Kin Groups and Descent. The Yanomamö practice patrilocal residence and trace descent patrilineally. Patrilineal descent does not lead to the development of named kinship groups. Members of the same patrilineage refer to themselves as mashi , which simply means "people who are related patrilineally." Kin groups tend to be localized in villages, and their genealogical depth is rather shallow. Kinship is critical in the arrangement of marriage, and very strong bonds develop between kin groups who exchange women.
Kinship Terminology. Yanomamö kinship terminology is bifurcate merging with Iroquoian cousin terms. Relations between brothers-in-law (cross cousins) are close and intimate, whereas relations between same-age parallel cousins are cool and reserved. A son-in-law should avoid his mother-in-law and be deferential and respectful to his father-in-law.