The influence of maternal care in shaping human survival and fertility.

The influence of maternal care on child survival has evolved throughout human history due to variation in altriciality, allocare, and maternal behaviors. Here, we study the impact of these factors on the force of selection acting on age-specific survival and fertility (measured with elasticity analysis) in a model that incorporates the dependence of child survival on maternal survival. Results reveal life-history changes that cannot be elucidated when considering child's survival independent of maternal survival: decrease of late fertility and increase of late survival, and concomitant decrease of early and late fertility. We also show that an increase of child altriciality in early humans might explain the main human life-history traits: a high life expectancy and postreproductive life; a long juvenile period and a higher, and narrowed, fertility at the peak of the reproductive period.