Links to Present-day Primates

Researchers believe that present-day monkeys in South America have probably retained many of the characteristics of their early ancestors. But as the anthropoid primates evolved in Africa, some of the most distinguishing primate characteristics generally became even more distinct—relatively large brains became larger, and grasping hands became more dexterous. Apes, which are similar to monkeys but are larger and smarter, began to appear less than 20 million years ago in Africa. Finally, many anthropologists believe that between 4 million and 2 million years ago, the ancestors of humans arose from apes in Africa.

Although early primates probably emerged during the Paleocene Epoch or perhaps even earlier, the evidence telling scientists what those animals were like is inconclusive. Primates such as Altiatlasius and Altanius, which were part of the transition from the elusive Paleocene species to the primates of the Eocene, could provide vital clues to the origins of primates by linking them with the plesiadapiforms or some other mammals of the Paleocene. But that is far from certain—they may not be linked to any known animals at all. Whatever new fossils are unearthed in coming years, scientists know that the primates of the Eocene gave rise to a remarkable group of animals, the anthropoids, from which the human species evolved. Human beings are the greatest generalists on Earth, climbing not just trees but also mountains, judging distances to the furthermost reaches of the universe, and manipulating tools to build civilizations and to solve the mystery of their own origin.