Chimpanzees and baboons are social primates. They live in groups and cooperate with each other. Studying social primates can show researchers who, why, and how primates live together. Many social primates live with their relatives. These group-living primates help warn each other of predators. They cooperate to defend resources and even to go hunting. Primate kids learn how to behave by watching adults. To do all this, they need to know about the different members of their group -- if they are related, how skilled they are, and if they will get any benefit from cooperating. Humans today live in huge groups and cooperate with many people, even if they don't get any reward. Our early hominin ancestors were probably like chimps and baboons. They could protect against predators, hunt together, and care for children. Eventually, this led to them becoming even more social.