabat in the family Pteropodidae. It is the only species in the genus ''Plerotes''. It is found in Angola, Democratic Republic of the Congo, Malawi, ...
'' ** tribe Rousettini *** genus '' Rousettus'' – rousette fruit bats **tribe Scotonycterini *** genus '' Casinycteris'' *** genus '' Scotonycteris'' ** tribe Stenonycterini *** genus '' Stenonycteris'' * ''
Incertae sedis ' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertain ...
'' ** genus '' Notopteris'' – long-tailed fruit bats ** genus '' Mirimiri'' ** genus '' Neopteryx'' ** genus '' Desmalopex'' ** genus '' Turkanycteris'' ** tribe
Macroglossini Macroglossini is a tribe of moths of the family Sphingidae described by Thaddeus William Harris in 1839. Taxonomy * Subtribe Choerocampina Grote & Robinson, 1865 **Genus ''Basiothia'' Walker, 1856 **Genus '' Cechenena'' Rothschild & Jorda ...
*** genus ''
Macroglossus ''Macroglossus'' (nectar bat) is a genus of megabats (family Pteropodidae) found in Indonesia and Southeast Asia. It has two species: * Long-tongued nectar bat, ''Macroglossus minimus'' *Long-tongued fruit bat The long-tongued fruit bat (''M ...
'' – long-tongued fruit bats *** genus ''
Syconycteris ''Syconycteris'' (blossom bat) is a genus of megabat in the family Pteropodidae. There are three described species at present, with more likely to be added. Members of this genus are found in Indonesia, New Guinea and Australia. Their diet mainly ...
'' – blossom bats


Description


Appearance

Megabats are so called for their larger weight and size; the largest, the
great flying fox The great flying fox (''Pteropus neohibernicus''), also known as the greater flying fox or Bismarck flying fox, is a species of megabat in the genus ''Pteropus'', found throughout lowland areas of New Guinea and in the Bismarck Archipelago. Confl ...
(''Pteropus neohibernicus'') weighs up to ; some members of ''Acerodon'' and ''Pteropus'' have wingspans reaching up to . Despite the fact that body size was a defining characteristic that Dobson used to separate microbats and megabats, not all species of megabat are larger than microbats; the
spotted-winged fruit bat The spotted-winged fruit bat, (''Balionycteris maculata'') is the smallest megabat in the world, and the only species in the genus ''Balionycteris''. It inhabits forests in Indonesia and Malaysia. Description Spotted-winged fruit bats are unusu ...
(''Balionycteris maculata''), a megabat, weighs only . The flying foxes of ''Pteropus'' and '' Acerodon'' are often taken as exemplars of the whole family in terms of body size. In reality, these genera are outliers, creating a misconception of the true size of most megabat species. A 2004 review stated that 28% of megabat species weigh less than . Megabats can be distinguished from microbats in appearance by their dog-like faces, by the presence of claws on the second digit (see Megabat#Postcrania), and by their simple ears. The simple appearance of the ear is due in part to the lack of tragi (cartilage flaps projecting in front of the ear canal), which are found in many microbat species. Megabats of the genus '' Nyctimene'' appear less dog-like, with shorter faces and tubular nostrils. A 2011 study of 167 megabat species found that while the majority (63%) have fur that is a uniform color, other patterns are seen in this family. These include countershading in four percent of species, a neck band or mantle in five percent of species, stripes in ten percent of species, and spots in nineteen percent of species. Unlike microbats, megabats have a greatly reduced uropatagium, which is an expanse of flight membrane that runs between the hind limbs. Additionally, the tail is absent or greatly reduced, with the exception of ''Notopteris'' species, which have a long tail. Most megabat wings insert laterally (attach to the body directly at the sides). In '' Dobsonia'' species, the wings attach nearer the spine, giving them the common name of "bare-backed" or "naked-backed" fruit bats.


Skeleton


Skull and dentition

Megabats have large
orbits In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as a ...
, which are bordered by well-developed postorbital processes posteriorly. The postorbital processes sometimes join to form the postorbital bar. The
snout A snout is the protruding portion of an animal's face, consisting of its nose, mouth, and jaw. In many animals, the structure is called a muzzle, rostrum, or proboscis. The wet furless surface around the nostrils of the nose of many mammals is ...
is simple in appearance and not highly modified, as is seen in other bat families. The length of the snout varies among genera. The
premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has ...
is well-developed and usually free, meaning that it is not fused with the
maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The ...
; instead, it articulates with the maxilla via ligaments, making it freely movable. The premaxilla always lack a palatal branch. In species with a longer snout, the skull is usually arched. In genera with shorter faces (''Penthetor'', ''Nyctimene'', ''Dobsonia'', and ''Myonycteris''), the skull has little to no bending. The number of teeth varies among megabat species; totals for various species range from 24 to 34. All megabats have two or four each of upper and lower
incisor Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, w ...
s, with the exception Bulmer's fruit bat (''Aproteles bulmerae''), which completely lacks incisors, and the São Tomé collared fruit bat (''Myonycteris brachycephala''), which has two upper and three lower incisors. This makes it the only mammal species with an asymmetrical
dental formula Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiolog ...
. All species have two upper and lower
canine teeth In mammalian oral anatomy, the canine teeth, also called cuspids, dog teeth, or (in the context of the upper jaw) fangs, eye teeth, vampire teeth, or vampire fangs, are the relatively long, pointed teeth. They can appear more flattened however ...
. The number of premolars is variable, with four or six each of upper and lower premolars. The first upper and lower molars are always present, meaning that all megabats have at least four molars. The remaining molars may be present, present but reduced, or absent. Megabat molars and premolars are simplified, with a reduction in the cusps and ridges resulting in a more flattened
crown A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, partic ...
. Like most mammals, megabats are diphyodont, meaning that the young have a set of deciduous teeth (milk teeth) that falls out and is replaced by permanent teeth. For most species, there are 20 deciduous teeth. As is typical for mammals, the deciduous set does not include molars.


