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.

What environmental factor contributed to the division of the ape population?

• The presence of predators

• The widening of the Congo River

• The change in climate

• The migration of other animals

Why did northern apes become more aggressive?

• To defend against predators

• To compete for scarce ground plants

• To establish territory

• To attract mates with their strength

What was a key factor in the amiable nature of southern apes?

• Abundant ground plants

• Presence of gorillas

• Scarcity of food

• Harsh climate conditions

Which species evolved in the northern region?

• Orangutans

• Bonobos

• Chimpanzees

• Gorillas

What is still uncertain about the evolution of the two ape species?

• The role of climate change

• The influence of gorillas versus vegetation

• The migration patterns of apes

• The impact of human intervention