The abundance of game increases as the group travels farther from the overexploited land around the village. This increased intake of protein is necessary to maintain the health of the group. This necessitates that they hunt. When the game supply near the village becomes depleted, the village must go on a trek. The Yanomamo are known for their fierce, aggressive natures and their frequent violent disputes.
Disagreements can erupt at any time within a village or between villages.
If a dispute occurs within a village, it is advantageous for the village to separate into two factions, each going on separate treks. This separation gives the groups time to cool down and make peace with each other. War raids can also precipitate a departure on a trek. Often, after a group of warriors returns from a raid, their entire village will leave on a trek to prevent a revenge killing by the victim s kin group. Another adaptive advantage of the trekking system is that it enables different groups within the village to explore possible cultivation sites and split off into new village groups.