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Ateles chamek 


Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Primates Atelidae

Scientific Name: Ateles chamek
Species Authority: (Humboldt, 1812)
Common Name(s):
English Black-faced Black Spider Monkey, Peruvian Black Spider Monkey, Peruvian Spider Monkey, Chamek Spider Monkey
Spanish Macaco Aranha, Maquisapa, Marimono, Mono Araña
Taxonomic Notes: The taxonomy of the spider monkeys is based on Kellogg and Goldman (1944) and Hill (1962). The forms hybridus, chamek and marginatus are listed as distinct species (see Rylands et al. 2000).

Froehlich et al. (1991), and Medeiros (1994, 1997) argued that A. paniscus is a distinct form with no subspecies. De Boer and Bruijn (1990) indicated that chamek should be considered a full species, and likewise Sampaio et al. (1993) argued that the forms paniscus and chamek should be considered distinct species on the basis of the genetic distance between them. Ateles chamek was found to be closer to belzebuth than to paniscus (see also Nieves et al., 2005).

M. G. M. van Roosmalen reported on the rediscovery of Ateles longimembris Allen, 1914, from Barão de Melgaço, headwaters of the Rio Gy-paraná, Mato Grosso, Brazil (Website , 5 August 2003; accessed 26 September 2003). Cruz Lima (1945) recognized this spider monkey as a subspecies of Ateles paniscus. The description of the range given by Cruz Lima (1945; p.127) extends west into what is now recognized to be that of A. chamek. Groves (2001) considered it to be a synonym of A. chamek. Van Roosmalen reported that it occurs “east of the lower and middle Rio Aripuanã in the interfluve confined by the Rios Madeira, Aripuanã and Jí-Paraná”. He described it as differing from A. chamek by “cranial characters (i.e., proportionally heavy jaws and canines not enabling adults to fully close their mouth), triangular pink muzzle including chin, black face, and black triangular blaze of backwardly directed black hairs on the forehead”. Van Roosmalen went on to report another closely-related, but undescribed, spider monkey “along the right bank of the Rio Aripuanã and Rio Madeira north of the town of Novo Aripuanã, east to the Rio Canumã, and along the Rios Arara, Acarí, and Canumã.”

M. G. M. van Roosmalen reported (5 August 2003) that the spider monkey east of the Rio Purus and south of the Rio Ipixuna (a region formerly lacking any record of the existence of a spider monkey) was an undescribed species. It differs from A. chamek in having “a triangular forehead patch or blaze, with black, backward directed hairs and triangular flesh-colored muzzle, lacking the pink circumocular rings and mouth/lips.” It is found only in upland rain forest, away from igapó. Van Roosmalen referred a living holotype, a pet juvenile female in the community Belo Monte along the right bank of the middle Rio Purus.

Assessment Information [top]

Red List Category & Criteria: Endangered A2cd ver 3.1
Year Published: 2008
Date Assessed: 2008-06-30
Assessor(s): Wallace, R.B., Mittermeier, R.A., Cornejo, F. & Boubli, J.-P.
Reviewer(s): Mittermeier, R.A. & Rylands, A.B. (Primate Red List Authority)
Listed as Endangered as there is reason to believe the species has declined by at least 50% over the past 45 years (three generations) due primarily to hunting and habitat loss. The forests of the southern part of its range in the states of Rondônia, Mato Grosso and Acre in particular are being devastated along the agricultural frontier/arc of deforestation moving south to north through the Brazilian Amazon. Cattle farming and forest loss are also widespread in northern Bolivia and south-eastern Peru. The Transoceanic highways provide future threats of hunting and widespread deforestation throughout the southern part of its range.
Previously published Red List assessments:
  • 2003 – Least Concern (LC)
  • 1996 – Lower Risk/least concern (LR/lc)

Geographic Range [top]

