Chiropotes satanas (Hoffmannsegg, 1807)

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 : 479-480

38.

Black Bearded Saki

Chiropotes satanas

French: Saki noir / German: Satansaffe / Spanish: Saki barbudo negro

Other common names: Black Saki, Brown-bearded Saki

Taxonomy. Cebus satanas Hoffmannsegg, 1807 ,

Brazil, Para, lower Rio Tocantins, Cameta.

This species is monotypic.

Distribution. N Brazil, S of the lower Rio Amazonas, from the Rio Tocantins to the E limits of the Amazonian rainforest in Para and Maranhao states.

Descriptive notes. Head-body 38-42 cm (males) and 34-39 cm (females), tail 36— 42 cm (males) and 36-41 cm (females); weight 2.5-4 kg (males) and 2.3-5 kg (females). Head, beard, tail, and underparts of the Black Bearded Saki are glossy-black, and back and upper limbs are dark brown to blackish. Facial skin is black but sometimes mottled. Both sexes have prominent coronal tufts and black beards, which are more pronounced in males. Tail is thick and bushy. The male has a bright pink scrotum.

Habitat. Predominantly tall terra firma rainforests. Black Bearded Sakis are also found in secondary forests, forested areas in the transitional zone between Amazon Forest and cerrado savanna, and, on rare occasions, coastal mangrove forest.

Food and Feeding. The Black Bearded Saki is a specialist seed predator, with a highly frugivorous diet. R. Santos,S. Silva, and L. Veiga studied their feeding ecology on the right bank of the Tucurui hydroelectric reservoir. Seeds accounted for 30-60% of the diet and mature fruits 10-42%. Flowers comprised more than 10% of the diet, and in two groups, they were a very large proportion of the diet. The highest consumption of flowers was observed by R. Santos (50%) and S. Silva (58%) for a group on a 16ha island. These results were biased by small samples collected during only six months, with a preponderance of dry months when fruits were in short supply and flowering reached its peak. In a 12month study comparing the ecology of two groups, one in a 1300ha mainland peninsula fragment and the other on a 19ha forested island, Veiga found that immature seeds can represent as much as 90% ofthe diet in certain months. Small quantities ofpith, shoots, and young leaves are also eaten, as well as arthropods, including caterpillars, termites, ants, and spiders. The two groups used a large number of different plant species (peninsula = 173, island = 132, both groups = 240 species), and their diets varied significantly in terms of items consumed and taxonomic composition. Lecythidaceae , Arecaceae , Sapotaceae , Fabaceae , and Simaroubaceae were important plant families in the different studies in Tucurui. Simarouba amara ( Simaroubaceae ), Alexa grandiflora ( Fabaceae ), Eschweilera subglandulosa ( Lecythidaceae ), and Orbignya phalerata ( Arecaceae ) were among the most used plant species.

Breeding. Breeding of the Black Bearded Saki is seasonal, but copulation is seen through the year. Most births occur from the end of the dry season to the early wet season, which coincides with peak fruit production.

Activity patterns. Black Bearded Sakis are diurnal and arboreal. In her long-term study on Black Bearded Sakis in Tucurui, Veiga observed that both groups under study woke slightly before or at first light (c.06:00 h) and retreated to their sleeping trees before sunset (17:30-18:00 h), being active for 10-12 hours/day. The groups chose tall trees for sleeping and frequently made use of the same sleeping trees on successive nights (especially the group living on the island). The peninsula group traveled for 35% of its daily activity budget, fed for 26%, rested for 26%, engaged in social interactions for 9%, and foraged for 4%. The island group spent 30% of its time feeding, 26% traveling, 23% resting, 16% engaging in social interactions, and 5% foraging. Seasonal variations in the activity budget were found in both groups. In the dry season, they spent more time in feeding. Time spenttraveling increased in the wet months and was positively correlated with group size.

Movements, Home range and Social organization. Black Bearded Sakis live in multimale-multifemale groups of 7-39 individuals. Groups subdivide regularly into subgroups in a fission-fusion organization. The sex ratio of males to females is close to 1:1. Veiga observed affiliative relationships between males, which were in proximity to each other more frequently than they were to females and other females were to each other. Besides this high degree of gregariousness, social interactions (largely affiliative) among males were much higher than expected given group demography. Groups of Black Bearded Sakis associated frequently with Guianan Brown Capuchins (Sapajus apella) and Guianan Squirrel Monkeys (Saimiri sciureus). In the long-term study by Veiga, average daily movements were 2807 m (1900-3680 m) for the island group and 4025 m (1560-6270 m) for the peninsula group. Average daily movement and area used each month increased during the rainy season, and these variations were positively correlated to group size throughout the year. Groups used areas of ¢.99 ha on the peninsula and c.17 ha on the island. No studies of Black Bearded Sakis have been undertaken in areas of continuous forest, but it is expected that groups would use even larger areas.

Status and Conservation. CITES Appendix II. Classified as Critically Endangered on The IUCN Red List. The critically endangered status of the Black Bearded Saki is due to population decline caused primarily by habitat loss and hunting pressure. It has a restricted geographic distribution in one of the most densely populated parts of the Brazilian Amazon, where considerable forest destruction has already occurred. The meridional and oriental limits of the distribution of the Black Bearded Saki have shrunk, and its remaining area of occupancy is now very fragmented. Black Bearded Sakis occur in Gurupi Biological Reserve, but this area suffers from intensive pressure from local ranchers, timber companies, and illegal land settlers.

Bibliography. Ferrari, Emidio-Silva et al. (1999), Groves (2001), Hershkovitz (1985), Johns & Ayres (1987), Norconk (2011), Port-Carvalho & Ferrari (2002), van Roosmalen et al. (1981), Santos (2002), Silva, B.B.S. (2003), Silva, J.S. (1991), Silva, J.S. & Figueiredo (2002), Veiga (2006), Veiga & Ferrari (2006), Veiga, Silva, Ferrari & Rylands (2008b).

Figures

On following pages: 39. Rio Negro Bearded Saki (Chiropotes chiropotes); 40. Uta Hick's Bearded Saki (Chiropotes utahickae); 41. Guianan Bearded Saki (Chiropotes sagulatus); 42. Bald Uacari (Cacajao calvus): 43. Black- headed Uacari (Cacajao melanocephalus); 44. Spix's Black-headed Uacari (Cacajao ouakary).

Distribution. N Brazil, S of the lower Rio Amazonas, from the Rio Tocantins to the E limits of the Amazonian rainforest in Para and Maranhao states.