|Scientific Name:||Pan troglodytes (Blumenbach, 1799)|
|Infra-specific Taxa Assessed:|
Simia troglodytes Blumenbach, 1799
|Taxonomic Source(s):||Mittermeier, R.A., Rylands, A.B. and Wilson D.E. 2013. Handbook of the Mammals of the World: Volume 3 Primates. Lynx Edicions, Barcelona.|
Chimpanzee taxonomy remains an active area of research, particularly in population genetics. Four subspecies are commonly recognised: the Western Chimpanzee (Pan troglodytes verus); the Nigeria-Cameroon Chimpanzee (P. t. ellioti); the Central Chimpanzee (P. t. troglodytes); and the Eastern Chimpanzee (P. t. schweinfurthii). Genetic data, which include analyses of complete genomes (Prado-Martinez et al. 2013), suggest that the subspecies form two distinctive groups: one group includes P. t. verus and P. t. ellioti and the other group includes P. t. troglodytes and P. t. schweinfurthii (Fünfstück et al. 2015). Pan t. verus and P. t. ellioti separated from one another much earlier than P. t. troglodytes from P. t. schweinfurthii. Each subspecies has experienced markedly different demographic histories since their separation 100,000 years ago, with all punctuated by dramatic reductions in their effective populations size (Gonder et al. 2011, Mitchell et al. 2015, Prado-Martinez et al. 2013). The degree of connectivity between chimpanzee populations in western Nigeria and those in eastern Nigeria and western Cameroon has yet to be adequately examined. Published relationship trees based on the analysis of mitochondrial DNA do not group western Nigerian chimpanzees closely with those of either Upper Guinea or eastern Nigeria (Gonder et al. 2006); however, those analyses were based on a very small number of western Nigerian samples. A more comprehensive analysis using additional samples is urgently needed.
While taxonomic labelling is often debated and subject to revision, the relative importance of different threats faced by chimpanzees varies across Africa, making a regional approach valuable for conservation purposes.
|Red List Category & Criteria:||Endangered A4bcde ver 3.1|
|Assessor(s):||Humle, T., Maisels, F., Oates, J.F., Plumptre, A. & Williamson, E.A.|
|Reviewer(s):||Mittermeier, R.A. & Rylands, A.B.|
|Contributor(s):||Butynski, T.M., Tutin, C., Walsh, P.D. & Wilson, M.|
Although Pan troglodytes is the most abundant and widespread of the great apes, and many populations exist in protected areas, the declines that have occurred are expected to continue, satisfying the criteria for an Endangered listing (Oates 2006). Due to high levels of poaching, infectious diseases, and loss of habitat and habitat quality caused by expanding human activities, this species is estimated to have experienced a significant population reduction in the past 20–30 years and it is suspected that this reduction will continue for the next 30–40 years. Due to their slow life history and a generation time estimated to be 25 years, Chimpanzee populations cannot sustain high levels of mortality, whether disease-induced or caused by poaching. The maximum population reduction over a three-generation (75 year) period from 1975 to 2050 is suspected to exceed 50%, hence qualifying this taxon as Endangered under criterion A. Although conservation efforts directed at Chimpanzees and other wildlife have increased significantly in recent years, the assumption that population reductions will continue is a precautionary approach based on the rapid growth of human populations in sub-Saharan Africa, continuing poaching for bushmeat, the commercial bushmeat trade, the arrival of industrial agriculture (which requires clearcutting of forest), corruption and lack of law enforcement, lack of capacity and resources, and political instability in some range states. At the same time, zoonosis and disease outbreaks present significant risks; there is, for example, evidence that Ebolavirus will continue to spread in some parts of the Chimpanzee's geographic range (Walsh et al. 2005).
For more information, see the four Pan troglodytes subspecies accounts.
|Previously published Red List assessments:|
Chimpanzees have by far the widest geographic distribution of any great ape, with a range of over 2.6 million km² (derived from IUCN shapefiles). They have a discontinuous distribution from southern Senegal across the forested belt north of the Congo River to western Tanzania and western Uganda, between 13°N and 7°S. The four subspecies recognised here are distributed as follows:
The maximum elevation at which each subspecies has been confirmed is ca 2,000 m asl for P. t. ellioti, 2,790 m for P. t. schweinfurthii, 742 m for P. t. troglodytes, and 1,607 m for P. t. verus (Williamson et al. 2013).
Native:Angola; Burundi; Cameroon; Central African Republic; Congo; Congo, The Democratic Republic of the; Côte d'Ivoire; Equatorial Guinea (Equatorial Guinea (mainland)); Gabon; Ghana; Guinea; Guinea-Bissau; Liberia; Mali; Nigeria; Rwanda; Senegal; Sierra Leone; South Sudan; Tanzania, United Republic of; Uganda
Possibly extinct:Benin; Burkina Faso; Togo
|Range Map:||Click here to open the map viewer and explore range.|
Great ape population estimates are made using a standard index of abundance: night nest abundance and distribution, sometimes combined with predictive modelling. In 2003, the total Chimpanzee population size was estimated to be 172,700–299,700 (Butynski 2003). Current estimates for each subspecies are:
Pan t. ellioti is the least numerous subspecies. One of the largest and probably most secure subpopulations is in Gashaka-Gumti National Park, Nigeria, estimated at 900–1,000 individuals (Ogunjemite et al. 2010, Adanu et al. 2011). Other major subpopulations are found in Cameroon in Banyang-Mbo Wildlife Sanctuary (estimated at 500–900 or 800–1,450 individuals, depending on nest-decay parameters used; Greengrass and Maisels 2007), in the proposed Ebo National Park (estimated at 626–1,480 individuals, M. Ndimbe and B. Morgan pers. comm. 2015), and in Mbam and Djerem National Park (at least 500 individuals, Maisels et al. 2009).
