Overview
Bulmer’s Fruit Bat (Aproteles bulmerae) is one of the rarest, most endangered, and enigmatic bats in the world. First described from 12,000-year-old fossil bones unearthed in a prehistoric rock shelter and thought to have vanished at the end of the Pleistocene, this colossal bare-backed megabat was miraculously discovered alive in the 1970s roosting within the Luplupwintem cave in Papua New Guinea’s rugged Star Mountains. It represents the only living member of its genus and stands as an irreplaceable relic of Melanesian evolutionary history.
Biology and Physical Characteristics
With an expansive wingspan exceeding three feet, Bulmer’s fruit bat is among the largest cave-dwelling bats known. It features a unique anatomical adaptation shared with bare-backed bats (Dobsonia): its wing membranes meet and fuse along the dorsal midline of the spine rather than attaching at the flanks, creating a smooth, naked back that increases lift and aerodynamic glide efficiency. The head is covered in short brownish-gray fur with large, forward-facing brown eyes, a blunt dog-like muzzle, and simplified molars specialized for crushing fibrous mountain figs without damage to tooth enamel.
Behavior and Ecology
Aproteles bulmerae is an obligate subterranean cave rooster, inhabiting deep, pitch-black sinkholes and cave vaults perched above 2,000 meters elevation in freezing subalpine cloud forests. At dusk, colonies take flight to forage across high-altitude mossy ridges, consuming wild montane figs (Ficus) and canopy blossoms. As agile long-distance foragers, they act as indispensable keystone seed dispersers and pollinators for montane flora across the high New Guinea cordillera. Females give birth to a single pup annually in late spring.
Conservation and Human Impact
Bulmer’s Fruit Bat is designated as Critically Endangered on the IUCN Red List. In the late 1970s, introduction of modern firearms and commercial shotguns into the Hindenburg Wall area led to catastrophic hunting inside its primary known maternity roost at Luplupwintem cave, collapsing the population from thousands of individuals to fewer than two hundred. Rigorous indigenous community conservation pacts and scientific monitoring now protect the entrance to this sacred sinkhole, but extreme vulnerability to disturbance, mining prospecting, and low reproductive rates make its survival precarious.
Interesting Factoid
Bulmer’s Fruit Bat was initially classified as an extinct ice age fossil until scientists exploring a remote sinkhole in 1975 found living colonies hanging thousands of feet inside the cave darkness.
Last updated: October 2026