Postcrania

The
scapula The scapula (plural scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones, the scapulae are paired, with each scapula on eithe ...
e (shoulder blades) of megabats have been described as the most primitive of any chiropteran family. The shoulder is overall of simple construction, but has some specialized features. The primitive insertion of the
omohyoid muscle The omohyoid muscle is a muscle that depresses the hyoid. It is located in the front of the neck, and consists of two bellies separated by an intermediate tendon. The omohyoid muscle is proximally attached to the scapula and distally attached to t ...
from the
clavicle The clavicle, or collarbone, is a slender, S-shaped long bone approximately 6 inches (15 cm) long that serves as a strut between the shoulder blade and the sternum (breastbone). There are two clavicles, one on the left and one on the rig ...
(collarbone) to the scapula is laterally displaced (more towards the side of the body)—a feature also seen in the Phyllostomidae. The shoulder also has a well-developed system of muscular slips (narrow bands of muscle that augment larger muscles) that anchor the tendon of the occipitopollicalis muscle (muscle in bats that runs from base of neck to the base of the thumb) to the skin. While microbats only have claws on the
thumb The thumb is the first digit of the hand, next to the index finger. When a person is standing in the medical anatomical position (where the palm is facing to the front), the thumb is the outermost digit. The Medical Latin English noun for thu ...
s of their forelimbs, most megabats have a clawed second digit as well; only ''Eonycteris'', ''Dobsonia'', ''Notopteris'', and ''Neopteryx'' lack the second claw. The first digit is the shortest, while the third digit is the longest. The second digit is incapable of
flexion Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relativ ...
. Megabats' thumbs are longer relative to their forelimbs than those of microbats. Megabats' hindlimbs have the same skeletal components as humans. Most megabat species have an additional structure called the
calcar The calcar, also known as the calcaneum, is the name given to a spur of cartilage arising from inner side of ankle and running along part of outer interfemoral membrane in bats, as well as to a similar spur on the legs of some arthropods. The ...
, a cartilage spur arising from the
calcaneus In humans and many other primates, the calcaneus (; from the Latin ''calcaneus'' or ''calcaneum'', meaning heel) or heel bone is a bone of the tarsus of the foot which constitutes the heel. In some other animals, it is the point of the hock. ...
. Some authors alternately refer to this structure as the uropatagial spur to differentiate it from microbats' calcars, which are structured differently. The structure exists to stabilize the uropatagium, allowing bats to adjust the camber of the membrane during flight. Megabats lacking the calcar or spur include ''Notopteris'', ''Syconycteris'', and ''
Harpyionycteris ''Harpyionycteris'' is a genus of megabat Megabats constitute the family Pteropodidae of the order Chiroptera (bats). They are also called fruit bats, Old World fruit bats, or—especially the genera ''Acerodon'' and ''Pteropus''—flyi ...
''. The entire leg is rotated at the hip compared to normal mammal orientation, meaning that the knees face posteriorly. All five digits of the foot flex in the direction of the
sagittal plane The sagittal plane (; also known as the longitudinal plane) is an anatomical plane that divides the body into right and left sections. It is perpendicular to the transverse and coronal planes. The plane may be in the center of the body and div ...
, with no digit capable of flexing in the opposite direction, as in the feet of perching birds.


Internal systems

Flight is very energetically expensive, requiring several adaptations to the
cardiovascular system The blood circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the entire body of a human or other vertebrate. It includes the cardiovascular system, or vascular system, tha ...
. During flight, bats can raise their oxygen consumption by twenty times or more for sustained periods; human athletes can achieve an increase of a factor of twenty for a few minutes at most. A 1994 study of the straw-coloured fruit bat (''Eidolon helvum'') and
hammer-headed bat The hammer-headed bat ('), also known as hammer-headed fruit bat and big-lipped bat, is a megabat widely distributed in West and Central Africa. It is the only member of the genus ''Hypsignathus'', which is part of the tribe Epomophorini along w ...
(''Hypsignathus monstrosus'') found a mean respiratory exchange ratio (carbon dioxide produced:oxygen used) of approximately 0.78. Among these two species, the
gray-headed flying fox The grey-headed flying fox (''Pteropus poliocephalus'') is a megabat native to Australia. The species shares mainland Australia with three other members of the genus '' Pteropus'': the little red '' P. scapulatus'', spectacled '' P. conspicill ...
(''Pteropus poliocephalus'') and the Egyptian fruit bat (''Rousettus aegyptiacus''), maximum heart rates in flight varied between 476 beats per minute (gray-headed flying fox) and 728 beats per minute (Egyptian fruit bat). The maximum number of breaths per minute ranged from 163 (gray-headed flying fox) to 316 (straw-colored fruit bat). Additionally, megabats have exceptionally large lung volumes relative to their sizes. While terrestrial mammals such as
shrew Shrews (family Soricidae) are small mole-like mammals classified in the order Eulipotyphla. True shrews are not to be confused with treeshrews, otter shrews, elephant shrews, West Indies shrews, or marsupial shrews, which belong to diffe ...
s have a lung volume of 0.03 cm3 per gram of body weight (0.05 in3 per ounce of body weight), species such as the Wahlberg's epauletted fruit bat (''Epomophorus wahlbergi'') have lung volumes 4.3 times greater at 0.13 cm3 per gram (0.22 in3 per ounce). Megabats have rapid digestive systems, with a gut transit time of half an hour or less. The digestive system is structured to a
herbivorous A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...
diet sometimes restricted to soft fruit or nectar. The length of the digestive system is short for a herbivore (as well as shorter than those of insectivorous microchiropterans), as the fibrous content is mostly separated by the action of the palate, tongue, and teeth, and then discarded. Many megabats have U-shaped stomachs. There is no distinct difference between the small and large intestine, nor a distinct beginning of the
rectum The rectum is the final straight portion of the large intestine in humans and some other mammals, and the gut in others. The adult human rectum is about long, and begins at the rectosigmoid junction (the end of the sigmoid colon) at the l ...
. They have very high densities of intestinal microvilli, which creates a large surface area for the absorption of nutrients.


Biology and ecology


Genome size

Like all bats, megabats have much smaller
genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ...
s than other mammals. A 2009 study of 43 megabat species found that their genomes ranged from 1.86 picograms (pg, 978 Mbp per pg) in the straw-colored fruit bat to 2.51 pg in Lyle's flying fox (''Pteropus lylei''). All values were much lower than the mammalian average of 3.5 pg. Megabats have even smaller genomes than microbats, with a mean weight of 2.20 pg compared to 2.58 pg. It was speculated that this difference could be related to the fact that the megabat lineage has experienced an extinction of the LINE1—a type of
long interspersed nuclear element Long interspersed nuclear elements (LINEs) (also known as long interspersed nucleotide elements or long interspersed elements) are a group of non-LTR ( long terminal repeat) retrotransposons that are widespread in the genome of many eukaryotes. ...
. LINE1 constitutes 15–20% of the human genome and is considered the most prevalent long interspersed nuclear element among mammals.


