Primate Info Net Banner Wisconsin PRC Logo

Pan troglodytes

Other versions available: [Français]


CITES: Appendix I (What is CITES?)
IUCN Red List: P. troglodytes: EN (What is Red List?)
Key: EN = Endangered
(Click on species name to see IUCN Red List entry, including detailed status assessment information.)

With only 100,000 to 200,000 left in the wild and about 250 individuals in zoos in the United States, chimpanzees are among the most threatened primates in Africa for many reasons (Goodall 2001). Central chimpanzees are the most numerous, with about 80,000 found in Gabon and Congo, eastern chimpanzees number about 13,000 though the estimates from DRC are very rough, and western chimpanzees are very patchily distributed with no more than 12,000 remaining (Oates 1996). Several synergistic factors have led to the decrease in chimpanzee populations across Africa and some of the most salient threats include hunting, habitat loss and degradation due to industrialized logging and human population growth, and disease (Kormos 2003; Walsh et al. 2003; Poulsen & Clark 2004). Even in Gabon and Congo, widely considered stronghold countries for chimpanzees, populations are declining at a rate of at least 4.7% per year (Walsh et al. 2003).


Threat: Human Induced Habitat Loss and Degradation

Deforestation in the tropics has multiple causes including agricultural expansion, overgrazing, fuelwood gathering, commercial logging, and infrastructure and industrial development (Rowe et al. 1992). Particularly problematic in Africa is industrialized logging, which compromises the habitat in which chimpanzees thrive, both directly and indirectly. Direct consequences of logging include the loss of trees, but the indirect threats are more far reaching and include soil erosion, loss of biodiversity, climate change, desertification, watershed degradation, landscape fragmentation due to roads, and facilitation of access by settlers who convert logged forest into agricultural areas (Rowe et al. 1992; Wilkie et al. 2000). The roads that are created are particularly of concern because they provide access to once isolated forests that can then be exploited for resources, both floral and faunal.

Human population growth is another underlying factor of wild chimpanzee vulnerability. With population growth rates increasing, food production miserably inadequate, and political and economic insecurity a fact of life, Africans are struggling to meet short-term needs at the expense of chimpanzees (Butynski 2001). Demand for land for housing, development of infrastructure, agriculture, and grazing animals indirectly threatens chimpanzees because of forest loss. The need for forest products for subsistence usage such as vines for basketry, medicine, collection of food, and firewood also degrades chimpanzee habitat (Conserving the Chimpanzees of Uganda 1997). As human populations explode so will the development of infrastructure and habitat degradation will follow. Currently, more than 70% of chimpanzee habitat is affected by infrastructure and if current human population growth rates are maintained, it is estimated that by the year 2030 less than 10% of chimpanzee habitat will remain unaffected by development (Nellemen & Newton 2002).

Potential Solutions

Some possible suggestions to mitigate habitat degradation due to logging include responsible forest practices, including selective felling, use of pitsaws rather than power saws, and restrict access for loggers to only a few days per week (Endroma et al. 1997). Sustainable forestry practices that include selective logging and limited extraction can not only stop negative effects of logging on chimpanzee populations, but actually improve population densities because of higher abundance of fruits in successional plots and a decrease in mechanized logging equipment (Plumptre and Grieser Johns 2001). Establishment of strict protection areas in high priority conservation areas thereby precluding logging activity is another possible mechanism to decrease habitat loss. This solution is only possible, though, if alternative income strategies are provided for the communities that depend on logging for income.

Threat: Invasive Alien Species

As humans come into contact with chimpanzees more readily through bushmeat availability and open-access logging roads, the spread of zoonotic diseases such as Ebola, a deadly hemorrhagic fever, threaten both human and ape populations. In some areas, Ebola is a concern for the viability of chimpanzee populations because of its acute deadliness and misunderstood etiology (Walsh et al. 2003). Other infectious diseases that threaten chimpanzees include the common cold, pneumonia, paralytic poliomyelitis, tuberculosis, chicken pox, and influenza (among others) (Butynski 2001). An epidemic of any of these diseases could cause massive mortality within a small population and potentially cause rapid extinction of subspecies and species. In 1966, multiple infants were killed and many adults paralyzed in an outbreak of a paralytic disease (probably polio) at Gombe (Goodall 1986). Frequent close contact due to increasing human populations or even tourists, guides, and park personnel may increase the risk of transmitting these diseases to chimpanzees, and the problem could worsen.

