Cooperative breeding in humans: which kin help and why?

Monique Borgerhoff Mulder, University of California, Davis

There is growing interest in the effects of kin on breeding success in humans. This is in part because of recent suggestions that some of the unique features of our life history evolved in conditions where reproduction is subsidized by kin. To date however data are scarce, and often inconsistent, with most attention focused on the role of maternal grandmothers. Within the broader framework of local resource competition and enhancement I develop hypotheses about the conditions in which kin, both maternal and paternal, affect survival, and test these ideas with data from different Sub Saharan populations. The results suggest that the sensitivity of child mortality to the availability of various kin relatives in the neighbourhood is highly sensitive to different ecological and institutional conditions.