Senses


Sight

With very few exceptions, megabats do not echolocate, and therefore rely on sight and smell to navigate. They have large eyes positioned at the front of their heads. These are larger than those of the common ancestor of all bats, with one study suggesting a trend of increasing eye size among pteropodids. A study that examined the eyes of 18 megabat species determined that the
common blossom bat The common blossom bat (''Syconycteris australis'') also known as the southern blossom bat or Queensland blossom bat, is a megabat in the family Pteropodidae. The common blossom bat feeds mostly on nectar and pollen rather than fruit. It is one ...
(''Syconycteris australis'') had the smallest eyes at a diameter of , while the largest eyes were those of large flying fox (''Pteropus vampyrus'') at in diameter. Megabat irises are usually brown, but they can be red or orange, as in '' Desmalopex'', '' Mirimiri'', '' Pteralopex'', and some ''Pteropus''. At high brightness levels, megabat
visual acuity Visual acuity (VA) commonly refers to the clarity of vision, but technically rates an examinee's ability to recognize small details with precision. Visual acuity is dependent on optical and neural factors, i.e. (1) the sharpness of the retinal ...
is poorer than that of humans; at low brightness it is superior. One study that examined the eyes of some ''Rousettus'', ''Epomophorus'', ''Eidolon'', and ''Pteropus'' species determined that the first three genera possess a ''
tapetum lucidum The ''tapetum lucidum'' ( ; ; ) is a layer of tissue in the eye of many vertebrates and some other animals. Lying immediately behind the retina, it is a retroreflector. It reflects visible light back through the retina, increasing the light av ...
'', a reflective structure in the eyes that improves vision at low light levels, while the ''Pteropus'' species do not. All species examined had
retina The retina (from la, rete "net") is the innermost, light-sensitive layer of tissue of the eye of most vertebrates and some molluscs. The optics of the eye create a focused two-dimensional image of the visual world on the retina, which then ...
e with both
rod cell Rod cells are photoreceptor cells in the retina of the eye that can function in lower light better than the other type of visual photoreceptor, cone cells. Rods are usually found concentrated at the outer edges of the retina and are used in p ...
s and
cone cell Cone cells, or cones, are photoreceptor cells in the retinas of vertebrate eyes including the human eye. They respond differently to light of different wavelengths, and the combination of their responses is responsible for color vision. Con ...
s, but only the ''Pteropus'' species had S-cones, which detect the shortest wavelengths of light; because the spectral tuning of the
opsin Animal opsins are G-protein-coupled receptors and a group of proteins made light-sensitive via a chromophore, typically retinal. When bound to retinal, opsins become Retinylidene proteins, but are usually still called opsins regardless. Most pro ...
s was not discernible, it is unclear whether the S-cones of ''Pteropus'' species detect blue or ultraviolet light. ''Pteropus'' bats are
dichromatic Dichromatic may refer to: * Dichromacy, a form of color-blindness in which only two light wavelengths are distinguished rather than the usual three * Dichromatic, describing an optical device which splits light into two parts according to its wave ...
, possessing two kinds of cone cells. The other three genera, with their lack of S-cones, are
monochromatic A monochrome or monochromatic image, object or palette is composed of one color (or values of one color). Images using only shades of grey are called grayscale (typically digital) or black-and-white (typically analog). In physics, monochro ...
, unable to see color. All genera had very high densities of rod cells, resulting in high sensitivity to light, which corresponds with their nocturnal activity patterns. In ''Pteropus'' and ''Rousettus'', measured rod cell densities were 350,000–800,000 per square millimeter, equal to or exceeding other nocturnal or
crepuscular In zoology, a crepuscular animal is one that is active primarily during the twilight period, being matutinal, vespertine, or both. This is distinguished from diurnal and nocturnal behavior, where an animal is active during the hours of dayli ...
animals such as the
house mouse The house mouse (''Mus musculus'') is a small mammal of the order Rodentia, characteristically having a pointed snout, large rounded ears, and a long and almost hairless tail. It is one of the most abundant species of the genus ''Mus''. Althoug ...
,
domestic cat The cat (''Felis catus'') is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members of ...
, and domestic rabbit.


Smell

Megabats use smell to find food sources like fruit and nectar. They have keen senses of smell that rival that of the
domestic dog The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the wolf. Also called the domestic dog, it is derived from the extinct Pleistocene wolf, and the modern wolf is the dog's nearest living relative. Do ...
. Tube-nosed fruit bats such as the eastern tube-nosed bat (''Nyctimene robinsoni'') have stereo olfaction, meaning they are able to map and follow odor plumes three-dimensionally. Along with most (or perhaps all) other bat species, megabats mothers and offspring also use scent to recognize each other, as well as for recognition of individuals. In flying foxes, males have enlarged
androgen An androgen (from Greek ''andr-'', the stem of the word meaning "man") is any natural or synthetic steroid hormone that regulates the development and maintenance of male characteristics in vertebrates by binding to androgen receptors. This in ...
-sensitive
sebaceous gland A sebaceous gland is a microscopic exocrine gland in the skin that opens into a hair follicle to secrete an oily or waxy matter, called sebum, which lubricates the hair and skin of mammals. In humans, sebaceous glands occur in the greatest numb ...
s on their shoulders they use for scent-marking their territories, particularly during the mating season. The secretions of these glands vary by species—of the 65 chemical compounds isolated from the glands of four species, no compound was found in all species. Males also engage in
urine washing Urination, also known as micturition, is the release of urine from the urinary bladder through the urethra to the outside of the body. It is the urinary system's form of excretion. It is also known medically as micturition, voiding, uresis, ...
, or coating themselves in their own urine.


Taste

Megabats possess the '' TAS1R2'' gene, meaning they have the ability to detect sweetness in foods. This gene is present among all bats except
vampire bat Vampire bats, species of the subfamily Desmodontinae, are leaf-nosed bats found in Central and South America. Their food source is blood of other animals, a dietary trait called hematophagy. Three extant bat species feed solely on blood: the c ...
s. Like all other bats, megabats cannot taste '' umami'', due to the absence of the '' TAS1R1'' gene. Among other mammals, only
giant panda The giant panda (''Ailuropoda melanoleuca''), also known as the panda bear (or simply the panda), is a bear species endemic to China. It is characterised by its bold black-and-white coat and rotund body. The name "giant panda" is sometimes u ...
s have been shown to lack this gene. Megabats also have multiple ''TAS2R'' genes, indicating that they can taste bitterness.


