Evidence has been found that shows that primate ancestors developed the ability to see color. Previously, like most mammals, they could only see shapes using light and shadow. This evolutionary development was retained over millions of years as early primates evolved into modern primates, including humans. What is the best reason why this characteristic was incorporated into future hominid lineages rather than lost?

Evolution is the process by which character trait mutations give a benefit to the gene holder over other members of the same species. Moving from seeing merely shadows and light to seeing colors yields the obvious benefit of more easily detecting predators and prey, thereby at once making the gene holder more alert to potential dangers and more readily able to find food. These obvious benefits made primates more likely to thrive.