Yellow-tailed Woolly Monkey
(Oreonax flavicauda)
First discovered by scientists at the beginning of the nineteenth century, this distinct species of woolly monkey was thought to be extinct until its rediscovery in 1974. The species is named after the small yellow band on the underside of its tail but can be more easily distinguished from other woolly monkeys by the prominent yellow scrotal tuft of the males and less prominent vaginal tuft of females, it is also distinguishable by its long dark reddish-brown fur and white hairs around the mouth. The inaccessibility of its habitat protected the species until the 1970’s, but the construction of new roads since then has fragmented this monkey’s restricted habitat, and has increased habitat destruction for logging and cattle farming which are pushing the species to the verge of extinction. Fewer than 250 individuals are thought to survive today.
Urgent Conservation Actions
There are proposals for a number of protected areas within the species’ range, including the National Sanctuaries of Cordillera de Colán and Este del Marañón.
Restricted to a small area of montane forest on the eastern slopes of the Andes in northern Peru.
Associated Blog Posts
20th Feb 10
This week the list of the World’s 25 most endangered primates was released, highlighting which of man’s closest relatives are on the brink extinction and...  Read

17th Jun 09
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Evolutionary Distinctiveness
Order: Primates
Family: Atelidae
New World and Old World primate lineages split during the early Oligocene around 35 million years ago, when ancestral New World primates dispersed from Africa to South America (together with hystricomorph rodents) when the continents were much closer together. Four families of New World monkeys are currently recognised: the Cebidae (marmosets, tamarins, capuchins and squirrel monkeys), Aotidae (night monkeys, owl monkeys, and douroucoulis), Pitheciidae (titis, sakis and uakaris) and Atelidae (howler, spider and woolly monkeys). There are 5 species of woolly monkeys, placed in either one or two genera. The yellow-tailed woolly monkey is often included in the genus Lagothrix, but is also frequently regarded as the only representative of a separate genus, Oreonax, as it is distinct from all other woolly monkey species.
Head and body length: 508-686 mm
Tail length: 600-720 mm
Weight: 5.5-10.8 kg
The hair of the yellow-tailed woolly monkey is long, thick and woolly, an adaptation to its cold montane forest habitat. Its colour is dark reddish-brown above, and slightly lighter below. The face is naked and almost black, except for a characteristic patch of white hair around the mouth. This species can be distinguished from other woolly monkeys by the prominent yellow scrotal tuft of the males and less prominent vaginal tuft of the females and also by the presence of a yellow band on the undersurface of the tail, near the tip. The tail is fully prehensile and used like a fifth limb.
The species is arboreal and diurnal. It lives in groups of varying sizes, ranging from as few as 4 individuals to as many as 30 in some areas. Group size may be related to available habitat or changes in food resources throughout the year (e.g. smaller groups may join together when food is abundant). Groups include adult males and females and their offspring. Although each group is thought to contain a single dominant male, competition among group members appears to be low, and the mating system is believed to be polygamous. Home ranges are thought to be relatively large, possibly due to the difficulties of finding food in a degraded habitat. The diet consists primarily of leaves, fruits and flowers, supplemented with succulent roots of epiphytes and petioles and buds. The species has a relatively low birth rate, with females giving birth to a single young every 2-3 years. Sexual maturity is thought to be reached at 4 years. The main natural predator of the species is probably the puma (Felis concolor).
Inhabits montane cloud forests of the Peruvian Andes at elevations of 1,500 to 2,700 m.
Restricted to a small area of montane rainforest in the Departments of San Martín (eastern part) and Amazonas (western part) in the Peruvian Andes
Population Estimate
Considered to number fewer than 250 individuals.
Population Trend
Classified as Critically Endangered (CR A4c) on the 2010 IUCN Red List of Threatened Species.
The inaccessibility of its habitat protected the species until the 1950s. However, increasing pressure on the forests due to a burgeoning human population, together with habitat loss and fragmentation due to the construction of new roads, logging and agriculture, and subsistence hunting, has led to the species’ current Critically Endangered status. The monkey’s naturally low population densities, low reproductive rate, and restricted geographic distribution mean that it is particularly vulnerable to these threats.
Conservation Underway
The species occurs in three protected areas – the 182,000 ha Bosque de Protección (Protected Forest) de Alto Mayo (BPAM), est. 1987, in the department of San Martin in northern Peru, the 274,500 ha Río Abiseo National Park (est. 1983) in the south of the Department of San Martin and the 64,115 Cordillera de Colan reserved zone. However, these areas offer limited protection to the species since they are highly deforested and under pressure from factors associated with increasing human populations.

Since its rediscovery in 1974, there has been only one extended study on yellow-tailed woolly monkey behavior and ecology; that of Mariela Leo Luna in the early 1980s. A short survey was carried out in 1995, recording various sightings of a single group, during an expedition in the Cordillera de Colán, Amazonas Department, Peru.