Reproduction and life cycle

Megabats, like all bats, are long-lived relative to their size for mammals. Some captive megabats have had lifespans exceeding thirty years. Relative to their sizes, megabats have low reproductive outputs and delayed sexual maturity, with females of most species not giving birth until the age of one or two. Some megabats appear to be able to breed throughout the year, but the majority of species are likely
seasonal breeder Seasonal breeders are animal species that successfully mate only during certain times of the year. These times of year allow for the optimization of survival of young due to factors such as ambient temperature, food and water availability, and ch ...
s. Mating occurs at the roost. Gestation length is variable, but is four to six months in most species. Different species of megabats have reproductive adaptations that lengthen the period between copulation and giving birth. Some species such as the straw-colored fruit bat have the reproductive adaptation of
delayed implantation Embryonic diapause (from late 19th century English: dia- ‘through’ + pause- 'delay') (aka delayed implantation in mammals) is an evolutionary reproductive strategy used by several animal species across a number of kingdoms, including approximate ...
, meaning that copulation occurs in June or July, but the
zygote A zygote (, ) is a eukaryotic cell formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information of a new individual organism. In multicell ...
does not implant into the uterine wall until months later in November. The
Fischer's pygmy fruit bat The Fischer's pygmy fruit bat or Philippine pygmy fruit bat (''Haplonycteris fischeri'')named after Arthur Frederick Fischer is a species of megabat in the family Pteropodidae. It is monotypic within the genus ''Haplonycteris''. It is endemic to ...
(''Haplonycteris fischeri''), with the adaptation of post-implantation delay, has the longest gestation length of any bat species, at up to 11.5 months. The post-implantation delay means that development of the embryo is suspended for up to eight months after implantation in the uterine wall, which is responsible for its very long pregnancies. Shorter gestation lengths are found in the greater short-nosed fruit bat (''Cynopterus sphinx'') with a period of three months. The litter size of all megabats is usually one. There are scarce records of twins in the following species: Madagascan flying fox (''Pteropus rufus''),
Dobson's epauletted fruit bat Dobson's epauletted fruit bat, or Dobson's fruit bat (''Epomophorus dobsonii'') is a species of megabat in the family Pteropodidae. It is found in Angola, Democratic Republic of the Congo, Malawi, Mozambique, Rwanda, Tanzania, and Zambia ...
(''Epomops dobsoni''), the gray-headed flying fox, the black flying fox (''Pteropus alecto''), the spectacled flying fox (''Pteropus conspicillatus''), the greater short-nosed fruit bat, Peters's epauletted fruit bat (''Epomophorus crypturus''), the hammer-headed bat, the straw-colored fruit bat, the little collared fruit bat (''Myonycteris torquata''), the Egyptian fruit bat, and Leschenault's rousette (''Rousettus leschenaultii''). In the cases of twins, it is rare that both offspring survive. Because megabats, like all bats, have low reproductive rates, their populations are slow to recover from declines. At birth, megabat offspring are, on average, 17.5% of their mother's post-partum weight. This is the smallest offspring-to-mother ratio for any bat family; across all bats, newborns are 22.3% of their mother's post-partum weight. Megabat offspring are not easily categorized into the traditional categories of
altricial In biology, altricial species are those in which the young are underdeveloped at the time of birth, but with the aid of their parents mature after birth. Precocial species are those in which the young are relatively mature and mobile from the mome ...
(helpless at birth) or
precocial In biology, altricial species are those in which the young are underdeveloped at the time of birth, but with the aid of their parents mature after birth. Precocial species are those in which the young are relatively mature and mobile from the mome ...
(capable at birth). Species such as the greater short-nosed fruit bat are born with their eyes open (a sign of precocial offspring), whereas the Egyptian fruit bat offspring's eyes do not open until nine days after birth (a sign of altricial offspring). As with nearly all bat species, males do not assist females in parental care. The young stay with their mothers until they are
weaned Weaning is the process of gradually introducing an infant human or another mammal to what will be its adult diet while withdrawing the supply of its mother's milk. The process takes place only in mammals, as only mammals produce milk. The infa ...
; how long weaning takes varies throughout the family. Megabats, like all bats, have relatively long nursing periods: offspring will nurse until they are approximately 71% of adult body mass, compared to 40% of adult body mass in non-bat mammals. Species in the genus '' Micropteropus'' wean their young by seven to eight weeks of age, whereas the Indian flying fox (''Pteropus medius'') does not wean its young until five months of age. Very unusually, male individuals of two megabat species, the Bismarck masked flying fox (''Pteropus capistratus'') and the Dayak fruit bat (''Dyacopterus spadiceus''), have been observed producing milk, but there has never been an observation of a male nursing young. It is unclear if the lactation is functional and males actually nurse pups or if it is a result of stress or
malnutrition Malnutrition occurs when an organism gets too few or too many nutrients, resulting in health problems. Specifically, it is "a deficiency, excess, or imbalance of energy, protein and other nutrients" which adversely affects the body's tissues ...
.


Behavior and social systems

Many megabat species are highly
gregarious Sociality is the degree to which individuals in an animal population tend to associate in social groups (gregariousness) and form cooperative societies. Sociality is a survival response to evolutionary pressures. For example, when a mother w ...
or social. Megabats will vocalize to communicate with each other, creating noises described as "trill-like bursts of sound", honking, or loud, bleat-like calls in various genera. At least one species, the Egyptian fruit bat, is capable of a kind of vocal learning called vocal production learning, defined as "the ability to modify vocalizations in response to interactions with conspecifics". Young Egyptian fruit bats are capable of acquiring a
dialect The term dialect (from Latin , , from the Ancient Greek word , 'discourse', from , 'through' and , 'I speak') can refer to either of two distinctly different types of linguistic phenomena: One usage refers to a variety of a language that ...
by listening to their mothers, as well as other individuals in their colonies. It has been postulated that these dialect differences may result in individuals of different colonies communicating at different frequencies, for instance. Megabat social behavior includes using sexual behaviors for more than just reproduction. Evidence suggests that female Egyptian fruit bats take food from males in exchange for sex. Paternity tests confirmed that the males from which each female scrounged food had a greater likelihood of fathering the scrounging female's offspring. Homosexual fellatio has been observed in at least one species, the Bonin flying fox (''Pteropus pselaphon''). This same-sex fellatio is hypothesized to encourage colony formation of otherwise-antagonistic males in colder climates. Megabats are mostly
nocturnal Nocturnality is an ethology, animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatures generally have ...
and
crepuscular In zoology, a crepuscular animal is one that is active primarily during the twilight period, being matutinal, vespertine, or both. This is distinguished from diurnal and nocturnal behavior, where an animal is active during the hours of dayli ...
, though some have been observed flying during the day. A few island species and subspecies are diurnal, hypothesized as a response to a lack of predators. Diurnal taxa include a subspecies of the black-eared flying fox (''Pteropus melanotus natalis''), the Mauritian flying fox (''Pteropus niger''), the Caroline flying fox (''Pteropus molossinus''), a subspecies of '' Pteropus pelagicus'' (''P. p. insularis''), and the Seychelles fruit bat (''Pteropus seychellensis'').


Roosting

A 1992 summary of forty-one megabat genera noted that twenty-nine are tree-roosting genera. A further eleven genera roost in caves, and the remaining six genera roost in other kinds of sites (human structures, mines, and crevices, for example). Tree-roosting species can be solitary or highly
colonial Colonial or The Colonial may refer to: * Colonial, of, relating to, or characteristic of a colony or colony (biology) Architecture * American colonial architecture * French Colonial * Spanish Colonial architecture Automobiles * Colonial (1920 a ...
, forming aggregations of up to one million individuals. Cave-roosting species form aggregations ranging from ten individuals up to several thousand. Highly colonial species often exhibit roost fidelity, meaning that their trees or caves may be used as roosts for many years. Solitary species or those that aggregate in smaller numbers have less fidelity to their roosts.


Diet and foraging

Most megabats are primarily
frugivorous A frugivore is an animal that thrives mostly on raw fruits or succulent fruit-like produce of plants such as roots, shoots, nuts and seeds. Approximately 20% of mammalian herbivores eat fruit. Frugivores are highly dependent on the abundance an ...
. Throughout the family, a diverse array of fruit is consumed from nearly 188 plant genera. Some species are also nectarivorous, meaning that they also drink nectar from flowers. In Australia, ''
Eucalyptus ''Eucalyptus'' () is a genus of over seven hundred species of Flowering plant, flowering trees, shrubs or Mallee (habit), mallees in the Myrtaceae, myrtle Family (biology), family, Myrtaceae. Along with several other genera in the Tribe (biology) ...
'' flowers are an especially important food source. Other food resources include leaves, shoots, buds, pollen, seed pods, sap, cones, bark, and twigs. They are prodigious eaters and can consume up to 2.5 times their own body weight in fruit per night. Megabats fly to roosting and foraging resources. They typically fly straight and relatively fast for bats; some species are slower with greater maneuverability. Species can commute in a night.
Migratory species Migration, in ecology, is the large-scale movement of members of a species to a different environment. Migration is a natural behavior and component of the life cycle of many species of mobile organisms, not limited to animals, though animal migr ...
of the genera ''Eidolon'', ''Pteropus'', ''Epomophorus'', ''Rousettus'', ''Myonycteris'', and ''Nanonycteris'' can migrate distances up to . Most megabats have below-average aspect ratios, which is measurement relating wingspan and wing area. Wing loading, which measures weight relative to wing area, is average or higher than average in megabats.