The vast majority of P. t. schweinfurthii are found in DRC (173,000–248,000, Plumptre et al. 2010a, 2015). Outside the DRC, there are roughly 5,000 in Uganda (Plumptre et al. 2003a), just over 400 in Rwanda (WCS Rwanda unpubl. data), fewer than 400 in Burundi (Hakizimana and Huynen 2013), and fewer than 2,500 in Tanzania (A. Piel and F. Stewart, pers. comm.). Almost all Chimpanzees in Tanzania are found in the Greater Mahale Ecosystem, and their populations appear to be stable (Piel et al. 2015). Similarly, Chimpanzee numbers in Rwanda’s Nyungwe National Park are relatively stable (Sop et al. 2015). In western Uganda, forest is being lost at many Chimpanzee sites; however, data from the protected areas (Budongo and Bugoma forest reserves, Kibale National Park) indicate that Chimpanzee populations there are relatively stable (Wanyama et al. 2009, Plumptre et al. 2010b).
The forests of central Africa where Pan t. troglodytes occurs are by far the least disturbed in the species’ range. About one third of the subspecies population resides in Gabon and around 40% in Congo, followed by Cameroon (Strindberg et al. in prep.). The area of forest in these countries is very roughly representative of the proportion of Chimpanzees that it holds. A few thousand individuals remain in Equatorial Guinea, and a few hundred in CAR; the size of the populations in Angola (Cabinda) and DRC is unknown.
The P. t. verus strongholds are Guinea, Liberia and Sierra Leone (Ham 1998, Kormos, Humle et al. 2003, Brncic et al. 2010, Tweh et al. 2015). The largest population, estimated at 17,700 individuals (WCF 2012), is in the Fouta Djallon in Guinea.
For more details, see the four Pan troglodytes subspecies accounts.
|Current Population Trend:||Decreasing|
|Habitat and Ecology:|
Chimpanzees are found discontinuously across the forest belt of Africa, occupying primary and secondary moist lowland forest, swamp forest, submontane and montane forest, dry forest, forest galleries in savanna woodland, and farmland (Oates 2011). In West Africa, Chimpanzees are also found in fallow-agricultural matrixes dominated by wild or feral oil palm (Leciak et al. 2005, Brncic et al. 2010, Sousa et al. 2011). They live in multimale-multifemale, fission-fusion communities averaging 35 members. The largest known community has c.150 members (Mitani and Watts 2005). Annual home ranges are smaller in mixed forest than in woodland forest mosaics: one of the smallest known is 6 km² at Budongo in Uganda (Newton-Fisher 2003), while one of the largest is 72 km² at Semliki, also in Uganda (Samson and Hunt 2012). Chimpanzees are omnivorous and opportunistic feeders. Fruit forms about half the diet, typically supplemented with terrestrial herbaceous vegetation, leaves, stems, seeds, flowers, bark, pith, honey, mushrooms, resin, eggs, and animal prey such as insects and medium-sized mammals. They are the most carnivorous of the great apes. Chimpanzees are also proficient tool users. Tools made from plant parts are used to extract bees, ants and termites from their nests (e.g., Fowler and Sommer 2007), and stone and wooden hammers are used to crack nuts (e.g., Boesch and Boesch 1984, Matsuzawa et al. 2011).
Life History (as summarised in Williamson et al. 2013): Male and female Chimpanzees reach puberty at 7–8 years of age. Females have a 35-day reproductive cycle. The first parturition is generally at 13–14 years of age, but as early as 9–10 years in one population of western Chimpanzees. Chimpanzees reproduce throughout the year. Gestation is c.230 days. The norm is a single infant, but occasionally twins are born. Offspring are typically weaned at 4–5 years of age. The interbirth interval averages 4.6–7.2 years when the preceding infant survives. Females can remain reproductive into their late forties. Maximum life span is unknown, but thought to be ca 50 years. Female Chimpanzees may give birth to as many as nine offspring during their lifetime, but only one third of them survive beyond infancy. Generation time is estimated to be 25 years (Langergraber et al. 2012).
|Generation Length (years):||25|
|Movement patterns:||Not a Migrant|
|Use and Trade:||
Chimpanzees are completely protected by national and international laws in all countries of their range, and it is, therefore, illegal to kill, capture or trade in live Chimpanzees or their body parts.
