the first being a personal cost in labor contributed to the bride’s family and the second a personal cost in terms of risk. However, polygyny extends the male reproductive period as new and younger wives are added through time.

The high frequency of polygynous marriages associated with horticulture may be because each wife is essentially able to support herself and her children through her own labor (Lancaster and Kaplan, 1992; Murdock, 1967). Males do not have to ponder whether they can afford additional wives and children, only how they can get and keep them. As White and Burton (1988) found, polygyny is most associated with fraternal interest groups, warfare for the capture of women, absence of constraints on expansion into new lands, especially for horticulturalists, environmental quality, and homogeneity. The practice of widow inheritance by husband’s kin also increases the frequency of polygyny (Kirwin, 1979). The form, sororal polygyny, is at its highest frequency due to the ease of sisters forming collaborative horticultural work groups (Irons, 1979b).

Parental investment in horticultural societies focuses on raising healthy children without concern for their marriage market endowments or inheritance of resources. Birth into a social group provides all the inheritance a child would need to access the means of production and reproduction. Such concepts as bastardy or disinheritance do not play a formal role in family dynamics. Child labor is valuable to families since horticulture provides a number of relatively low-skilled tasks that older children can perform. In fact, Kramer (2002) demonstrated that among Maya horticulturalists older children contribute at the level of “helpers-at-the-nest,” significantly increasing their parents’ fertility and without whose help their parents could not add further offspring to the family.

Variance in reproductive success is relatively low for women because marriage is universal, and female fertility and fecundity depend on their own productivity and work effort (Ellison, 2001a; Jasienska, 2000; Prentice and Whitehead, 1987). Greater variance among men was possible on the basis of raiding and bride capture, but the social system itself is not stratified and individual men cannot amass or control access to resources relative to other men or pass them on to their sons.

Extrasomatic Wealth and Tribal Pastoralism

The Socioecological Context

The domestication of animals, particularly large herd animals such as cattle, camels, and horses, proved to have a profound effect on human social and reproductive patterns. Large domesticated livestock have intrinsic qualities that affected human social relationships, marriage patterns,



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