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Dobsonia chapmaniNegros naked-backed fruit bat

By Monica Wayner

Geographic Range

Philippine naked-back fruit bats (Dobsonia chapmani) are endemic to 2 islands in the Philippines, Cebu and Negros, at elevations from sea level to 800 m. They were presumed extinct in the 1970's from habitat loss, hunting and disturbances through guano mining. Recently, the species was rediscovered on Cebu Island in the towns of Carmen and Catmon in 2001, then in southwestern Negros Island, near Sipalay City in 2003. They are the only species of genus Dobsonia found in the Philippines. (Hamburger, 2010; Heaney, et al., 1998; Heaney, et al., 2012)

Habitat

Habitat destruction is one of the leading threats to this once common species, along with disturbances from guano mining. They roost mostly in karst limestone caves, in secondary-growth forests that have less rainfall than other areas of the Philippines. Paguntalan et al (2004) cite 3 individuals of this species roosting on coconut fronds, showing Philippine naked-back fruit bats have the potential to make use of degraded or highly disturbed habitats. This is beneficial for them, since the habitat available is a fragmented array of small lowland forests, which are all very disturbed. (Hamburger, 2010; Heaney, et al., 2012; Paguntalan, et al., 2004; "www.fieldmuseum.org", 2010a)

  • Other Habitat Features
  • caves
  • Range elevation
    sea level to 860 m
    to 2821.52 ft

Physical Description

At around 220 mm in total length, Philippine naked-back fruit bats are the largest cave dwelling bats in the Philippines. Their tail length is between 23 and 26 mm and their ear length is 25 to 27 mm. These bats get their name from the wings attachment on the midline of their back, which gives them a naked appearance. Philippine naked-back fruit bats have 2 larger upper incisors, and two small lower incisors. Their thumb has a claw, but not the first phalange on the wing leading edge. Their forearm is 123 to 133 mm in length. ("AnAge entry for Dobsonia moluccensis", 2012; Paguntalan, et al., 2004; "www.fieldmuseum.org", 2010a)

  • Range mass
    125 to 143 g
    4.41 to 5.04 oz
  • Range length
    218 to 221 mm
    8.58 to 8.70 in

Reproduction

The mating system of Philippine naked-back fruit bats is unknown, however, it is likely similar to other Pteropodid species.

There is little information available about reproduction in this species. According to Hamburger (2010), Philippine naked-back fruit bats give birth in May or June and young are able to fly around August or September. ("Dobsonia magna", 2005; Hamburger, 2010)

  • Breeding interval
    Philippine naked-back fruit bats breed once a year, yielding one pup.
  • Breeding season
    Philippine naked-back fruit bats breed from April to June.
  • Average number of offspring
    1
  • Average gestation period
    5 months
  • Range weaning age
    5 to 6 months

In closely related New Guinea naked-backed fruit bats (Dobsonia magna), parental care falls mostly on the mother. She carries the pup for its first month and nurses for another 4 to 5 months. According to Newman et al. (2011) Dobsonia is a highly social genus, so mothers likely form nursing colonies. ("Dobsonia magna", 2005; Newman, et al., 2011)

Lifespan/Longevity

Lifespan studies on Philippine naked-back fruit bats are limited and there are not many details on this species in captivity, although they have been used in the pet trade. However, Moluccan naked-backed fruit bats (Dobsonia moluccensis) have lived up to 12.3 years in captivity. (Heaney, et al., 2012; "AnAge entry for Dobsonia moluccensis", 2012)

Behavior

Not much is known about the behaviour of this species, which is why further research is so critical to their survival.

Home Range

Philippine naked-backed fruit bats are found in secondary lowland forests of Negros and Cebu in karst limestone caves. The home range size of this species has not been established. (Heaney, et al., 2012; "www.fieldmuseum.org", 2010b)

Communication and Perception

More research is needed on how Philippine naked-backed fruit bats communicate with others. Most Old World fruit bats rely primarily on sight and smell for navigation and locating food. ("Dobsonia magna", 2005)

Food Habits

According to the IUCN, the natural vegetation in their environment is batino (Alstonia macrophylla), hindunganon (Macaranga), tubug (Ficus septica) and matamban (Mallotus), all of which grow on steep slopes; surrounding agricultural areas also have abacca (Musa textiles), gabi (Colocasia esculenta) and coconuts (Cocos nucifera). However, the specific plants consumed by these bats are not known. Ficus septica is a likely food source, since Moluccan naked-backed fruit bats eat it, and in general, members of the ficus genus are eaten by old world fruit bats. (Heaney, et al., 2012; "Global Species", 2013)

  • Plant Foods
  • fruit

Predation

Specific predators of Philippine naked-back fruit bats are not known. However, leopard cats (Prionailurus bengalensis) live on Negros and Cebu, and have a diet that makes them a likely predator. Further possible predators are common palm civets (Paradoxurus hermaphroditus) and Malay civets (Viverra tangalunga), which are both omnivores that eat small mammals. In general, a bats' flight is their greatest adaptation against predators, this species has dark coloured fur, which also camouflages them against the night sky. ("www.fieldmuseum.org", 2010b; "www.fieldmuseum.org", 2010c; "www.fieldmuseum.org", 2010a; "www.fieldmuseum.org", 2010d)

Ecosystem Roles

As frugivores, one of the main roles Philippine naked-back fruit bats may serve is dispersing seeds. They are also a likely prey species for several carnivores. (Heaney, et al., 2012)