The four Chimpanzee subspecies face similar threats, but to varying degrees in different regions. The major threats to Pan troglodytes are:
Despite the fact that all killing, capture or consumption of great apes is illegal, poaching is the greatest threat to most Chimpanzees. Due to their low population densities and slow reproductive rates, hunting often leads to the local extirpation of Chimpanzee populations. Increases in human populations, the ease of obtaining guns and ammunition, transport system efficiency, and high financial incentives for supplying urban markets with bushmeat and other forest commodities have resulted in swathes of land in the forest zone of Africa being cleared of wildlife. Chimpanzees are generally hunted opportunistically, but are sometimes targeted because they provide more meat than smaller mammals, such as duikers. Throughout the African moist forest region, poaching is intense around resources extraction camps – especially industrial and artisanal mining sites and logging camps – where bushmeat is usually the main source of protein available. Hunting with guns (targeting individuals) and snaring (an indiscriminate method of trapping) are the most common ways that Chimpanzees are killed. The widespread use of wire snares across Africa means that Chimpanzees can be caught and killed (or maimed) in snares set for other terrestrial mammals (e.g., Quiatt et al. 2002).
When Chimpanzees are killed for meat, their infants sometimes become pets, and some are trafficked (e.g., Hicks et al. 2010). Although all trade in Chimpanzees and their body parts is illegal, a small but pernicious and clandestine trade persists is some parts of Africa (e.g., CITES Secretariat 2014). Chimpanzees are sometimes killed intentionally–even poisoned–by people protecting their crops or as retribution for crop raiding (e.g., Brncic et al. 2010). Such trends are likely to increase as more natural habitat is converted to agricultural fields or plantations. Instances of crop foraging and encounters between people and Chimpanzees are becoming more frequent, especially in West Africa. This exacerbates negative perceptions and aggravates people’s attitudes towards Chimpanzees, thus potentially intensifying rates of killing, and subsequently fuelling the live trade with orphaned infants. Close to one thousand confiscated chimpanzees are now housed in sanctuaries in their range countries.
Until the mid-1990s, much of Central Africa was a series of vast, roadless forest blocks, to which access was extremely difficult and where human population density was very low. In the last quarter of a century, however, almost all terra firma forest in the non-protected areas of the central Chimpanzee’s range has been assigned as logging concessions (Global Forest Watch 2016). This means that most of the once-remote, previously inaccessible forests are now covered by a network of logging roads (Laporte et al. 2007), which provides rapid access to hunters entering the forest and to traffickers taking consignments of bushmeat out of the forest to distant destinations – often towns and cities where bushmeat fetches the highest prices. In recent years, extractive industries have stimulated very high rates of human immigration and the creation of yet more access roads, which are also used for poaching (e.g., Edwards et al. 2014).
2. Habitat loss and degradation
(a) Subsistence/slash-and-burn agriculture: the conversion of forest to farmland across Africa has severely reduced the availability of Chimpanzee habitat. Such habitat loss is especially acute in West Africa, where it is estimated that more than 80% of the region’s original forest cover had been lost by the early 2000s (Kormos et al. 2003). Extensive land conversion in eastern DRC, western Rwanda and western Uganda has destroyed much of the sub-montane forest used by Chimpanzees. In Central Africa, annual rates of loss are lower, averaging about 0.14% (2000–2010 data; Desclée et al. 2014). Ongoing rapid growth in human populations is expected to lead to further widespread conversion of forest and woodland to agricultural land. Along the northern border of the forest-savanna boundary at about 6°N, forests are also being lost to fires and grazing of livestock.
(b) Extractive industries – logging, mining and oil: logging generally has a negative impact on Chimpanzee densities due to habitat alteration (principally removal of important food trees) and disturbance (Morgan et al. 2007). As timber concessions undergo repeated cycles of logging, degradation over time will lead to profound changes in forest composition (Zimmerman and Kormos 2012), as the mature trees of certain species–some of high importance to Chimpanzees for food–are logged out. Mining of precious metals and mineral ores, and drilling for oil not only devastate wildlife habitat, but typically also lead to human inmigration and the building of roads, railways and other infrastructure. As with logging, the resulting increased accessibility to remote areas exacerbates risks to Chimpanzees through habitat degradation and fragmentation in areas not previously impacted by such anthropogenic pressures. The creation of open-pit mines leads to irretrievable loss of forest (Lanjouw 2014).
(c) Industrial agriculture – as tropical Asia nears its capacity for oil-palm plantations, Africa has become the new frontier for this crop, which offers excellent economic prospects in countries with appropriate rainfall, soil and temperature conditions (Rival and Lavang 2014). Unfortunately, these areas coincide with good great ape habitat: 42.3% of the African apes’ range is suitable for oil palm (Wich et al. 2014), so the spread of plantations is likely to hit Chimpanzee populations hard in coming years. This situation is of special concern for Chimpanzees living outside protected areas. Changes caused by the rapid transformation of their habitat can have profound impacts on their diet, activity patterns, dispersal and ranging patterns, as well as introducing new pathogens and other risks linked to close proximity with people (Ancrenaz et al. 2015).
(d) Major transportation infrastructure – huge road projects, which can be several kilometres wide, are currently underway across Africa and these will substantially fragment great ape habitat and add further to the area of “lost forest” (Laurance et al. 2015). This phenomenon is not confined to the African continent (Laurance et al. 2014).
