Simias concolor 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Primates Cercopithecidae

Scientific Name: Simias concolor Miller, 1903
Infra-specific Taxa Assessed:
Common Name(s):
English Pig-tailed Langur, Pig-tailed Snub-nosed Monkey
Taxonomic Notes: This species was formerly placed in the genus Nasalis. Recent molecular analysis does not support a genus-level distinction (Whittaker et al. 2006). There are currently two recognized subspecies: S. c. concolor, which is found in Indonesia on the islands of Sipora, North Pagai, and South Pagai, and S. c. siberu, which is found on the island of Siberut (Whittaker 2006).

Assessment Information [top]

Red List Category & Criteria: Critically Endangered A2cd ver 3.1
Year Published: 2008
Date Assessed: 2008-06-30
Assessor(s): Whittaker, D. & Mittermeier, R.A.
Reviewer(s): Mittermeier, R.A. & Rylands, A.B. (Primate Red List Authority)
Listed as Critically Endangered as it was estimated a population decline of 73-90% in 10 years due to heavy hunting pressure and extensive habitat loss (especially on southern islands but quite significant throughout species range). It has been relatively well studied and thus documentation is fairly recent and intensive (Whittaker 2006). However, there is need for further extensive research across the entire range.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species is endemic to Indonesia. It is confined to the Mentawai Islands off the western coast of Sumatra (Pagai Selatan, Pagai Utara, Siberut, Sipora, and a few offshore islets).

S. s. concolor
Occurs in the Mentawai Archipelago (Pagai Selatan, Pagai Utara, Sipora, and the nearby islets of Simalegu and Sinakak).

S. s. siberu
Occurs in the Mentawai Archipelago (Siberut).
Countries occurrence:
Indonesia (Sumatera)
Additional data:
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:The Siberut subspecies has the largest population size, with an estimated 6,000-15,500 individuals within Siberut National Park. The southern subspecies is urgently in need of protective measures, with a total population of 700-1,800 individuals (Whittaker 2006). The current estimate for the species as a whole is therefore from 6,700 to 17,300 individuals, down from an estimated population of 26,000 in 1980. This represents a decline of 33 to 75% in 20 years. The most recent surveys of this species estimated densities from 5 individuals/km2 in unlogged forest, to 2.5 individuals in forest patches logged 20 years ago (Paciulli 2004). The mean population density for this species was estimated at 21 individuals/km2 in 1994 (Tenaza and Fuentes 1995). This would indicate a decline of 73 to 90% in 10 years (Whittaker 2006).
Current Population Trend:Decreasing
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:This species is found in swamp forests and lowland rainforests (Tenaza 1987), as well as primary forests on the hillsides of the interior region of the islands (Tilson 1977). It is diurnal, semi-terrestrial, and primarily folivorous (D. Whittaker pers. comm.). The birth season is from June to July (Tilson 1977).

Threats [top]

Major Threat(s): This species is threatened mainly by heavy hunting and commercial logging (Whittaker 2006). It is also threatened by conversion to oil palm plantations, and forest clearing and product extraction by local people (Whittaker 2006).
Recently, hunting pressure has increased because of improved access to remote areas due to logging roads and tracks, as well as the replacement of bows and arrows with 177 caliber air rifles (Whittaker 2006). Also, local rituals and taboos that formerly regulated hunting have been replaced by Christianity (Whittaker 2006). S. concolor is the preferred game species of most Mentawai hunters (Mitchell and Tilson 1986; Fuentes 2002; Paciulli 2004). Tenaza (1989) estimated that twice as many individuals are killed by hunters each year as are born in the Pagai Islands. Animals are sometimes taken for the pet trade.

Conservation Actions [top]

Conservation Actions: This species is listed on CITES Appendix I and is protected by the Indonesian law. It currently occurs in only one officially protected area (Siberut National Park), and is never seen in captivity (M. Richardson pers. comm.). Whittaker (2006) suggests the following conservation actions: "1) increased protection for Siberut National Park, which currently lacks enforcement, 2) formal protection of the Peleonan forest in North Siberut, which is home to unusually high primate populations and is easily accessible, 3) protection of areas in the Pagai Islands by cooperating with a logging corporation that has practiced sustainable logging technique there since 1971, 4) conservation education, especially regarding hunting, and 5) the development of alternative economic models for the local people to reduce the likelihood of selling off their lands to logging companies."

