The Dani tribe of Papua New Guinea practices something called “ritual warfare.” Every so often the tribe meets on a field and they do a mock battle (but not really), they throw spears at each other. If someone happens to get hit, it just happens. They are appeasing the ghost of their ancestors. Most of the warfare observed among the Dani does not occur under “raid or starve” conditions, but is instead a kind of ritual warfare. They rationalize warfare in terms of their religious mythology, “to appease the spirits of the ghosts.” Some blood must be spilled on the ground in times of prolonged peace, so the ghost ancestors do not get restless and cause misfortunes or curse the tribe. A way that outsiders tend to look at it is they are keeping their warrior skills sharp, should a serious battle break out. Yes, sometimes people are seriously injured, sometimes they die, and sometimes they just get a scratch. The point is the ritual aspect of it.