The second major driver of decline in central Chimpanzee populations is infectious disease, especially Ebola virus disease (EVD). Surveys carried out from the 1980s to the present day indicate that EVD caused a series of massive great ape die-offs in a large, mostly-intact forested area straddling the border between northeastern Gabon and northwestern Congo, which includes several national parks and logging concessions (Walsh et al. 2003, Maisels et al. 2004, 2013). Since the early 1990s, about 14% of their total area of distribution has been affected by Ebola virus (Ebolavirus). The virus is still present in the region’s forests: thus, as large areas can be affected by each outbreak, and transmission between individuals is rapid (Walsh et al 2007, 2009), large numbers of central Chimpanzees could succumb to this deadly virus within a span of weeks or months. Although both the Sangha and the Ngoko rivers are barriers to great ape movements (Anthony et al. 2007, Fünfstück et al. 2014), Ebolavirus can cross rivers and has already been detected to the east of the major river barrier between Odzala-Kokoua National Park and the Sangha River (Reed et al. 2014), thus a future outbreak in this region is a strong possibility. There is no evidence to date that the recent dramatic Ebola epidemic in West Africa has affected Chimpanzees, although Ebola killed Chimpanzees in Côte d’Ivoire in the mid-1990s (Formenty et al. 1999).
Because Chimpanzees and humans are so similar, Chimpanzees succumb to many diseases that afflict humans. Infectious diseases, including outbreaks of respiratory disease and anthrax, are the main cause of death in several Chimpanzee populations that have been habituated to human presence (e.g., Goodall 1986, Nishida et al. 2003, Hanamura et al. 2006, Leendertz et al. 2006, Köndgen et al. 2008, Humle 2011). If not properly managed, research and tourism present opportunities for disease transmission between humans and Chimpanzees (Gilardi et al. 2015).
For information on threats specific to each taxon, including climate change impacts, see the four Pan troglodytes subspecies accounts.
Pan troglodytes is listed on Appendix I of CITES and as Class A under the African Convention on the Conservation of Nature and Natural Resources. Chimpanzees are protected by national and international laws throughout their range, but enforcement is generally weak. All four subspecies occur in numerous national parks; however, the majority occur outside protected areas (IUCN SSC A.P.E.S. database 2016). Even within protected areas, safe haven is not guaranteed: many protected areas in tropical Africa lack adequate management and suffer from poorly-controlled poaching. Stricter enforcement of wildlife laws and more effective management of what may become the last refuges for many great ape populations are needed urgently.
Conservation needs for Chimpanzees across Africa fall into several broad areas:
Maintaining large, well-protected areas of forest will be key to maintaining Chimpanzee populations in the long term, and this can only be done by a combination of the actions detailed above. The IUCN SSC Primate Specialist Group has published regional conservation action plans for each subspecies of Chimpanzee. The most recent of these documents are Kormos et al. (2003), Plumptre et al. (2010a), Morgan et al. (2011) and IUCN (2014); all are available for download at: www.primate-sg.org/action_plans
|Errata reason:||This is an errata version of the 2016 assessment to remove erroneous italics from the Taxonomic Notes section.|
Adanu, J., Sommer, V. and Fowler, A. 2011. Hunters, fire, cattle. Conservation challenges in eastern Nigeria, with special reference to chimpanzees. In: V. Sommer and C. Ross (eds), Primates of Gashaka: Socioecology and Conservation in Nigeria’s Biodiversity Hotspot, pp. 55–100. Springer, New York.
Ancrenaz, M., Cheyne, S.M., Humle, T. and Robbins, M.M. 2015. Impacts of industrial agriculture on ape ecology. In: Arcus Foundation (ed.), State of the Apes 2015: Industrial Agriculture and Ape Conservation, pp. 165–192. Cambridge University Press, Cambridge, UK.
Anthony, N.M., Johnson-Bawe, M., Jeffery, K., Clifford, S.L., Abernethy, K.A., Tutin, C.E., Lahm, S.A., White, L.J.T., Utley, J.F., Wickings, E.J. and Bruford, M.W. 2007. The role of Pleistocene refugia and rivers in shaping gorilla genetic diversity in central Africa. Proceedings of the National Academy of Sciences of the United States of America 104: 20432–20436.
Boesch, C. and Boesch, H. 1984. Possible causes of sex-differences in the use of natural hammers by wild chimpanzees. Journal of Human Evolution 13: 415–440.
Brncic, T., Amarasekaran, B. and McKenna, A. 2010. Sierra Leone National Chimpanzee Census. September 2010. Tacugama Chimpanzee Sanctuary, Freetown, Sierra Leone.
Butynski, T.M. 2003. The robust chimpanzee Pan troglodytes: Taxonomy, distribution, abundance, and conservation status. In: R. Kormos, C. Boesch, M.I. Bakarr, T.M. Butynski (eds). West African Chimpanzees, Status Survey and Conservation Action Plan, pp. 5-12. IUCN/SSC Primate Specialist Group, Gland, Switzerland and Cambridge, UK.
CITES Secretariat. 2014. Great apes exported from Guinea to China from 2009 to 2011. Available at: https://cites.org/sites/default/files/common/docs/CITES-Guinea-China-great-apes.pdf.
Desclée, B., Hansen, M., Lola Amani, P., Sannier, C., Mertens, B. et al. 2014. Evolution of forest cover at a national and regional scale and drivers of change. In: de Wasseige, C., Flynn, J., Louppe, D., Hiol Hiol, F. and Mayaux, P. (eds), The Forests of the Congo Basin – State of the Forest 2013, pp. 21–46. Weyrich Édition, Neufchâteau, Belgium.
