There is no formai leadership. Informal leadership resides in sets of brothers, especially those with oratorical ( puruN ) skills and knowledge of genealogy; women claim to be unable to understand puruN. The leader cannot apply sanctions, but can orchestrate consensus. In cases of dispute requiring an immediate resolution, the offended party may require that the alleged offender undergo an ordeal to establish innocence. Warfare is practiced in the form of headhunting. The reasons for headhunting are an unsettled feud, a death in one's household, and the obligatory requirement of a young man to kill before marrying. A pig is sacrificed when the headhunters return. Warring groups may establish peace through negotiations and exchanges.