Geoffroy's Rousette (Rousettus amplexicaudatus)
The Geoffroy's Rousette occurs throughout the whole of Southeast Asia: Myanmar, Thailand, Cambodia, Laos, Vietnam, Singapore, Indonesia, the island of Borneo, East Timor, the Philippines, the Solomon Islands and Bismarck Archipelago, and Papua New Guinea. This species is known from Yunnan in China (Smith et al. 2008) extending to Cambodia, Thailand, Myanmar, Viet Nam (Borissenko and Kruskop 2003), Lao PDR (Duckworth et al. 1999), Peninsular Malaysia through Indonesia (including Java and Bali), and the Philippines. It is present on many of the Molucca Islands, including the islands of Halmahera, Morotai, Buru and Seram. It is widespread throughout much of New Guinea (Indonesia and Papua New Guinea), the Bismarck Archipelago and adjacent islands. It has been recorded from the island of Bougainville and Buka (S. Hamilton pers. comm.) and many of the Solomon Islands as far south as the island of San Cristobal.
It is found throughout the Philippines, with records from Balabac, Babuyan Group (Garcia pers. comm.), Barit, Biliran, Bohol, Boracay, Busuanga, Caluya, Camotes (L. Paguntalan pers. comm.), Carabao, Catanduanes, Cebu, Dalupiri, Dinagat, Fuga, Ilin (J. C. Gonzales pers. comm.), Jolo, Leyte, Lubang, Luzon (Abra, Cagayan, Ilocos Norte, Isabela, Laguna, Quezon, Rizal, Sorsogon, Zambales provinces), Maripipi, Marinduque, Mindanao (Bukidnon, Davao del Norte, Davao del Sur, Lanao del Norte, Lanao del Sur, Misamis Oriental, Misamis Occidental (Ramayla pers. comm.), South Cotabato, Surigao del Sur, Zamboanga del Sur), Mindoro, Negros, Palawan , Panay, Polillo, Samal, Samar (J. C. Gonzales pers. comm.), Semirara, Siargao, Sibay, Sibuyan, Siquijor, Tablas, Ticao (L. Paguntalan pers. comm.), Tincansan (Alcala and Alviola 1970; Heaney et al. 1998). It has been recorded from sea level up to 2,200 m asl.
Brunei Darussalam; Cambodia; China; Indonesia (Bali, Jawa, Lesser Sunda Is., Maluku, Sulawesi, Sumatera); Lao People's Democratic Republic; Malaysia; Myanmar; Papua New Guinea (Bismarck Archipelago); Philippines; Singapore; Solomon Islands; Thailand; Timor-Leste; Vietnam. Population: This is a locally abundant species in Southeast Asia and the Philippines (Utzurrum 1992). In Southeast Asia it has probably experienced declines due to hunting as a large cave roosting species (C. Francis pers. comm.).
Population Trend: Unknown
HB: 105-115; T:15-17; FA: 79-87; E: 18.5-19.7; HF: 20-22.8; W:
Like other fruit bats, R. amplexicaudatus have sensitive hearing and sense of smell and good eyesight which help them to manoeuvre well during flight, specifically at night. What makes them different from other fruit bats is their echolocating ability. It can be distinguished by their grey-brown to brown upperparts which is darker on top of their head and paler underparts which is usually grey-brown. They have long pale hairs on the chin and neck despite having short and sparse fur. They sometimes have pale yellow tufts of hair on the side of the neck which occur in adult for this species, especially males. Most males are substantially larger than females. The most distinguishable figure of this bat besides producing a distinctive, audible clicking call is their wings. It is attached to the sides of the back and separated by a broad band of fur. The lower incisors are bifid, the canines have a longitudinal groove on the outer surface which is slightly medial to centre and the first premolars are smaller than second premolars, especially on the upper jaw.
Biology and Ecology
This is a colonial species which forms cave roosts of
several thousand animals. Roosts are known from caves, rock crevices, and old
tombs. It can be found in a wide variety of habitat types including secondary
forest, agricultural areas, and other disturbed habitats like rural gardens,
fruit orchards and at the forest edge (Heaney et al. 1991, 1998; Heideman and
Heaney 1989; Lepiten 1995; Rickart et al. 1993). It is present, but less common,
in primary tropical moist forest.
They may travel long distances each night, in search of appropriate fruit. Rousettus are known to use a primitive form of echolocation while foraging. Gestation is thought to be about 15 weeks, and lactation about three months. The species may have two litters of a single young annually in New Guinea (Bonaccorso 1998).
Specimens in the Sabah Museum were collected from coconut plantations on Mantani Island and the highland of Crocker Range while the one from Sarawak was from Niah Cave. This medium-sized bat normally roosts in caves; feeds on fruit, nectar and pollen (Payne et al. 1985). It roosts dark caves, rock crevices and old tombs (Lekagul and McNeely 1977).
The Monfort Bat Cave in the Southern Philippines has the largest gathering of these bats.
Overall there are no major threats to this species. It is
regarded as a pest in some parts of its range. In the Philippines and Indochina
it is subject to intense hunting at some cave roosts (Utzurrum 1992).
It is present in several protected areas. Identification and protection of important roosting sites would benefit the conservation of this species across its range. In the Philippines, caves are protected under the Cave Management Act, although this is not fully enforced. Elsewhere in southeast Asia the species requires protection from hunting and education is needed on the actual impact of the species on orchards (C. Francis pers. comm. 2006).