Polyandry is a form of marriage in which two or more husbands share a single wife. For example, in the Himalaya Mountains of Tibet polyandry is practiced and takes the form of the eldest brother marrying a woman and sharing her with his younger brothers.
A brother who moves away from the home of the eldest brother ceases to be a husband of the joint wife.
The emphasis in polyandry is on men choosing to share a wife, and not on a woman deciding to have two or more husbands. The rule of access to the wife is different in different places, but usually the eldest brother has preference.
Polyandrous unions of a nonfraternal type are found among the Nairs (or Nayars) of Cochin, Malabar, and Travancore. This has been confirmed by travelers from the beginning of the 15th century onward. Among the Nairs every girl, before she attains puberty, is subjected to a certain marriage ceremony, after which the husband goes on his way and she is allowed to cohabit with any Brahman or Nair she chooses; usually she has several lovers who cohabit with her by agreement among themselves, but do not live with her.
This does not mean that in a polyandrous union the wife is completely subservient to the will and desire of the husbands. Generally she follows the customary expectations of her society. She may, however, exercise her pleasure and welcome certain of the brothers more than others.
The particular biological parentage of a child is unimportant in families in which polyandry is practiced. Parentage is defined by the customs of the society. In some societies permitting polyandry the eldest brother is the father of the first child, the next oldest is father of the second child, and so on. In still other groups the wife is permitted to name the father of each child. In polyandrous families custom rather than biology determines the parents of the child. In places where polyandry is practiced the people consider it a good, right, and proper form of marriage. There are rules and regulations defining the privileges and obligations of the wife, the husbands, and the children.
Polyandry serves at least two functions. It is a device for the conservation and continuity of property, particularly land; if farms were divided into parts upon the death of the father, soon the farms would become very small in size. Under polyandry this does not occur. Each brother has economic security and a stake in the family farm and household. The second function is the economy which occurs in sharing a wife. Marriage usually entails considerable expense and the poor in certain societies find it economical for brothers to share a wife.
Polyandry was or is found among the people of Tibet, the Todas of southern India, the Gilyaks of Russian Siberia, some African societies, Indians of South America, the Aleut and the Kaniagmiut of the Alaskan coast, the Canary Islands, Madagascar, the Malay Archipelago, certain South Sea Islands, and the Marshall Islands. Thus polyandry was or is very widely practiced.
In societies where polyandry is permitted, monogamy is usually the prevalent form. This is due to the fact that the sexes are generally equal in number.