Kin Groups and Descent. In the broadest sense, all of the Mehinaku regard themselves as kin and use the phrase "all of us" to mark their special relationship. More narrowly, kinship is reckoned bilaterally, through both parents' lines. "Our grandfathers," the villagers will say in justifying a kinship tie, "were of one group," meaning that they were siblings or at least cousins. In some respects, the system of descent follows lines of same-sex individuals, in that the chieftainship descends from father to son and from mother to daughter. Moreover, children are said to be "the former selves" of their parents of the same sex, replicating the qualities and attributes of their fathers and mothers. Often the Mehinaku are vague about precise relationships, since genealogies are shallow. Individuals are seldom able to name their grandparents' siblings. This pattern, combined with endogamous marriage, makes for an extraordinarily flexible system in which distantly related individuals can choose among the multiple ties that may associate them. Hence, a man and a woman who are romantically involved may choose to be cross cousins (a relationship appropriate for sexual interest) even though it would have been possible to reckon a different tie.
Kinship Terminology. Mehinaku kinship follows a pattern reported elsewhere in the upper Xingu. Grandparents and their siblings are called by terms that recognize differences of sex, as is also true of relatives of the generation of one's grandchildren. One's parents and their siblings, and one's own siblings and cousins, however, are distinguished by both gender and the sex of the linking relatives. Following this form of bifurcate-merging terminology, mother's brothers are distinguished from father's brothers (who are called by the same term as father), and mother's sisters (who are called by the same term as mother) are distinguished from father's sisters. The children of persons called father and mother are labeled by sibling terms, whereas the children of mother's brothers and father's sisters are differentiated by special terms.