"It's the people around us who do that teaching—often quite well. Once again, however, humans aren't the ones who dreamed up such a mentoring system. At the Arnhem Zoo in the Netherlands, de Waal was struck by how vigorously apes enforced group norms one evening when the zookeepers were calling their chimpanzees in for dinner. The keepers' rule at Arnhem was that no chimps would eat until the entire community was present, but two adolescents grew willful, staying outside the building. The hours it took to coax them inside caused the mood in the hungry colony to turn surly. That night the keepers put the delinquents to bed in a separate area—a sort of protective custody to shield them from reprisals. But the next day the adolescents were on their own, and the troop made its feelings plain, administering a sound beating. The chastened chimps were the first to come in that evening. Animals have what de Waal calls "oughts"—rules that the group must follow—and the community enforces them."Another story about evolutionary morality, showing that we're more in need for community than God to behave moral.