After the broader great ape story unfolded, and after the human line split from the chimpanzee-bonobo line about 7 million years ago, the genus Pan continued along its own path. Around 1.5 to 2 million years ago, ancient African ape populations gave rise to the two living species we now know as chimpanzees and bonobos.

This pivotal moment unfolded roughly 5 million years after our last common ancestor with chimpanzees and bonobos took a different evolutionary road. As with so many chapters in primate evolution, the stage was Africa: the cradle of humans, chimpanzees, bonobos, gorillas, and so much of the great ape story.

This era does not mark the beginning of chimp-like intelligence, but it does mark the modern split within the chimpanzee family. North of the Congo River, the common chimpanzee continued its path. South of it, the bonobo evolved along a gentler but equally fascinating road. One ancestral family became two living cousins.

Chimpanzees are smart. Very smart. They use tools, learn socially, cooperate, deceive, comfort, and wage conflict. But compared with early Homo, especially Homo habilis around 2.3 million years ago, they were likely still on a different cognitive path. Homo habilis had a larger average brain and is strongly associated with early stone tools, while chimpanzees and bonobos remained brilliant forest apes with rich but more limited tool cultures.