Range Description:Found in northern and central lowland Bolivia, western Brazil and north-eastern Peru. It ranges south of the Rio Amazonas-Solimões, west of the Rio Tapajós, to the Río Ucayali in Peru (replaced by Ateles belzebuth on the left bank of the lower Ucayali) (Aquino and Encarnación 1994a). It crosses the middle Ucayali south of the Río Cushabatay (a left bank tributary of the Ucayali), extending into the interfluvium of the ríos Ucayali and Huallaga. From there, it extends south along the eastern Cordillera into Bolivia, south of the Río Madre de Dios, south to about 17ºS, and from there extending north-east through the Noel Kempf Mercado National Park (Wallace et al. 1998), into the state of Mato Grosso, Brazil, to the left bank of the Rio Teles Pires and Rio Tapajós. It occurs through a large part of the state of Rondônia in Brazil, where there is suitable forest (Iwanaga and Ferrari 2002)
Countries occurrence:
Bolivia, Plurinational States of; Brazil (Acre, Amazonas, Mato Grosso, Rondônia); Peru
Additional data:
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:This species may be one of the most common primates. In Bolivia, it is usually found at between 5 and 25 animals/km², up to 80 animals/km² at some non-hunted sites (R. Wallace pers. comm.). Where density is highest, it more or less correlates with local habitat heterogeneity. Wallace et al. (1998) estimated a density of 32.1 individuals/km² in lowland forest in the Noel Kempff Mercado National Park in eastern central Bolivia. The highest recorded density for Amazonian spider monkeys is for A. chamek in the Manu National Park in Peru, where Janson and Terborgh (1985) estimated 24 individuals/km², and White (1985, 1986) 31/km². Factors determining different Ateles population densities in various species and study sites are discussed by McFarland Symington (1988a), who concluded that these involve the abundance and productivity of certain key plant resources.

In Brazil, Peres (1997) estimated densities of Ateles chamek in a number of terra firma sites: Barro Vermelho I 3.1 individuals/km²; Vira Volta 6.0 individuals/km²; Vaoi Quem Quer 9.6 individuals/km²; Riozinho 3.9 individuals/km²; Porongaba 3.1 individuals/km²; Condor 6.0 individuals/km²; Altamira 3.2 individuals/km². Densities in várzea (white-water flooded forest) were similar: Boa Esperança 2.6 individuals/km²; Barro Vermelho II 3.6 individuals/km².

Iwanaga and Ferrari (2002) recorded sighting rates averaging 0.69 individuals/10 km (range 0.11-2.40) at 33 survey sites in the state of Rondônia, Brazil. They found that the sighting rate was slightly lower in areas where A. chamek and Lagothrix cana occurred together (0.58 individuals/10 km) than when L .cana was absent (0.73 individuals/10 km).
Current Population Trend:Decreasing
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:Occurs in primary lowland rain forest. In Bolivia, in the Noel Kempff Mercado National park, Wallace et al. (1998) recorded A. chamek most often in tall forest (4.42 encounters per 10 km of trail), followed by so-called saternejal forest (along the forest–savanna border, in the vicinity of small forest streams and suffering periodic flash floods) (2.49 encounters per 10 km). Garcia and Tarifa (1988) found A. chamek to be restricted to high forest in the Beni Biological Station.

Spider monkeys travel and forage in the upper levels of the forest. They spend much time in the canopy and also use the middle and lower strata but are rarely seen in the understory. In accordance with their use of the highest levels of the forest, they are highly suspensory. When travelling they spend more time hanging from branches, moving by brachiation and arm swinging, and climbing than they do walking or running on all fours. They are highly frugivorous and feed largely on the mature, soft parts of a very wide variety of fruits, which comprise 83% of their diet and are found mainly in the emergent trees and upper part of the forest canopy (Van Roosmalen and Klein 1988). They also eat young leaves and flowers (both especially at times of fruit shortage during the beginning of the dry season), and besides such as young seeds, floral buds, pseudobulbs, aerial roots, bark, decaying wood, and honey, and very occasionally small insects such as termites and caterpillars. They play a significant role as seed dispersers. Van Roosmalen (1985; Van Roosmalen and Klein 1988) found that A. paniscuswas dispersing the seeds of at least 138 species (93.5% of all fruits species used) through their ingestion and subsequent defecation (endozoochory). A further 10 species were being dispersed by the monkeys carrying them off some distance from the tree before dropping them (exozoochory). In only 23 species were the seeds being ruined or eaten (seed predation).

