Chimpanzee vs Bonobo: Behavior, Looks and Key Differences

Key differences at a glance

The chimpanzee and the bonobo are the only two species in the genus Pan and humanity’s closest living relatives. Their ancestors separated roughly 1 to 2 million years ago, probably when populations were split by the Congo River, and neither ape can swim. They look alike at first glance, but they differ in build, face, social life, behavior and range.

Bonobos were first described in 1929 from a skull and recognized as a full species in 1933. They are sometimes still called “pygmy chimpanzees,” a misleading name because the two species are close in size.

Range: on either side of the Congo River

Chimpanzees live across a wide belt of equatorial Africa, from Senegal and Guinea in the west through Nigeria, Cameroon, Gabon and the Republic of the Congo to Uganda, Rwanda and western Tanzania. They use many habitats, from rainforest to dry savanna woodland.

Bonobos live only in the Democratic Republic of the Congo, in the lowland rainforests south of the great bend of the Congo River, bordered by the Kasai River system to the south. Their range covers about 500,000 km² (190,000 sq mi), but they are patchily distributed within it. Nowhere do the two species live side by side. More on their home in Where do bonobos live?

Build and face

The two species overlap broadly in weight. Wild chimpanzees weigh about 26–70 kg (57–154 lb), with males heavier than females, and bonobos about 27–61 kg (60–134 lb). The difference is in shape:

• Bonobos have a slimmer upper body, narrower shoulders, a thinner neck and relatively long legs. These proportions give them a more humanlike posture when they stand upright.
• Chimpanzees are more robust, with a heavier head, a more prominent brow ridge and larger ears.

The face is the easiest clue. Bonobos have black faces from birth, pink lips and long, fine head hair that often looks neatly parted in the middle. Young chimpanzees have pale or pinkish faces that usually darken with age. Bonobos also keep a white tuft of hair on the rump into adulthood, while chimpanzees usually lose it as they grow up.

Social life: male-led vs female-led

Both species live in communities that split into smaller, changing parties during the day. The difference is in who holds power.

In chimpanzee communities, adult males are dominant. They form a strict rank order, compete for the alpha position and build alliances with each other. Females usually rank below males and spend much time foraging alone with their offspring.

In bonobo communities, females form strong bonds and alliances, even though most of them have moved in from other groups. Together they can dominate males, control access to the best food and protect each other from harassment. A male’s status depends heavily on his mother, who supports him throughout his life. Most bonobo groups are led by a coalition of senior females with a few high-ranking males.

Aggression and peacemaking

Chimpanzee males patrol their territory and sometimes attack and kill members of neighboring communities. A 2014 study that pulled together decades of data from 18 chimpanzee communities and 4 bonobo communities recorded more than 150 killings by chimpanzees and only a single suspected killing by bonobos. The authors concluded that lethal aggression is a natural strategy in chimpanzees rather than a reaction to human disturbance.

Bonobos are much less violent, and meetings between neighboring bonobo groups are often relaxed, with grooming, play and food sharing. Bonobos use sexual contact, between and within sexes, to ease tension, reconcile after conflicts and bond. They are not perfect pacifists, though: males compete fiercely and can be badly injured. See Why are bonobos called the peaceful ape?

Voices and communication

Both apes communicate with calls, gestures, facial expressions and touch, but they sound different. The chimpanzee’s signature call is the pant-hoot, a series of hoots rising to a loud climax that carries far through the forest. Bonobo calls are noticeably higher-pitched, partly because bonobos have a shorter voice box, and the two species can usually be told apart by ear. Both species use dozens of hand and body gestures, many of them shared.

Diet, hunting and tools

Both apes eat mostly ripe fruit, along with leaves, pith, seeds and insects. Bonobos also eat a lot of herbs and shoots from the forest floor, which are abundant in their range and may be one reason they can travel in larger, more stable groups with less competition.

Chimpanzees hunt more often, especially monkeys such as red colobus, and the hunters are mostly males. Bonobos hunt duikers, flying squirrels and other small mammals, and have occasionally been seen catching monkeys; females sometimes take part in and control the hunts.

Chimpanzees are among the most skilled tool users of any animal, fishing for termites, dipping for ants and cracking nuts with stones. Wild bonobos use tools much less, for example using leaves as rain covers, although captive bonobos can learn complex tool tasks.

Which is closer to humans, and can they interbreed?

Neither species is closer to us. Humans, chimpanzees and bonobos share a common ancestor that lived roughly 6–8 million years ago, and the two Pan species split long after that. Humans are therefore equally related to both, and both share about 98.7–98.8 percent of their DNA letters with us. See How much DNA do we share with chimpanzees?

In captivity, chimpanzees and bonobos have produced hybrid offspring. In the wild, the Congo River separates them today, but genome studies show that genes flowed between the two species on at least two occasions within the last 550,000 years or so, mostly into the ancestors of central and eastern chimpanzees.

Conservation status

Both species are listed as Endangered on the IUCN Red List. Chimpanzees are far more numerous, with an estimated 170,000–300,000 animals spread over many countries. Bonobos number far fewer, probably a few tens of thousands, and all live in one country, where war, bushmeat hunting and forest loss have hit them hard. Their limited range and the difficulty of surveying remote forests make bonobos especially vulnerable.