Northern Muriqui
(Brachyteles hypoxanthus)
This species is endemic to Brazil’s Atlantic Forest region. They live in multi-male groups that can reach more than 50 animals. They have suffered from hunting and the destruction of their forests since the 16th century. Today the population is less than 1,000 individuals and is highly fragmented, with no subpopulation believed to be viable in the long term. The name muriqui comes from the Tupi Indians of Brazil, but they have also previously been called woolly spider monkeys. The use of the name woolly spider monkey has fallen out of favor, as the term is misleading, implying that the animal is a hybrid of woolly monkeys and spider monkeys, when in fact muriquis are unique.
Urgent Conservation Actions
Four key priorities have been identified to conserve wild populations; habitat conservation and restoration, supplementation of existing populations through translocation, establishment of corridors and hunting regulation.
Brazil (Bahia, Espírito Santo, Minas Gerais, Rio de Janiero)
Evolutionary Distinctiveness
Order: Primates
Family: Atelidae

There are 24 species in the family Atelidae, including 10 species of howler monkeys (Alouatta), 7 spider monkeys (Ateles), 2 muriquis (Brachyteles), 4 woolly monkeys (Lagothrix), and 1 yellow-tailed woolly monkey (Oreonax). All atelids have prehensile tails that are sensitive and used for grasping objects. Brachyteles are the largest New World primates. Morphological and genetic differences between southern populations from Sa˜o Paulo state and northern populations from the states of Minas Gerais and Espı´rito Santo, have led to taxonomic revisions that recognize separate species, B. arachnoides and B. hypoxanthus, for the southern and northern varieties, respectively.

Weight: Adult male: 9.25-9.6 kg
Muriquis have long limbs and a long prehensile tail, allowing them to be particularly agile amongst the trees. The thick coat is greyish-brown in colour and males may have a more yellow tinge.
Almost all of the information available on the ecology, behaviour, reproduction and demography of the northern muriqui comes from a single population at the Caratinga Biological Station (Reserva Particular do Patrimônio Natural Feliciano Miguel Abdala), Minas Gerais. There, muriquis have been systematically monitored and researched since 1982.

Muriquis are arboreal and active during the day. Their diet consists mostly of young leaves and fruit which individuals often eat whilst hanging from the branches of a tree with their prehensile tail. Their diet may be supplemented with seeds, bark, flowers and some insects during the more abundant rainy season.

Individuals live in mixed-sex groups of between 8 and 80 individuals. Groups are not territorial; there is little aggression between members and related males often cooperate with each other. Females tend to give birth to a single offspring during the May - September dry season. Male offspring remain with their natal group. Females disperse to join other groups once they have reached adolescence at 5 – 7 years.

Inhabits the humid coastal forests of the Serra do Mar to the semi-deciduous forests inland in the states of São Paulo and Minas Gerais.
The range of the northern muriqui covers the Atlantic forest of the states of Minas Gerais, Espírito Santo, Rio de Janiero and Bahia, excluding the lowland forests in the extreme south of Bahia and northern Espírito Santo.
Population Estimate
Believed to number less than 1,000 individuals (distribution is fragmented with the largest sub-population recorded having only 157 individuals)
Population Trend
Decreasing. This species has suffered a past and ongoing population decline greater that 80% over the last 3 generations.
Classified as Critically Endangered (CR A2cd) on the 2010 IUCN Red List of Threatened Species.
This species survives in very reduced and isolated populations none of which number more than 500 individuals and so are not believed to be viable in the long term.

The main threats to the species have been hunting for food and sport accompanied by the widespread destruction of forests. Although hunting is relatively infrequent today, the rarity and small size of the populations of these animals means that even the loss of a few can have serious impacts. As the number of protected areas increases, hunting will have less of an impact. The remnant populations in the fragmented forests of the montane region of Espírito Santo (Santa Maria do Jetibá) have survived only because hunting has long been discouraged by the local communities there. Despite some fairly extensive remaining forests in the north of its range, very few muriquis survive today, and those in only the remotest areas, because of the predisposition of the local people (in Bahia particularly), to hunting.
Conservation Underway

The northern muriqui was once widespread in the Atlantic Forest region, but today there are only a handful of sub-populations in nine or more protected areas, including Rio Doce State Park, Caparaó National Park, Serra do Brigadeiro State Park, and Augusto Ruschi Biological Reserve.

A Population and Habitat Viability Analysis (PHVA) was held for both species of Brachyteles in 1998. This has now resulted in a series of surveys in Minas Gerais, Rio de Janeiro, Espírito Santo and Bahia. The use of population viability modelling has been continued since then as a tool for conservation planning for muriquis.

From 2001 to 2003 the Project for the Conservation and Sustainable Use of Brazilian Biological Diversity (PROBIO), of the Ministry of the Environment (MMA), approved financing for three projects for the conservation and management of the northern muriqui. They provided the information and directives for the elaboration of a management plan for the species.

