This text provides a detailed account of a predator-prey relationship involving two primates, documents a six-year investigation into how the risk of predation molds primate society. It explores how predation by wild chimpanzees - in the Gombe National Park - has influenced the behaviour, ecology, and demography of a population of red colobus monkeys. As he explores the effects of chimpanzees' hunting, Craig Stanford also asks why these creatures prey on the red colobus. Because chimpanzees are often used as models of how early humans might have lived. These findings offer insight into the possible role of early hominids as predators.