He also discusses more male-dominated though relatively extensive farming systems such as those that exist in much of West Africa, in particular the West African savannah, where polygyny is desired more for the creation of sons, whose labor is valued. He notes Dorjahn's (1959) comparison of East and West Africa, showing higher female agricultural contributions in East Africa and higher polygyny rates in West Africa, especially in the West African savannah, where one finds especially high male agricultural contributions.Goody says, "The reasons behind polygyny are sexual and reproductive rather than economic and productive" (199), arguing that men marry polygynously to maximize their fertility and to obtain large households containing many young dependent males." Polygynous marriages can be distinguished between sororal polygyny, in which the co-wives are sisters, and non-sororal, where the co-wives are not related.Polyandry is much less popular than polygyny and is illegal in virtually every state in the world. 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.For example, in the Himalayan Mountains polyandry is related to the scarcity of land; the marriage of all brothers in a family to the same wife allows family land to remain intact and undivided.This provides support for the widow and her children (usually also members of the brothers' kin group) and maintains the tie between the husband and wives' kin groups.The sororate is like the levirate, in that a widower must marry the sister of his dead wife.This favours polygamous marriages in which men sought to monopolize the production of women "who are valued both as workers and as child bearers".Goody however, observes that the correlation is imperfect and varied. Burton discuss and support Jack Goody's observation regarding African male farming systems in "Causes of Polygyny: Ecology, Economy, Kinship, and Warfare" where these authors note: "Goody (1973) argues against the female contributions hypothesis.
Senior wives can benefit as well when their work load is lightened by the addition of junior wives to the family.Polygyny may also result from the practice of levirate marriage.In such cases, the deceased man's heir may inherit his assets and wife; or, more usually, his brothers may marry the widow.According to the Ethnographic Atlas (1998), of 1,231 societies noted, 588 had frequent polygyny, 453 had occasional polygyny, 186 were monogamous and 4 had polyandry; From a religious point of view, in contemporary society polygyny is associated with the Muslim religion, although not all Muslim cultures practice it, and neither is it restricted to this religion.In cultures which practice polygamy, its prevalence among that population is often connected to class and socioeconomic status.