How This River Made Chimps Violent

A population of apes was divided by the expanding Congo River, leading to two distinct environments. The northern apes faced competition from gorillas and had fewer ground plants, promoting aggressive behavior for survival and mating. In contrast, the southern apes had abundant resources, favoring amiable behavior. Over generations, these behavioral adaptations led to the evolution of two species: aggressive chimpanzees in the north and friendly bonobos in the south. The exact influence of gorillas and vegetation on this divergence remains uncertain.

How did the behavior of apes change over thousands of generations after the split?

What are the names of the two species that evolved from the original ape population?