INCLUSIVE FITNESS: THE GRANDMOTHER HYPOTHESIS
Evolutionary Success Through Caregiving and Longevity BIOLOGICAL BASIS Inclusive Fitness (Kin Selection) GENETIC SHAREDNESS 25% with Grandchildren FIELD OF STUDY Evolutionary Biology / Anthropology CORE PHENOMENON Post-Reproductive Longevity in Humans The Grandmother Hypothesis is one of the most famous examples of Inclusive Fitness in action. It helps solve a biological mystery: Why do human women live so long after they can no longer have children? In most of the animal kingdom, individuals do not live much longer once they stop reproducing, but humans are a major exception. The Step-by-Step Logic The Energy Problem: Human babies are "expensive" to raise, staying dependent on adults for years. The Grandmother's Role: Instead of having more of her own children—which becomes riskier with age—a grandmother provides food and care for her grandchildren . The Survival Boost: With a grandmother’s help, the mother can have her next baby sooner, and the grandchildren are mor...