Polygyny and child growth in a traditional pastoral society - The case of the Datoga of Tanzania

In this paper I use measures of childhood growth to assess from both an evo lutionary theoretical and an applied public health perspective the impact o f polygyny on maternal-child welfare among the Datoga pastoralists of Tanza nia. I report that the growth and body composition of children varies in su ch a way as to suggest that polygyny is not generally beneficial to women i n terms of offspring quality. Cross-sectional analysis of covariance by mat ernal marriage status revealed that children of first and second wives in p olygynous marriages grow relatively poorly, that this is correlated with ma ternal physical status, and that the pattern is not modified by household w ealth. I discuss how the dynamics of sexual conflicts operating during the formation and maintenance of marriages may be important factors in the etio logy of poor child growth in this population, leading to complex patterns o f variation in anthropometric indicators of both women and children. The th eoretical conclusion is that improved evolutionary models of polygyny shoul d be designed to examine the potential for adaptive tradeoffs between the c urrencies of offspring quality and quantity for all types of parents in a p olygynous population. The practical conclusion is that a better understandi ng of the relationships between marriage practices and health outcomes woul d assist in the development of culturally appropriate health and nutrition interventions.