Why does women's fertility end in mid-life? Grandmothering and age at last birth.

摘要: Great apes, the other living members of our hominid family, become decrepit before age forty and rarely outlive their fertile years. In contrast, women - even in high mortality hunter-gatherer populations usually remain healthy productive well beyond menopause. The grandmother hypothesis aims to account for evolution this distinctive feature human life history. Our previous mathematical simulations that fixed end female fertility at 45, based on similarities among hominids, then modeled human-like longevity from an ancestral state, like great due only effects. A major modification here allows ends vary as well, directly addressing a version question, influentially posed by GC Williams six decades ago: Why isn't menopause later humans? model is agent-based (ABM) accounts coevolution both expected adult lifespan selection maximizes reproductive value. We find effects not drive population equilibrium representing ape-like new longevity, they also maintain observed termination women's 50.