Even bugs have wars but I think the difference is the sheer brutality and why we fight. When war is done for necessary resources like food and water, it's a lot more palatable than the ideologies and greed that drives the human desire for war. The military industrial complex is a very different beast from chimps wanting more bananas.
Every species that wages "wars" by definition must live in a society. If they live in a society, they understand coexistence. In every case, both sides know what coexistence is, and yet we still choose violence to reach our goals. That is just the natural course, not just tied to human nature but to needs and desires which every living being with a conscience has