Chiropotes utahickae (Hershkovitz, 1985)

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 : 480-481

40.

Uta Hick’s Bearded Saki

Chiropotes utahickae

French: Saki de Hick / German: Uta-Hick-Saki / Spanish: Saki barbudo de Uta Hick

Other common names: Uta Hick's Saki

Taxonomy. Chiropotes satanas utahicki Hershkovitz, 1985 ,

Tapara, right (east) bank of Rio Xingu, near mouth, Para, Brazil.

This species is monotypic.

Distribution. Amazonian Brazil, S of the Rio Amazonas, between the rios Xingu and Tocantins-Araguaia; the exact S limits of its distribution are unknown, but it has been recorded in the lower rio Tapirapé in NE Mato Grosso State, near the forestsavanna transition.

Descriptive notes. Head-body 37-42 cm (males) and 36-37 cm (females), tail 37-41 cm (males) and 37-58 cm (females); weight 2.5-4 kg (males) and 2.3-5 kg (females). Coat of Uta Hick’s Bearded Saki is predominantly reddish brown to buffy, and its extremities are slightly darker than its dorsum. Both sexes have coronal tufts and beards, which are more developed in males. Tail is long, full, and shaggy.

Habitat. Tall terra firma forests at low elevations. Uta Hick’s Bearded Saki can tolerate some degree of human disturbance, as long there is no hunting and there are sufficient key resources.

Food and Feeding. Feeding ecology of one group of Uta Hick’s Bearded Saki was studied in different years by R. Santos and T. Vieira on the 129ha Germoplasma Island, on the left bank of the Tucurui hydroelectric reservoir. In July-November 2001 (dry season), Santos recorded a diet primarily of immature seeds (70%), complemented by flowers (19%), ripe fruit (4%), and immature mesocarps (1%). In March-August 2004 (late wet season and early dry season), the diet in Vieira’s study was made up mainly of immature seeds (32%), immature mesocarps (21%), ripe fruit (18%), and flowers (14%). Santos recorded 87 food plant species in the diet, and Vieira, 110.

Important species included Alexa grandiflora and Inga alba (Fabaceae) , Annona tenuipes ( Annonaceae ), Attalea speciosa ( Arecaceae ), and Bertholletia excelsa and Eschweilera sp. (Lecythidaceae) . In fragmented areas where palms (Orbignya martiana, Arecaceae ) are abundant, Uta Hick’s Bearded Saki eats the energy-rich mesocarp ofits fruits to deal with food scarcity in the dry season, as was found by U. L. Bobadilla at Fazenda Aratau.

Breeding. Vieira found a peak in mating in May, and pregnant females and two females with infants were noted in September (dry season). She recorded males sniffing the genitals of females before copulation. Copulation lasted 23-62 seconds.

Activity patterns. Uta Hick’s Bearded Sakis are diurnal and arboreal. They wake at dawn (c.06:00 h) and retreat to the sleeping trees at dusk (c.18:00 h). During the dry season, the Germoplasma group of Santos’s study spent a relatively large proportion of its time feeding (59%), followed by traveling (31%), and much less time resting (9%). Social interactions were uncommon and represented less than 1% ofits activities. Vieira found a different pattern in the use of time when following the same group in the late wet season and early dry season. Although resting and social behaviors were similar (11% and 1%, respectively), the group spent more time traveling (51%) and less time feeding (32%).

Movements, Home range and Social organization. Uta Hick’s Bearded Sakis live in multimale-multifemale groups, in a fission-fusion organization in which one group often divides into smaller subgroups. Bobadilla found an average group size of 9-2 individuals in continuous forest and 6-6 individuals in a disturbed forest fragment. Bobadilla observed that Uta Hick’s Bearded Sakis are usually found at low densities in continuous forest tracts (2-9 ind/km?) but at higher densities (23-8 ind/km?) in forest fragments,if there is a combination of crucial ecological factors such as abundance of key resources and minimal or no hunting pressure. Nevertheless, these populations are isolated and are probably smaller than the minimum long-term viable size. On Germoplasma Island, the 24 group members would split into subgroups of 3-21 individuals. Santos estimated a home range of ¢.100 ha. Vieira reported an average daily travel distance of 2530 m (1940-4080 m) and a home range of ¢.58 ha.

Status and Conservation. CITES Appendix II. Classified as Endangered on The IUCN Red List. Major threats to Uta Hick’s Bearded Sakis are loss and fragmentation oftheir forests and hunting. It can be found in Tapirapé Biological Reserve and Caxiuana National Forest.

Bibliography. Bobadilla & Ferrari (1998, 2000), Groves (2001), Hershkovitz (1985), Johns & Ayres (1987), Norconk (2011), van Roosmalen et al. (1981), Santos (2002), Veiga, Silva, Ferrari & Rylands (2008a), Vieira (2005).

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. Amazonian Brazil, S of the Rio Amazonas, between the rios Xingu and Tocantins-Araguaia; the exact S limits of its distribution are unknown, but it has been recorded in the lower rio Tapirapé in NE Mato Grosso State, near the forestsavanna transition.