Kin Groups and Descent. Nonlocalized exogamous patrimoieties are named after birds, the kwandú (harpie eagle) and mytum (curassow). The Kwandú moiety was also associated with the macaw, taravé , the name of the corresponding Tenharem moiety. The system is complicated by a Kwandú subgroup, the Gwyrai'gwara (associated with the japú bird), who intermarry with other Kwandú as well as with the Mytum, constituting a third de facto patrisib.
Kinship Terminology. The kin terminology is a two-line system appropriate to moieties, with sibling terms extended to same-generation members of one's own moiety, all cross cousins of the opposite moiety designated amotehe (a term for "lover" in other Tupí languages), and so on. Married amotehe observe a formal avoidance of one another.
Marriage. Marriage was determined by a series of arrangements beginning at birth. An infant was named by a selected mother's brother ( tuty ), establishing a betrothal with the latter's infant of the opposite sex. When of age, the betrothed pair were married, the bride given away by two real or classificatory brothers who thus gained the right to name one of her children and claim that child in betrothal to one of their own children.
Marriage was effected by a period of bride-service to the father-in-law (tuty)—5 years for the first wife and less for later marriages—after which the son-in-law was theoretically free to leave, but usually remained in uxorilocal residence.
Polygyny was practiced, preferably sororal, but was never widely popular because of the complexity of familial relations involved: a man with five wives was scoffed at as imprudent. When a man took a second wife, his first might leave him if she so desired.
Socialization. An infant is given a "first name" or "play name" ( mbotagwahav ) by a mother's brother and, in later childhood, a moiety-associated name by a father's brother ( ruvy ). Thereafter, new names (selected from moiety sets of age- and sex-appropriate names) were assumed on entering new stages of life, on major changes of status, or at certain special events. Boys received their first ka'a, penis sheath, from a father's brother. A woman, on her first menarche, was isolated for ten days in a hammock behind a partition, observing strict taboos, at the end of which she was carried to the river by her father and ritually bathed. Her first wedding followed the ceremony.
Conflict and Social Control. Raids were organized by any warrior moved to call one and led by two nhimboypara'ga, "raid callers," whose position lasted only for the duration of the expedition. A principal objective was to take an enemy head, which would be exhibited at an akagwera toryva ("head-trophy feast"), a lavish ceremonial display celebrating the exploit, cosponsored by the head taker (who thus achieved the honored status of okokwahav ) and another prominent warrior. There is some evidence for ritual consumption of parts of the slain enemy. The killer was obliged to undergo a period of ritual seclusion (like a woman's menarche seclusion), and he assumed a new name.