Spider monkeys live in groups of up to 20-30 individuals (for review see Van Roosmalen and Klein 1988). However, they are very rarely all seen together, and nearly always to be found travelling, feeding and resting small in groups of varying size and composition (most usually 2-4), the only persistent association being that of a mother and her offspring (McFarland Symington 1990). Iwanaga and Ferrari (2002) recorded men groups size of 3.34±2.60 (n = 219 sightings) in a number of localities in the state of Rondônia, Brazil. Group members will also travel on their own. Each female in the group has a “core area” of the group’s home range which she uses most. Klein and Klein (1976, 1977) estimated 259-388 ha ranges with 20-30% overlap for A. belzebuth in La Macarena National Park, Colombia. Ateles are rarely seen in association with other primates and mostly they are occasional and ephemeral, resulting from the simultaneous occupation of fruiting trees.

MacFarland Symington (1988a,b,c) studied the behaviour, ecology and demography of Ateles chamek in the Manu National Park, Peru (see also White [1985, 1986] who published censuses and preliminary observations on the Majnu population).

Six estimated birth dates given by Klein (1971) for A. belzebuth, were spread throughout the year (December, January, April, September, October and November). Spider monkeys apparently reach sexual maturity at 4-5 years of age (Klein 1971; Eisenberg 1973, 1976). They give birth to single offspring after a long gestation period of 226-232 days, with a minimum theoretical interbirth interval in captivity of 17.5 months, but in the wild probably as long as 28-30 months (Eisenberg 1973, 1976). Late maturation and long inter-birth intervals make it difficult for them to recover from hunting and other threats.

Threats [top]

Major Threat(s): The major threat is subsistence and market hunting for food (with guns). An additional threat is habitat loss due to agricultural expansion in the southern portion (soy) and parts of the Peruvian Amazon (mining), and habitat degradation from selective logging, which may affect key fruiting species and forest structure and also opens up new areas for hunting.

Conservation Actions [top]

Conservation Actions: This species is confirmed, or may occur, in numerous protected areas.

Manuripi Heath National Park (1,884,000 ha) (in range)
Amboró National Park (180,000 ha) (in range)
Carrasco National Park (622,600 ha) (in range)
Noel Kempf Mercado National Park (1,500,000 ha) (Wallace et al. 1998)
Isiboro-Secure National Park (1,200,000 ha (in range)
Ríos Blanco y Negro National Reserve (1,423,900 ha) (Wallace et al. 2000)
Beni Biosphere Reserve (Painter et al. 1995)
Beni Biological Station (135 ha) (Garcia and Tarifa 1988)

Amazônia National Park (1,114,917 ha) (in range)
Serra dio Divisor National Park (846,408 ha) (in range)
Serra da Cutia National Park (284,923 ha) (in range)
Mapinguari National Park (1,572,422 ha) (in range)
Abufari Biological Reserve (224,819 ha) (in range)
Jaru Biological Reserve (353,386 ha) (in range)
Guaporé Biological Reserve (618,173 ha) (in range)
Jutaí-Solimões Ecological Station (287,101 ha) (in range)
Rio Acre Ecological Station (79,418 ha) (in range)
Iquê Ecological Station (217,184 ha) (in range)
Cuniã Ecological Station (49,886 ha) (in range)

Manu National Park (Soini et al. 1989; Terborgh 1983)
Bahuaja-Sonene National Park (1,091,416 ha) (in range)
Pacaya-Samiria National Reserve (2,080,000 ha) (Aquino and Encarnación 1994a: Neville et al. (1976) reported one sighting of Ateles chamek in the reserve: Soini et al. (1989) reported that it occurs in low numbers there).

It is listed on Appendix II of CITES.

Citation: Wallace, R.B., Mittermeier, R.A., Cornejo, F. & Boubli, J.-P. 2008. Ateles chamek. The IUCN Red List of Threatened Species 2008: e.T41547A10497375. . Downloaded on 02 July 2016.
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