Father death and adult success among the Tsimane: implications for marriage and divorce

Human fathers are heavily involved in the rearing of children around the world. Early evolutionary explanations focused on the greater need of human children and mothers compared to other species and the consequent increased benefits available to investing fathers and pair-bonded husbands. Contrary to this hypothesis, research suggests that the impact of men's care on the survivorship and physical well-being of juvenile offspring is cross-culturally variable and often unsubstantial. Proper testing of the hypothesis, however, also requires exploring how well children raised with paternal investment fare as adults, compared to those raised in the absence of fathers. We explore this issue among the Tsimane, who exhibit high levels of paternal provisioning and very low divorce rates, by testing the impact of early father death on five measures of adult success: completed height, body mass index (BMI), age of first reproduction, completed fertility for age and number of surviving offspring for age. Of these five tests, a significant effect in the predicted direction was found only for body mass index of adult daughters. Therefore, there is no substantial evidence that Tsimane fathers have a large impact on the success of adult children. We explore alternative explanations for the high levels of paternal involvement and low divorce rates observed among the Tsimane, including the positive effects of men's investments on couple fertility and the constraints imposed by female preferences and the availability of alternative partners.