Currently there are research programmes on, and conservation initiatives for, muriquis being carried out in six locations, four in Minas Gerais (RPPN Feliciano Miguel Abdala, RPPN Mata do Sossego, and Serra do Brigadeiro and Rio Doce state parks) and two in Espírito Santo (Caparaó National Park and Santa Maria de Jetibá). These studies and initiatives cover about 90% of the entire population of B. hypoxanthus. Besides population monitoring and ecological/behavioural studies, research is being carried on population genetics and captive breeding. There is also a small but promising captive breeding programme for the species.

The muriqui has been a flagship species for the conservation of Brazil’s fragile Atlantic Forest region. In 2002, the Brazilian Institute for the Environment (IBAMA) set up the Committee for the Conservation and Management of the Muriqui. However, information on these critically endangered primates is still lacking and data on population distribution and status is urgently required. Programme Muriqui has been undertaking research on populations within the Serra dos Organos National Park; the possibility of reintroductions is being investigated and an ongoing education programme has been established.


This species is additionally receiving conservation attention through two national action plans formulated in Brazil. The ‘National Action Plan for the Conservation of Muriquis’, which was developed between 2005 and 2010, aims to increase both awareness and protection of muriqui populations and in the process reduce each species' IUCN threat category by 2020. As of 2012 new protected areas will have been created, existing fragmented habitats re-connected and a fund to research and conserve Muriqui species initiated. By 2015 the aim is to have quantified remaining populations, implemented a long term species research programme and to have effectively increased measures to prevent hunting in protected areas.


The northern muriqui is also one of 27 species included in the ‘National Action Plan for the conservation of Central Atlantic Forest Mammals’. This conservation plan was instigated via an exhaustive compilation of biological and species threat data from which six main goals and 100 specific actions were formulated. These goals will aim to both reverse population declines of target species and improve connectivity within fragmented habitats. Costing US$32 million, this action plan is in effect for 5 years, expiring in 2015.

Conservation Proposed
Central Rio de Janeiro state still harbours large tracts of intact forests potentially available to muriquis. Thus, if conservation actions could be targeted to mitigate the main threat of hunting there is potential for the recovery of muriquis in the state of Rio de Janeiro, at least in the short-term.

In order to maintain and improve muriqui’s genetic diversity it is of paramount importance to increase population sizes, and management options to achieve this goal should deal with:

(1) Habitat conservation and restoration.

The Atlantic Forest has a long history of habitat destruction and degradation, therefore the preservation of forest remnants and the establishment of programs dealing with habitat restoration and recovering forest habitat would greatly benefit the persistence and genetic health of remaining populations. Adequate management of existing habitat, the creation of new protected areas (both private and public) and the restoration of degraded habitat are goals of strategic importance.

(2) Supplementation of existing populations through translocation. There are several small populations inhabiting reserves and protected areas that would support a larger number of muriquis. The translocation of new individuals for these areas would result in demographic and genetic benefits for the local populations. Reserves with large and growing populations, which are already near their carrying capacity, could be the source for individuals for the genetic reinforcement of the smaller populations, rescuing them from genetic impoverishment. A detailed monitoring program must be established in order to evaluate the advances and success of translocation schemes.

(3) Establishment of corridors.

Due to the high rate of habitat destruction and fragmentation in the Atlantic Forest, insularization and isolation may be a serious threat to the persistence and the genetic health of wildlife. Improving connectivity among populations would help mitigating genetic deterioration by allowing dispersing individuals, sources of new genetic material, to reach other populations and consequently improving genetic diversity in the populations which are receiving them. There is a management plan to improve habitat connectivity in the Atlantic Forest with the creation of three regional ecological corridors, and one of them, the Central Atlantic Forest Corridor, would benefit B. hypoxanthus preservation. The creation of corridors on a local spatial scale should be a complementary approach for the regional corridor network.
Cunha, A. A. et al. 2009. Short Communication: Distribution, population size and conservation of the endemic muriquis (Brachyteles spp.) of the Brazilian Atlantic Forest. Oryx, 43(2), 254–257

Fagundes, V. et al. 2008. Genetic structure in two northern muriqui populations (Brachyteles hypoxanthus, Primates, Atelidae) as inferred from fecal DNA. Genetics and Molecular Biology, 31, 1, 166-171

Macdonald, D. 2001. The New Encyclopedia of Mammals. Oxford University Press, Oxford.

Mendes, S.L., de Oliveira, M.M., Mittermeier, R.A. & Rylands, A.B. 2008. Brachyteles hypoxanthus. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4. <www.iucnredlist.org>. Downloaded on 15 November 2010.

Strier, K. B. 2000. Population Viabilities and Conservation Implications for Muriquis (Brachyteles arachnoides) in Brazil’s Atlantic Forest. Biotropica 32(4b): 903–913

Strier, K.B. & Boubli, J. P. 2006.  A History of Long-term Research and Conservation of Northern Muriquis (Brachyteles hypoxanthus) at the Estação Biológica de Caratinga/RPPN-FMA. Primate Conservation 20: 53–63.

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