Aethalops aequalisBorneo fruit bat

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Geographic Range

Borneo fruit bats (Aethalops aequalis) have been found in the northwestern mountains of Borneo, Sabah, Sarawak, Brunei and Kalimantan, with a range spanning the northwestern border of Malaysia and Indonesia. (Bates, et al., 2008)

Habitat

This species is known to inhabit highland montane primary forests at elevations of 600 m, although it has been reported on Mount Kinabalu in Sabah, Malaysia at 1,833 and 2700 m, respectively. (Bates, et al., 2008; Benda, 2010; Tingga and Abdullah, 2012)

  • Range elevation
    600 to 2700 m
    1968.50 to 8858.27 ft
  • Average elevation
    1000 m
    3280.84 ft

Physical Description

Borneo fruit bats have grey-brown to dark reddish-brown fur that is thick and long on the dorsal surface, with paler coloring on their ventral side. Their calcar is not visible due to their dark wing membranes. Their interfemoral membrane is very small and reduced. Their muzzle is narrow and pointed. As one of the smallest Old World Fruit bats, Borneo fruit bats have forearm lengths between 42 and 46 mm. These bats do not have a tail or spots on their wings, which distinguishes them from spotted-winged fruit bats. Their most distinctive characteristic is their teeth; Borneo fruit bats may be distinguished from pygmy fruit bats by the equal length of their upper and lower incisors. A few of their characteristics are sexually dimorphic, specifically their skull length, the distance between their upper canine and first upper molar, their palate length and their dentary length. (Allen, 1938; Tingga and Abdullah, 2012)

  • Average length
    66 mm
    2.60 in

Reproduction

There is little available information on the mating systems of Borneo fruit bats.

There is little information available about the reproductive behavior of Borneo fruit bats, although most old world fruit bats are seasonal breeders and females produce one offspring per year. Gestation for fruit bats typically lasts between 4 and 6 months. (O'Brien, 1993)

  • Breeding interval
    Fruit bats breed once yearly
  • Average number of offspring
    1
  • Range gestation period
    4 to 6 months

There is little information about the parental investment of Borneo fruit bats.

Lifespan/Longevity

There is little information available about the lifespan of Borneo fruit bats, but closely related fruit bats live long lives with low fecundity. (Welbergen, 2012)

Behavior

There is little information available about the behavior of Borneo fruit bats, though their close relatives roost upside down by their feet in large groups in trees during the day and are active at night, dawn and dusk. (Welbergen, 2012)

Home Range

There is currently no information available about the home range size of Borneo fruit bats. (Welbergen, 2012)

Communication and Perception

This species, as with most other fruit bats, uses their eyes and nose (senses of sight and smell) to perceive their environment and search for fruits and flowers. (Welbergen, 2012)

Food Habits

There is little specific information available about this species' diet. Like other Old World fruit bats, Borneo fruit bats feed on fruit juices. They bite into a fruit and mash it with their teeth, consuming the juice, and spitting out the fibrous parts. Their narrow muzzle allows them to reach into flowers and consume nectar. As a smaller fruit bat, they can hover in front of flowers or fruit while consuming them. (Welbergen, 2012)

  • Plant Foods
  • fruit
  • nectar

Predation

There is little information about the predators of Borneo fruit bats, although humans are the major predator of species closely related to them. They may also be preyed on by large reptiles or birds of prey. (Welbergen, 2012)

Ecosystem Roles

There is little information on the ecosystem roles of Borneo fruit bats, although other fruit bats play a large role in pollination and seed dispersal. (Welbergen, 2012)

  • Ecosystem Impact
  • disperses seeds
  • pollinates

Economic Importance for Humans: Positive

Although this species is typically found in mountainous habitats that are not used for agriculture, Borneo fruit bats may aid in pollination of economically important crops. ("Old World Fruit Bats An Action Plan for their Conservation", 1992; Welbergen, 2012)

  • Positive Impacts
  • pollinates crops

Economic Importance for Humans: Negative

There are no known adverse effects of Borneo fruit bats on humans, but if their range in Borneo is encroached upon by humans for agriculture or road construction, they may be considered agricultural pests. ("Old World Fruit Bats An Action Plan for their Conservation", 1992)

Conservation Status

Deforestation is the largest concern in the conservation of Borneo fruit bats, though it is a species of least concern according to the IUCN Redlist. There is concern that in the future more deforestation may occur due to road construction, montane vacation home construction and the expansion of agriculture in the mountains of Borneo. (Bates, et al., 2008)

Contributors

Sarah Freier (author), University of Wisconsin-Stevens Point, Christopher Yahnke (editor), University of Wisconsin-Stevens Point, Leila Siciliano Martina (editor), Animal Diversity Web Staff.

Glossary

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

frugivore

an animal that mainly eats fruit

herbivore

An animal that eats mainly plants or parts of plants.

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

terrestrial

Living on the ground.

visual

uses sight to communicate

References

IUCN. Old World Fruit Bats An Action Plan for their Conservation. ISBN 2-8317-0055-8. Gland, Switzerland: IUCN. 1992. Accessed May 09, 2013 at http://data.iucn.org/dbtw-wpd/edocs/1992-034.pdf.

Allen, G. 1938. A New Pygmy Fruit Bat From Borneo. Journal of Mammology, 19-4: 496-498. Accessed May 08, 2013 at http://www.jstor.org/stable/1374243.

Bates, P., C. Francis, T. Kingston, I. Maryanto. 2008. "Aethalops aequalis" (On-line). IUCN Red List. Accessed May 08, 2013 at http://www.iucnredlist.org/details/136541/0.

Benda, P. 2010. On a small collection of bats (Chiroptera) from western Sabah (North Borneo, East Malaysia). Vespertilio, 13-14: 45-76. Accessed May 08, 2013 at http://www.ceson.org/vespertilio/13/Benda2010vesp1.pdf.

O'Brien, G. 1993. Seasonal reproduction in flying foxes, reviewed in the context of other tropical mammals. Reproduction, Fertility and Development, 5-5: 499-521. Accessed May 09, 2013 at http://www.publish.csiro.au/?paper=RD9930499.

Tingga, R., M. Abdullah. 2012. Phylogeny and Phylogeography of Aethalops from Sundaland using Mitochondrial 12S rRNA Gene. Pertanika Journal of Tropical Agricultural Science, 35-3: 485-510. Accessed May 08, 2013 at http://www.pertanika2.upm.edu.my/Pertanika%20PAPERS/JTAS%20Vol.%2035%20(3)%20Aug.%202012/07%20pg%20485-510.pdf.

Welbergen, J. 2012. "Brief History of Megachiroptera" (On-line). Accessed May 09, 2013 at http://www.zoo.cam.ac.uk/zoostaff/BBE/Welbergen/Megachiroptera.htm.