Potential Solutions

Limiting human proximity to chimpanzees as much as possible will decrease the likelihood of infectious diseases traveling between humans and chimpanzees. In areas of high tourism, research activity, and where interactions between chimpanzees and local communities are common, stricter precautions are needed to protect chimpanzees from human diseases as well as safeguard humans against novel chimpanzee diseases (Butynski 2001). For tourists and researchers that come into close contact with chimpanzees, certain regulations should be implemented and adhered to including regular screening for and vaccination against diseases such as tuberculosis and proper sanitation including hand-washing, disinfectant footbaths, or surgical masks within a certain distance of the apes.

Threat: Harvesting (hunting/gathering)

Though the trade of chimpanzees is restricted, the unstable political situation and rampant corruption in many countries translates into little enforcement (Ammann 2001). The increase in availability of firearms over the last few decades has greatly increased poaching efficacy. The prevalence of guns in poaching activity is 80% greater than other weapons (including traps, spears, and harpoons) (Poulsen & Clark 2004). Modern firearms make poaching these large, strong apes much easier and more successful than when using traditional weapons. For hunters that poach chimpanzees for commercial purposes, the use of guns ensures a higher yield as well, so populations may be dropping exponentially faster than if traditional weapons were used. Moreover, because of their life history characteristics, chimpanzees are more likely to go extinct due to hunting than other primates. Those primates most vulnerable to hunting pressures are those dependent on old-growth forest, that weigh at least 4 kg (8.82 lb), spend a significant amount of time on the ground, are noisy and conspicuous, and live in areas of high or increasing human populations that have a tradition of hunting primates or where a demand for bushmeat exists (Struhsaker 1999). Especially troubling is the problem of orphaned chimpanzees. Poachers are only interested in adults for their meat, but killing an adult female with dependent offspring ensures that those infants or juveniles will either be sold into the pet trade or die because they lack the support of their mother so integral to chimpanzee development.

Another factor that has made hunting easier is the spread of industrialized logging. Commercial logging transforms roadless forests into major thoroughfares which can be easily accessed by commercial hunters. Poachers can find their own transportation or hitchhike on logging trucks into the forests and loggers, after their daily work, can stay to hunt before driving back to the village (Ammann 2001). Not only does the infrastructure provided create ease of access to forests for poachers (including restricted natural areas and parks), but an influx of men working for logging companies drives up the demand for bushmeat, which is much less expensive than other protein sources available at markets in logging towns (Walsh et al. 2003). More than just providing access to areas where chimpanzees are available, logging companies provide guns, materials for snares, transportation to and from hunting areas as well as transportation of carcasses to markets in large cities. Employees of some logging companies are involved at every step of the bushmeat process from the tools to make the guns to the consumption of the meat (Ammann 2001).

Potential Solutions

If the bushmeat trade is to stop, there are some very important and difficult objectives that must be achieved. First, the governments of African countries have to implement sustainable use policies for the natural resources in their countries and global institutions such as the World Bank must begin to offer financial and political incentives to implement environmentally responsible development projects that do not include the unsustainable use of natural resources (Butynski 2001). These projects should include the development of alternate food sources for bushmeat.

Furthermore, logging companies should be held to corporate codes of conduct and responsibility by western consumers. Logging companies with leases to forests are usually from developed countries; certainly international pressure on these companies could be great enough to change some of their policies. Certification programs based on sustainable techniques and extraction practices are another option to decrease bushmeat hunting (Butynski 2001). Reviewed by independent parties, the criteria of certification can involve control of the bushmeat trade and maintenance of biodiversity as central parts of the accreditation process. Education programs and materials at zoos and on the internet can get the message across to western consumers that purchasing uncertified tropical woods from Africa has deleterious effects on biodiversity, chimpanzee habitat, as well as the people of Africa.

