The chimpanzee is not just our closest living relative — it is the species that changed our understanding of what it means to be human. Tool use, culture, warfare, empathy, deception, language acquisition — every one of these capacities, once thought uniquely human, has been documented in wild chimpanzee populations. Uganda holds the largest chimpanzee population in East Africa, and Kibale National Park offers the most reliable wild chimpanzee encounters in the world. Here is everything science currently knows about the species that shares 98.7 percent of our DNA.
Taxonomy and Distribution
Chimpanzees (Pan troglodytes) are divided into four subspecies: the western (P. t. verus), Nigerian-Cameroon (P. t. ellioti), central (P. t. troglodytes), and eastern chimpanzee (P. t. schweinfurthii). Uganda’s population belongs to the eastern subspecies, which has the widest range of any subspecies, extending from Uganda and Tanzania through Rwanda, Burundi, and DRC into Central Africa. The total wild chimpanzee population is estimated at between 172,000 and 300,000 individuals — a significant decline from historical numbers due to habitat loss and hunting.
Chimpanzees are the closest living relatives of both humans and bonobos (Pan paniscus), the three species forming a closely related clade. The common ancestor of humans and chimpanzees existed approximately 6 to 8 million years ago. Of the approximately 35,000 protein-coding genes in the human genome, around 98.7 percent are shared with chimpanzees — the genetic divergence between the two species is smaller than that between some species of birds that look nearly identical.
Intelligence and Tool Use
Chimpanzees are among the most cognitively complex non-human animals on Earth. In the 1960s, Jane Goodall’s groundbreaking observations at Gombe Stream in Tanzania documented chimpanzees modifying grass stems to extract termites from mounds — the first documented tool use in a non-human species. The discovery prompted Louis Leakey’s famous response: “Now we must redefine tool, redefine man, or accept chimpanzees as humans.”
Since Goodall’s discovery, dozens of tool use behaviours have been documented across different chimpanzee populations. Chimpanzees in West Africa use stone hammers and anvils to crack open hard-shelled nuts — a behaviour that takes young chimpanzees years to master and constitutes a form of cultural transmission. Different populations use different tools for different purposes, and these traditions vary by region — a phenomenon researchers call chimpanzee culture.
Problem Solving and Memory
Laboratory studies have demonstrated that chimpanzees have exceptional short-term memory, in some tasks outperforming human adults. In one famous experiment, Japanese chimpanzees (particularly Ayumu at Primate Research Institute) could memorise the positions of numbers on a screen in a fraction of a second and reproduce the sequence correctly — a capacity far exceeding the human average. Chimpanzees can learn symbolic communication systems, solve multi-step problems, and demonstrate planning behaviour by selecting tools hours before they are needed.
Social Structure and Community Life
Chimpanzees live in communities of typically 15 to 150 individuals, organised around a fission-fusion social system — the community ranges over a large territory together but regularly splits into smaller parties for foraging and social interaction. The composition of parties changes daily or even hourly. A community has a dominance hierarchy among males, typically led by an alpha male who achieves and maintains status through coalition-building, displays, and sometimes physical aggression.
Female chimpanzees have a more peripheral relationship with the core group and often forage in smaller, more stable subgroups with their offspring. Young chimpanzees remain closely associated with their mothers for the first several years of life and maintain long-term bonds with siblings throughout adulthood. Social bonds between individuals are reinforced through mutual grooming, which serves both a hygienic function and a social bonding role.
Warfare and Territorial Behaviour
Chimpanzees are one of the few non-human species that engage in what can accurately be called warfare — coordinated, lethal attacks by one community against members of another. Goodall’s long-term observations at Gombe documented the Kasekela community systematically killing all members of a neighbouring Kahama community over a period of years. Similar inter-community violence has been documented at multiple sites. The behaviour is not universal but occurs in some populations, particularly where territory and resources are contested.
Communication and Language
Chimpanzees communicate through a rich vocabulary of vocalisations, facial expressions, body postures, and gestures. The pant-hoot — a distinctive call that begins with soft hoots and builds to loud screams — is used to communicate over distances and to coordinate group movements. Individual pant-hoots are distinguishable between individuals and serve as a form of identity communication. Chimpanzees have alarm calls that specify the type of predator, contact calls, food calls, and a variety of social vocalisations.
In captivity, chimpanzees have been taught to communicate using American Sign Language, symbol boards, and computer interfaces, achieving vocabularies of hundreds of signs or symbols and demonstrating the ability to combine them in novel ways. While debate continues about whether this constitutes true language, the cognitive capacity for symbolic communication is not in question.
Chimpanzees in Uganda
Uganda holds an estimated 5,000 eastern chimpanzees — the largest national population in East Africa. Kibale National Park is the premier site, with approximately 1,500 individuals including several habituated communities that allow trekking encounters. The Ngogo community in Kibale is one of the largest and most studied chimpanzee communities in the world, with over 200 individuals. Budongo Forest, Bwindi, and Kyambura Gorge also have resident populations.
Kibale chimpanzee trekking allows up to one hour with a habituated community, guided by researchers and rangers. Encounters are among the most intense wildlife experiences available in Africa — chimpanzees are fast, loud, and physically compelling in a way that reminds you at every moment of their relationship to us. Watching them move through the canopy, watching a mother nurse her infant, watching a male display for dominance, you understand the 98.7 percent not as an abstraction but as something you can see with your own eyes.
