Traditional warfare: Dani tribesmen fighting with spears in the Baliem Valley of the New Guinea Highlands. The highest one-day death toll in those wars occurred on June 4, 1966, when northern Dani killed face-to-face 125 southern Dani, many of whom the attackers would personally have known (or known of). The death toll constituted 5% of the southerners’ population. Photo credit: Karl G. Heider.