Megabat Fossil range: Mid Oligocene to Recent |
||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
![]() Large flying fox, Pteropus vampyrus
|
||||||||||||
Scientific classification | ||||||||||||
|
||||||||||||
Subfamilies | ||||||||||||
Macroglossinae |
Megabats is the term used informally to refer to bats of the family Pteropodidae. They are also referred to as fruit bats, old world fruit bats, or flying foxes. According to the most commonly used classification, they constitute a single suborder Megachiroptera, within the order Chiroptera (bats).
Contents |
The megabat, contrary to its name, is not always large: the smallest species is 6 centimeters (2.4 inches) long and thus smaller than some microbats. The largest reach 40 cm (16 inches) in length and attain a wingspan of 150 cm (5 feet), weighing in at nearly 1 kg (more than 2 pounds). Most fruit bats have large eyes, allowing them to orient visually in the twilight of dusk and inside caves and forests.
The sense of smell is excellent in these creatures. In contrast to the microbats, the fruit bats do not, as a rule, use echolocation (with one exception, the Egyptian fruit bat Rousettus egyptiacus, which uses high-pitched clicks to navigate in caves).
In specimens of the Egyptian fruit bat the epidemical Marburg virus was found in 2007, confirming the suspicion that this species may be a reservoir for this dangerous virus.[1]
Fruit bats are frugivorous or nectarivorous, i.e., they eat fruits or lick nectar from flowers. Often the fruits are crushed and only the juices consumed. The teeth are adapted to bite through hard fruit skins. Large fruit bats must land in order to eat fruit, while the smaller species are able to hover with flapping wings in front of a flower or fruit.
Frugivorous bats aid the distribution of plants (and therefore, forests) by carrying the fruits with them and spitting the seeds or eliminating them elsewhere. Nectarivores actually pollinate visited plants. They bear long tongues that are inserted deep into the flower; pollen thereby passed to the bat is then transported to the next blossom visited, pollinating it. This relationship between plants and bats is a form of mutualism known as chiropterophily. Examples of plants that benefit from this arrangement include the baobabs of the genus Adansonia and the sausage tree (Kigelia).
Researchers tested for presence of the Ebola virus in fruit bats between 2001 and 2003. Three species of bats tested positive for Ebola, but had no symptoms of the virus. This indicates that the bats may be acting as a reservoir for the virus. Of the infected animals identified during these field collections, immunoglobulin G (IgG) specific for Ebola virus was detected in Hypsignathus monstrosus, Epomops franqueti, and Myonycteris torquata.
Bats are usually thought to belong to one of two monophyletic groups, a view that is reflected in their classification into two suborders (Megachiroptera and Microchiroptera). According to this hypothesis, all living megabats and microbats are descendants of a common ancestor species that was already capable of flight. However, there have been other views, and a vigorous debate persists to this date. For example, in the 1980s and 1990s, some researchers proposed (based primarily on the similarity of the visual pathways) that the Megachiroptera were in fact more closely affiliated with the primates than the Microchiroptera, with the two groups of bats having therefore evolved flight via convergence (see Flying primates theory).[2] However, a recent flurry of genetic studies confirms the more longstanding notion that all bats are indeed members of the same clade, the Chiroptera.[3][4] Other studies have recently suggested that certain families of microbats (possibly the horseshoe bats, mouse-tailed bats and the false vampires) are evolutionarily closer to the fruit bats than to other microbats.[3][5]
On September 17, 2007, a new species of flying fox, or fruit bat — orange-coloured with a distinctive, white-striped face — was discovered in a protected wildlife area in the Sablayan region, Mindoro, Philippines. The Mindoro Stripe-Faced Fruitbat was discovered through a joint research effort by the University of Kansas's Biodiversity Research Center and the Comparative Biogeography and Conservation of Philippine Vertebrates (CBCPV). The Journal of Mammalogy published its details. The total number of bat species in the Philippines is 74, with 26 unique to the Philippines.[6]
The family Pteropodidae is divided into two subfamilies with 173 total species, represented by 42 genera:
Subfamily Macroglossinae
Subfamily Pteropodinae
Because of their large size and somewhat "spectral" appearance, fruit bats are sometimes used in horror movies to represent vampires or to otherwise lend an aura of spookiness. In reality, as noted above, the bats of this group are purely herbivorous creatures and pose no direct threat to human beings, baby cows, or ill children. Some works of fiction are more in line with this fact, portraying fruit bats as sympathetic or even featuring them as characters. For example, in the book series Silverwing by Kenneth Oppel, a fruit bat named Java is one of the main characters in the final book of the series. In Stellaluna, a popular children's book by Janell Cannon, the story revolves around the plight of a young fruit bat who is separated from her mother.