Seed dispersal

Megabats play an important role in
seed dispersal In Spermatophyte plants, seed dispersal is the movement, spread or transport of seeds away from the parent plant. Plants have limited mobility and rely upon a variety of dispersal vectors to transport their seeds, including both abiotic vecto ...
. As a result of their long evolutionary history, some plants have evolved characteristics compatible with bat senses, including fruits that are strongly scented, brightly colored, and prominently exposed away from foliage. The bright colors and positioning of the fruit may reflect megabats' reliance on visual cues and inability to navigate through clutter. In a study that examined the fruits of more than forty fig species, only one fig species was consumed by both birds and megabats; most species are consumed by one or the other. Bird-consumed figs are frequently red or orange, while megabat-consumed figs are often yellow or green. Most seeds are excreted shortly after consumption due to a rapid gut transit time, but some seeds can remain in the gut for more than twelve hours. This heightens megabats' capacity to disperse seeds far from parent trees. As highly mobile frugivores, megabats have the capacity to restore forest between isolated forest fragments by dispersing tree seeds to deforested landscapes. This dispersal ability is limited to plants with small seeds that are less than in length, as seeds larger than this are not ingested.


Predators and parasites

Megabats, especially those living on islands, have few native predators: species like the small flying fox (''Pteropus hypomelanus'') have no known natural predators. Non-native predators of flying foxes include domestic
cat The cat (''Felis catus'') is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members of ...
s and
rat Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus ''Rattus''. Other rat genera include ''Neotoma'' ( pack rats), ''Bandicota'' (bandicoot ...
s. The mangrove monitor, which is a native predator for some megabat species but an introduced predator for others, opportunistically preys on megabats, as it is a capable tree climber. Another species, the brown tree snake, can seriously impact megabat populations; as a non-native predator in
Guam Guam (; ch, Guåhan ) is an organized, unincorporated territory of the United States in the Micronesia subregion of the western Pacific Ocean. It is the westernmost point and territory of the United States (reckoned from the geographic ce ...
, the snake consumes so many offspring that it reduced the
recruitment Recruitment is the overall process of identifying, sourcing, screening, shortlisting, and interviewing candidates for jobs (either permanent or temporary) within an organization. Recruitment also is the processes involved in choosing individua ...
of the population of the Mariana fruit bat (''Pteropus mariannus'') to essentially zero. The island is now considered a
sink A sink is a bowl-shaped plumbing fixture for washing hands, dishwashing, and other purposes. Sinks have a tap (faucet) that supply hot and cold water and may include a spray feature to be used for faster rinsing. They also include a drain ...
for the Mariana fruit bat, as its population there relies on bats immigrating from the nearby island of
Rota Rota or ROTA may refer to: Places * Rota (island), in the Marianas archipelago * Rota (volcano), in Nicaragua * Rota, Andalusia, a town in Andalusia, Spain * Naval Station Rota, Spain People * Rota (surname), a surname (including a list of peop ...
to bolster it rather than successful reproduction. Predators that are naturally
sympatric In biology, two related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter one another. An initially interbreeding population that splits into two or more distinct species s ...
with megabats include reptiles such as
crocodilian Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period ( Cenomanian stage) and are the closest living ...
s, snakes, and large lizards, as well as birds like
falcon Falcons () are birds of prey in the genus ''Falco'', which includes about 40 species. Falcons are widely distributed on all continents of the world except Antarctica, though closely related raptors did occur there in the Eocene. Adult falcons ...
s,
hawk Hawks are birds of prey of the family Accipitridae. They are widely distributed and are found on all continents except Antarctica. * The subfamily Accipitrinae includes goshawks, sparrowhawks, sharp-shinned hawks and others. This subfa ...
s, and owls. The
saltwater crocodile The saltwater crocodile (''Crocodylus porosus'') is a crocodilian native to saltwater habitats and brackish wetlands from India's east coast across Southeast Asia and the Sundaic region to northern Australia and Micronesia. It has been list ...
is a known predator of megabats, based on analysis of crocodile stomach contents in northern Australia. During extreme heat events, megabats like the little red flying fox (''Pteropus scapulatus'') must cool off and rehydrate by drinking from waterways, making them susceptible to opportunistic depredation by
freshwater crocodiles The freshwater crocodile (''Crocodylus johnstoni''), also known as the Australian freshwater crocodile, Johnstone's crocodile or the freshie, is a species of crocodile endemic to the northern regions of Australia. Unlike their much larger Austr ...
. Megabats are the hosts of several
parasite Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted structurally to this way of lif ...
taxa. Known parasites include
Nycteribiidae Nycteribiidae is a family of the true fly superfamily Hippoboscoidea are known as "bat flies", together with their close relatives the Streblidae. As the latter do not seem to be a monophyletic group, it is conceivable that bat flies cannot be ...
and
Streblidae The Streblidae are a family of flies in the superfamily Hippoboscoidea, and together with their relatives the Nycteribiidae, are known as bat flies. They are winged or wingless ectoparasites of bats, and often have long legs. They appear to b ...
species ("bat flies"), as well as
mites Mites are small arachnids (eight-legged arthropods). Mites span two large orders of arachnids, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari, but genetic analysis does not show clear evi ...
of the genus '' Demodex''. Blood parasites of the family
Haemoproteidae The Haemoproteidae are a family of parasitic alveolates in the phylum Apicomplexa.Euzéby J (1988) Comparative Medical Protozoology, Vol. 3: Apicomplexa, 2: Haemosporidioses, Part 1: Plasmodiids, Haemoproteids, Piroplasms (general characters The ...
and intestinal nematodes of Toxocaridae also affect megabat species.


