Let's cap off this slideshow with a little navel-gazing, shall we? We humans are blessed with a fascinating heritage, filled with treetop swinging, volcanic eruptions, and mysteries aplenty. One of the most important grandparent species was this adorable quadruped primate, named Aegyptopithecus, who lived about 34 million years ago. This guy is our common ancestor with Old World monkeys like baboons and macaques, and its forward-facing eye sockets are a great omen of human faces to come. The Aegyptopithecus was small, weighing only about 10 pounds, but without its determined survivalism, humans would never have evolved. So thanks for the awesome genes, gramps!