Ritual warfare

Examples includes the Nuer of South Sudan,[2] the Māori of New Zealand, the Dugum Dani of Papua,[2] and the Yanomami (dubbed "the Fierce People") of the Amazon.

[4] The Yanomami of Amazonas traditionally practiced a system of escalation of violence in several discrete stages.

Finally, the highest stage of escalation is Nomohoni or all-out massacres brought about by treachery.

Similar customs were known to the Dugum Dani and the Chimbu of New Guinea, the Nuer of Sudan and the North American Plains Indians.

Warfare serves the function of easing intra-group tensions and has aspects of a game, or "overenthusiastic football".

An armed woman of the Mursi tribe of Ethiopia
The percentages of male deaths caused by war in eight tribal societies. ( Lawrence H. Keeley , Archeologist, War Before Civilization )