Another step for African governments is to turn so-called "paper parks" into legitimate protected areas. Enforcement of protected areas and the laws regarding the trade of chimpanzees would also affect the number of chimpanzees killed for bushmeat. Guards and park patrols are needed to deter hunters from entering protected areas in search of chimpanzees.

Finally, sanctuaries for orphaned chimpanzees are necessary to rehabilitate the infants and juveniles and save them from an unnatural life in a home. Chimpanzee orphanages, while not ideal for developing chimpanzees, could ensure a relatively normal socialization and learning period, and eventually orphaned chimpanzees may be returned to the wild or be used in captive breeding programs, if necessary.

For more reading about the bushmeat crisis and commercial logging: Peterson D. 2003. Eating apes. Berkeley, CA: Univ Calif Pr. 320 p.

Threat: Accidental Mortality

Across much of their range chimpanzees are threatened by snares set by poachers and farmers. Though snares do not kill adult chimpanzees immediately, wounds caused by snares can become infected or snares can disfigure chimpanzees to the point that they can no longer obtain and eat food (Endroma et al. 1997; Quiatt et al. 2002; Reynolds et al. 2003). In Kibale, snares injure chimpanzees at a rate of 3.7 percent per year, and though chimpanzees have learned to recognize snares, they often are caught when their attention is distracted (Wrangham 2001).

Potential Solutions

Guards and patrols in parks and protected areas that survey and disarm snares and traps could decrease accidental mortality. Habituated chimpanzees in field research groups could receive basic medical treatment, including antibiotics, for infected wounds, if necessary, though immobilization of chimpanzees for veterinary treatment is often difficult and dangerous (Wrangham 2001).

Threat: Persecution

As alluded to above, where chimpanzees coexist with humans that practice agriculture, these apes may be considered pests, raiding crops, and in a few, very rare instances, killing children (Endroma et al. 1997; Wrangham 2001; Reynolds et al. 2003). Pest chimpanzees are often killed by farmers and then sold for profit or fed to their hunting dogs (Wrangham 2001).

Potential Solutions

Given the growing human population across Africa, it is unlikely that human-chimpanzee conflict will decrease. Therefore, the best solution to increase tolerance of chimpanzees and decrease their persecution in areas where humans and chimpanzees coexist is to make them valuable to the local people through ecotourism and research (Wrangham 2001). Though neither solution is perfect and both have risks and benefits, both offer an opportunity for local people to fiscally benefit from the presence of chimpanzees and thereby increase their tolerance of crop-raiding behavior. Either directly through employment or generating revenues to reimburse people for crops lost to chimpanzees, ecotourism and research programs change the attitudes of people towards chimpanzees and increase their acceptance as these apes begin to "pay for themselves."

Threat: Changes in Native Species Dynamics

Though it is not well documented, the potential exists for parasitic or pathogenic infections to cause massive mortality in chimpanzee populations (Butynski 2001). Over 100 parasitic diseases, including protozoal and metazoal pathogens, affect the great apes and they are fatal or cause morbidity with severe consequences for behavior and reproduction. Often mortality results from a secondary infection in lesions caused by the primary pathogen (Toft 1986).

Potential Solutions

In some field sites where chimpanzees are habituated, it is possible to administer antibiotics for these and other diseases, which may mitigate the effects but do not eliminate the source or prevent recurrent infections (Goodall 1986).

Threat: Intrinsic Factors

Some intrinsic factors, shaped by human-induced environmental changes, threaten chimpanzee populations. High juvenile mortality and sex differences in mortality threaten recruitment slow population growth rates (Hill et al. 2001). Factors that contribute to high mortality in wild chimpanzees include poor nutrition, lack of regular veterinary health care, and natural hazards such as predators and conspecific aggressiveness. Moreover, because of their long lifespan and reproductive characteristics, a female chimpanzee is expected to produce only .8 daughters, on average, in her entire lifetime (Hill et al. 2001). This is well below the population replacement rate, and even a slight change in population composition, caused by diseases, habitat fragmentation, or poaching could negatively affect growth rate, causing extirpation.

