Polyandry is a form of marriage in which one woman has multiple husbands. It is rare. The best-documented cases come from Tibet, Nepal, and parts of northern India, where brothers sometimes share a single wife. This practice, called fraternal polyandry, keeps family land from being divided among heirs. It also limits population growth in environments where arable land is scarce.

Polyandry takes other forms too. In some societies, a woman marries one man but may take additional husbands later. In others, the husbands are not related. The arrangements vary in how residence, sexual access, and paternity are handled. Children may be raised by all husbands collectively, or paternity may be assigned to the eldest. Polyandry is not a mirror image of polygyny. It arises from specific ecological and economic conditions, not from a general rule about gender.

Why it happens

• Keeps inherited land in one household.
• Reduces population pressure in scarce environments.
• Provides multiple male laborers for one family.
• Balances sex ratios in some communities.

Polyandry challenges the assumption that marriage is naturally between one man and one woman. It shows that marriage systems adapt to circumstance.