Bonobo apes are a good example of speciation.

speciation: The evolution of new populations that are reproductively isolated from other populations.

Genetic sequence could solve mystery of why bonobos are more peaceful than other chimpanzees.

When the Congo River in central Africa formed, a group of apes was forever stranded on its southern banks. Two million years later, the descendants of these apes — the bonobos — have developed distinct social patterns. Unlike their chimpanzee relatives on the northern shore, they shun violent male dominance and instead forge bonds through food-sharing, play and casual sex.

Humans, chimps and bonobos all share a common ancestor that lived about 6 million years ago in Africa, when the human lineage splintered off. By the time that our Homo erectus ancestors were roaming the African savannah 2 million to 1.5 million years ago, populations of the common ancestor of chimpanzees and bonobos had been separated by the Congo River.

Nature.com suggested bonobos evolved to make love instead making war because on their side of the Congo River there was no competition from gorillas for food.