The Ecology, Biogeography and Conservation of the Uakaris, Cacajao (Pitheciinae)

Abstract

With the sakis (Pithecia) and the bearded sakis (Chiropotes), the uakaris (Cacajao) constitute the cebid subfamily, Pitheciinae. The most recent revision recognized six Cacajao subspecies in two species, confined to the Amazon basin. Before 1970 most field information derived from 19th century travellers. Studies still lag behind those of other cebid genera. This paper summarises the known ecology of Cacajao, and identifies future research and conservation priorities. The relevance of Pleistocene refugia and metachromism in analysing its biogeography is discussed. Range size remains obscure but, with the exception of C. c. calvus, may be extensive, as all other subspecies appear to migrate in the dry season from flooded riverine forest to terra firme. Observed group size ranges from 5 to 50, indicating the operation of a fission-fusion society. Social organization appears to be multi-male and non-hierarchical. This accords with the minimal sexual dimorphism. The highly developed canines function primarily as fruit openers. Cacajao is a dietary specialist on hard-shelled fruit, and appears unique among Amazonian cebids in its dependence (at least seasonally) on riverine forests. Hunting may be a problem locally, but local taboos sometimes offer protection. They appear vulnerable to habitat disturbance. On the Rio Negro, the range of C. m. melanocephalus appears to have greatly diminished. To ensure protection of viable populations, the inferred dietary dependence on seasonal migration may require accommodation. Research priorities include the status, habitat preference, diet and social ecology of all taxa except C. c. calvus. A more complete knowledge of the biogeography of the genus would be valuable.

Cacajao melanocephalus

“…Both subspecies are known only from margins and interfluvial basins of Amazonian black-water rivers. Here they have been most commonly recorded in the igap6 (Barnett and Brandon-Jones 1997), a seasonally inundated forest on the margins of black-water rivers (Prance 1979). Sightings are most frequent during the forest's annual inundation (Barnett and Brandon-Jones 1997;Defler 2001), when fruit availability is highest (Goulding et al 1988).…”

“…Here they have been most commonly recorded in the igap6 (Barnett and Brandon-Jones 1997), a seasonally inundated forest on the margins of black-water rivers (Prance 1979). Sightings are most frequent during the forest's annual inundation (Barnett and Brandon-Jones 1997;Defler 2001), when fruit availability is highest (Goulding et al 1988). Although C. m. melanocephalus lives in igap6 (Lehman and Robertson 1994), C. m. melanocephalus from Pico de Neblina National Park, Brazil, lived throughout the year in uninundated Eperua-and Micranda-dominated caatinga forest (Boubli 1997(Boubli , 1998.…”

“…Cacajao melanocephalus lives in mixed-sex, multiple-male, multiple-female groups (Dixson 1987;Kinzey and Cunningham 1994). Group size is relatively large, with reported maxima ranging from 20 to 30 (Ayres 1986;Boubli 1999;Fontaine 1981) to 120 (Defier 1989), but small groups of 3-10 also occur (Barnett and Brandon-Jones 1997;Barnett et al 2002). Black-backed uacaris travel in well-dispersed aggregations, coordinating their movements through constant calling (Boubli 1999).…”

The meanings of <i>Cacajao</i> and <i>Uacari</i>: folk etymology in Neotropical primate taxonomy

“…Uacaris are medium-sized Amazonian primates (3-5 kg) with short tails and a dentition adapted for a diet of hard fruits (Barnett and Brandon-Jones, 1997). Endemic to the Amazon basin, there are seven recognized forms (Hershkovitz, 1987) in two species: the bald uacari, Cacajao calvus (five subspecies), and the black-headed uacari, C. melanocephalus (two subspecies).…”

“…These terms, then, originated from native languages that were once spoken within the geographic range of Cacajao melanocephalus. This range covers a large area of northwestern Amazonia (see Hershkovitz, 1987;Barnett and Brandon-Jones, 1997) and overlaps with an area of considerable linguistic diversity (see maps in Dixon and Aikhenvald, 1999). Uacaris occur in large groups, spend much of the year being highly visible in riverside forests, are hunted (Barnett and Brandon-Jones, 1997), and frequently appear in folk taxonomies (e.g., Defler, 2003).…”