The spotted-winged fruit bat (''Balionycteris maculata'') is the smallest

megabat Megabats constitute the Family (biology), family Pteropodidae of the Order (biology), order Chiroptera. They are also called fruit bats, Old World fruit bats, or—especially the genus, genera ''Acerodon'' and ''Pteropus''—Pteropus, flyin ...

in the world. It inhabits forests in

Brunei Brunei, officially Brunei Darussalam, is a country in Southeast Asia, situated on the northern coast of the island of Borneo. Apart from its coastline on the South China Sea, it is completely surrounded by the Malaysian state of Sarawak, with ...

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...

Malaysia Malaysia is a country in Southeast Asia. Featuring the Tanjung Piai, southernmost point of continental Eurasia, it is a federation, federal constitutional monarchy consisting of States and federal territories of Malaysia, 13 states and thre ...

, and

Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...

Description

Spotted-winged fruit bats are unusually small megabats, with a head-body length of , a wingspan of , and an adult body weight of around . Most of the head and body are covered in thick blackish-brown fur, while the underparts are a pale grey-brown. Their wings are dark brown, with distinctive pale cream spots, which are most noticeable on the joints, but are also found in a variable pattern across the wing membranes. The wings have been reported to have an

aspect ratio The aspect ratio of a geometry, geometric shape is the ratio of its sizes in different dimensions. For example, the aspect ratio of a rectangle is the ratio of its longer side to its shorter side—the ratio of width to height, when the rectangl ...

of 5.8 and a

wing loading In aerodynamics, wing loading is the total weight of an aircraft or flying animal divided by the area of its wing. The stalling speed, takeoff speed and landing speed of an aircraft are partly determined by its wing loading. The faster an airc ...

of 9.51 N/m². There are also pale markings in front of the large eyes, and on the ears, which are simple in shape, compared with those of

microbat Microbats constitute the suborder Microchiroptera within the order Chiroptera (bats). Bats have long been differentiated into Megachiroptera (megabats) and Microchiroptera, based on their size, the use of echolocation by the Microchiroptera an ...

s. The nostrils are elongated, and splayed to the side of the snout. The species can be distinguished from other small fruit bats by the presence of the spots on its wings, but also by its unusual dental formula of .

Distribution and habitat

Spotted-winged fruit bats inhabit

primary Primary or primaries may refer to: Arts, entertainment, and media Music Groups and labels * Primary (band), from Australia * Primary (musician), hip hop musician and record producer from South Korea * Primary Music, Israeli record label Work ...

rain forest Rainforests are forests characterized by a closed and continuous tree Canopy (biology), canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforests can be generally classified as tropi ...

up to elevation, and coastal

mangrove A mangrove is a shrub or tree that grows mainly in coastal saline water, saline or brackish water. Mangroves grow in an equatorial climate, typically along coastlines and tidal rivers. They have particular adaptations to take in extra oxygen a ...

forests. They are found across

and

, and in the northern and western parts of the island of

Borneo Borneo () is the List of islands by area, third-largest island in the world, with an area of , and population of 23,053,723 (2020 national censuses). Situated at the geographic centre of Maritime Southeast Asia, it is one of the Greater Sunda ...

. At the edges of their range, they have also been reported from

Trang Province Trang (, ; ), also called ''Mueang Thap Thiang'', is one of the southern Provinces of Thailand, provinces (''changwat'') of Thailand, on the west side of the Malay Peninsula facing the Strait of Malacca. Neighboring provinces are (from north clo ...

in southern

, from a small area in

Sumatra Sumatra () is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the list of islands by area, sixth-largest island in the world at 482,286.55 km2 (182,812 mi. ...

, and from the

Riau Archipelago The Riau Archipelago is a ''geographic'' term (as opposed to administrative region) for the core group of islands within the Riau Islands Province in Indonesia, and located south of Singapore and east of Riau on Sumatra. Before the province of Ri ...

. No subspecies are known.

Behaviour and biology

Spotted-winged fruit bats forage in the understory of dense forest where they feed on a range of generally small, inconspicuous fruit, such as

fig The fig is the edible fruit of ''Ficus carica'', a species of tree or shrub in the flowering plant family Moraceae, native to the Mediterranean region, together with western and southern Asia. It has been cultivated since ancient times and i ...

s and

persimmon The persimmon () is the edible fruit of a number of species of trees in the genus '' Diospyros''. The most widely cultivated of these is the Chinese and Japanese kaki persimmon, ''Diospyros kaki''. In 2022, China produced 77% of the world's p ...

, and on some insects and spiders. They spend the day roosting alone or in small groups consisting of a male and up to nine females and their young. Rather than remaining with a single male, females may visit up to three different males. Males return regularly to their roosts during the night, suggesting that they gain access to females by controlling and defending prime roosting sites. They forage as individuals, rather than in a group, and rarely travel more than from their roost site. They have been observed to make high-pitched "peep" noises when foraging, as well as more complex series of sounds when socialising. Roosts are of a consistent shape and size, and may be partially excavated by the bats, a behaviour that is otherwise unknown in this group of animals. They are generally located in the root masses of

epiphytic An epiphyte is a plant or plant-like organism that grows on the surface of another plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphyt ...

plants, such as ferns, and also in the nests of ants and termites. Females give birth to a single young up to twice a year, typically between June and January. The young are born blind, and weighing around , after a gestation of 135 days. They are weaned by 40–80 days, and are able to fly by the time they have reached in weight. Females are sexually mature at ten months of age.

References

External links

*ARKive
images and movies of the spotted-winged fruit bat ''(Balionycteris maculata)''
{{Taxonbar, from=Q134342 Megabats Bats of Southeast Asia Bats of Indonesia Bats of Malaysia Bats of Borneo Mammals of Brunei Mammals of Thailand Mammals described in 1893 Taxa named by Oldfield Thomas