Edwards, D.P., Sloan, S., Weng, L., Dirks, P., Sayer, J. and Laurance, W.F. 2014. Mining and the African environment. Conservation Letters 7(3): 302-311.
Formenty, P., Boesch, C., Wyers, M., Steiner, C., Donati, F., Dind, F., Walker, F. and Le Guenno, B. 1999. Ebola virus outbreak among wild chimpanzees living in a rain forest of Cote d'Ivoire. Journal of Infectious Disease 179(Suppl 1): S120–126.
Fowler, A. and Sommer, V. 2007. Subsistence technology of Nigerian chimpanzees. International Journal of Primatology 28: 997–1023.
Fünfstück, T., Arandjelovic, M., Morgan, D.B., Sanz, C., Breuer, T. et al. 2014. The genetic population structure of wild western lowland gorillas (Gorilla gorilla gorilla) living in continuous rain forest. American Journal of Primatology 76: 868–878.
Fünfstück, T., Arandjelovic, M., Morgan, D.B., Sanz, C., Olson, S.H., Cameron, K., Ondzie, A., Peeters, M. and Vigilant, L. 2015. The sampling scheme matters: Pan troglodytes troglodytes and P. t. schweinfurthii are characterized by clinal genetic variation rather than a strong subspecies break. American Journal of Physical Anthropology 156: 181–191.
Gilardi, K.V., Gillespie, T.R., Leendertz, F.H., Macfie, E.J., Travis, D.A., Whittier, C.A. and Williamson, E.A. 2015. Best Practice Guidelines for Health Monitoring and Disease Control in Great Ape Populations. IUCN SSC Primate Specialist Group, Gland, Switzerland.
Global Forest Watch. 2016. Available at: http://www.globalforestwatch.org/map/6/0.74/15.68/ALL/grayscale/none/581.
Gonder, M.K., Disotell, T.R. and Oates, J.F. 2006. New genetic evidence on the evolution of chimpanzee populations, and implications for taxonomy. International Journal of Primatology 27: 1103–1127.
Gonder, M.K., Locatelli, S., Ghobrial, L., Mitchell, M.W., Kujawski, J.T., Lankester, F.J., Stewart, C-B. and Tishkoff, S.A. 2011. Evidence from Cameroon reveals differences in the genetic structure and histories of chimpanzee populations. Proceedings of the National Academy of Sciences 108: 4766–4771.
Goodall, J. 1986. The chimpanzees of Gombe: Patterns of behavior. Harvard University Press.
Greengrass, E.J. and Maisels, F. 2007. Conservation of the Nigerian-Cameroon chimpanzee P. t. vellerosus (and other mammals) in and around the Banyang-Mbo Wildlife Sanctuary, South-west Province, Cameroon. Wildlife Conservation Society, Yaoundé, Cameroon.
Hakizimana, D. and Huynen, M.-C. 2013. Chimpanzee (Pan troglodytes schweinfurthii) population density and abundance in Kibira National Park, Burundi. Pan Africa News 20: 16–19.
Ham, R. 1998. Nationwide chimpanzee survey and large mammal survey, Republic of Guinea. European Union, Guinea-Conakry.
Hanamura, S., Kiyono, M., Nakamura, M., Sakamaki, T., Itoh, N., Zamma, K., Kitopeni, R., Matumula, M. and Nishida, T. 2006. A new code of observation employed at Mahale: prevention against a flu-like disease. Pan Africa News 13(2): 13-16.
Hicks, C., Darby, L., Hart, J., Swinkels, J., January, N. and Menken, S. 2010. Trade in orphans and bushmeat threatens one of the Democratic Republic of the Congo's most important populations of eastern chimpanzees (Pan troglodytes schweinfurthii). African Primates 7: 1–18.
Hicks, T.C., Tranquilli, S., Kühl, H.S., Campbell, G., Swinkels, J., Darby, L., Boesch, C., Hart, J. and Menken, S.B. 2014. Absence of evidence is not evidence of absence: discovery of a large, continuous population of Pan troglodytes schweinfurthii in the Central Uele region of northern DRC. Biological Conservation 171: 107–113.
Humle, T. 2011. The 2003 epidemic of a flu-like respiratory disease at Bossou. In: T. Matsuzawa, T. Humle and Y. Sugiyama (eds), Chimpanzees of Bossou and Nimba, pp. 325–333. Springer Verlag, Tokyo.
IUCN. 2014. Regional Action Plan for the Conservation of Western Lowland Gorillas and Central Chimpanzees 2015–2025. IUCN SSC Primate Specialist Group, Gland, Switzerland.
IUCN. 2016. The IUCN Red List of Threatened Species. Version 2016-2. Available at: www.iucnredlist.org. (Accessed: 04 September 2016).
IUCN. 2016. The IUCN Red List of Threatened Species. Version 2016-3. Available at: www.iucnredlist.org. (Accessed: 07 December 2016).
IUCN SSC A.P.E.S. database. 2016. Ape Populations, Environments and Surveys database. Leipzig Available at: http://apesportal.eva.mpg.de/database/archiveTable.
