Final answer:
Tibetan peasants practice fraternal polyandry to manage scarce resources efficiently, keep family land intact, and minimize population growth, which, in turn, reduces inequality within the household.
Step-by-step explanation:
The reasoning behind Tibetan peasants practicing polyandry, specifically fraternal polyandry, is primarily attributed to economic and resource considerations within their society. In areas where there is a scarcity of resources, such as land and food, polyandry helps in preventing the division of land among brothers, ensuring that the family unit can survive on their shared inheritance. By having multiple husbands, typically brothers, sharing one wife, it keeps the land intact, minimizes population growth, and allows for efficient management of the family's resources. Additionally, this form of polyandry helps reduce inequality within the household, as the family works collectively and supports each other. Furthermore, polyandry also assists in labor management as brothers can alternate their work between tending to distant herds or fields and spending time at home.