Polygyny is defined as marriage between one man and two or more wives concurrently. It is one form of polygamy, the marriage of a male or female to two or more spouses concurrently. It contrasts with polyandry, the marriage of a woman to two or more husbands at the same time, which is rare, and with monogamy, the marriage of a man or woman to just one spouse. Serial monogamy is the marriage of a person to two or more spouses in sequence, and can have consequences not unlike those of polygamy.
The concept of polygyny presupposes the universal applicability of the category of “marriage,” which is not in fact a straightforward matter; during the period when anthropologists were trying to agree on the definition of terms of art, it proved difficult to arrive at criteria for marriage that were universally, or even very generally applicable. Consequently, what one anthropologist describes as polygyny another may describe as concubinage. Polygyny entails inequalities in the ability of men to reproduce sexually, but the political and economic consequences of polygyny vary greatly with the bases of social organization.
The Distribution of Polygyny
Polygyny has been widely distributed in human societies through prehistory and recorded history. Ireanus Eibl-Eibesfelt found that it occurred in 83.5% of a large sample of modern societies, although monogamous unions were 2.5 times more frequent than polygynous unions. Its occurrence has been reported in many recent and contemporary hunter-gatherer and horticultural societies, in precolonial South America, Africa, Polynesia, and Australia, for example. Polygyny was practiced in ancient Hebrew society, and with the exception of certain liberal Islamic movements, is accepted in Islamic societies. It was not officially permitted, however, in ancient Greece and Rome, or in Christian societies, with the exception of early Mormonism.
Perspectives From Sociobiology and Evolutionary Psychology
Sociobiologists and evolutionary psychologists have sought to explain the incidence of polygyny in terms of natural selection. Trivers’s theory of sexual selection and parental investment has been influential. Socio-biologists have explained the widespread institution of polygyny in terms of the differences in male and female reproductive strategies. Pregnancy, it has been argued, involves a much greater investment than male insemination. Men have evolved a desire for sexual access to a large number of women and will compete for access to women, whereas natural selection predisposes women to assess men as potential providers, and for the quality of their genes, as indicated by various markers such as symmetry.
Sexual strategies theory attempts to explain why men tend to adopt short-term mating tactics to a greater extent than women, but recent studies emphasize that both men and women have evolved mixed strategies, and that strategies are conditional in particular circumstances. Depending on environmental conditions, women ought to make a trade-off between male genetic quality and parental investment. For example, with latitude and geographical regions held constant it has been shown that polygyny is more common in societies where pathogens are more prevalent. This has been explained as resulting from women’s favoring indicators of good genes (and hence, resistance to pathogens) as against indicators of exclusive parental investment. Polygyny has also been found to be more prevalent where women have more control over resources. This has been explained by their decreased dependence on male parental investment.
Polygyny in Evolution
Biologists use the term “polygyny” to indicate differences in access to mates, whether or not associated among humans with the institution of marriage. DNA studies have found that lineages associated with the Y-chromosome are fewer than lineages associated with mitochondrial DNA, suggesting that until recently a small proportion of men contributed a large fraction of the Y-chromosome pool at every generation. Dupanloup and colleagues have argued that humans have been “polygynous” through most of their history, but the number of breeding males may have increased and the variance of their reproductive success may have decreased through a recent shift from (institutional) polygyny to monogamy.
Polygyny in Egalitarian Societies
In relatively egalitarian societies polygyny is technically possible where there is an unequal sex ratio, due perhaps to warfare, or where men marry later than women. The latter is the condition that prevailed among Australian Aboriginal people such as the Yolngu and the Yanomamo of the Orinoco basin.
In assertively egalitarian societies such as the G/wi people of the Kalahari Desert, where marriage is by mutual consent, but subject to parental approval, polygyny occurs by mutual consent and is uncommon. In Australian Aboriginal societies polygyny was highly institutionalized, and associated with systems of marriage bestowal (including infant bestowal) in which marriage choices were limited by kinship, and arranged between potential husband and wife’s kin. A female was first bestowed as an infant, or even before her birth, but usually took up residence with the husband around puberty. Marriage was an exchange either in kind (as in brother-sister exchange) or for a prolonged series of gifts and services. Combined with bestowal, leviratic marriage increased the possibility of polygynous marriage. Polygyny in most regions reached levels of two to three women among some older men, but reached very high levels in some regions in the north of the continent.
Polygyny in these societies provided a route to power and influence. Combined with patrilineal groups it was a strategy for increasing group size and political support, and spreading alliances. In some pastoral societies, such as the Turkana, the requirement for bride wealth, together with the control of stock by older men, delayed the marriages of younger men, and was associated with an age grade of bachelor warriors. In other pastoral societies such as the Samburu, an age-set system together with elaborate initiation rites delayed young men’s marriages.
Polygyny in Hierarchical Societies
In the hunter-gatherer societies of the Northwest Coast of North America, which were unusual among such societies in having marked inequalities of status, wealth, and power, polygynous marriage was undertaken to establish alliances between families, because it increased household size and labor power, and because it enhanced the ability of high-ranking heads of households to organize potlatch exchanges, and increased the size and competitive advantage of the descent group.
Polygyny was also a feature of African farming chiefdoms, where marriage was associated with bride wealth in the form of cattle and other stock, as well as money. For example, among the Kgatla of what is now Botswana in southern Africa, most commoner men in the precolonial past had only one wife at a time, some-times two, and rarely three or four. Households with four or more wives were found among members of the royal family or other prominent or wealthy individuals. Chief Kgagamanye, who was chief of the Kgatla from 1848-1875, had 46 wives. Comaroff found that Tswana men had later substituted serial monogamy for polygyny to make strategic alliances.
Turning to an example of a state system, some authors have depicted concubinage in China as polygyny. Patricia Ebrey argues, however, that in traditional China it was illegal and socially disreputable for a man to have more than one wife at a time, but he could have as many concubines as he could afford. During the Song dynasty, concubines, like servants, were most common in wealthy families. The status of concubines differed from that of wives in that no wedding ceremony was prescribed, there was a market for concubines, and they were ranked lower than wives. Rules of incest and exogamy applied to concubines, however, and children of concubines had the same status as children of wives. In the Qing dynasty it became permissible to promote a concubine to a wife under certain conditions.
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- Dupanloup, I., Pereira, L., Bertorelle, G., Calafe, F., Prata, M. J., Amorim, A., et al. (2003). A recent shift from polygyny to monogamy in humans is suggested by the analysis of worldwide Y-chromosome diversity. Journal of Molecular Evolution, 57, 85-97.
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