Range and habitat

Megabats are widely distributed in the
tropics The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred ...
of the
Old World The "Old World" is a term for Afro-Eurasia that originated in Europe , after Europeans became aware of the existence of the Americas. It is used to contrast the continents of Africa, Europe, and Asia, which were previously thought of by th ...
, occurring throughout Africa, Asia, Australia, and throughout the islands of the Indian Ocean and
Oceania Oceania (, , ) is a region, geographical region that includes Australasia, Melanesia, Micronesia, and Polynesia. Spanning the Eastern Hemisphere, Eastern and Western Hemisphere, Western hemispheres, Oceania is estimated to have a land area of ...
. As of 2013, fourteen genera of megabat are present in Africa, representing twenty-eight species. Of those twenty-eight species, twenty-four are only found in tropical or subtropical climates. The remaining four species are mostly found in the tropics, but their ranges also encompass
temperate climate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout ...
s. In respect to habitat types, eight are exclusively or mostly found in
forest A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...
ed habitat; nine are found in both forests and
savanna A savanna or savannah is a mixed woodland-grassland (i.e. grassy woodland) ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to ...
s; nine are found exclusively or mostly in savannas; and two are found on islands. Only one African species, the
long-haired rousette The long-haired fruit bat (''Stenonycteris lanosus''), also known as the long-haired rousette, is a species of megabat in the family Pteropodidae. It is the only member of the genus ''Stenonycteris''. It was formerly classified in the genus ''Rou ...
(''Rousettus lanosus''), is found mostly in montane ecosystems, but an additional thirteen species' ranges extend into montane habitat. Outside of Southeast Asia, megabats have relatively low species richness in Asia. The Egyptian fruit bat is the only megabat whose range is mostly in the
Palearctic realm The Palearctic or Palaearctic is the largest of the eight biogeographic realms of the Earth. It stretches across all of Eurasia north of the foothills of the Himalayas, and North Africa. The realm consists of several bioregions: the Euro-Si ...
; it and the straw-colored fruit bat are the only species found in the
Middle East The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabia (including the Arabian Peninsula and Bahrain), Asia Minor (Asian part of Turkey except Hatay Province), East Thrace (Europ ...
. The northernmost extent of the Egyptian fruit bat's range is the northeastern
Mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on th ...
. In
East Asia East Asia is the eastern region of Asia, which is defined in both geographical and ethno-cultural terms. The modern states of East Asia include China, Japan, Mongolia, North Korea, South Korea, and Taiwan. China, North Korea, South Korea ...
, megabats are found only in China and Japan. In China, only six species of megabat are considered resident, while another seven are present marginally (at the edge of their ranges), questionably (due to possible misidentification), or as accidental migrants. Four megabat species, all ''Pteropus'', are found on Japan, but none on its five main islands. In
South Asia South Asia is the southern subregion of Asia, which is defined in both geographical and ethno-cultural terms. The region consists of the countries of Afghanistan, Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan, and Sri Lanka.;;;;; ...
, megabat species richness ranges from two species in the
Maldives The Maldives, officially the Republic of Maldives,, ) and historically known as the Maldive Islands, is a country and archipelagic state in South Asia in the Indian Ocean. The Maldives is southwest of Sri Lanka and India, about from the A ...
to thirteen species in
India India, officially the Republic of India ( Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the ...
. Megabat species richness in Southeast Asia is as few as five species in the small country of Singapore and seventy-six species in
Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...
. Of the ninety-eight species of megabat found in Asia, forest is a habitat for ninety-five of them. Other habitat types include human-modified land (66 species), caves (23 species), savanna (7 species), shrubland (4 species), rocky areas (3 species), grassland (2 species), and desert (1 species). In Australia, five genera and eight species of megabat are present. These genera are ''Pteropus'', ''Syconycteris'', ''Dobsonia'', ''Nyctimene'', and ''Macroglossus''. ''Pteropus'' species of Australia are found in a variety of habitats, including
mangrove A mangrove is a shrub or tree that grows in coastal saline or brackish water. The term is also used for tropical coastal vegetation consisting of such species. Mangroves are taxonomically diverse, as a result of convergent evolution in several ...
-dominated forests,
rainforest Rainforests are characterized by a closed and continuous tree canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforest can be classified as tropical rainforest or temperate rainfo ...
s, and the wet sclerophyll forests of the Australian bush. Australian ''Pteropus'' are often found in association with humans, as they situate their large colonies in
urban areas An urban area, built-up area or urban agglomeration is a human settlement with a high population density and infrastructure of built environment. Urban areas are created through urbanization and are categorized by urban morphology as cities, ...
, particularly in May and June when the greatest proportions of ''Pteropus'' species populations are found in these urban colonies. In Oceania, the countries of
Palau Palau,, officially the Republic of Palau and historically ''Belau'', ''Palaos'' or ''Pelew'', is an island country and microstate in the western Pacific. The nation has approximately 340 islands and connects the western chain of the Ca ...
and
Tonga Tonga (, ; ), officially the Kingdom of Tonga ( to, Puleʻanga Fakatuʻi ʻo Tonga), is a Polynesian country and archipelago. The country has 171 islands – of which 45 are inhabited. Its total surface area is about , scattered over in ...
have the fewest megabat species, with one each.
Papua New Guinea Papua New Guinea (abbreviated PNG; , ; tpi, Papua Niugini; ho, Papua Niu Gini), officially the Independent State of Papua New Guinea ( tpi, Independen Stet bilong Papua Niugini; ho, Independen Stet bilong Papua Niu Gini), is a country i ...
has the greatest number of species with thirty-six. Of the sixty-five species of Oceania, forest is a habitat for fifty-eight. Other habitat types include human-modified land (42 species), caves (9 species), savanna (5 species), shrubland (3 species), and rocky areas (3 species). An estimated nineteen percent of all megabat species are
endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found els ...
to a single island; of all bat families, only Myzopodidae—containing two species, both single-island endemics—has a higher rate of single-island endemism.


Relationship to humans


Food

Megabats are killed and eaten as
bushmeat Bushmeat is meat from wildlife species that are hunted for human consumption, most often referring to the meat of game in Africa. Bushmeat represents a primary source of animal protein and a cash-earning commodity for inhabitants of humid tro ...
throughout their range. Bats are consumed extensively throughout Asia, as well as in islands of the West Indian Ocean and the Pacific, where ''Pteropus'' species are heavily hunted. In continental Africa where no ''Pteropus'' species live, the straw-colored fruit bat, the region's largest megabat, is a preferred hunting target. In Guam, consumption of the Mariana fruit bat exposes locals to the
neurotoxin Neurotoxins are toxins that are destructive to nerve tissue (causing neurotoxicity). Neurotoxins are an extensive class of exogenous chemical neurological insultsSpencer 2000 that can adversely affect function in both developing and matur ...
beta-Methylamino-L-alanine β-Methylamino--alanine, or BMAA, is a non-proteinogenic amino acid produced by cyanobacteria. BMAA is a neurotoxin and its potential role in various neurodegenerative disorders is the subject of scientific research. Structure and properties ...
(BMAA) which may later lead to neurodegenerative diseases. BMAA may become particularly biomagnified in humans who consume flying foxes; flying foxes are exposed to BMAA by eating
cycad Cycads are seed plants that typically have a stout and woody (ligneous) trunk with a crown of large, hard, stiff, evergreen and (usually) pinnate leaves. The species are dioecious, that is, individual plants of a species are either male or f ...
fruits.


