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Symphalangus syndactylus

Taxonomy (Name)

Class MAMMALIAIUCN
Order DIPROTODONTIAIUCN
Family HYLOBATIDAEIUCN
Scientific Name Symphalangus syndactylusIUCN
Author (Raffles, 1821)IUCN
Synonyms Hylobates syndactylus (Raffles, 1821)
Symphalangus continentis Thomas, 1908
Symphalangus gibbon (C. Miller, 1779)
Symphalangus subfossilis Hooijer, 1960
Symphalangus volzi (Pohl, 1911) IUCN
Common Name SiamangIUCN
Local name Brunei Darussalam  
Cambodia  
China  
Indonesia Owa, Kera tak berbuntut (semua jenis dari familiHylobatidae)
Japan  
Lao PDR  
Malaysia Siamang
Myanmar  
Mongolia  
Philippines  
Singapore  
Republic of Korea  
Thailand ????????
Vietnam  

 

Picture

 

 

Distribution, Range

This species is found in Indonesia (Barisan Mountains of west-central Sumatra), Malaysia (mountains of the Malay Peninsula south of the Perak River), and a small area of southern peninsular Thailand (Chivers 1974; Khan, 1970; O?Brien et al. 2003; Treesucon and Tantithadapitak 1997). It may have formerly occurred on the island of Bangka (Indonesia) as well. Reports of this species from Myanmar are almost certainly erroneous.

IUCN

Map

Country

Brunei Darussalam  
Cambodia  
China  
Indonesia checkIUCN
Japan  
Lao PDR  
Malaysia checkIUCN
Myanmar  
Mongolia  
Philippines  
Singapore  
Republic of Korea  
Thailand checkIUCN
Vietnam  

 

Status

International Status

IUCN Red List Category

ENIUCN

Justification

Listed as Endangered as, there is reason to believe the species has declined by at least 50% over the past 40 years (three generations) due primarily to hunting for pet trade and continued rates of habitat loss (mainly as a result of expanding agriculture and road building). Although there has likely been 70-80% habitat loss of primary habitat within the past 50 years within the range of the species, this species is one of the most adaptable gibbons to habitat change. Although the species occurs in numerous protected areas and retains a number of viable populations, it could in future be considered Critically Endangered due to historic habitat loss, and should be closely monitored in the future.

IUCN

CITES

Appendix IIUCN

CMS

 

National Status

Country Category Reference
Brunei Darussalam    
Cambodia    
China    
Indonesia    
Japan    
Korea    
Lao PDR    
Malaysia NT Red List of Mammals for Peninsular Malaysia(DWNP, 2010)
Mongolia    
Myanmar    
Philippines    
Singapore    
Thailand NT (as Hylobates syndactylus) Thailand Red Data: Mammals, Reptiles and Amphibians(Nabhitabhata and Chan-ard, 2005)
Vietnam    

 

 

Ecology Discription

Appearance

 

Habitat

This species lives in primary and secondary semi-deciduous and tropical evergreen forest. All levels of the canopy are used, although emergent trees are required for resting and sleeping. Siamangs occur at lower densities in secondary forest, but can persist in secondary areas. They range from the lowlands up to 1,500 m in elevation. During a short survey in southern Sumatra, siamangs appeared to be less sensitive to habitat degradation than sympatric agile gibbons, Hylobates agilis (Geissmann et al. 2006). Since Bukit Barisan Selatan National Park coffee plantations have no canopy, they provide no habitat for this species (O'Brien et al. 2004).

IUCN

Population size

In a study on this species in Bukit Barisan Selatan National Park, Sumatra, O'Brien et al. (2004) calculated an average group density of one group for every 2.23 km2, with an average group size of 3.9, and a population estimate of 22,390 individuals. Healthy populations persist at the southern limit of its range in Bukit Barisan Selatan National Park, and these populations should survive over the long-term if the park maintains its present forest area, and if illegal hunting and habitat degradation are stopped (O?Brien et al. 2004). While some populations of this species appear secure today, its future is uncertain and will depend on vastly improved conservation efforts, especially in Sumatra?s remaining parks and protected areas (O?Brien et al. 2004). Population densities for this species range from 2.4 to 24.6 individuals/km2 (O?Brien et al. 2004).

IUCN

Behavior

Siamang are strictly arboreal, highly territorial, and primarily monogamous (Chivers 1974). Extra-pair copulations have been reported in Ketambe, Gunung Leuser National Park, Sumatra (Palombit 1994), and groups with more than one adult male have been reported in the Way Kambas National Park population, Sumatra (O?Brien et al. 2003; Lappan 2005, 2007). Home range has been recorded at 15-47 ha on the Malayan peninsula (Chivers 1974; Raemaekers 1977; MacKinnon and MacKinnon 1980), and dispersal distance is less than 3 km. O?Brien et al. (2003) found that monogamy and strict territoriality may limit the range of possible response to fire and other severe disturbances by this species.

