The closest living species to modern humans are not monkeys. They are the two living species in the genus Pan: chimpanzees and bonobos. If you want the cleanest answer, say “chimpanzees and bonobos,” not just “chimpanzees.”

That answer can feel a little surprising because people often hear only about chimpanzees. But bonobos are just as important. A Nature paper on the bonobo genome begins by saying that the two African apes, chimpanzees and bonobos, are the closest living relatives of humans.

This does not mean humans came from today’s chimpanzees or today’s bonobos. That is a common misunderstanding. Humans, chimpanzees, and bonobos are more like cousins. We share an older ancestor, and the different lineages changed in different directions after they split.

Nature Education explains that humans shared a common ancestor with chimpanzees and bonobos sometime around 6 million years ago. The exact family tree is complicated, but the main idea is simple: the connection is evolutionary cousinship, not a straight parent-child line.

Chimpanzees and bonobos are also close to each other. The bonobo genome paper says chimpanzees and bonobos are estimated to have shared a common ancestor about one million years ago. So from a family-tree point of view, humans are one branch, while chimpanzees and bonobos are two very close branches on the Pan side.

Genomes tell the same story. The bonobo genome study reports that one bonobo genome was about 98.7 percent identical to corresponding human genome sequences in single-copy autosomal regions. Duke’s Evolutionary Anthropology department gives the broader classroom version: bonobos and chimpanzees both share close to 98 percent of their genomes with humans. Those numbers are useful, but they should not be read as “humans are basically chimpanzees.” Small DNA differences can have large effects, and genomes are compared in several different ways.

Behavior makes the answer feel even more interesting. Chimpanzees and bonobos are equally close to humans, but they are not interchangeable animals. The Duke page says they differ significantly in morphology, behavior, emotions, and cognition, then gives examples such as chimpanzee tool use and cooperative hunting, while bonobos are described with different social patterns.

So the best answer is: our closest living relatives are chimpanzees and bonobos together. They are not primitive humans, and humans are not improved chimpanzees. We are three living branches from a deeper evolutionary family tree, with chimpanzees and bonobos standing nearest to us among species alive today.

References

1. Overview of Hominin Evolution – Nature Education
2. The bonobo genome compared with the chimpanzee and human genomes – Nature
3. What is a Bonobo? – Duke Evolutionary Anthropology

Explore More

• Are humans more similar to chimpanzees or bonobos?
• Why are chimpanzees and bonobos so different from each other?
• Did humans evolve from monkeys?
• What does it mean to share 98 percent of DNA?
• When did the human lineage split from other apes?