How female friendships help chimp babies survive

Female chimpanzees that forge strong, grooming-rich friendships with other females dramatically boost their infants’ odds of making it past the perilous first year—no kin required. Three decades of Gombe observations show that well-integrated mothers enjoy a survival rate of up to 95% for their young, regardless of male allies or sisters. The payoff may come from shared defense, reduced stress, or better access to food, hinting that such alliances laid early groundwork for humanity’s extraordinary cooperative spirit.