Bulmer's Fruit Bat
(Aproteles bulmerae)
Bulmer’s fruit bat is the largest bat species to roost in caves. It is predominantly nocturnal and, like other fruit bats, relies on sight rather than echolocation to navigate. It has a remarkable ability to manoeuvre, and is one of the few species of bats that can hover and even fly backwards. Believed to have become extinct at the end of the last Ice Age glaciation, the species was rediscovered in a precipitous mountain cave in 1975. Shortly after its rediscovery, this small population was almost wiped out by local hunters with guns. There are no other known populations, making this remarkable animal one of the most endangered species of bats in the world.
Urgent Conservation Actions
A management plan is urgently needed. A captive breeding programme or relocation of a few individuals to start a new colony should also be considered to safeguard against extinction.
Papua New Guinea.
Evolutionary Distinctiveness
Order: Chiroptera
Family: Pteropodidae
Bats are divided into two suborders: the Microchiroptera (echo-locating bats) and the Megachiroptera (flying foxes and Old World fruit bats). The Pteropodidae is the sole family in the suborder Megachiroptera. It includes around 186 living species, placed in 42 genera. The fossil record of this group extends to the middle Oligocene (around 46 million years ago). Aproteles bulmerae is the only species of its genus. Recent biochemical studies have shown that its nearest relatives are the species of Dobsonia, but they are only distantly related.
Head and body length: 242 mm
Tail length: 32 mm
Forearm length: 166 mm
Weight: 600 g
A large member of the flying fox family, this species is dark brown or blackish in colour and has a wingspan of almost one metre. One of its most striking features is its naked back, a result of the wing membranes meeting in the middle of the back. This configuration allows for great manoeuvrability in flight. It is one of the few bats that can hover and even fly backwards. Adults give off a very strong, musky odour. These bats can be distinguished from similar species by their lack of lower incisor teeth (hence the generic name “Aproteles”, meaning “incomplete at the front”).
Bulmer’s fruit bat is the largest bat species known to roost in caves. It is nocturnal, and usually leaves the cave at dusk to forage for food. Based on dental structures and its close relationship to other fruit-eating bats, the species is thought to eat only fruit. It does not have a well-developed echolocation system like the insectivorous bat species, but instead relies on sight to navigate and find food. The bats are extremely cautious. When leaving the cave they first send out a couple of scouts who circle the cave entrance and utter strange bird-like calls for several minutes before departing. If people are present they will delay their exit from the cave until after dark. The bats are thought to fly considerable distances to feed (one individual was found approximately 32 km away from the roost). They return to the roost at about 6am, before light. Although predominantly nocturnal, they will occasionally emerge during the day in sunny weather. Females are thought to become sexually active at around three years of age. They give birth in April and carry the young for the first few weeks of life whilst foraging.
The only known roost of the species is an enormous vertical-sided cave near the edge of a large escarpment at an altitude of 2,400 m. The cave is surrounded by mossy montane forest dominated by conifers.
The species is endemic to the island of New Guinea. It is currently known only to inhabit a single cave, known locally as Luplupwintem, located in the Hindenburg ranges of far western Papua New Guinea. It is possible that other populations exist in remote mountainous regions of the island.
Population Estimate
In April 1993 the population was estimated to be approximately 160 individuals.
Population Trend
Classified as Critically Endangered B2ab(v); C2a(ii) on the 2010 IUCN Red List of Threatened Species.
Believed to have been hunted to extinction at the end of the last Ice Age glaciation, this species was rediscovered roosting in a remote cave in 1975. At that time, local inhabitants described the bat as being abundant, perhaps numbering in the thousands. However, just two years later the colony had been virtually eliminated. The bats had traditionally been protected by the local people, and the fact that the cave was so treacherous that virtually no-one could enter it. However, mining operations that began in the mid 1970s enabled the local men to work for cash for the first time. With the money they were earning they bought ropes with which to enter the cave. Once inside they had used shotguns to kill hundreds of bats at a time for their meat. Several searches over the next decade failed to find any trace of the bats and they were believed once again to have become extinct at the hands of humans.

In May 1992 a small colony of 137 individuals was rediscovered at Luplupwintem. By April 1993, the colony had increased to about 160 individuals. However, this is much less than the potential natural rate of increase, and it is likely that significant hunting may still be taking place. Other threats may include human disturbance and the removal of wood from its feeding grounds.
Conservation Underway
There do not appear to be any conservation measures in place.
Conservation Proposed
International conservation groups should work with the PNG government and local people to develop and implement a management plan for the species. Since the species is known from a single, small colony, a captive breeding programme or relocation of a few individuals to start a new colony should be considered to guard against extinction of the wild population.
Bonaccorso, F.J. 1998. Bats of Papua New Guinea. Conservation International, Washington, DC.

Flannery, T. 1995. Mammals of New Guinea. Reed books. Australia.

Flannery, T. F. 1994. The Rediscovery of Bulmer's Fruit Bat. BATS 12(1): 3-5.

Hutson, T., Helgen, K., Flannery, T. & Wright, D. 2008. Aproteles bulmerae. In: 2010 IUCN Red List of Threatened Species. Version 2010.4. Downloaded on 12 November 2010.

Nowak, R.M. 1999. Walker's Mammals of the World. Sixth edition. The Johns Hopkins University Press, Baltimore and London.

Distribution map based on data provided by the IUCN Global Mammal Assessment.

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Forum comments
  1. Anonymous

    This site is very helpful.

    Posted 8 years ago #

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