Final answer:
Warfare in tribal societies occurs for various anthropologically recognized reasons including resource competition, social structure maintenance, social prestige, technological shifts, and defense against invasions or aggression.
Step-by-step explanation:
Anthropologists have studied the occurrences of warfare within tribal societies and offer several explanations for its prevalence. The motivations for war in these societies can be multifaceted, ranging from the need for self-defense, competition for scarce resources, the quest for social prestige, to the preservation or re-establishment of social order after it has been weakened.
In regions where ecological conditions lead to competition for resources, warfare may arise from the need to ensure access to these vital commodities. Societies with a social structure based around lineages, secret societies, and associations may engage in warfare to maintain these structures, especially when they are threatened by external or internal conflicts. Additionally, societal values, such as the concept of counting coup in Plains societies, can encourage acts of bravery in combat, conferring prestige and status on successful warriors.
Farming communities may turn to warfare due to aggressive incursions from neighboring groups seeking political domination or as a result of the accumulation of wealth within fortified settlements which become targets for conquest. The advent of new technologies such as firearms has historically changed the dynamics of warfare, rendering some traditional fighting styles ineffective and compelling changes to societal organization.