The interaction between predator and prey is a major force driving evolution. This video segment from Evolution: Evolutionary Arms Race tells the story of a species of newt and its garter snake predator. Although the skin of the newt secretes enough toxin to kill 12 adult humans, the garter snake can eat the newt and survive. Scientists Edmund Brodie, Jr., and Edmund Brodie III, a father and son team, investigate this relationship and the factors that complicate this seemingly simple escalation of adaptations.