|Scientific Name:||Hylobates muelleri|
|Species Authority:||Martin, 1841|
|Infra-specific Taxa Assessed:|
|Taxonomic Notes:||This species hybridizes with H. albibarbis in a wide area of central Borneo (Marshall and Sugardjito 1986, Mather 1992). In addition, there are wide inter-grade zones between the three subspecies (Marshall and Sugardjito 1986).|
|Red List Category & Criteria:||Endangered A2cd ver 3.1|
|Assessor(s):||Geissmann, T. & Nijman, V.|
|Reviewer(s):||Mittermeier, R.A. & Rylands, A.B. (Primate Red List Authority)|
The species is considered Endangered based on an estimated population reduction of over 50% over the past 45 years (3 generations) due to rampant habitat loss and over-utilization. Where the species persists there is hunting and collection for the wildlife trade and for human consumption.
|Range Description:||The species as a whole occurs throughout Borneo except for the southwest (where H. albibarbis is found), from the north bank of the Kapuas River clockwise around the island to the east bank of the Barito River (Groves 2001).
Hylobates muelleri muelleri
This taxon is found in southeast Kalimantan, Indonesia, approximately south of the Mahakam River and west of the Barito River (Groves 2001).
Hylobates muelleri funereus
This taxon is found in Brunei, Indonesia (Kalimantan) and Malaysia (Sabah and Sarawak). It ranges from the northeast of Borneo (Sabah) south to the Mahakam River and perhaps west to the Baram District and the IV Division of Sarawak (Groves 2001).
Hylobates muelleri abbotti
This taxon is found in Indonesia (Kalimantan) and Malaysia (Sarawak). It occurs north of the Kapuas River and east as far east as the Saribas District of Sarawak (Groves 2001).
Native:Brunei Darussalam; Indonesia (Kalimantan); Malaysia (Sabah)
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||This species is generally common in areas where good forest remains (J. Hon pers. comm.). Densities estimated using various techniques at three Indonesian sites ranged from 9-14.6 individuals/km2 at Kutai National Park, to 6.9-9.9 at Kayang Mentarang National Park, and 7.9-9.5 at Sungai Wain Protection Forest (Nijman and Menken 2005). Out of 11 studies on the effects of logging, 6 reported decline and 3 were neutral (Meijaard et al. 2005). Meijaard and Nijman (unpubl. data) conservatively estimate the total population to be approximately 250,000-375,000 individuals.|
|Habitat and Ecology:||The species is found in tropical evergreen forests of primary, selectively logged and secondary forest types. Mueller's gibbons are arboreal and diurnal, and frugviorous (preferring fruits high in sugar), but will also eat immature leaves and insects (Leighton 1987; Rodman 1978). They have been recorded from forests up to 1,500 m (Leighton 1987) or 1,700 m in Sabah (Yasuma and Andau 2000), with densities decreasing at higher elevations (V. Nijman pers. comm.). In Kutai National Park, average home range size was 36 ha (Leighton 1987).|
|Major Threat(s):||Deforestation and trade in illegal pets are the predominant threats, and in interior areas hunting is also a threat (Mejiaard et al. 2005; Nijman 2005). From 2003-2004, Nijman (2005) recorded 54 individuals in markets in Kalimantan. Much habitat is being lost due to expanding oil palm plantations and logging.|
|Conservation Actions:||This species is listed on CITES Appendix I. It occurs in a number of protected areas across its range, including Betung-Kerihun National Park, Bukit Baka Bukit Raya National Park, Kayan Mentarang National Park, Kutai National Park, Sungai Wain Protection Forest, Tanjung Puting National Park (Indonesia); Lanjak-Entimau Sanctuary, Semengok Forest Reserve (Malaysia) (Richardson pers. comm.).|
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|Citation:||Geissmann, T. & Nijman, V. 2008. Hylobates muelleri. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 20 October 2014.|