Tribal warring is common even in apes. Territorialism is especially strong. There are also plenty of things to war over besides food, such as space, shelter, ma

Tribal warring is common even in apes. Territorialism is especially strong. There are also plenty of things to war over besides food, such as space, shelter, mates, glory, gods, historical feuds, etc. Remember if we don't sacrifice one human before nightfall, the sun won't rise tomorrow.