Within each ant colony there is peace. When two colonies touch there is war. If they were never divided there would always just be peace.

But they are divided because of size since too many destroy it's efficiency.

They do not attempt to communicate across lines and kill all which are different. They war because they have no better sense.

But if the ants of the world expanded their network to share, spread their strengths and reinforce weaknesses, to distribute in each and every colony, they would absolutely dominate this planet as equals having no need to fight.

Too bad they are too stupid to realize helping one another instead of killing is what creates peace.