Kin Groups and Descent. Betsileo kinship and descent is ambilineal (optative, nonexclusive), with a strong patrilineal bias. Most marriages are (patri)virilocal. A Betsileo is simultaneously a member of several descent groups. One is the local descent group, with whom a man resides and cultivates his main rice field, usually from his father's or father's father's estate, although fields may also be inherited through the mother. After marriage, a woman retains membership in the local descent group of her origin. When she dies, a delegation from her village will ask that she be buried in her ancestral tomb there. Such a request is usually denied, and she is buried in her husband's family tomb.
Aside from one's primary membership in a mostly patrilineal local descent group, a Betsileo (man or woman) also belongs to several totally ambilineal tomb-focused descent groups. People have the right to be buried in any tomb in which they have an ancestor. This can (in theory, but rarely in practice) extend back to eight great-grandparents. Betsileo maintain their membership in tomb groups by contributing to their construction costs and upkeep. Despite ambilineal rights, the social organization of the dead people in the tombs is patrilineally skewed because most people are buried in the tomb of their local descent group.
Descent groups are named; many are supralocal, with branches in several villages. The more prominent ones span regions and ancient political divisions. Some villages have a single named descent group; others have two or more. Each local descent group has its own tomb. Sometimes the coresidence of multiple descent groups in the same village is a continuation of phratry organization of the past, when three to five local descent groups banded together for defense or were united in the same political division (perhaps as an advisory council for a chief). In some villages (especially among recent migrants or descendants of slaves) descent is unimportant as an organizing principle.
In a 1966-1967 survey, 998 named descent groups were identified in the Betsileo homeland, spanning 1,300 settlements (Kottak 1980). About half of them existed only as local descent groups, confined to a single village. Another 154 spanned just two villages, whereas 244 were present in between 3 and 9 villages. Only 83 (less than 10 percent of the total) appeared as local descent groups in 10 or more villages. Just 16 named descent groups spanned 50 or more of the villages in the sample, with the largest and most geographically dispersed located in 183 villages. The larger and more expansive groups are those that have played major historic roles, as nobles and senior commoners (see "Social Organization"). The smaller groups include junior commoners, migrants, and descendants of slaves.
The Betsileo use fictive kinship rituals (e.g., that establishing blood siblinghood, vaki-ra ) to convert nonkin (including people from other ethnic groups, such as the Bara) into structural analogues of blood relatives. Fosterage (usually of relatives) is common; adoption (of nonrelatives) is allowed but rare.
Kinship Terminology. The Betsileo use generational terminology for the parental generation and Hawaiian terminology for Ego's generation. Siblings' children and own children are called by the same term ( zanaka ), as are children of the grandchild generation ( zafy ). Kin terms recognize age differences among siblings, distinguishing between older ( zoky ) and younger ( zandry ). The cross-parallel distinction, which does not show up in cousin terminology, is, however, implicit in the terms that brothers and sisters use for their siblings of the same and other gender. Raha- means "same," and ana- denotes "difference"; lahy means "male" and vavy, "female." Thus men refer to their brothers as rahalahy (same, male), and women refer to their sisters as rahavavy (same, female). Men's sisters are anabavy (different, female) and women's brothers are anadahy (different, male).
The Betsileo use teknonymy. Many parents change their name when a child (usually the first) is born. The terms for father and mother are ray and reny. 1f the child is named "Talata" (born on Tuesday), the father and mother will become "Rainitalata" (Tuesday's father) and "Renitalata" (Tuesday's mother), respectively.