  • Ecosystem Impact
  • disperses seeds

Economic Importance for Humans: Positive

These bats are used by humans as bush meat and their guano is mined for fertilizer, along with habitat destruction, these are the main reasons for this species' decline. When humans enter caves for guano mining, they disturb the animals there, disrupting feeding and reproduction. This species has been successfully bred in captivity for the pet trade. Additionally, to help conservation efforts, the local government of Carmen municipality has adopted Philippine naked-back fruit bats as a flagship species. However, not much research has been done due to political unrest. (Heaney, et al., 2012)

Economic Importance for Humans: Negative

There are no documented negative economic impacts from these bats. Any interactions seem to benefit humans. Their decline is caused by humans altering their habitat, like clearing forests for farming. (Heaney, et al., 2012; Paguntalan, et al., 2004; "www.fieldmuseum.org", 2010a)

Conservation Status

Philippine naked-back fruit bats were listed as critically endangered by the IUCN in 2008 because in 15 to 20 years their population has declined by at least 80%. This is inferred by hunting levels, along with degradation and fragmentation of their habitat. Despite intensive surveys, Philippine naked-back fruit bats were not recorded from 1964 until 2001, leading to their incorrect designation as extinct. To avoid extinction, immediate action needs to be taken to preserve and restore this species' habitat. Reconstruction can be started in the places they are already found, like Carmen and Catmon on Cebu Island. Carmen is well on its way, declaring this a flagship species and organizing environment protection coordinators who patrol the habitat and report violations to the mayor and council. The coordinators look after caves where they are found and have officially named naked-backed fruit bat sanctuaries. Likewise, two towns in Negros are debating making them a flagship species. (Heaney, et al., 2012; Paguntalan, et al., 2004)

Contributors

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

Glossary

acoustic

uses sound to communicate

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.

female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

food

A substance that provides both nutrients and energy to a living thing.

frugivore

an animal that mainly eats fruit

herbivore

An animal that eats mainly plants or parts of plants.

island endemic

animals that live only on an island or set of islands.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

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

pet trade

the business of buying and selling animals for people to keep in their homes as pets.

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

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

tactile

uses touch to communicate

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

young precocial

young are relatively well-developed when born

References

Human Aging Genomic Recourses. 2012. "AnAge entry for Dobsonia moluccensis" (On-line). AnAge: The Animal Aging and Longevity Database. Accessed April 28, 2013 at http://genomics.senescence.info/species/entry.php?species=Dobsonia_moluccensis.

2005. "Dobsonia magna" (On-line). The Henipavirus Ecology Collaborative Research Group. Accessed April 28, 2013 at http://www.henipavirus.org/virus_and_host_info/bats/dobsonia_magna.htm.

Myers Enterprises II. 2013. "Global Species" (On-line). Accessed May 07, 2013 at http://www.globalspecies.org/relations/dietoverlap/952235/952236.

The Field Museum. 2010. "www.fieldmuseum.org" (On-line). Synopsis of Philippine Mammals-Dobsonia Chapmani. Accessed April 24, 2013 at http://archive.fieldmuseum.org/philippine_mammals/species/SP_89.asp.

The Field Museum. 2010. "www.fieldmuseum.org" (On-line). Synopsis of Philippine Mammals-Paradoxurus hermaphroditus. Accessed May 09, 2013 at http://archive.fieldmuseum.org/philippine_mammals/species/SP_159.asp.

The Field Museum. 2010. "www.fieldmuseum.org" (On-line). Synopsis of Philippine Mammals-Prionailurus bengalensis. Accessed May 08, 2013 at http://archive.fieldmuseum.org/philippine_mammals/species_location/SP_174.asp.

The Field Museum. 2010. "www.fieldmuseum.org" (On-line). Synopsis of Philippine Mammals-Synopsis of Philippine Mammals-. Accessed May 09, 2013 at http://archive.fieldmuseum.org/philippine_mammals/species/SP_250.asp.

Hamburger, J. 2010. Petition to List 15 Bat Species Under the Endangered Species Act. Petition Submitted to the U.S. Secretary of Interior Acting through the U.S. Fish and Wildlife Service: 102-111. Accessed March 28, 2013 at wildearthguardians.org.

Heaney, L., B. Ong, B. Tabaranze, G. Rosell-Ambal, D. Balete, E. Alcala, L. Paguntulan, S. Pedregosa, A. Cariño. 2012. "Dobsonia chapmani" (On-line). The IUCN Red List of Threatened Species. Accessed March 28, 2013 at http://www.iucnredlist.org/details/full/6773/0.

Heaney, L., D. Balete, M. Lepiten, M. Dolar, W. Oliver, A. Alcala, P. Ong, A. Dans, E. Rickart, P. Gonzales, B. Tabaranza Jr, N. Ingle, R. Utzurrum. 1998. A Synopsis of the Mammalian Fauna of the Philippine Islands. Fieldiana Zoology, 88: 1-55.

Newman, S., H. Field, J. Epstein, C. de Jong. 2011. Investigating the Role of Bats in Emerging Zoonoses:Balancing ecology, conservation and public health interest. FAO Animal Production and Health Manual, 12: 29, 34.

Paguntalan, L., M. Pedregosa, M. Gadiana. 2004. The Philippine bare-backed fruit bat Dobsonia chapmani Rabor, 1952: rediscovery and conservation status on Cebu Island. Silliman Journal, 45: 113-122. Accessed April 26, 2013 at http://agris.fao.org/agris-search/search/display.do?f=2007/PH/PH0702.xml;PH2006S00043.

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