Humans as co-operative breeders: a case study in the Gambia

Rebecca Sear, London School of Economics and Political Science (LSE)
Ruth Mace, University College London

We have analysed the effects of kin on demographic outcomes and child health in a farming community in rural Gambia. We find that the presence of maternal grandmothers and elder sisters improves both the anthropometric status and survival prospects of children. Male and paternal kin appear less important to child outcomes, but do affect female fertility. Having a living father or elder brothers lowers a woman’s age at first birth, and her fertility rate is increased in the presence of both her mother-in-law and father-in-law. These analyses demonstrate the importance of kin to reproductive outcomes, but also show that different relatives have different roles to play in a woman’s life history. Maternal grandmothers and elder sisters help women out by providing direct care to young children. Male and paternal kin have no role to play in direct childcare, but do affect women’s reproductive lives through their social roles.

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Presented in Session 123: Evolutionary ecology, kinship and reproduction