Occurs in primary high forest, and seldom found in edge or degraded forest. In Suriname, A. paniscus is almost entirely restricted to high forests in the interior, and, like Chiropotes and Cebus olivaceus, it enters the old coastal plain only in the western part of the country. Although Sanderson (1949) mentioned that Ateles is met with "over certain good areas along a belt 8-15 miles from the coast", this is evidently not the case today. In Guyana, it is also restricted in its habitat, occurring mainly in high forest (Muckenhirn et al. 1975; Sussman and Phillips-Conroy 1995). In Suriname, it rarely enters river edge forest, but Muckenhirn et al. (1975) made several observations of A. paniscus while surveying by canoe along the Berbice River. Van Roosmalen (1980, 1985) argued that this may due to differences in hunting pressure between the areas. To what degree A. paniscus extends to the coastal region of French Guiana is unknown. Kellogg and Goldman (1944) listed three localities for French Guiana: the Camopi River, and two on the coast, Cayenne and the Lunier River. Due to forest destruction and development, the high forest preference of the species, and its susceptibility to hunting, it is reasonable to suppose that if it occurred there in the past it is rare or absent today through large parts at least of the coastal forests. In Brazil, it occurs in lowland, submontane and montane (Serra da Pacaraima) forest.

Ateles paniscus is very much a canopy species. Nearly three-quarters of all first sightings of A. paniscus during a three-year field study carried out by Marc van Roosmalen (1980, 1985) in the Voltzberg-Raleighvallen Nature Reserve were of animals in the emergent trees (above 30 m) or upper part of the canopy (25-30 m). They also enter the middle and lower parts of the canopy, but were very rarely seen in the understorey. 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 (Fleagle and Mittermeier 1980). Ateles paniscus, like all spider monkeys, is highly frugivorous and feeds largely on the mature, soft parts of a very wide variety of fruits, which comprise 83% of their diet and are found mainly (77% of its feeding time) in the emergent trees and upper part of the forest canopy (van Roosmalen 1980, 1985; Zhang and Wang 1995a). 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. Guillotin et al. (1993) and Simmen and Sabatier (1996) obtained a similar picture for A. paniscus in French Guiana. The pulp of ripe fruits accounted for 85% of their diet. They also recorded the occasional consumption of fungi and mature seeds. Many even quite large fruits are swallowed whole. Swallowing the entire fruit is characteristic of nearly 40% of the fruit species they eat, and in a further 45% of the fruits they bite off the outer layer and swallow the aril or mesocarp along with the seed or seeds.

Due to their specialization on ripe fruits, and the fact that they tend to swallow whole fruits and intact seeds, Ateles are very important seed dispersers for many trees and lianes. Van Roosmalen (1980, 1985; van Roosmalen and Klein 1988) found that A. paniscus was 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 groupings of varying size and composition, the only persistent association being that of a mother and her offspring (McFarland Symington 1990). 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. In Guyana, Muckenhirn et al. (1975) reported an average sub-group size of 2.4 individuals. In Suriname, Van Roosmalen’s (1980, 1985) study group consisted of 18 animals (three adult males, eight adult females, one subadult female, four juveniles and two infants), but the largest subgroup he observed was of nine individuals.

Only van Roosmalen’s (1980, 1985) study has provided an estimate of the home range size for A. paniscus. His study group covered approximately 255 ha (220 ha with suitable habitat), most of it in high forest and a small portion in high mountain savanna forest. He believes that they maintain discrete, non-overlapping ranges with clearly-defined borders defended by the males, although only a single intergroup encounter was observed at one of these borders. Home range sizes may be bigger in other areas, depending on the distribution and year-round availability of food sources. Within their ranges, subgroups may travel distances from 500 to 5,000 m a day, depending on subgroup size and composition, weather, season, and the distribution of their current food sources (van Roosmalen 1980, 1985). During the dry season, they tend to travel less, especially when leaves have become a more significant component of their diet. Their day typically has two resting periods, one between 08h00 and 10h00 hours, and the other between 12h00 and 14h30. They spend more time resting during the dry season when fruit is scarce. Feeding activity is highest for the first two hours of the morning, and likewise the last two hours before entering their sleeping trees. Van Roosmalen (1980, 1985) recorded 43 different sleeping trees over the three years of his study, but just a few of them were frequently used. They are always tall, emergent trees, well free of the canopy, with a broad, open crown, either small-leaved, leafless or in leaf flush, horizontally branched, and located strategically near the next days feeding site, or better still are the next days feeding site.