IUCN SSC Primate Specialist Group. 2014. Industrial oil palm expansion in great ape habitat in Africa. A policy statement from the Section on Great Apes (SGA) of the IUCN SSC Primate Specialist Group. Available at: http://www.primate-sg.org/position-statements.
Köndgen, S., Kühl, H., N'Goran, P.K., Walsh, P.D., Schenk, S., Ernst, N., Biek, R., Formenty, P., Maetz-Rensing, K., Schweiger, B., Junglen, S., Ellerbrok, H., Nitsche, A., Briese, T., Lipkin, W. I., Pauli, G., Boesch, C. and Leendertz, F.H. 2008. Pandemic human viruses cause decline of endangered great apes. Current Biology 18: 260–264.
Kormos, R. and Boesch, C. (eds). 2003. Regional Action Plan for the Conservation of Chimpanzees in West Africa. IUCN/SSC Primate Specialist Group and Conservation International, Washington D.C.
Kormos, R., Boesch, C., Bakarr, M.I. and Butynski, T.M. (eds). 2003. West African Chimpanzees: Status Survey and Conservation Action Plan. pp. 219. IUCN, Gland.
Kormos, R., Humle, T., Brugière, D. Fleury-Brugière, M.-C., Matsuzawa, T., Sugiyama, Y., Carter, J., Diallo, M.S., Sagno, C. and Tounkara, E.O. 2003. The Republic of Guinea. In: Kormos, R., Boesch, C., Bakkar, M. and Butynski, T.M. (eds), West African Chimpanzees: Status Survey and Conservation Action Plan, pp. 63–76. IUCN, Gland.
Kühl, H., Maisels, F., Ancrenaz, M. and Williamson, E.A. 2008. Best Practice Guidelines for Surveys and Monitoring of Great Ape Populations. IUCN/SSC Primate Specialist Group, Gland, Switzerland.
Langergraber, K.E., Prüfer, K., Rowney, C., Boesch, C., Crockford, C., Fawcett, K., Inoue, E., Inoue-Muruyama, M., Mitani, J.C., Muller, M.N., Robbins, M.M., Schubert, G., Stoinski, T.S., Viola, B., Watts, D., Wittig, R.M., Wrangham, R.W., Zuberbühler, K., Pääbo, S. and Vigilant, L. 2012. Generation times in wild chimpanzees and gorillas suggest earlier divergence times in great ape and human evolution. Proceedings of the National Academy of Sciences 109: 15716–15721.
Lanjouw, A. 2014. Mining/oil extraction and ape populations and habitats. In: Arcus Foundation (ed.), State of the Apes 2013: Extractive Industries and Ape Conservation, pp. 127–161. Cambridge University Press, Cambridge, UK.
Laporte, N.T., Stabach, J.A., Grosch, R., Lin, T.S. and Goetz, S.J. 2007. Expansion of industrial logging in Central Africa. Science 316: 1451.
Laurance, W.F., Clements, G.R., Sloan, S., O/'Connell, C.S., Mueller, N.D., Goosem, M., Venter, O., Edwards, D.P., Phalan, B., Balmford, A., Van Der Ree, R. and Arrea, I.B. 2014. A global strategy for road building. Nature 513: 229–232.
Leciak, E., Hladik, A. and Hladik, C.M. 2005. The oil palm (Elaeis guineensis) and the cores of high biodiversity in gallery forests of Guinea in relation to human and chimpanzees commensalism. Revue d’Ecologie (Terre et Vie) 60: 179–184.
Leendertz, F.H., Pauli, G., Maetz-Rensing, K., Boardman, W., Nunn, C. et al. 2006. Pathogens as drivers of population declines: the importance of systematic monitoring in great apes and other threatened mammals. Biological Conservation 131: 325–337.
Maisels, F., Ambahe, E., Ambassa, R., Nyemgah Yara C. and Fosso, B. 2009. Great ape and human impact monitoring in the Mbam et Djerem National park, Cameroon. Final report to USFWS. Wildlife Conservation Society, New York.
Maisels, F., Ella Akou, M., Douckaga, M. and Moundounga, A. 2004. Mwagne National Park, Gabon: large mammals and human impact. WCS/WWF Gabon.
Maisels, F., Strindberg, S., Kiminou, F., Ndzai, C., Ngounga, R. et al. 2013. Wildlife and Human Impact Survey 2012, and monitoring 2005–2008–2012. Odzala-Kokoua National Park, Republic of Congo. Fondation Odzala-Kokoua and Wildlife Conservation Society, Brazzaville, Congo.
Matsuzawa, T., Humle, T. and Sugiyama, Y. (eds). 2011. Chimpanzees of Bossou and Nimba. Springer Verlag, Tokyo.
Mitani, J.C. and Watts, D.P. 2005. Correlates of territorial boundary patrol behaviour in wild chimpanzees. Animal Behaviour 70: 1079–1086.
Mitchell M.W., Locatelli S., Ghobrial L., Pokempner, A.A., Sesink Clee, P.R., Abwe, E.E., Nicholas, A., Nkembi, L., Anthony, N.M., Morgan, B.J., Fotso, R., Peeters, M., Hahn, B.H. and Gonder, M.K. 2015a. The population genetics of wild chimpanzees in Cameroon and Nigeria suggests a positive role for selection in the evolution of chimpanzee subspecies. BMC Evolutionary Biology 15: 3.