In 2004 surveys were carried out over a period of two months in order to investigate the possibility of conducting a long-term behavioral-ecological study on the species. The survey team collected preliminary data, and examined the status of this species in the northern part of BPAM. The study also included an educational outreach component.

In 2007 researchers from UK based NGO Neotropical Primate Conservation, with support from the Woolly Monkey Project and IKAMA Peru, completed surveys of the species throughout its range in north-eastern Peru. Yambrasbamba was identified as an important area for the conservation of the species. The group is now working to create a new community-run reserve in Yambrasbamba, in which further monitoring programmes will take place. The project includes a reforestation programme, in which native tree species that will be beneficial to humans and wildlife are planted and environmental education programmes for local communities. An important part of this work is helping local people to develop eco-friendly income alternatives to the current non-sustainable practices in the area. For example, the group is currently assisting with the development of markets for native agriculture products and handicrafts made in the communities.

The Peruvian Association for Conservation of Nature (APECO) has been supporting the Rio Abiseo National Park since its establishment in 1983 and the creation of the Corrdillera de Colan National Sanctuary. Among other projects, the Association conducted a 4 year fieldwork of fauna inventory in the Park’s upper range, and is supporting rural development of neighbouring communities.
Conservation Proposed
Range-wide surveys of remaining habitat and populations are urgently needed to assess the conservation status of the species and make appropriate conservation recommendations. Existing protected areas are in need of greater protection from threats such as land invasion, logging and hunting. Efforts should also be made to create and combine large reserves or parks in both the departments of San Martín and Amazonas. Widespread and rapid ongoing deforestation throughout the species’ geographic range means that a vital step will be to ensure a truly protected area for this species. There are proposals for a number of additional protected areas within the species’ range, including the National Sanctuaries of Este del Marañón and La Esperanza biological corridor. Educational projects in local communities would also be beneficial, as would sustainable-use projects to ensure that the species’ habitat is managed appropriately.
Associated EDGE Community members

Noga is a co-founder of the Neotropical Primate Conservation

Sam is a co-founder of the Neotropical Primate Conservation

APECO The Peruvian Association for the Conservation of Nature
Park Jose Acosta 187 Magdalena - It files 17 Tel.: (511) 264 0094 - (511) 264 5804/Fax (511) 264 3027 email apeco@apeco.org.pe

Neotropical Primate Conservation (NPC)
A non-profit organization, founded by Sam and Noga Shanee and Lizzie Cooke in 2007. It aims to promote the conservation of monkeys and their habitat in the tropical rainforests of South and Central America though land protection; research; improvement of degraded habitat for wildlife; creation of public awareness; environmental education; and facilitation of the commercialisation of sustainable, ecological products on behalf of local people. The organisation is currently working with communities in the La Esperanza area to protect the habitat of the yellow-tailed woolly monkey.

A Peruvian organisation supporting habitat restoration work in the Alto Mayo area.

Woolly Monkey Project
A project initiated by researchers from Oxford Brookes University, UK. The project is working to highlight and conserve woolly monkeys in the Colombian Amazon, but is also providing support to the Neotropical Primate Conservation organisation’s work in Peru.
Cornejo, F., Rylands, A.B., Mittermeier, R.A. & Heymann, E. 2008. Oreonax flavicauda. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4.www.iucnredlist.org . Downloaded on 14 November 2010.

Butchart, S.H.M., Barnes, R., Davies, C.W.N., Fernandez, M, and Seddon, N. 1995. Observations of two threatened primates in the Peruvian Andes. Primate Conservation 16: 15-19.

Butchart, S.H.M., Barnes, R., Davies, C.W.N., Fernandez, M. and Seddon, N. 1995. Threatened mammals of the Cordillera de Colan, Peru. Oryx 29(4): 275-281.

DeLuycker, A. M. 2007. Notes on the Yellow-Tailed Woolly Monkey (Oreonax flavicauda) and its Status in the Protected Forest of Alto Mayo, Northern Peru. Primate Conservation 22.

Luna, M.L. 1987. Primate conservation in Peru: a case study of the yellow-tailed woolly monkey. Primate Conservation 8: 122-123.

Nowak, R.M. 1999. Walker's Mammals of the World. Sixth edition. The Johns Hopkins University Press, Baltimore and London.

Shanee, N., Shanee, S., and Maldonado, A.M. 2007. Conservation assessment and planning for the yellow tailed woolly monkey (Oreonax flavicauda) in Peru. Wildlife Biology in Practice 2(3): 73-82

Shanee, S., Shanee, N. and Maldonado, A.M. 2007. Distribution and Conservation Status of the Yellow-Tailed Woolly Monkey (Oreonax flavicauda, Humboldt 1812) in Amazonas and San Martin, Peru. Neotropical Primates. ?(?): ??-??

Distribution map based on data provided by the IUCN Global Mammal Assessment.

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