Marriage. Landtman suggests that often there was tension between individual desires and traditional marriage rules. Traditionally, a Kiwai man could marry only if he compensated his bride's father with a woman who was given as a wife to a man of the bride's family. Although some marriages began as love affairs, older people often ignored young people's wishes in arranging marriages because of this requirement of reciprocity. When Landtman was living with the Kiwai, marriages by exchange were still the rule, but marriage through the prestation of gifts to the bride's family (i.e., bride-wealth) was becoming increasingly common. Landtman argues that these gifts were primarily intended to indicate "the importance and prosperity of the donors," and he notes that reciprocal gifts were given by the bride's family to the groom's family. In some instances, a man could also obtain a wife by working for her father for a short period of time. Girls usually marry shortly after puberty. Men and women with the same totem cannot marry, nor can they marry if any of their four parents have the same totem. First cousins cannot marry, and boys and girls who are not related but have grown up together because of adoption cannot marry. There is no formal marriage ceremony, but a feast is usually held with the food provided by the groom's family. A groom should not have sexual intercourse with his bride until he has taken an enemy's head since sons who are born before their father has taken a head are subject to ridicule as they grow up. After marriage the woman moves into her husband's house. Polygyny is accepted but not generally practiced. According to Landtman, divorce was frequent and usually resulted from the wife's "incompetence" as a housekeeper and worker or from the wife's barrenness.
Domestic Unit. The nuclear family is the typical unit of production. Traditionally, the members of a totemic clan lived together in their clan's móto.
Inheritance. Land and personal belongings are divided among a man's sons. As his sons grow up a man will give them land with the final partition taking place at the time of the man's death. If a man leaves a widow and children, his sons are expected to support their mother and sisters. If a man does not have any sons, the land passes to his brothers who are supposed to look after the dead man's family. Some personal belongings are deposited in the grave, but the remainder is divided among the dead person's sons. Daughters are not entitled to inherit personal belongings, but they are often given some by their brothers.
Socialization. Children are usually nursed until they begin to talk. Women will sometimes rub ginger on their nipples to expedite weaning. A child's hair is not cut until the child begins to walk, and shortly thereafter his or her earlobes and septum are pierced. The hair is kept short until puberty when boys and girls begin to let their hair grow. Boys are not initiated at any one time but are introduced to different Ceremonies as they take place. A boy, however, must have Experienced the mogúru ceremony (see below) before he is ready to marry. After the mogúru ceremony, a boy will sleep in the dárimo or men's house. Landtman notes that, at least in some areas, boys "must practice sodomy in order to become tall and strong," but he states that he is not certain how wide-spread this belief and practice is among the Kiwai. Girls are initiated shortly after menarche. Their initiation consists of a procession and ritual bath, and the symbolism of the event emphasizes their transition from childhood to eligibility for marriage.