Kin Groups and Descent. Legends indicate that there were previously at least six endogamous divisions of Piro. Today the names of those divisions function primarily in establishing relationships among the Piro and in providing surnames for dealing with Spanish speakers. When members of different clans are married, children usually receive the father's clan name or surname, and occasionally also that of the mother. This corresponds to the practice of Spanish speakers.
Kinship Terminology. Kinship is assumed and kinship terminology is employed among all members of the Piro community. Use of proper names is avoided.