Peruvian spider monkey  (Ateles chamek)

Classified as Endangered (EN) on the IUCN Red List (1) and listed on Appendix II of CITES (3).

Previously considered a subspecies of either the black spider monkey (Ateles paniscus) or the white-bellied spider monkey (Ateles belzebuth), the Peruvian spider monkey is now considered a separate species on the basis of its dark rather than pink face, its all-black body, slightly smaller size, and differences in its DNA (1) (4) (5) (6) (7). Like all spider monkeys, it is a large, slender monkey with long, spider-like limbs and a long, flexible, prehensile tail, which can be used like a fifth limb. The underside of the tail tip is hairless, giving extra grip, while hook-like hands and a highly mobile shoulder joint help the spider monkey to swing easily beneath branches (2) (4) (5) (8) (9). The head is relatively small, with a prominent blackish muzzle (2) (8), and the fur of the adults is entirely black except for a silvery genital patch and sometimes a few white hairs on the muzzle, cheeks and forehead (7). Male and female Peruvian spider monkeys are similar in appearance, although the female can be mistaken for a male as a result of an unusually elongated clitoris (8) (9) (10). The calls of this species include screams, barks and a horse-like whinnying (4) (8).

The Peruvian spider monkey occurs in eastern Peru, northern and central Bolivia, and western Brazil (Acre, Amazonas, Mato Grosso and Rondonia states), where it is found west of Rio Jurua, south of Rio Solimões, and south into the state of Mato Grosso (1) (2) (4) (8).

The Peruvian spider monkey inhabits primary lowland rainforest as well as riverine and flooded forest, and mainly uses the upper levels of the forest canopy (1) (2) (4) (8) (10).

Active during the day, the Peruvian spider monkey feeds on a wide variety of ripe fruits, particularly figs (Ficus), although unripe fruit, new leaves and flowers are also eaten, particularly when fruit is scarce. The diet may also be supplemented with seeds, buds, bark, wood, honey and occasionally small insects (2) (11) (12) (13) (14), and the Peruvian spider monkey is believed to be an important seed disperser (1) (12). Spider monkeys are highly agile primates, able to move swiftly through the trees by swinging, climbing, running, or walking bipedally, and can even hang suspended entirely by the tail (2) (8) (9) (10).

The Peruvian spider monkey lives in groups of up to 20 to 30 individuals, but members of the group are rarely seen together, usually splitting into smaller, temporary groups to travel, feed and rest. Each female has a core area of the group’s territory which she uses most, while males cooperate in defending the whole territory against neighbouring groups (1) (2) (10) (12) (15). Breeding may occur at any time of year, the female giving birth to a single young after a gestation period of around 226 to 232 days. Spider monkeys reproduce slowly, each female giving birth only once every two to four years, and individuals not reaching maturity until around four to five years old. When mature, young males generally remain within the group, while females leave to join another group (1) (2) (8) (10) (15). The Peruvian spider monkey has been recorded living to about 40 years (8).

The Peruvian spider monkey is under serious threat from hunting for food, as well as from habitat loss as forests are cleared for agriculture, cattle ranching and mining (1). Selective logging may also remove key fruiting trees, such as figs, and open up the forest to further hunting (1) (14), while the building of the Transoceanic highway between Brazil and Peru brings the threat of increased hunting and deforestation throughout the southern part of the species’ range (1). Its dependence on mature, undisturbed forest makes the Peruvian spider monkey particularly vulnerable to habitat loss and degradation, while its slow reproductive rate means that populations take a long time to recover from any losses (1) (2) (5) (8) (15).

The Peruvian spider monkey occurs in many protected areas throughout its range (1), and international trade in the species should be regulated under its listing on Appendix II of the Convention on International Trade in Endangered Species (CITES) (3). However, tighter controls on hunting, together with stronger measures to preserve its habitat, are likely to be needed if this charismatic primate is to be properly protected.

View information on this species at the UNEP World Conservation Monitoring Centre.

To find out more about the conservation of this and other primates see:

• IUCN/SSC Primate Specialist Group:
  http://www.primate-sg.org/