Hylobates albibarbs
Creators: name: Russell A. Mittermeier
name: Anthony B. Rylands
name: Don E. Wilson
Publisher: name: Lynx Edicions
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Primates
Hylobatidae
Hylobates
Hylobates albibarbs

description: 4.
Bornean White-bearded Gibbon
Hylobates albibarbs
French: Gibbon a barbe blanche / German: Weil 3bartgibbon / Spanish: Gibén barbiblanco
Other common names: Bornean Agile Gibbon
Taxonomy. Hylobates mülleri albibarbis Lyon, 1911,
Indonesia, near Sukadana, south-west Borneo.
Previously regarded as a subspecies of H. agilis. This species hybridizes with H. muelleri and H. abbotti in a wide area of central Borneo. Monotypic.
Distribution. SW Borneo (West Kalimantan & Central Kalimantan provinces), S of the Kapuas River and W of the Barito River.
Descriptive notes. There are no specific body measurements available; weight 4.9-6 kg (males) and 6.1-6.8 kg (females). The Bornean White-bearded Gibbon is similar to the Agile Gibbon (H. agilis), but with no black morph. Of all the gibbons, this species has the most colorful and distinctive coat pattern. It is light grayish-brown, becoming golden-toned on the rump and with a blackened ventral zone, hands, and feet. The crown hair is directed fanwise from the front of the scalp, and the cap is dark although margined with buff. Males often have a light genital tuft.
Habitat. Primary, secondary, and selectively logged tropical evergreen forest up to 1200 m above sea level and peat-swamp forest. Population densities decrease at higher elevations.
Food and Feeding. The Bornean White-bearded Gibbon is predominantly frugivorous, preferring fruits high in sugar, butit also eats immature leaves and insects.
Breeding. Full maturity of male and female Bornean White-bearded Gibbons occurs at 6-8 years of age.
Activity patterns. The Bornean White-bearded Gibbon is diurnal and arboreal. In Sabangau National Park, Central Kalimantan, they spend, on average, 29% their day feeding, 29% traveling, 29% resting, 9% in singing, and 4% engaged in social activities.
Movements, Home range and Social organization. Polygynous pairings have been reported in the H. albibarbis x H. muelleri (Miller's Gibbon) hybrid zone. Average home range sizes were 28 ha and 47 ha for Bornean White-bearded Gibbons in Gunung Palung and Sabangau national parks, respectively. In general, males are aggressive toward other males and also defend their group's territory. Females usually lead the group's daily progressions and keep away other females. Population densities range from 7-4 ind/km? (2-2 groups/km?) in logged peatswamp forest of Sabangau National Park and 8-7 ind/km? in primarily heath forest in Tanjung Puting National Park, Central Kalimantan, to 14-9 ind/km? in mountain forests in Gunung Palung National Park, West Kalimantan.
Status and Conservation. CITES Appendix I. Classified as Endangered on The IUCN Red List. The Bornean White-bearded Gibbon is legally protected in Indonesia. It is threatened mainly by habitat loss due to fires,illegal logging, and oil palm plantations. A'large part ofits distribution occurs in peat swamp—an extremely threatened ecosystem because of draining, logging, and burning. The Bornean White-bearded Gibbon was certainly affected by the widespread forest fires in the 1990s and continuing deforestation, but no recent surveys are available on population trends. The Bornean Whitebearded Gibbon is frequently captured for pets and occasionally hunted for meat. It occurs in six protected areas: Bukit Baka Bukit Raya, Gunung Palung, Tanjung Puting, and Sabangau national parks and Hampapak and Kendawangan nature reserves in Indonesia. The Bornean White-bearded Gibbon is generally common in suitable habitat. A tentative estimate suggests that ¢.19,000 individuals live in the mixed-swamp forest subtype in Sabangau National Park, which has one of the largest remaining continuous populations. An estimate of the total population is not available.
Bibliography. Buckley (2004), Buckley et al. (2006), Cheyne (2010), Cheyne & Brulé (2004), Cheyne et al. (2008), Chivers (1977, 2001), Groves (2001), Hirai, Hayano et al. (2009), Hirai, Wijayanto et al. (2005), Kloss (1929), Marshall & Sugardjito (1986), Mather (1992), McConkey (2000, 2005a, 2005b), McConkey, Aldy et al. (2002), McConkey, Ario et al. (2003), Meijaard et al. (2005), Mitani (1987a, 1987b, 1988, 1990a), Mitani & Marler (1989), Nijman (2005b), Nijman, Richardson & Geissmann (2008), Short (2004), Sugardjito (1978, 1988), Van Ngoc Thinh, Mootnick, Geissmann et al. (2010).
description: Published as part of Russell A. Mittermeier, Anthony B. Rylands & Don E. Wilson, 2013, Hylobatidae, pp. 778-791 in Handbook of the Mammals of the World – Volume 3 Primates, Barcelona :Lynx Edicions on pages 780-781, DOI: 10.5281/zenodo.6727957