|Scientific Name:||Presbytis hosei|
|Species Authority:||(Thomas, 1889)|
|Infra-specific Taxa Assessed:|
|Taxonomic Notes:||There are strong indications that the canicrus subspecies can be separated from the others as a distinct species (Meijaard and Groves unpubl. data). The subspecies hosei is based on just a few specimens (type locality) and is of unclear taxonomic status.|
|Red List Category & Criteria:||Vulnerable A2cd ver 3.1|
|Assessor(s):||Nijman, V., Meijaard, E. & Hon, J.|
|Reviewer(s):||Mittermeier, R.A. & Rylands, A.B. (Primate Red List Authority)|
This species is considered Vulnerable in light of a continuing decline of the population inferred from extensive habitat loss and hunting. Habitat loss was probably between 30-50% of the range in the past 30 years (approximately three generations). Where the species does remain it is heavily hunted.
Presbytis hosei is found in northern Borneo, specifically northern Sarawak and Sabah (Malaysia), northern East Kalimantan (Indonesia), and Brunei Darussalam (Nijman 2004). The southern boundary of the species' range is not yet clear, and the distribution map should be regarded as provisional.
Presbytis hosei hosei may only be found around the lower Baram River in coastal Sarawak, Malaysia (Groves 2001).
Presbytis hosei everetti is found in Brunei, Indonesia (Kalimantan) and Malaysia (Sabah and Sarawak). The range extends from about latitude 2°40’N to Mount Kinabalu and along the northwestern coast of Sabah into Brunei (Groves 2001).
Presbytis hosei sabana is confined to central and eastern Sabah, and perhaps also in far northeastern Kalimantan (Groves 2001).
Presbytis hosei canicrus is found on the eastern coast of Borneo (Kalimantan, Indonesia), from Kutai to Gunung Talisayan (Groves 2001).
Native:Brunei Darussalam; Indonesia (Kalimantan); Malaysia (Sabah)
|Range Map:||Click here to open the map viewer and explore range.|
A population in the Kayan Mentarang National Park in East Kalimantan was assessed by counts along transects as well as data from all other encounters. A follow-up census 7 years later concluded that densities had dropped by 50-80%, and the species had become rare to observe. It is suggested that hunting for various reasons was the principal cause of this decline (Nijman 2004, 2005).
In Brunei, average size is 6 individuals per group (Hon pers. comm.); this may be the last stronghold for this species. Densities for P. h. sabana are estimated at 2.1 groups/km2, or approximately 16 individuals/km2; estimates for P. h. everetti are 1.3 groups/km2, or approximately 10.1 individuals/km2; estimates for P. h. canicus are 2.3 groups/km2, or approximately 19 individuals/km2 (V. Nijman pers comm.).
|Habitat and Ecology:||This species occurs in lowland to hill dipterocarp rainforest (on Mount Kinabalu). It is known from sea-level up to approximately 1,000 m elevation, with records to 1,600 m (Goodman 1989) and possibly higher. Animals occasionally enter plantations. It is primarily folivorous, but will consume flowers, fruits and seeds, as well as eggs and nestlings.|
|Use and Trade:||It is hunted for lucrative “bezoar stones” (visceral secretions used in traditional “medicines”). These monkeys are also hunted for food.|
|Major Threat(s):||Though not totally impervious, Hose’s sureli is relatively tolerant of forest disturbance. However, hunting poses the biggest danger to this species. The hunting of surelis correlates with the presence of inland settlements, the timber industry, and a demand for lucrative “bezoar stones” (visceral secretions used in traditional “medicines”). These monkeys are also hunted for food and to deter crop-raiding (Nijman 2004).|
|Conservation Actions:||This species is legally protected in Indonesia, though wrongly named P. aygula, a misidentification that may serve to subvert prosecution of offenders. P. aygula is the former name for P. comata, a species with which P. hosei has sometimes been incorrectly lumped in the past. It is listed on CITES Appendix II. The largest population in a protected area is found in Kayan Mentarang, East Kalimantan (Nijman 2005), and the next largest protected area that harbors P. hosei is the Betung-Kerihun / Lanjak Entimau trans-boundary reserves in West Kalimantan and Sarawak (Nijman 2004). These protected habitats do not prevent the decline of many forest species, including Hose’s sureli, however, due to the absence of meaningful enforcement of laws to prevent illegal hunting (Nijman 2005). The species occurs as well in Kutai National Park (Indonesia) and in Mount Kinabalu National Park (Malaysia). There are no specimens reported in captivity.|
Goodman, S. 1989. Predation by the grey leaf monkey Presbytis hosei of the contents of a bird’s nest at Mt. Kinabalu Park, Sabah. Primates 31(1): 127–128.
Groves, C. P. 2001. Primate taxonomy. Smithsonian Institution Press, Washington, DC, USA.
Mitchell, A. 1994. Ecology of Hose’s langur (Presbytis hosei) in logged and unlogged Dipterocarp forest of northeast Borneo. Thesis, Yale University.
Nijman, V. 2004. Effects of habitat disturbance and hunting on the density and the biomass of the endemic Hose’s leaf monkey Presbytis hosei (Thomas, 1889) (Mammalia: primates: Cercopithecidae) in east Borneo. Contributions to Zoology 73(4).
Nijman, V. 2005. Decline of the endemic Hose’s langur Presbytis hosei in Kayan Mentarang National Park, east Borneo. Oryx 39: 223–226.
Payne, J., Francis, C.M. and Phillipps, K. 1985. A field guide to the mammals of Borneo. The Sabah Society and WWF Malaysia, Kota Kinabalu and Kuala Lumpur, Malaysia.
|Citation:||Nijman, V., Meijaard, E. & Hon, J. 2008. Presbytis hosei. The IUCN Red List of Threatened Species. Version 2015.2. <www.iucnredlist.org>. Downloaded on 04 September 2015.|
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