Ateles are rarely seen in association with other primates and mostly they are occasional and ephemeral, resulting from the simultaneous occupation of fruiting trees.

Although Husson (1957) mentions seeing young animals throughout the year, Ateles have a clearly defined birth season in Suriname. Newborn infants are seen only in November, December and January, indicating that they are born at the end of the long dry season and during the short wet season. However, the few data available from other areas indicate the a lack of a breeding season. 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 1972; 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). However, for A. paniscus, van Roosmalen (1980) estimated an interbirth interval of 46-50 months for females successfully rearing their young. They show lactational anoestrus for about three years. When in oestrus, females tend to manipulate, inspect and rub their clitoris. Sexual receptivity lasts 8-10 days, with an interestrus of 15-17 days (van Roosmalen 1980). Copulation is generally preceded by much place sniffing and urine licking on the part of the male, who consorts the female during her oestrus, although van Roosmalen (1980) observed that receptive females appeared to choose their mate. It is the receptive female which initiates sexual activity by rushing towards a male and sitting in his lap. If he does not respond she leaves and then returns to repeat the action some minutes later. Behaviour prior to copulation resembles play, involving head-shaking, heavy panting, and even growling and wrestling. Copulation takes place with both monkeys sitting, the male behind the female, grasping the female around her chest and with his legs over and between the females thighs (van Roosmalen 1980). The female copulates three or four times a day during oestrus.

When two individuals meet after a period of separation, they may show a ritualized form of greeting behaviour that includes embracing and pectoral (chest) sniffing (Ateles have olfactory skin glands in this region, but in the wild at least they have never been observed to rub them on branches as has been seen for A. belzebuth for example). Each put their arms around each other and their nose to the others chest which they may lick or sniff. In A. paniscus this may be accompanied by grunting vocalizations, and the embrace is usually initiated by the lower ranking animal of the two (van Roosmalen 1980). It is often followed by genital sniffing. Klein (1971) suggested that the hypertrophied clitoris is for depositing drops of urine as scent marks, and rubbing of the anogenital region also undoubtedly serves in olfactory communication. Communicative tactile signals include also grooming, and wrapping the tail and limbs around other individuals, which often follows embraces. Other behaviours shown in varying contexts, many of them aggressive or agonistic, include head-shaking, chest-scratching, pilo-erection, hopping and bounding, vigorous arm swaying, and branch shaking and dropping, and, when highly aroused, defecation. In agonistic displays the tail may be held up and curled at the tip. Detailed studies of their behaviours and their possible social meanings are described in Eisenberg (1976: see also van Roosmalen and Klein 1988).

Size:
Three males in the British Museum had a mean H&B length of 545 mm (range: 515-580) and a mean TL of 807 mm (range: 720-852); 10 females had a mean H&B length of 540 mm (range: 490-620) and a mean TL of 814 mm (range: 640-930) (Napier 1976). Four females cited in Kellogg and Goldman (1944) had the following measurements: H&B length: 460, 418, 570 and 660; TL 870, 920, 880 and 753. Male A. paniscus are more robust and larger than females. There has been some controversy concerning the possibility that the reverse is true (Ford and Davis 1992; Peres 1994), but a review by Smith (1996) specifically examining this problem points out this supposition was based on statistical error. Body mass for A. paniscus is estimated at 9.11 kg for males and 8.44 kg for females (Mittermeier 1977; Ayres 1986; Smith 1996).

