“Our earliest ancestors were descended from primates who thrived for millions of years in a treetop environment, and who in the process had evolved one of the most remarkable visual systems in nature. To move quickly and efficiently in such a world, they developed extremely sophisticated eye and muscle coordination. Their eyes slowly evolved into a full-frontal position on the face, giving them binocular, stereoscopic vision. This system provides the brain a highly accurate three-dimensional and detailed perspective, but is rather narrow. Animals that possess such vision—as opposed to eyes on the side or half side—are generally efficient predators like owls or cats. They use this powerful sight to home in on prey in the distance. Tree-living primates evolved this vision for a different purpose—to navigate branches, and to spot fruits, berries, and insects with greater effectiveness. They also evolved elaborate color vision.”