Maternal grandmothers improve the nutritional status and survival of children in rural Gambia

Hypotheses for the evolution of human female life history characteristics have often focussed on the social nature of human societies, which allows women to share the burden of child-care and provisioning amongst other members of their kin group. We test the hypothesis that child health and survival probabilities will be improved by the presence of kin using a longitudinal database from rural Gambia. We find that the only kin to significantly improve the nutritional status of children (apart from mothers) are maternal grandmothers, and that this is reflected in higher survival probabilities of children with living maternal grandmothers. There is also evidence that the reproductive status of the maternal grandmother influences child nutrition, with young children being taller in the presence of non-reproductive grandmothers than grandmothers who are still reproductively active. Paternal grandmothers and male kin, including fathers, have negligible impacts on the nutritional status and survival of children.