Scientists from the Max Planck Institute for Evolutionary Anthropology studied chimpanzees in Taï National Park in Côte d’Ivoire. The project followed four groups of chimpanzees for twenty years. They found that female chimpanzees patrolled territory and fought with chimpanzees from other groups too, not just males. The scientists wondered if human beings have been imagining that male chimpanzees do all the fighting because we think of human warfare being done mostly by men.