Cacajao melanocephalus (Humboldt, 1812)

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 : 482

43.

Black-headed Uacari

Cacajao melanocephalus

French: Ouakari a téte noire / German: Schwarzkopfuakari / Spanish: Uakari de cabeza negra

Other common names: Black Uacari/Uakari, Black-faced Uacari/Uakari, Black-headed Uakari, Golden-backed Black Uacari/Uakari; Ayres'’s Black-headed Uacari/Uakari (ayresi), Humboldt's Black-headed Uacari / Uakari (melanocephalus)

Taxonomy. Simia melanocephala Humboldt, 1812 ,

San Francisco Solano Mission, Rio Cassiquiare, Venezuela.

An alternative taxonomy was proposed by J. Boubli and coworkers in 2008. They argued that the correct name for C. ouakary (between the rios Japura-Caqueta and Negro) is C. melanocephalus and gave the black-headed uacari north of the Rio Negro a new name, C. hosomi . Here the taxonomic arrangement of P. Hershkovitz in 1987 is followed, as proposed by S. Ferrari and colleagues in 2010. Two subspecies recognized.

Subspecies and Distribution.

C.m.melanocephalusHumboldt,1812—NWAmazoninSVenezuelaandNWBrazil,betweentheupperRioOrinocoandupperRioNegro.

C. m. ayresi Boubli et al., 2008 — NW Amazon in Brazil, evidently limited to a small area comprising the Rio Curuduri Basin and the middle to lower Rio Araca N of the Rio Negro.

Descriptive notes. Head-body 40-50 cm (males) and 30-40 cm (females), tail 13— 21 cm (males) and 13-21 cm (females); weight 3.4-5 kg (males) and 2.4-3 kg (females). Male Black-headed Uacaris are slightly larger than females. Head is covered with hair, forwardly directed above forehead. Underside is sparsely furred, with red skin showing below black hairs of chest. Tail is short and bushy. External genitalia are fully pigmented. “Humboldt’s Black-headed Uacari” (C. m. melanocephalus ) is mostly black, and middle of its back is reddish brown without a marked contrast with lower back and thighs. Its face is very dark, except for a patch of pink around its mouth, and almost totally hairless. Its crown has long forwardly directed blackish pelage. “Ayres’s Black-headed Uacari” (C. m. ayresi) is mostly black, and its darker mantle does not contrast strongly with its blackish mid-dorsum and lower back. Its tail and thighs are blackish. Pelage is not very long; hairs on its crown project forward only a little and do not completely coverits ears.

Habitat. [Lowland forest in permanently or seasonally flooded forest near black-water streams (igapo), palm swamp forest, and terra firma forest and caatinga xeric forest on white sand. Black-headed Uacaris are found at elevations of 100-1500 m. As in other uacaris, the Black-headed Uacari prefers the forest canopy, but they often travel just above water level in vines and bushes in flooded forests.

Food and Feeding. Black-headed Uacaris are seed predators. A specialized dentition, with large splayed canines, procumbent incisors and low-crowned molars,is used for extracting and processing seeds from hard fruits.J. Boubli in his study in Pico da Neblina National Park found that seeds of immature fruits accounted for 64% of the diet of Humboldt’s Black-headed Uacari, while seeds and pulp of mature fruits represented 27%. Flowers, leaves, and buds comprised 7% of the records, and arthropods 2%. Arthropods ingested included grasshoppers, ants, spiders, katydids, and cockroaches. The most important plant families providing fruits were Euphorbiaceae , Fabaceae , Sapotaceae , Lecythidaceae , and Arecaceae . There is no specific data on feeding ecology of Ayres’s Black-headed Uacari.

Breeding. Gestation is ¢.190 days, after which a single infant is born. At Pico da Neblina, J. Boubli observed births in the beginning of the rainy season—the period of peak fruit availability.

Activity patterns. Black-headed Uacaris begin their activities at dawn and are active until dusk. The activity budget of Humboldt’s Black-headed Uacari in the Pico da Neblina was 31% foraging, 27% traveling, 22% resting, and 20% feeding.

Movements, Home range and Social organization. Black-headed Uacaris live in large multimale—multifemale groups of 35-100 individuals. The Pico da Neblina study group had c.70 individuals and used 1053 ha. Seasonal migrations were not observed. Daily movements averaged 2300 m (1200-4400 m). When traveling, Black-headed Uacaris are dispersed, coordinating their movements through contact calls.

Status and Conservation. CITES Appendix I. Classified as Least Concern on The IUCN Red List. The nominate subspecies melanocephalus (under C. hosomi ) and ayres: (as C. ayresi) are listed as Vulnerable on The IUCN Red List. The vulnerable status of the subspecies is due to their limited distributions, and hunting. Generally, the Black-headed Uacari is little-known and considered rare. Humboldt’s Black-headed Uacari occurs in Pico da Neblina National Park in Brazil and Serrania de la Neblina National Park in Venezuela. Ayres’s Black-headed Uacari is not known to occur in any protected areas.

Bibliography. Barnett, Boubli et al. (2008), Barnett, Bowler et al. (2013), Boubli (1993, 1994, 1997, 1999, 2002), Boubli & Veiga (2008a, 2008b), Boubli, Silva et al. (2008), Ferrari, Guedes et al. (2010), Groves (2001), Hershkovitz (1987b), Lehman & Robertson (1994), Mittermeier & Coimbra-Filho (1977), Norconk (2011).

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)

Subspecies and Distribution. C.m.melanocephalusHumboldt,1812—NWAmazoninSVenezuelaandNWBrazil,betweentheupperRioOrinocoandupperRioNegro. C. m. ayresi Boubli et al., 2008 — NW Amazon in Brazil, evidently limited to a small area comprising the Rio Curuduri Basin and the middle to lower Rio Araca N of the Rio Negro.