Chimpanzee

The chimpanzee is a species of great ape native to the woodlands and savannahs of tropical Africa. One of only two living members of the genus Pan, alongside the bonobo, it is widely recognised as humanity’s closest living relative. Its biology, behaviour, and evolutionary history make it a central subject in primatology, anthropology, and conservation science. Populations across equatorial Africa demonstrate considerable regional variation, reflected today in several formally recognised subspecies.

Taxonomy, Naming, and Evolutionary Context

The English term chimpanzee dates from the eighteenth century and is derived from Central African languages with meanings equivalent to “ape” or “mock-man”. The generic name Pan has mythological associations, while the species name troglodytes refers to a legendary cave-dwelling people described in classical sources.
Early Western scientific descriptions of African apes date to the seventeenth century, although initial accounts often conflated orangutans, chimpanzees, and bonobos. By the late eighteenth century, anatomists had distinguished the African apes from Asian species, culminating in the classification of the chimpanzee within the genus Pan in 1816. The bonobo was formally recognised as a separate species in 1933.
The evolutionary divergence between humans and the genus Pan is estimated to have occurred around eight million years ago. Subsequent divergence between chimpanzees and bonobos took place roughly two million years ago. Fossil evidence for the genus Pan is scarce; nevertheless, discoveries in East Africa indicate its presence in regions also associated with early human evolution. Recent genetic analyses reveal episodes of genetic exchange among ancestral chimpanzee and bonobo lineages, contributing to present-day population differentiation.

Subspecies and Geographic Distribution

Four subspecies of Pan troglodytes are widely acknowledged, with a possible fifth proposed by some primatologists. Their ranges extend across West and Central Africa, often separated by major rivers or ecological zones:

• Central chimpanzee (P. t. troglodytes) inhabits Cameroon, Gabon, Equatorial Guinea, the Republic of the Congo, and parts of the Democratic Republic of the Congo. It is among the more numerous subspecies.
• Western chimpanzee (P. t. verus) occurs from Senegal to Ivory Coast and has experienced severe population declines.
• Nigeria–Cameroon chimpanzee (P. t. ellioti) lives in fragmented forests of eastern Nigeria and western Cameroon, forming the most restricted and least numerous subspecies.
• Eastern chimpanzee (P. t. schweinfurthii) ranges across the Democratic Republic of the Congo, Uganda, Rwanda, Burundi, Tanzania, South Sudan, and Zambia.
• Southeastern chimpanzee (P. t. marungensis), proposed on morphological and genetic grounds, comprises southern populations of the eastern chimpanzee but is not formally recognised by all authorities.

Across these regions, combined wild numbers are estimated between 170,000 and 300,000 individuals, although local populations vary considerably in stability and density.

Anatomy and Physical Characteristics

Chimpanzees possess a robust build, though less massive than that of gorillas. Adults typically stand around one to one and a half metres tall when upright. Males are larger than females, with strong sexual dimorphism evident in body mass and canine tooth size. Limbs are adapted for climbing and knuckle-walking, with arms longer than legs, elongated fingers, and grasping feet.
Body hair is coarse and usually black but may appear brown or ginger in some individuals. Hair is absent from the face, fingers, palms, toes, and soles. Patterns of skin pigmentation vary geographically: western chimpanzees often show dark facial pigmentation, while eastern and central populations may exhibit mottled or light facial tones that change with age. Ageing individuals commonly display greying patches, especially on the chin.
The skull features a prominent brow ridge, prognathous face, and rounded braincase. Unlike gorillas, chimpanzees lack a sagittal crest. Their dental formula is typical of great apes, comprising incisors, canines, premolars, and molars suited to an omnivorous diet.

Genetics and Genomic Insights

The sequencing of the chimpanzee genome in 2005 established a genetic architecture remarkably close to that of humans. Both species share similar gene counts, and protein-coding sequences show high homology, with many proteins differing by only a few amino acids. While point mutations contribute to genomic divergence, structural changes such as duplications and deletions account for a substantial proportion of genetic differences. These insights continue to inform studies of human evolution, cognition, and disease.

Behaviour, Social Structure, and Cognition

Chimpanzee societies are multi-male, multi-female communities ranging from 15 to over 100 individuals. Within these communities, social organisation is fluid, with members forming temporary foraging groups during daily activities. Social hierarchy is dominated by males, often led by an alpha male who maintains status through alliances, displays, and social intelligence rather than persistent aggression.
Females and their offspring form enduring relationships, with mothers providing intensive care for several years. Infants are weaned at around three years of age but may remain close to their mothers into adolescence.
Chimpanzees are renowned for tool use and manufacture. Populations use sticks to extract termites, leaves to sponge water, stones to crack nuts, and sharpened sticks to hunt small mammals. Such behaviours exhibit cultural variation, passed through social learning rather than genetic inheritance.
Communication involves vocalisations, gestures, facial expressions, and postures. Attempts to teach human sign languages to captive chimpanzees have demonstrated limited symbolic acquisition but have significantly advanced the study of primate cognition.

Locomotion and Ecological Adaptations

Chimpanzees are both arboreal and terrestrial. They climb vertically, brachiate through trees, and travel on the ground using knuckle-walking, though bipedal locomotion appears in short bouts. Their ecological flexibility allows them to inhabit dense rainforests, woodland mosaics, and open savannah–forest interfaces.
Diet is omnivorous, incorporating fruits, leaves, insects, and occasionally vertebrate prey. Cooperative hunting of small mammals, including monkeys, has been documented in several populations.

Conservation Status and Human Interactions

Listed as endangered by the International Union for Conservation of Nature (IUCN), the chimpanzee faces significant threats across its range. Habitat destruction due to agriculture, logging, and infrastructure development fragments populations. Poaching for bushmeat and illegal wildlife trade poses severe risks, as do outbreaks of infectious diseases.
Chimpanzees have long appeared in Western popular culture, particularly in entertainment contexts that presented them as comic or childlike figures. However, increased awareness of their strength, unpredictability, and complex needs has led to sharp declines in their use in performance and captivity. Within research settings, hundreds were once used in biomedical laboratories; many countries have since severely restricted or banned such practices.