Inbreeding necessitated by habitat fragmentation could also pose a threat to chimpanzee conservation. Strategies of inbreeding avoidance are evident in the mating behavior of female chimpanzees; they often seek extra-group copulations and actively avoid mating with close community members. Habitat fragmentation could isolate female chimpanzees and either force them to mate with community members that may be related to them or even inhibit successful dispersal from their natal communities (Gagneux et al. 1999). The potential problems associated with inbreeding are particularly devastating in small communities and include inbreeding depression and genetic drift (Marsh 2003).

Potential Solutions

Intrinsic factors which threaten chimpanzees that are compounded by human influence such as inbreeding depression due to habitat fragmentation and high juvenile mortality due to zoonotic disease transfer should be the focus of conservation programs. Creating habitat corridors to increase gene flow between populations and increasing the number protected areas could help decrease the possibility of inbreeding while providing supportive veterinary care to sites where habituated chimpanzees are found may alleviate undue suffering from diseases transferred from local human populations.

Threat: Human Disturbance

Much time and energy has been devoted to habituating chimpanzees at some research sites in Africa. Where they have been studied for great lengths, chimpanzees are accustomed to humans, and while this is helpful for researchers, it also poses a risk to the apes' health. Moreover, where chimpanzees have not been habituated to human presence but researchers have tried to habituate them, the most common response is curiosity and trust of humans (Tutin & Fernandez 1991; Morgan & Sans 2003). Chimpanzees that are accustomed to humans or are not afraid of them on first contact are vulnerable to poaching and diseases.

War and civil unrest is, unfortunately, relatively common in post-colonial Africa. The effects of political instability and conflict on wildlife, especially chimpanzees, should not be underestimated. In Rwanda, for example, civil war starting in 1990 directly affected the chimpanzees because of landmines and mortars in the forests, while the indirect consequences were habitat degradation due to the massive number of people seeking refuge in protected forests and withdrawal of funding for conservation projects and research (Plumptre et al. 2001).

Potential Solutions

It is enormously important that research, including direct observation, continues on chimpanzees. Current field research practices are non-invasive and there is little evidence that field workers' presence disturbs chimpanzees' social or physiological patterns, still the risks of exposure to disease and trust of humans may threaten chimpanzees. If chimpanzees are habituated at a field site, much effort should be focused on physically protecting that area and keeping it free of poachers as well as precautionary measures to ensure the subjects are not exposed to infectious diseases.

While intractable ethnic divisions lead to instability and conflict in many African nations, there are a few things that can be done to minimize damage to protected areas and conservation projects during future times of instability. When possible, researchers should maintain a presence of committed staff at the project site, ensure continued funding through continued research, plan ahead for unsafe conditions, train junior staff thoroughly, maintain neutrality, and provide good communication systems between field sites and elsewhere (Plumptre et al. 2001).

The threats to chimpanzee survival are closely linked and it will take much effort to create solutions to these problems. The economic atmosphere in many of the chimpanzee range countries serves to fuel hunting and logging (Wilkie et al. 2000). Unfortunately, the problems of scarce economic opportunity, political strife, and civil unrest, are too complicated to be solved before chimpanzee populations are annihilated. Ecotourism is not a viable income-earning alternative because of the civil conflict in certain regions of Africa. Because ecotourism is not a reliable solution to the continuous decline of chimpanzee populations, conservationists should invest in massive law enforcement campaigns to guard parks and other formally protected areas from poachers (Walsh et al. 2003). Other options are to focus on areas where high densities of chimpanzees occur naturally and human populations are currently scarce, for example, the swamp forests of Congo. In these areas, chimpanzees utilize swamp forests during the dry season and terra firma during the wet season, but human population density is low because of the difficulty of access, low timber values in the area, and few agricultural possibilities (Poulsen & Clark 2004). Protection of swamp forests would be simple and effective during the wet season and because of the limited access to gathering areas during the dry season, it would be easy to protect large numbers of chimpanzees at other times of the year.





Content last modified: April 13, 2006

Written by Kristina Cawthon Lang. Reviewed by Elaine Videan.

Cite this page as:
Cawthon Lang KA. 2006 April 13. Primate Factsheets: Chimpanzee (Pan troglodytes) Conservation . <>. Accessed 2020 July 6.