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CITES: Appendix I (What is CITES?)
IUCN Red List: B. hypoxanthus: CR; B. arachnoides: EN (What is Red List?)
Key: CR = Critically endangered, EN = Endangered
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The most serious threats to muriqui conservation include habitat loss and fragmentation as well as illegal hunting. While Brazilian law protects remaining stands of Brazilian Atlantic forest and many muriqui populations exist on private lands, land clearing and hunting continue to threaten their survival (Strier 1992). It is estimated that there are fewer than 2000 muriquis left in the wild (Strier 2000; Mittermeier et al. 2005).


Threat: Human Induced Habitat Loss and Degradation

The loss of the Brazilian Atlantic forest dates back to the 1500s, when Portuguese explorers first entered Brazil and began to establish ports and trading posts. The forest was first cleared for sugar cane, an important export crop, but other natural resources such as gold and diamonds were soon discovered and extracted (da Fonseca 1985). As the economy boomed, human populations grew and more land was cleared for agriculture, an industry that has continued to expand in this region of Brazil since the 17th century. The human population of Brazil is concentrated in this area and as a result of centuries of forest clearing and land exploitation, only a fraction of the Brazilian Atlantic forest remains (da Fonseca 1985; Morellato & Haddad 2000). Endemic fauna and flora of this region have either been pushed to extinction or, like muriquis, are in serious threat of disappearing because the unique forest in which they evolved has been all but eliminated (Morellato & Haddad 2000). Ongoing human activities with a major impact on muriqui habitat loss and destruction include sprawling coffee plantation and cattle grazing, both of which occur on land cleared by fires, small-scale timber extraction, hydroelectric dams, and road development. Another human-induced cause of habitat degredation is palm heart harvesting, an important export resource (Rylands et al. 1998).

Agriculture continues to be an important part of the economy in this region of Brazil and the land has been parceled out for centuries. While some plantation owners have stands of primary and secondary growth which can support muriqui groups, there is uncertainty in the future ability of landowners to protect these stands for muriquis as economic incentives to either clear the land for timber or additional pasture and crop land still exist. Furthermore, because so much of the land in the region is privately owned, acquiring land for parks and reserves is nearly impossible as it would mean buying multiple adjacent properties to establish one suitable plot for forest regeneration (da Fonseca 1985).

Land fragmentation has been particularly devastating to the northern muriqui, whose populations are isolated from each other, compared to the southern muriqui, which survives in one of the largest tracts of Brazilian Atlantic forest remaining, Serra do Mar in Rio de Janeiro and São Paulo (Strier 2000; Mittermeier et al. 2005). In addition to losing places to establish home ranges, habitat destruction can cause ecological stress and influence the way in which muriquis forage and the overall composition of their diet. This can lead to lower rates of reproduction and slower population growth (Strier 1992a).

Potential Solutions

The single most important factor in conserving muriquis is protecting forest from further destruction and fragmentation (Brooks & Rylands 2003). One solution is the private faunal refuge system administered by the Brazilian Institute of Forest Development (IBDF) in which private land owners have legal backing to prohibit hunting on their lands. Small, adjacent private reserves can be useful in preserving connecting tracts of regenerating forest and provide refuge for endangered species such as muriquis (da Fonseca 1985; Strier 1992). Despite historical habitat destruction, in areas where forests are allowed to regenerate through protection such as at Montes Claros, muriqui populations show marked growth. Given larger areas of suitable habitat, muriquis have been able to expand their home ranges and increase their overall population size, indicating that habitat protection is a sensible and worthwhile endeavor (Strier 1992; 2000).

One incentive for private landowners to curb habitat destruction and create economic opportunity is through ecotourism. By protecting forests and creating ecotourism destinations on their lands, private landowners can personally gain from having muriquis on their land (Strier 1992a). Montes Claros is a popular tourist site, with income from visitors contributing to continuing research (Strier 1992a). At other sites, income could be split between researchers and land owners, or could solely benefit landowners.

