Kin Groups and Descent. The band, a collection of interrelated nuclear families, is the basic unit of Yuqui social organization. There are no recognized groups larger than the band and no ceremonial occasions when all Yuqui gather. As noted earlier, even bands of related individuals may have hostile relations with one another as a result of quarrels that may have caused fissioning earlier. In tracing lines of kinship, it is apparent that the three extant bands of Yuqui now living at the Chimore are all directly related to each other through consanguineal ties. All three bands, then, can be traced to a larger, parent group that fissioned in the 1930s and then again in the 1950s as a result of internal stresses. Patrilineal descent may have been the normative rule, and vestiges of this are seen in the patterns of inherited leadership and the inheritance of slave status through the male line.
Kinship Terminology. Again, signs of an earlier, more complex and perhaps more typically Tupí form of social organization are apparent among the Yuqui. They may have had a Dravidian form of kinship terminology with preferential cross-cousin marriage in that they still recognize that "it is good" for a man to marry his sister's daughter. Because of severe depopulation, however, the Yuqui have for some time simply married anyone who does not specifically violate incest taboos. Incest is defined as sexual intercourse with one's parents, full siblings, and children of women with whom one has had sexual relations. In the latter case, the Yuqui have been less rigorous in enforcing this taboo, creating a situation where a man potentially could be married to his biological daughter. Kinship terminology falls into no specific category but is highly classificatory, with terms reflecting primarily differences in sex and relative age. The Yuqui differentiate terms of address from terms of reference.