Chiropotes chiropotes

Russell A. Mittermeier, Anthony B. Rylands & Don E. Wilson, 2013, Phitheciidae, Handbook of the Mammals of the World – Volume 3 Primates, Barcelona: Lynx Edicions, pp. 432-483 : 480

39.

Rio Negro Bearded Saki

Chiropotes chiropotes

French: Saki du Rio Negro / German: Rotrickensaki / Spanish: Saki barbudo de dorso rojo

Other common names: Bearded Saki, Red-backed Saki, Tawny-olive Bearded Saki

Taxonomy. Simia chiropotes Humboldt, 1812 ,

Upper Rio Orinoco south of the cataracts, Amazonas, Venezuela.

In 2003, C. R. Bonvicino and colleagues resurrected the name C. israelita (given by Spix in 1823) for the bearded sakis west of the Rio Branco. C. chiropotes is distinguished from the bearded sakis of the Guianas by genetic and pelage differences but, in 2002 J. Silva Jr. and W. Figueiredo concluded that C. sagulatus was the correct name of the form present to the east of the Rio Branco, and C. chiropotes that of the form found to the west, on the understanding that the type locality for C. chiropotes is to the west of the Rio Branco. Monotypic.

Distribution. N Brazil (Amazonas and Roraima states) and S Venezuela (Bolivar State), delimited by the Rio Orinoco in the N, the Rio Branco to the E, and by the Rio Negro in the S.

Descriptive notes. Head-body 36-46 cm (males) and 35-46 cm (females), tail 30-46 cm (males) and 34-45 cm (females); weight 2.2-4 kg (males) and 2.3-5 kg (females). Coloration of the Rio Negro Bearded Saki is brown, with an olivaceous back and upper limbs. Face is black and sparsely covered with hair. Both sexes have prominent coronal tufts and beards, which are more pronounced in males. Tail is long, full, and shaggy. Scrotum in males and vaginal lips of females are bright pink.

Habitat. Terra firma and transitional semi-deciduous tropical moist forest.

Food and Feeding. Like other bearded sakis, the Rio Negro Bearded Saki is a seed predator, capable of opening very hard fruits. Its feeding ecology was studied by M. Norconk, W. Kinzey, and A. Peetz on a 180ha island in Lago Guri, Venezuela. The diet was composed essentially of fruits and parts of fruits. Proportions of seeds were 51-75%, and mature fruits were 22-41%. Their diets also included flowers, leaves, shoots, pith, and arthropods. The contribution of arthropods varied considerably (0-2-20-8%) in the study of Peetz and were mostly caterpillars and cicadas. Diets varied seasonally. Seeds were the major food source in dry months, and contributions of mature fruit were greater during wet months. The diets of the Rio Negro Bearded Sakis studied by Norconk were less diverse in wet months when the most preferred food resource became available. The three top-ranked plant families in Lago Guri were Sapotaceae , Loranthaceae , and Moraceae . The most important species included Pradosia caracasana ( Sapotaceae ), Oryctanthus alveolatus ( Loranthaceae ), Brosimum alicastrum ( Moraceae ), Chrysophyllum lucentifolium, and C. argenteum ( Sapotaceae ). Kinzey and Norconk reported 39 plant species in their diets during five months. Peetz recorded that parts of at least 100 plant species from 35 families were consumed during 15 months. Despite high dietary diversity in this study, only a small number of preferred species made up the majority of the diet. Pradosia caracasana was the most important (37%), followed by Oryctanthus alveolatus (19%).

Breeding. Peetz estimated the birth intervals of Rio Negro Bearded Sakis to be at least 24 months. Copulation usually lasts 40-90 seconds, but on one occasion, it lasted more than three minutes. Genital sniffing and other precopulatory behavior were rarely observed. Post-copulatory behaviors were not observed. Births occurred at the end of the rainy season and in the dry season (December—April). Infants are carried ventrally for the first two months and dorsally through the fifth month. After that, they begin progressively to travel short distances independently, and by 10-13 months of age, they are able to travel autonomously. Sexual maturation is c.3 years.

Activity patterns. Rio Negro Bearded Sakis are diurnal and arboreal. At Lago Guri, the average daily active period was correlated with daylight length and ranged from ten hours and five minutes to twelve hours and 40 minutes. The group under study chose tall trees with a large canopy for sleeping, using forks and branches at the periphery of the canopy. They usually slept in differentsites each night, and movement from sleeping trees began at first light. Average activity budget was 37% feeding, 22% resting, 19% traveling, 12% engaging in social behaviors, and 10% foraging. Time budgets were influenced by seasonality and food selection.

Movements, Home range and Social organization. Home range of Rio Negro Bearded Sakis at Lago Guri was 122 ha, it was limited by the island's size. Daily movement averaged 1600 m (500-2700 m) and was influenced by availability of fruits from the highest ranked food species, Pradosia caracasana. Fission-fusion behavior was observed, but the group rarely spread out over more than one hectare. Peetz observed affiliative relationships between males. Rio Negro Bearded Sakis shared the island with Guianan Red Howlers ( Alouatta macconnelli) and Guianan Weeper Capuchins (Cebus olivaceus), but interspecific associations were not observed.

Status and Conservation. CITES Appendix II. Classified as Least Concern on The [UCN Red List. IUCN, however, considers the two forms north of the Rio Amazonas as a single taxon (here considered to be two species, the Rio Negro Bearded Saki , west of the Rio Branco, and the Guianan Bearded Saki , C. sagulatus , east of the Rio Branco). In Brazil, the Rio Negro Bearded Saki occurs in Pico da Neblina National Park and Niquia, Maraca, and Caracarai ecologicalstations. It also occurs in Parima Tapirapeco, Jaua-Sarisarinama, and Canaima National Park in Venezuela.

Bibliography. Groves (2001), Hershkovitz (1985), Norconk (1996, 2011), Norconk et al. (1997), Peetz (2001), van Roosmalen, Mittermeier & Fleagle (1988), van Roosmalen, Mittermeier & Milton (1981), Silva & Figueiredo (2002), Silva et al. (2013), Veiga, Silva, Mittermeier & Boubli (2008).

Figures

32. White-faced Saki (Pithecia pithecia), 33. Monk Saki (Pithecia monachus), 34. Gray's Bald-faced Saki (Pithecia irrorata), 35. Bufty Saki (Pithecia albicans), 36. Equatorial Saki (Pithecia aequatorialis)

Distribution. N Brazil (Amazonas and Roraima states) and S Venezuela (Bolivar State), delimited by the Rio Orinoco in the N, the Rio Branco to the E, and by the Rio Negro in the S.