Threat: Harvesting (hunting/gathering)

Muriquis are the largest of the New World primates and are prized trophies for hunters. Not only are they sought after because of their large body size, they may also experience heightened risk because they are easily spotted by hunters (Pinto et al. 1993). Where they are found in state parks and reserves, there are too few guards to effectively protect against poaching. Private landowners are more successful in preventing trespassers from hunting muriquis living on their land, but illegal hunting still occurs (Strier 1992a). Hunting is particularly devastating for small populations in isolated forest fragments where poachers can essentially drive a group to local extinction either through directly killing adults or disrupting the population structure so significantly that the group cannot rebound (Chiarello 2003).

Potential Solutions

Hunting of muriquis is illegal, and prosecution of poachers is one way to deter hunting, but apprehension of hunters is necessary if they are to be prosecuted. Eliminating illegal harvesting of muriquis is a near-impossible endeavor as parks and private lands are scarcely patrolled by guards and forests are often difficult to effectively patrol. One method of decreasing poaching is to accentuate the cultural or economic value to the muriquis through education or ecotourism. For example, while the muriqui has become a flagship species of the region, appearing on postage stamps, telephone directories, t-shirts, and posters, continuing education and information dissemination is critical to teach people about the unique resource found in nearby forests (Strier 1992a). Ecotourism, which often gives an economic value to protecting wildlife, is another option for involving local people in conservation measures. Providing alternate sources of income as field guides or other service related jobs could change attitudes about hunting muriquis and create incentives to protect them (Strier 1992a).

Threat: Changes in Native Species Dynamics

While habitat loss is a serious concern for muriqui populations, one side effect of fragmentation is the depletion or local extinction of predator species, many of which require large, continuous forests in which to hunt (González-Solís et al. 2001). Heavy predation pressure is therefore not a factor in conserving small, isolated subpopulations of muriquis (Lemos de Sá & Strier 1992).

Threat: Intrinsic Factors

One serious concern for animals living in small, fragmented populations that are isolated from each other is that inbreeding depression can make groups vulnerable to extinction. Low birth rates and high mortality rates characterize populations with limited gene flow and result in dwindling populations over time (Strier 2000). Furthermore, smaller populations with low genetic diversity are more vulnerable to stochastic events such as drought and disease outbreaks. While many muriqui populations are separated from each other and gene flow is limited, ill-effects have not been noted up to this point (Strier 1991; 1993/1994; 2000). For example, the muriquis at Montes Claros have been successfully reproducing and the group has steadily increased in size since Karen Strier began her work there in the early 1980s. With continued protection on private land and future forest regeneration on adjacent land, the population is projected to survive in the next 100 years (Strier 1993/1994).

Another intrinsic factor that may affect muriqui conservation is their slow rate of population growth which can be attributed to long interbirth intervals and late onset of sexual maturity and age at first parturition (Strier 1991b).

Potential Solutions

While the lower extinction probability for the population at Montes Claros is heartening, long-term viability of other muriqui populations cannot be extrapolated from their success. Further research is necessary to understand how small home ranges, fluctuations in habitat quality, and low population densities affect muriquis at other sites and ongoing efforts to secure contiguous primary or regenerating forest is necessary (Strier 2000). The size of the group at Montes Claros increased steadily as home ranges increased in association with forest regeneration and land protection (Strier 1991b; 1992a). If the data from Montes Claros can be applied to other study sights, the most important consideration for increasing population size is increasing available habitat.

In addition to land protection, intensive management of small populations may be necessary to avoid inbreeding depression. Translocation of muriquis between isolated forests would be one way to introduce new individuals to the breeding population and decrease the risk of close relatives mating. This process is risky for individual animals, and the costs should be weighed against the potential benefits (Strier 1992a).

Threat: Human Disturbance

Forest fires are rare in moist tropical forests, but the impact of logging and clearing of land can contribute to an unnaturally high risk of fires. While this has been greatly studied elsewhere in South America, there are no data regarding the impact of human-caused forest fires on muriquis (Chiarello 2003). At Montes Claros, Strier (1992a) documented one forest fire that was potentially catastrophic for the muriqui population when a fire used to clear land for a garden burned out of control. The threat of fires coupled with small populations means there is potential for even small forest fires to destroy entire muriqui populations.




Content last modified: August 30, 2006

Written by Kristina Cawthon Lang. Reviewed by Karen Strier.

Cite this page as:
Cawthon Lang KA. 2006 August 30. Primate Factsheets: Muriqui (Brachyteles) Conservation . <>. Accessed 2019 December 14.