Gombe Chimpanzee War - Violent conflict between two communities of chimpanzees in Gombe Stream National Park in the Kigoma region of Tanzania between 1974 and 1978

I believe Chimps are the only other animals, besides humans, that will form war parties and travel to wage war i.e. leave their territory with the express purpose of engaging in a conflict. As well as make their own weapons e.g. clubs/sticks.

Although I could be mistaken, someone correct me if I'm wrong.