The Yanomamö Indian tribe of Southern Venezuela has a unique tradition — they are allowed to kill for revenge. In their culture a man or a man’s family can be killed if he commits one of a number of crimes. These crimes often begin with a dispute over a woman — reproductive revenge killings are common among the tribesmen.
Killings are acceptable and common for infidelity and suspicion of infidelity, attempts to seduce another man’s wife, sexual jealousy, forcible appropriation of women from visiting groups, failure to give a promised girl in marriage, and rape.
Once a killing occurs, the community that lost a loved one may retaliate with a revenge raid on the murderer’s community. The Yanomamö culture has a graded sequence of events that usually take place before a revenge raid. Their sequence of events goes like this: “shouting matches, chest pounding duels, side slapping duels, club fights, fights with axes and machetes, and shooting with bows and arrows with the intent to kill”.
These “fights” are not meant to kill the opponent except the one with bows and arrows. They are more like punishment fights. If a man is killed in a fight his group may make a revenge raid against the group of the killer. Once a group is raided, the members of the group must retaliate the sooner the better. The quicker they retaliate, the stronger and more powerful they look in the eyes of other groups. This show of strength and power, in the Yanomamö culture, will keep them from more retaliatory raids thus keeping them alive longer. Having a fierce reputation will also deter other groups from raiding to abduct their young women.
The Yanomamös who has killed and have not been killed themselves are called Unokais and considered fierce. (Imprecise quote from Chagnon, N.A. (Feb 26, 1988) Life Histories, Blood Revenge, and Warfare in a Tribal Population. Science. Vol. 239. http://www.columbia.edu/~lnp3/chagnon.pdf).
Anthropologist Napoleon Chagnon, now at the University of Missouri, Columbia, spent decades studying the Yanomamö. He gathered reams of information about their marriages, wars and alliances.
Lethal coalitionary aggression and long-term alliance formation among Yanomamö men (Shane J. Macfarlan, Robert S. Walker, Mark V. Flinn and Napoleon A. Chagnon) is a recent article examining the composition of Yanomamös lethal coalitions and their unique social structure.
Humans, like chimpanzees, engage in coalitionary violence: Members of both species coordinate lethal activity against conspecifics. The origin and adaptive functions of this behavior are poorly understood.
Unfortunately, the data from tribal populations are very rare. Data gathered by Chagnon during his 3 decades of researching Yanomamö and used in this atricle is simply invaluable.
In contrast to chimpanzees, Yanomamö lethal coalitions are composed of individuals from different lineages and natal communities. Many coalition partners are ideal marriage exchange partners. Men who kill together more often are more likely to live together in the same village later in life and to engage in marriage exchange.
The results of this research highlight connections between coalitionary aggression and alliance formation, illuminating differences in social structure that distinguish humans from other primates.
From the article’s abstract:
Some cross-cultural evidence suggests lethal coalitionary aggression in humans is the product of residence and descent rules that promote fraternal interest groups, i.e., power groups of coresident males bonded by kinship. As such, human lethal coalitions are hypothesized to be homologous to chimpanzee (Pan troglodytes) border patrols. However, humans demonstrate a unique metagroup social structure in which strategic alliances allow individuals to form coalitions transcending local community boundaries.
The article examines the social characteristics of co-unokais or men who jointly kill others. Analyses indicate co-unokais generally are
- from the same population but from different villages and patrilines,
- close age mates, and
- maternal half-first cousins.
The incident rate for co-unokai killings increases if men are similar in age, from the same population, and from different natal communities.
Co-unokais who have killed more times in the past and who are more genetically related to each other have a higher probability of coresidence in adulthood.
Lastly, a relationship exists between lethal coalitions and marriage exchange. In this population, internal warfare unites multiple communities, and co-unokais strategically form new residential groups and marriage alliances.