Classifications [top]

1. Forest -> 1.6. Forest - Subtropical/Tropical Moist Lowland
1. Forest -> 1.8. Forest - Subtropical/Tropical Swamp
1. Land/water protection -> 1.1. Site/area protection
1. Land/water protection -> 1.2. Resource & habitat protection
2. Land/water management -> 2.1. Site/area management
3. Species management -> 3.1. Species management -> 3.1.1. Harvest management
4. Education & awareness -> 4.1. Formal education
4. Education & awareness -> 4.3. Awareness & communications
5. Law & policy -> 5.4. Compliance and enforcement -> 5.4.2. National level

In-Place Research, Monitoring and Planning
In-Place Land/Water Protection and Management
  Occur in at least one PA:Yes
In-Place Species Management
In-Place Education
  Included in international legislation:Yes
  Subject to any international management/trade controls:Yes
2. Agriculture & aquaculture -> 2.1. Annual & perennial non-timber crops -> 2.1.3. Agro-industry farming
♦ timing:Ongoing    
→ Stresses
  • 1. Ecosystem stresses -> 1.1. Ecosystem conversion
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

5. Biological resource use -> 5.1. Hunting & trapping terrestrial animals -> 5.1.1. Intentional use (species is the target)
♦ timing:Ongoing    
→ Stresses
  • 2. Species Stresses -> 2.1. Species mortality

5. Biological resource use -> 5.3. Logging & wood harvesting -> 5.3.5. Motivation Unknown/Unrecorded
♦ timing:Ongoing    
→ Stresses
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

1. Research -> 1.2. Population size, distribution & trends
1. Research -> 1.3. Life history & ecology
1. Research -> 1.5. Threats
1. Research -> 1.6. Actions
3. Monitoring -> 3.1. Population trends

♦  Food - human
 Local : ✓ 

♦  Pets/display animals, horticulture
 Local : ✓   National : ✓ 

Bibliography [top]

Fuentes, A. 2002. Monkeys, humans and politics in the Mentawai Islands: no simple solutions in a complex world. In: A. Fuentes and L. D. Wolfe (eds), Primates Face to Face: Conservation Implications of Human-Nonhuman Primate Interactions, pp. 187-207. Cambridge University Press, Cambridge, UK.

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

Mitchell, A. and Tilson, R. 1986. Restoring the balance: Tradtitional hunting and primate conservation in the Mentawai islands, Indonesia. In: J. Else and P. Lee (eds), Primate ecology and conservation, Cambridge University Press, Cambridge, UK and London, UK.

Paciulli, L. 2004. The effects of logging, hunting, and vegetation on the densities of the Pagai, Mentawai Islands primates. Thesis, State University of New York.

Paciulli, L., Fuentes, A. and Konstant, W. R. 2005. Pagai Pig-tailed Snub-nosed Monkey or Simakobu, Simias concolor Miller, 1903. In: R. A. Mittermeier, C. Valladares-Pádua, A. B. Rylands, A. A. Eudey, T. M. Butynski, J. U. Ganzhorn, R. Kormos, J. M. Aguiar and S. Walker (eds), Primates in Peril: The World's 25 Most Endangered Primates 2004-2006, pp. 25-26. Report to IUCN/SSC Primate Specialist Group (PSG), International Primatological Society (IPS) and Conservation International (CI), Washington, DC, USA.

Tenaza, R. 1987. The status of primates and their habitats in the Pagai Islands, Indonesia. Primate Conservation 8: 104-110.

Tenaza, R. and Fuentes, A. 1995. Monandrous social organization of pigtailed langurs (Simias concolor) in the Pagai Islands, Indonesia. International Journal of Primatology 16(2): 295–310.

Tilson, R. L. 1977. Social organization of Simakobu monkeys (Nasalis concolor) in Siberut Island, Indonesia. Journal of Mammalogy 58: 202-212.

Whittaker, D. 2006. A conservation action plan for the Mentawai primates. Primate Conservation 20: 95-105.

Whittaker, D., Morales, J. and Melnick, D. 2006. Molecular phylogenetic affinities of the simakobu monkey (Simias concolor). Molecular Phylogenetics and Evolution 39: 887-892.

Citation: Whittaker, D. & Mittermeier, R.A. 2008. Simias concolor. The IUCN Red List of Threatened Species 2008: e.T20229A9181121. . Downloaded on 20 April 2018.
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