For millennia, adults have told children stories not only to entertain but also to impart important moral lessons to promote prosocial behaviors. Many such stories contain anthropomorphized animals because it is believed that children learn from anthropomorphic stories as effectively, if not better than, from stories with human characters, and thus are more inclined to act according to the moral lessons of the stories. Here we experimentally tested this belief by reading preschoolers a sharing story with either human characters or anthropomorphized animal characters. Reading the human story significantly increased preschoolers' altruistic giving but reading the anthropomorphic story or a control story decreased it. Thus, contrary to the common belief, realistic stories, not anthropomorphic ones, are better for promoting young children's prosocial behavior.