Morgan, B., Adeleke, A., Bassey, T., Bergl, R., Dunn, A., Fotso, R., Gadsby, E., Gonder, K., Greengrass, E., Koulagna, D.K., Mbah, G., Nicholas, A., Oates, J., Omeni, F., Saidu, Y., Sommer, V., Sunderland-Groves, J., Tiebou, J. and Williamson, E.A. 2011. Regional Action Plan for the Conservation of the Nigeria-Cameroon Chimpanzee (Pan troglodytes ellioti). IUCN/SSC Primate Specialist Group and Zoological Society of San Diego, San Diego.
Morgan, D. and Sanz, C. 2007. Best Practice Guidelines for Reducing the Impact of Commercial Logging on Great Apes in Western Equatorial Africa. IUCN/SSC Primate Specialist Group, Gland, Switzerland.
Morgan, D., Sanz, C., Greer, D., Rayden, T., Maisels, F. and Williamson, E.A. 2013. Great Apes and FSC: Implementing ‘Ape Friendly’ Practices in Central Africa’s Logging Concessions. IUCN/SSC Primate Specialist Group, Gland, Switzerland.
Newton-Fisher, N.E. 2003. The home range of the Sonso community of chimpanzees from the Budongo Forest, Uganda. African Journal of Ecology 41: 150–156.
Nishida, T., Corp, N., Hamai, M., Hasegawa, T., Hiraiwa-Hasegawa, M., Hosaka, K., Hunt, K. D., Itoh, N., Kawanaka, K., Matsumoto-Oda, A., Mitani, J. C., Nakamura, M., Norikoshi, K., Sakamaki, T., Turner, L., Uehara, S. and Zamma, K. 2003. Demography, female life history, and reproductive profiles among the chimpanzees of Mahale. American Journal of Primatology 59: 99-121.
Oates, J. 2006. Is the chimpanzee, Pan troglodytes, an endangered species? It depends on what ‘‘endangered’’ means. Primates 47: 102–112.
Ogunjemite, B.G., Ashimi, T.A., Adeleke, A. and Okeyoyin, O.A. 2010. Population status of the Nigerian chimpanzee (Pan troglodytes ellioti) in Gashaka-Mambilla Region, Nigeria. Journal of Sustainable Technology 1: 52–59.
Piel, A.K., Cohen, N., Ndimuligo, S.A., Pintea, L. and Stewart, F.A. 2015. Population status of chimpanzees in the Masito-Ugalla Ecosystem, Tanzania. American Journal of Primatology 77: 1027–1035.
Plumptre, A.J., Akwetaireho, S., Hanni, D.C., Leal, M., Mutungire, M., Kyamanywa, J., Tumuhamye, D., Johnson, A. and Isoke, S. 2010b. Biodiversity Surveys of Bugoma Forest Reserve, Smaller Central Forest Reserves, and Corridor Forests South of Bugoma. Report to UNDP/GEF project UG0031.01. Wildlife Conservation Society, Kampala, Uganda.
Plumptre A.J., Cox D. and Mugume, S. 2003a. The Status of Chimpanzees in Uganda. Albertine Rift Technical Report Series. Wildlife Conservation Society, Kampala, Uganda.
Plumptre, A.J., Nixon, S., Critchlow, R., Vieilledent, G., Nishuli, R., Kirkby, A., Williamson, E.A., Hall, J.S. and Kujirakwinja, D. 2015. Status of Grauer’s Gorilla and Chimpanzee in eastern Democratic Republic of Congo: Historical and Current Distribution and Abundance. Wildlife Conservation Society, Fauna & Flora International and Institut Congolais pour la Conservation de la Nature, New York.
Plumptre, A.J., Rose, R., Nangendo, G., Williamson, E.A., Didier, K., Hart, J., Mulindahabi, F., Hicks, C., Griffin, B., Ogawa, H., Nixon, S., Pintea, L., Vosper, A., McClennan, M., Amsini, F., McNeilage, A., Makana, J.R., Kanamori, M., Hernandez, A., Piel, A., Stewart, F., Moore, J., Zamma, K., Nakamura, M., Kamenya, S., Idani, G., Sakamaki, T., Yoshikawa, M., Greer, D., Tranquilli, S., Beyers, R., Furuichi, T., Hashimoto, C. and Bennett, E. 2010a. Eastern Chimpanzee (Pan troglodytes schweinfurthii): Status Survey and Conservation Action Plan 2010–2020. IUCN/SSC Primate Specialist Group, Gland, Switzerland.
Prado-Martinez, J., Sudmant, P.H., Kidd, J.M., Li H., Kelley J.L. et al. 2013. Great ape genetic diversity and population history. Nature 499: 471–475.
Quiatt, D., Reynolds, V. and Stokes, E.J. 2002. Snare injuries to chimpanzees (Pan troglodytes) at 10 study sites in East and West Africa. African Journal of Ecology 40: 303–305.
Reed, P.E., Cameron, K.N., Ondzie, A.U., Joly, D., Karesh, W.B. et al. 2014. A new approach for monitoring Ebolavirus in wild great apes. PLoS Neglected Tropical Diseases 8: e3143.