IUCN

Diet

Though this species is primarily folivorous in mainland Asia (Chivers 1974; Raemaekers 1984), it is primarily frugivorous on Sumatra (Palombit 1992; West 1982), feeding mostly on figs (O?Brien et al. 2003). Palombit (1992) argues that these animals are flexible foragers, preferring fruit when available, but able to switch to leaves when necessary. Such flexibility may help reduce siamang vulnerability to habitat disturbance (O?Brien et al. 2003).

IUCN

Reproduction

 

 

Threat

Major Threat(s)

This species is threatened by forest conversion and opportunistic collection for pet trade on Sumatra, where both of these threats extend to populations in national parks and protection forests (O?Brien et al. 2004). Between 1995 and 2000, almost 40% of the habitat for this species on Sumatra was damaged or destroyed by logging, road development (barrier and hunting) and conversion to agriculture or plantations (O?Brien unpubl. data). Legal logging seems to be accelerating in Sumatra (Geissmann et al. 2006). Forests, where they remain, are extremely fragmented. Coffee plantations present an increasing threat (O?Brien and Kinnaird 2003). The siamang is one of the most heavily traded gibbon species for illegal pet trade (V. Nijman pers. comm.).

IUCN

 

Conservation and Measurement

International

CITES, Appendix I. IUCN

National

This species is protected throughout its range, both by local laws

Conservation law

Country Status Reference
Brunei Darussalam    
Cambodia    
China    
Indonesia Protected Animals Goverment Regulation no. 7 / 1999, about Preservation of Plants and Animals
Japan    
Korea    
Lao PDR    
Malaysia Totally Protected Wild Animals (as Hylobates syndactylus) Law of Malaysia Act 76, Protection of Wild Life Act 1972
(Amend. 2006)
Mongolia    
Myanmar    
Philippines    
Singapore    
Thailand    
Vietnam    

 

Protected Area

It is known to occur in at least nine protected areas: Bukit Barisan National Park, Gunung Leuser National Park, Way Kambas National Park, West Langkat R (Indonesia); Fraser?s Hill R, Gunong Besout Forest Reserve, Krau Wildlife Reserve, Ulu Gombak Wildlife Reserve (Malaysia); Hala Bala Wildlife Sanctuary (Thailand) (M. Richardson pers. comm.).

IUCN

Other Coservation Projects

There is a large worldwide captive population, in 96 collections.

IUCN

 

Citation

Aldrich-Blake, F. and Chivers, D. 1973. On the genesis of a group of siamang. American Journal of Physical Anthropology 38: 631-636.

Anonymous. 1971. Clear felling threatens the siamang. Oryx 11(1): 6-8.

Bennett, E., Davison, G. and Kavanagh, M. 1983. Social change in a family of siamang (Hylobates syndactylus). Malayan Nature Journal 36: 187-196.

Chivers, D. 1971. Spatial relations within the siamang group. In: H. Kummer (ed.), Proceedings of the 3rd International Congress of Primatology, Zurich 1970, vol. 3: Behaviour, Basel and New York.

Chivers, D. 1971. The Malayan siamang. Malayan Nature Journal 24: 78-86.

Chivers, D. 1972. The siamang and the gibbon in the Malay Peninsula. In: D. Rumbaugh (ed.), Gibbon and siamang, vol. 1, Basel and New York.

Chivers, D. 1974. The siamang in Malaya: a field study of a primate in tropical rain forest. Contributions to Primatology 4: 1-335.

Chivers, D. 1975. Daily patterns of ranging and feeding in siamang.In: S. Kondo, M. Kawai and A. Ehara (eds), Contemporary primatology. 5th International Congress of Primatology, Nagoya 1974, Basel and New York.

Chivers, D. 1975. The behaviour of siamang in the Krau Game Reserve. Malayan Nature Journal 29: 7-22.

Chivers, D. 1977. The feeding behaviour of siamang (Symphalangus syndactylus). In: T. H. Clutton-Brock (ed.), Primate ecology: Studies of feeding and ranging behaviour in lemurs, monkeys and apes, London, UK and New York, USA.

Chivers, D. 1979. The siamang and the gibbon in the Malay Peninsula. New York, USA.

Chivers, D. and Chivers, S. 1975. Events preceding and following the birth of a wild siamang. Primates 16: 227-230.

Chivers, D. and Raemaekers, J. 1973. Behaviour of siamang. Malayan Nature Journal 26: 177.

Chivers, D., Raemaekers, J. and Aldrich-Blake, F. 1975. Long-term observations of siamang behaviour. Folia Primatologica 23(1-2): 1-49.

Geissmann, T., Nijman, V. and Dallmann, R. 2006. The fate of diurnal primates in southern Sumatra. Gibbon Journal 2: 18-24.

Gittins, S. and Raemaekers, J. 1980. Siamang, lar and agile gibbons. In: D. Chivers (ed.), Malayan forest primates ? Ten years? study in tropical rain forest, pp. 63-105. Plenum Press, New York, USA.

Groves, C. P. 2001. Primate taxonomy. Smithsonian Institution Press, Washington, DC, USA.

Groves, C. P. 2005. Order Primates. In: D. E. Wilson and D. M. Reeder (eds), Mammal Species of the World, pp. 111-184. The Johns Hopkins University Press, Baltimore, Maryland, USA.

