It has actually been suggested that warfare may have been the principle evolutionary pressure that created the huge gap between the human brain and that of our closest living relatives, the anthropoid apes. Whole groups of hominids with inferior brains could not win wars and were therefore exterminated.

Chimps are very quick to have a sudden fight or aggressive episode, but they're equally as good at reconciliation.

I think we're still in a muddle with our language, because once you get words and a spoken language it gets harder to communicate.

Jane Goodall Quotes