The chimpanzee (Pan troglodytes) is one of humanity’s closest living relatives. This species is indigenous solely to the continent of Africa, occupying a discontinuous belt that spans from West Africa eastward to the Great Rift Valley. Their presence is fragmented, constrained by both natural geography and human influence. The distribution of this species is most accurately mapped by examining the distinct territories of its four recognized subspecies.
Distribution by Subspecies
The geographical extent of chimpanzees is divided into four main regions, each corresponding to a genetically distinct subspecies. These subspecies were historically separated by major geographical features like rivers. The Western chimpanzee (Pan troglodytes verus) occupies the furthest reach, with populations found in Senegal, Guinea-Bissau, Guinea, Sierra Leone, Liberia, Côte d’Ivoire, and Ghana. This subspecies is geographically isolated from other groups by the Dahomey Gap, a dry savanna corridor.
East of this dry zone, the Nigeria-Cameroon chimpanzee (P. t. ellioti) is restricted to a small area in Nigeria and central-western Cameroon. This population is separated from the Central chimpanzee group by the Sanaga River, a natural barrier. The Central chimpanzee (P. t. troglodytes) has the largest range, covering much of the Congo Basin in Cameroon, Equatorial Guinea, Gabon, the Republic of the Congo, and the Democratic Republic of the Congo (DRC).
The Ubangi River serves as the primary northern boundary separating the Central and Eastern subspecies. The Eastern chimpanzee (P. t. schweinfurthii) occupies the easternmost distribution, with populations scattered across the DRC, the Central African Republic, South Sudan, Uganda, Rwanda, Burundi, and Tanzania.
Specific Ecosystems and Habitat Types
Chimpanzees inhabit a diverse array of environments. The most preferred habitat is the dense, lowland tropical rainforest, particularly within the Congo Basin, which offers an abundant supply of fruit, leaves, and nesting materials. These multi-layered forests allow them to be highly arboreal; much of their foraging and all their sleeping is done in high-altitude tree nests.
Their adaptability allows them to thrive in more marginal areas, including montane forests found at higher elevations, sometimes up to 2,750 meters above sea level. These higher-altitude forests, such as those in Uganda and Tanzania, still provide the necessary tree cover and food sources. Moving away from the equatorial core, some populations have adapted to life in savanna-forest mosaics, characterized by mixed grasslands and scattered woodlands.
In these drier, more open savanna habitats, chimpanzees spend more time on the ground to travel between fragmented patches of woodland. These areas still require a sufficient density of trees to provide food and secure sites for nightly nesting. The presence of permanent water sources is also a prerequisite, supporting the vegetation they rely on and meeting hydration needs.
Factors Limiting Their Current Range
The discontinuous distribution of chimpanzees results from both natural geographic history and increasing human pressure. While rivers and ecological barriers created the initial subspecies divisions, the most severe limitation is habitat fragmentation. Continuous forest cover is broken up by human activities, turning large, connected habitats into isolated patches.
Fragmentation severely restricts the movement of chimpanzee communities, preventing them from accessing distant food resources or interbreeding. The resulting small, isolated groups are genetically vulnerable and cannot easily shift their range in response to environmental changes. Human population density is another defining factor, as chimpanzees are typically absent from areas with high human settlement, even if the habitat is otherwise suitable.
The construction of roads and other infrastructure further exacerbates this isolation, acting as barriers that prevent dispersal and gene flow between forest blocks. The geographical constraints on the chimpanzee’s current existence are predominantly driven by the human footprint.