Hunt Curtin, S. and Chivers, D. 1978. Leaf-eating primates of peninsular Malaysia: The siamang and the dusky leaf monkey. In: G. G. Montgomery (ed.), The ecology of arboreal folivores, Washington, DC, USA.

Kawabe, M. 1970. A preliminary study of the wild siamang gibbon, Hylobates syndactylus, at Fraser?s Hill, Malaysia. Primates 11(3): 285-291.

Khan, B. 1970. Distribution and population of siamang and gibbons in the state of Perak. Malayan Nature Journal 24: 3-8.

Lappan, S. 2005. Biparental care and male reproductive strategies in siamangs (Symphalangus syndactylus) in southern Sumatra. Ph.D. Thesis, New York University.

Lappan, S. 2007. Patterns of dispersal in Sumatran siamangs (Symphalangus syndactylus): Preliminary mtDNA evidence suggests more frequent male than female dispersal to adjacent groups. American Journal of Primatology 69: 692?698.

MacKinnon, J. and MacKinnon, K. 1980. Niche differentiation in a primate community. In: D. Chivers (ed.), Malayan forest primates: Ten years? study in tropical rain forest, pp. 167-190. Plenum Press, New York, USA.

Norikoshi, K. 1986. Socio-ecological study of siamangs in Maninjau, West Sumatra. Kyoto University overseas research report of studies on Asian non-human primates, vol. 5, Kyoto University, Kyoto, Japan.

Nurcahyo, A. 1998. Laporan penelitian studi perilaku harian siamang (Hylobates syndactylus) di Taman Nasional Bukit Barisan Selatan, Lampung. Jurusan Konservasi Sumberdaya Hutan. Universitas Gadjah Mada, Fakultas Kehutanan.

O'Brien, T. G. and Kinnaird, M. F. 2003. Caffeine and conservation. Science 300: 587.

O? Brien, T. G., Kinnaird, M. F., Nurcahyo, A., Iqbal, A. and Rusmanto, M. 2004. Abundance and distribution of sympatric gibbons in a threatened Sumatran rain forest. International Journal of Primatology 25(2): 267-284.

O? Brien, T., Kinnaird, M., Nurcahyo, A., Prasetyaningrum, M. and Iqbal, M. 2003. Fire, demography and the persistence of siamang (Symphalangus syndactylus: Hylobatidae) in a Sumatran rainforest. Animal Conservation 6: 115 - 121.

Palombit, R. 1992. Pair bonds and monogamy in wild siamang (Hylobates syndactylus) and white-handed gibbon (Hylobates lar) in northern Sumatra. Ph.D. Thesis, University of California.

Palombit, R. 1994. Extra-pair copulations in a monogamous ape. Animal Behaviour 47: 721 - 723.

Palombit, R. 1995. Longitudinal patterns of reproduction in wild female siamang (Hylobates syndactylus) and white-handed gibbons (Hylobates lar). International Journal of Primatology 16: 739-760.

Palombit, R. 1996. Pair bonds in monogamous apes: A comparison of the siamang Hylobates syndactylus and the white-handed gibbons. Hylobates lar Behaviour 133: 321-356.

Palombit, R. 1997. Inter- and intraspecific variation in the diets of sympatric siamang (Hylobates syndactylus) and lar gibbons (Hylobates lar). Folia Primatologica 68: 321-337.

Raemaekers, J. 1977. Gibbons and trees: Comparative ecology of the siamang and lar gibbon. Ph.D. Thesis, University of Cambridge.

Raemaekers, J. 1978. Changes through the day in the food choice of wild gibbons. Folia Primatologica 30: 194-205.

Raemaekers, J. 1978. Competition for food between lesser apes. In: D. Chivers and J. Herbert (eds), Recent advances in primatology, vol. 1: Behaviour, London, UK and New York, USA.

Raemaekers, J. 1978. The sharing of food sources between two gibbon species in the wild. Malayan Nature Journal 31: 181-188.

Raemaekers, J. 1979. Ecology of sympatric gibbons. Folia Primatologica 31: 227-245.

Raemaekers, J. 1980. Causes of variation between months in the distance travelled by gibbons. Folia Primatologica 34: 46-60.

Raemaekers, J. 1984. Large versus small gibbons: Relative roles of bioenergetics and competition in their ecological segregation in sympatry. In: H. Preuschoft, D. Chivers, W. Brockelman and N. Creel (eds), The lesser apes. Evolutionary and behavioural biology, Edinburgh.

Raemaekers, J. and Chivers, D. 1980. Socio-ecology of Malayan forest primates. In: D. Chivers (ed.), Malayan forest primates ? Ten years' study in tropical rain forest, New York, USA.

Treesucon, U. and Tantithadapitak, T. 1997. Siamang (Hylobates syndactylus): A new mammal recorded for Thailand. Natural History Bulletin of the Siam Society 45: 123-124.

West, K. 1982. The ecology and behavior of the siamang (Hylobates syndactylus) in Sumatera. M.Sc. Thesis, University of California.

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