Polygamy is a heterosexual marriage which includes more than two partners, which is a monogamous marriage. When a man is married to more than one wife at the one time, the relationship is called polygyny, and there is no marriage bond between the wives; and when a woman is married to more than one husband at the one time, it is called polyandry, and there is no marrige bond between the husbands. If a marriage includes multiple husbands and wives, it can be called group marriage. Though there are three or more parties to such marriages, sexual activities between the parties are normally only heterosexual.
The term is used in related ways in social anthropology, sociobiology, sociology, as well as in popular speech. In social anthropology, polygamy is the practice of a person's making him/herself available for two or more spouses to mate with. In contrast, monogamy is a marriage consisting of only two parties. Like monogamy, the term is often used in a de facto sense, applying regardless of whether the relationships are recognized by the state (see marriage for a discussion on the extent to which states can and do recognize potentially and actually polygamous forms as valid). In sociobiology, and zoology polygamy is used in a broad sense to mean any form of multiple mating.
Forms of Polygamy
Polyandry
Polyandry is a practice where a woman has more than one husband at the same time. Fraternal polyandry was traditionally practised among nomadic Tibetans in Nepal, parts of China and part of northern India, in which two or more brothers are married to the same wife, with her having equal sexual access to them. Polyandry is believed to be more likely in societies with scarce environmental resources, as it is believed to limit human population growth and enhance child survival. It is a rare form of marriage that exists not only among poor families, but also the elite.
Group marriage
Group marriage is a marriage where the family unit consists of