Red List Category

Red List Criteria

Version

2008

Mittermeier, R.A., Rylands, A.B. & Boubli, J.-P.

Mittermeier, R.A., Rylands, A.B. (Primate Red List Authority) & Hoffmann, M. (Global Mammal Assessment Team)

Justification

History

• 2003
  Least Concern
  (IUCN 2003)
• 2000
  Lower Risk/least concern
• 1996
  Lower Risk/least concern
  (Baillie and Groombridge 1996)
• 1994
  Vulnerable
  (Groombridge 1994)
• 1990
  Vulnerable
  (IUCN 1990)
• 1988
  Vulnerable
  (IUCN Conservation Monitoring Centre 1988)
• 1986
  Vulnerable
  (IUCN Conservation Monitoring Centre 1986)
• 1982
  Vulnerable
  (Thornback and Jenkins 1982)

In the Voltzberg Study Area, spider monkeys were found to occur at a density of approximately 8.2 individuals/km² (Mittermeier and Van Roosmalen 1981). At Nourague, French Guiana, Guillotin et al. (1993) estimated a density of 14.0 individuals/km², with a biomass of 132.3 kg/km², the second highest in the primate community after the howling monkeys (144.6 kg/km²). Kessler (1998) estimated a slightly lower density in Nouragues: 7-10 individuals/km². Figures from other areas are usually in the same range. Muckenhirn et al. (1975) estimated lower densities of 2.4-6.2/km² for three areas in Guyana. Factors determining different Ateles population densities in various species and study sites are discussed by McFarland Symington (1988), who concluded that the main factors involve the abundance and productivity of certain key plant resources. Hunting is a major factor affecting primate population densities in French Guiana (Roussilhon 1988).

Decreasing

Spider monkeys are heavily hunted because of their large size, and along with their highly eclectic diet, their need for an enormous variety of fruiting trees, and the fact that they breed rather slowly (a female has one offspring about every three to four years), this renders them the first of the primates to suffer from hunting pressure and logging and other forms of degradation of the tall forests where they live. Although habitat loss is not as severe in the more northerly part of the range of A. paniscus, hunting remains a threat across the range and is taking place even within protected areas.

This species occurs in a number of protected areas in its range, some of them very large.

Brazil
Tumucumaque National Park (3,882,376 ha)
Cabo Orange National Park (630,017 ha)
Lago Piratuba Biological Reserve (394,223 ha)
Rio Trombetas Biological Reserve (409,578 ha)
Uatumã Biological Reserve (942,786 ha)
Anavilhanas Ecological Station (343,897 ha)
Jari Ecolopical Station (207,370 ha)
Niquia Ecological Station (282,803 ha)
Nhamundá State Park (28,370 ha)
Monte Alegre State Park (5,800 ha)
Rio Negro Setor Sul State Park (257,422 ha)
Maicuru State Biological Reserve (1,509,300 ha)
Grão Pará State Ecological Station (4,250,000 ha)

French Guiana
Parc amazonien de Guyane (3,300,000 ha)
Nouragues Natural Reserve (100,000 ha) (Kessler 1998; Zhang and Wang 1995a)
Kaw Reserved Area (76,800 ha)

Guyana
Kaietur National Park (11,655 ha)
Iwokrama Forest Reserve (364,000 ha)

Suriname
Brinckheuvel Nature Reserve (6,000 ha) (possible; Mittermeier and van Roosmalen 1982)
Central Suriname Nature Reserve (1,600,000 ha) (Mittermeier and van Roosmalen 1982)
Sipaliwini Nature Reserve (100,000 ha) (Mittermeier and van Roosmalen1982)
Brownsberg Nature Park (8,400 ha) (present: Mittermeier and van Roosmalen 1982; rare: Norconk et al. 2003).

It is listed on Appendix II of CITES.