As disease reservoirs

Megabats are the
reservoirs A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including control ...
of several
virus A virus is a wikt:submicroscopic, submicroscopic infectious agent that replicates only inside the living Cell (biology), cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and ...
es that can affect humans and cause disease. They can carry
filovirus ''Filoviridae'' () is a family of single-stranded negative-sense RNA viruses in the order ''Mononegavirales''. Two members of the family that are commonly known are Ebola virus and Marburg virus. Both viruses, and some of their lesser known rela ...
es, including the
Ebola virus ''Zaire ebolavirus'', more commonly known as Ebola virus (; EBOV), is one of six known species within the genus '' Ebolavirus''. Four of the six known ebolaviruses, including EBOV, cause a severe and often fatal hemorrhagic fever in humans and o ...
(EBOV) and ''
Marburgvirus The genus ''Marburgvirus'' is the taxonomic home of ''Marburg marburgvirus'', whose members are the two known marburgviruses, Marburg virus (MARV) and Ravn virus (RAVV). Both viruses cause Marburg virus disease in humans and nonhuman prim ...
''. The presence of ''Marburgvirus'', which causes Marburg virus disease, has been confirmed in one species, the Egyptian fruit bat. The disease is rare, but the fatality rate of an outbreak can reach up to 88%. The virus was first recognized after simultaneous outbreaks in the German cities of
Marburg Marburg ( or ) is a university town in the German federal state (''Bundesland'') of Hesse, capital of the Marburg-Biedenkopf district (''Landkreis''). The town area spreads along the valley of the river Lahn and has a population of approx ...
and
Frankfurt Frankfurt, officially Frankfurt am Main (; Hessian: , " Frank ford on the Main"), is the most populous city in the German state of Hesse. Its 791,000 inhabitants as of 2022 make it the fifth-most populous city in Germany. Located on its ...
as well as
Belgrade, Serbia Belgrade ( , ;, ; names in other languages) is the capital and largest city in Serbia. It is located at the confluence of the Sava and Danube rivers and the crossroads of the Pannonian Plain and the Balkan Peninsula. Nearly 1,166,763 mi ...
in 1967 where 31 people became ill and seven died. The outbreak was traced to
laboratory A laboratory (; ; colloquially lab) is a facility that provides controlled conditions in which scientific or technological research, experiments, and measurement may be performed. Laboratory services are provided in a variety of settings: physici ...
work with
vervet monkey The vervet monkey (''Chlorocebus pygerythrus''), or simply vervet, is an Old World monkey of the family Cercopithecidae native to Africa. The term "vervet" is also used to refer to all the members of the genus '' Chlorocebus''. The five distinc ...
s from
Uganda }), is a landlocked country in East Africa. The country is bordered to the east by Kenya, to the north by South Sudan, to the west by the Democratic Republic of the Congo, to the south-west by Rwanda, and to the south by Tanzania. The south ...
. The virus can pass from a bat host to a human (who has usually spent a prolonged period in a mine or cave where Egyptian fruit bats live); from there, it can spread person-to-person through contact with infected bodily fluids, including blood and
semen Semen, also known as seminal fluid, is an organic bodily fluid created to contain spermatozoa. It is secreted by the gonads (sexual glands) and other sexual organs of male or hermaphroditic animals and can fertilize the female ovum. Semen ...
. The United States
Centers for Disease Control and Prevention The Centers for Disease Control and Prevention (CDC) is the national public health agency of the United States. It is a United States federal agency, under the Department of Health and Human Services, and is headquartered in Atlanta, Georg ...
lists a total of 601 confirmed cases of Marburg virus disease from 1967 to 2014, of which 373 people died (62% overall mortality). Species that have tested positive for the presence of EBOV include Franquet's epauletted fruit bat (''Epomops franqueti''), the hammer-headed fruit bat, and the little collared fruit bat. Additionally, antibodies against EBOV have been found in the straw-colored fruit bat, Gambian epauletted fruit bat (''Epomophorus gambianus''), Peters's dwarf epauletted fruit bat (''Micropteropus pusillus''), Veldkamp's dwarf epauletted fruit bat (''Nanonycteris veldkampii''), Leschenault's rousette, and the Egyptian fruit bat. Much of how humans contract the Ebola virus is unknown. Scientists hypothesize that humans initially become infected through contact with an infected animal such as a megabat or non-human primate. Megabats are presumed to be a natural reservoir of the Ebola virus, but this has not been firmly established. Microbats are also being investigated as the reservoir of the virus, with the greater long-fingered bat (''Miniopterus inflatus'') once found to harbor a fifth of the virus's genome (though not testing positive for the actual virus) in 2019. Due to the likely association between Ebola infection and "hunting, butchering and processing meat from infected animals", several West African countries banned bushmeat (including megabats) or issued warnings about it during the 2013–2016 epidemic; many bans have since been lifted. Other megabats implicated as disease reservoirs are primarily ''Pteropus'' species. Notably, flying foxes can transmit Australian bat lyssavirus, which, along with the rabies virus, causes
rabies Rabies is a viral disease that causes encephalitis in humans and other mammals. Early symptoms can include fever and tingling at the site of exposure. These symptoms are followed by one or more of the following symptoms: nausea, vomiting, vio ...
. 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 a
mucous membrane A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It i ...
or an open
wound A wound is a rapid onset of injury that involves lacerated or punctured skin (an ''open'' wound), or a contusion (a ''closed'' wound) from blunt force trauma or compression. In pathology, a ''wound'' is an acute injury that damages the epider ...
. Exposure to flying fox blood, urine, or feces cannot cause infections of Australian bat lyssavirus. Since 1994, there have been three records of people becoming infected with it in
Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , established_ ...
—each case was fatal. Flying foxes are also reservoirs of henipaviruses such as Hendra virus and
Nipah virus Nipah virus, scientific name ''Nipah henipavirus'', is a bat-borne virus that causes Nipah virus infection in humans and other animals, a disease with a high mortality rate. Numerous disease outbreaks caused by Nipah virus have occurred in Sout ...
. Hendra virus was first identified in 1994; it rarely occurs in 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 with
horse The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million ...
s that have come into contact with flying fox
urine Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra. Cellular ...
. There are no documented instances of direct transmission between flying foxes and humans. As of 2012, there is a
vaccine A vaccine is a biological preparation that provides active acquired immunity to a particular infectious or malignant disease. The safety and effectiveness of vaccines has been widely studied and verified. ...
available for horses to decrease the likelihood of infection and transmission. Nipah virus was first identified in 1998 in Malaysia. Since 1998, there have been several Nipah outbreaks in Malaysia,
Singapore Singapore (), officially the Republic of Singapore, is a sovereign island country and city-state in maritime Southeast Asia. It lies about one degree of latitude () north of the equator, off the southern tip of the Malay Peninsula, borde ...
, India, and Bangladesh, resulting in over 100 casualties. A 2018 outbreak in Kerala, India resulted in 19 humans becoming infected—17 died. 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 intermediate host such as
domestic pig The pig (''Sus domesticus''), often called swine, hog, or domestic pig when distinguishing from other members of the genus ''Sus'', is an omnivorous, domesticated, even-toed, hoofed mammal. It is variously considered a subspecies of ''Sus ...
s, or from contact with an infected person. 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 of date 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 palm wine can be exposed to henipaviruses. The use of bamboo skirts on collecting pots lowers the risk of contamination from bat urine. Flying foxes can transmit several non-lethal diseases as well, such as Menangle virus and
Nelson Bay virus ''Nelson Bay orthoreovirus'', often called Nelson Bay virus (NBV) is a novel double-stranded RNA orthoreovirus species first isolated from a flying fox (Pteropus poliocephalus) near Nelson Bay in New South Wales, Australia.Gard G, Compans RW. Str ...
. These viruses rarely affect humans, and few cases have been reported. Megabats are not suspected to be vectors of coronaviruses.