Rival, A. and Levang, P. 2014. Palms of Controversies: Oil Palm and Development Challenges. CIFOR, Bogor, Indonesia.
Ruysschaert, D. and Rainer, H. 2015. From process to impact of a voluntary standard: the roundtable on sustainable palm oil. In: Arcus Foundation (ed.), Industrial Agriculture and Ape Conservation: State of the Apes 2015, pp. 135–163. Cambridge University Press, Cambridge, UK.
Samson, D.R. and Hunt, K.D. 2012. A thermodynamic comparison of arboreal and terrestrial sleeping sites for dry-habitat chimpanzees (Pan troglodytes schweinfurthii) at the Toro-Semliki Wildlife Reserve, Uganda. American Journal of Primatology 74: 811–818.
Sop, T., Cheyne, S.M., Maisels, F.G., Wich, S.A. and Williamson, E.A. 2015. Abundance annex: ape population abundance estimates. In: Arcus Foundation (ed.), State of the Apes 2015: Industrial Agriculture and Ape Conservation, pp. 1–41. Cambridge University Press, Cambridge, UK.
Sop, T., Mundry, R., Colleen, S. and Kühl, H.S. In prep. Report on estimated trends in abundance of western chimpanzees (Pan troglodytes verus).
Sousa, J., Barata, A.V., Sousa, C., Casanova, C.C.N. and Vicente, L. 2011. Chimpanzee oil-palm use in Southern Cantanhez National Park, Guinea-Bissau. American Journal of Primatology 73: 485–497.
Strindberg, S., Maisels, F. et al. In prep. Guns, germs and trees: key factors influencing the status of gorillas and chimpanzees in Western Equatorial Africa.
Tutin, C.,Stokes, E., Boesch, C., Morgan, D., Sanz, C., Reed, T., Blom, A., Walsh, P., Blake, S. and Kormos, R. 2005. Regional Action Plan for the Conservation of Chimpanzees and Gorillas in Western Equatorial Africa. IUCN/SSC Primate Specialist Group and Conservation International, Washington DC.
Tweh, C.G., Lormie, M.M., Kouakou, C.Y., Hillers, A., Kuhl, H.S. and Junker, J. 2015. Conservation status of chimpanzees Pan troglodytes verus and other large mammals in Liberia: a nationwide survey. Oryx 49: 710–718.
Walsh, P.D., Abernethy, K.A., Bermejo, M., Beyersk, R., De Wachter, P., Akou, M.E., Huijbregts, B., Mambounga, D.I., Toham, A.K., Kilbournk, A.M., Lahmq, S.A., Latourk, S., Maiselsk, S.F., Mbinak, C., Mihindouk, Y., Obiang, S.N., Effa, E.N., Starkeyk, M. 2003. Catastrophic ape decline in western equatorial Africa. Nature 422: 611–614.
Walsh, P.D., Bermejo, M. and Rodriguez-Teijeiro, J.D. 2009. Disease avoidance and the evolution of primate social connectivity: Ebola, bats, gorillas, and chimpanzees. In: M.A. Huffman and C.A. Chapman (eds), Primate Parasite Ecology: The Dynamics and Study of Host–Parasite Relationships, pp. 183–198. Cambridge University Press, Cambridge, UK.
Walsh, P.D., Biek, R. and Real, L.A. 2005. Wave-like spread of Ebola Zaire. PLoS Biology 3: 1946–1953.
Walsh, P.D., Breuer, T., Sanz, C., Morgan, D. and Doran-Sheehy, D. 2007. Potential for Ebola transmission between gorilla and chimpanzee social groups. American Naturalist 169: 684–689.
Wanyama, F., Muhabwe, R., Plumptre, A.J., Chapman, C.A. and Rothman, J.M. 2009. Censusing large mammals in Kibale National Park: evaluation of the intensity of sampling required to determine change. African Journal of Ecology 48: 953–961.
WCF. 2012. Etat de la faune et des ménaces dans les aires protégées terrestres et principales zones de forte biodiversité de République de Guinée. Wild Chimpanzee Foundation, Conakry, Guinea.
Wich, S.A., Garcia-Ulloa, J., Kühl, H.S., Humle, T., Lee, J.S. and Koh, L.P. 2014. Will oil palm's homecoming spell doom for Africa's great apes? Current Biology 24: 1659–1663.
Williamson, E.A., Maisels, F.G., Groves, C.P., Fruth, B., Humle, T.H., Morton, F.B., Richardson, M.C., Russon, A. and Singleton, I. 2013. Hominidae. In: R.A. Mittermeier, A.B. Rylands and D.E. Wilson (eds), Handbook of the Mammals of the World, pp. 792–854. Lynx Edicions, Barcelona, Spain.
Zimmerman, B.L. and Kormos, C.F. 2012. Prospects for sustainable logging in tropical forests. BioScience 62: 479–487.
|Citation:||Humle, T., Maisels, F., Oates, J.F., Plumptre, A. & Williamson, E.A. 2016. Pan troglodytes (errata version published in 2016). The IUCN Red List of Threatened Species 2016: e.T15933A102326672.Downloaded on 25 February 2018.|
|Feedback:||If you see any errors or have any questions or suggestions on what is shown on this page, please provide us with feedback so that we can correct or extend the information provided|