In culture

Megabats, particularly flying foxes, are featured in indigenous cultures and traditions. Folk stories from Australia and Papua New Guinea feature them. They were also included in Indigenous Australian cave art, as evinced by several surviving examples. 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. In New Caledonia, ceremonial axes made of
jade Jade is a mineral used as jewellery or for ornaments. It is typically green, although may be yellow or white. Jade can refer to either of two different silicate minerals: nephrite (a silicate of calcium and magnesium in the amphibole gro ...
were decorated with braids of flying fox fur. Flying fox wings were depicted on the war shields of the
Asmat people The Asmat are an ethnic group of New Guinea, residing in the province of South Papua, Indonesia. The Asmat inhabit a region on the island's southwestern coast bordering the Arafura Sea, with lands totaling approximately 18,000 km2 (7,336& ...
of Indonesia; they believed that the wings offered protection to their warriors. There are modern and historical references to flying fox byproducts used as
currency A currency, "in circulation", from la, currens, -entis, literally meaning "running" or "traversing" is a standardization of money in any form, in use or circulation as a medium of exchange, for example banknotes and coins. A more general ...
. In New Caledonia, braided flying fox fur was once used as currency. On the island of
Makira The island of Makira (also known as San Cristobal and San Cristóbal) is the largest island of Makira-Ulawa Province in the Solomon Islands. It is third most populous island after Malaita and Guadalcanal, with a population of 55,126 as of 202 ...
, which is part of the Solomon Islands, indigenous peoples still hunt flying foxes for their teeth as well as for bushmeat. The
canine teeth In mammalian oral anatomy, the canine teeth, also called cuspids, dog teeth, or (in the context of the upper jaw) fangs, eye teeth, vampire teeth, or vampire fangs, are the relatively long, pointed teeth. They can appear more flattened however ...
are strung together on necklaces that are used as currency. Teeth of the
insular flying fox The insular flying fox or Pacific flying fox (''Pteropus tonganus'') is a species of flying fox in the family Pteropodidae. It is geographically widespread, the most widespread flying fox in the Pacific: it is found in American Samoa, the Cook I ...
(''Pteropus tonganus'') are particularly prized, as they are usually large enough to drill holes in. The Makira flying fox (''Pteropus cognatus'') is also hunted, despite its smaller teeth. Deterring people 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." Emphasizing sustainable 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. 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."


Conservation


Status

As of 2014, the
International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natur ...
(IUCN) evaluated a quarter of all megabat species as
threatened Threatened species are any species (including animals, plants and fungi) which are vulnerable to endangerment in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of ''critical depensa ...
, which includes species listed as critically endangered,
endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...
, and
vulnerable Vulnerable may refer to: General * Vulnerability * Vulnerability (computing) * Vulnerable adult * Vulnerable species Music Albums * ''Vulnerable'' (Marvin Gaye album), 1997 * ''Vulnerable'' (Tricky album), 2003 * ''Vulnerable'' (The Used album) ...
. Megabats are substantially threatened by humans, as they are hunted for food and medicinal uses. Additionally, they are culled for actual or perceived damage to agriculture, especially to fruit production. As of 2019, the IUCN had evaluations for 187 megabat species. The status breakdown is as follows: * Extinct: 4 species (2.1%) * Critically endangered: 8 species (4.3%) * Endangered: 16 species (8.6%) * Vulnerable: 37 species (19.8%) * Near-threatened: 13 species (7.0%) * Least-concern: 89 species (47.6%) *
Data deficient A data deficient (DD) species is one which has been categorized by the International Union for Conservation of Nature (IUCN) as offering insufficient information for a proper assessment of conservation status to be made. This does not necessarily ...
: 20 species (10.7%)


Factors causing decline


Anthropogenic sources

Megabats are threatened by habitat destruction by humans.
Deforestation Deforestation or forest clearance is the removal of a forest or stand of trees from land that is then land conversion, converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban area, urban ...
of their habitats has resulted in the loss of critical roosting habitat. Deforestation also results in the loss of food resource, as native fruit-bearing trees are felled. Habitat loss and resulting urbanization leads to construction of new roadways, making megabat colonies easier to access for overharvesting. Additionally, habitat loss via deforestation compounds natural threats, as fragmented forests are more susceptible to damage from
typhoon A typhoon is a mature tropical cyclone that develops between 180° and 100°E in the Northern Hemisphere. This region is referred to as the Northwestern Pacific Basin, and is the most active tropical cyclone basin on Earth, accounting for a ...
-force winds. Cave-roosting megabats are threatened by human disturbance at their roost sites.
Guano Guano (Spanish from qu, wanu) is the accumulated excrement of Seabird, seabirds or bats. As a manure, guano is a highly effective fertilizer due to the high content of nitrogen, phosphate, and potassium, all key nutrients essential for plant ...
mining is a livelihood in some countries within their range, bringing people to caves. Caves are also disturbed by mineral mining and cave tourism. Megabats are also killed by humans, intentionally and unintentionally. Half of all megabat species are hunted for food, in comparison to only eight percent of insectivorous species, while human persecution stemming from perceived damage to crops is also a large source of mortality. Some megabats have been documented to have a preference for native fruit trees over fruit crops, but deforestation can reduce their food supply, causing them to rely on fruit crops. They are shot, beaten to death, or poisoned to reduce their populations. Mortality also occurs via accidental entanglement in netting used to prevent the bats from eating fruit. Culling campaigns can dramatically reduce megabat populations. In Mauritius, over 40,000 Mauritian flying foxes were culled between 2014 and 2016, reducing the species' population by an estimated 45%. Megabats are also killed by electrocution. In one Australian orchard, it is estimated that over 21,000 bats were electrocuted to death in an eight-week period. Farmers construct electrified grids over their fruit trees to kill megabats before they can consume their crop. The grids are questionably effective at preventing crop loss, with one farmer who operated such a grid estimating they still lost of fruit to flying foxes in a year. Some electrocution deaths are also accidental, such as when bats fly into
overhead power line An overhead power line is a structure used in electric power transmission and distribution to transmit electrical energy across large distances. It consists of one or more uninsulated electrical cables (commonly multiples of three for three-p ...
s. Climate change causes flying fox mortality and is a source of concern for species persistence. Extreme heat waves in Australia have been responsible for the deaths of more than 30,000 flying foxes from 1994 to 2008. Females and young bats are most susceptible to extreme heat, which affects a population's ability to recover. Megabats are threatened by sea level rise associated with climate change, as several species are endemic to low-lying
atoll An atoll () is a ring-shaped island, including a coral rim that encircles a lagoon partially or completely. There may be coral islands or cays on the rim. Atolls are located in warm tropical or subtropical oceans and seas where corals can ...
s.


Natural sources

Because many species are endemic to a single island, they are vulnerable to random events such as typhoons. A 1979 typhoon halved the remaining population of the
Rodrigues flying fox The Rodrigues flying fox or Rodrigues fruit bat (''Pteropus rodricensis'') is a species of bat in the family Pteropodidae, the flying foxes or fruit bats. It is endemic to Rodrigues, an island in the Indian Ocean belonging to Mauritius. Its na ...
(''Pteropus rodricensis''). Typhoons result in indirect mortality as well: because typhoons defoliate the trees, they make megabats more visible and thus more easily hunted by humans. Food resources for the bats become scarce after major storms, and megabats 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. As many megabat species are located in the tectonically active
Ring of Fire The Ring of Fire (also known as the Pacific Ring of Fire, the Rim of Fire, the Girdle of Fire or the Circum-Pacific belt) is a region around much of the rim of the Pacific Ocean where many volcanic eruptions and earthquakes occur. The Ring ...
, they are also threatened by volcanic eruptions. Flying foxes, including the endangered Mariana fruit bat, have been nearly exterminated from the island of Anatahan following a series of eruptions beginning in 2003.


References


External links

* * {{DEFAULTSORT:Megabat   Taxa named by John Edward Gray Mammal families