The 160,000-Year-Old Man

Perhaps the most intriguing discovery, however, is that these ancestors behaved like us in at least one poignant way: all three skulls were deliberately tampered with after death, evidently as part of some sort of mortuary practice. "This," says White, "is the earliest evidence of hominids continuing to handle skulls long after the individual died."

"Handle" is an understatement. Cut marks on the skulls indicate that the overlying skin, muscles, nerves and blood vessels were removed, probably with an obsidian flake. Then a stone tool was scraped back and forth, creating faint clusters of parallel lines. The modification of the child's skull is even more dramatic. The lower jaw was detached, and soft tissues at the base of the head were cut away, leaving fine, deep cut marks. Portions of the skull were smoothed and polished.

"The cut marks aren't a classic sign of cannibalism," White said while showing the skulls to a TIME reporter in Addis Ababa. "If you wanted to get at the brain in order to eat it, you'd just smash open the skull." Instead, he suspects, the scratches might be a form of decoration. As for the polished areas, he says, "we know they weren't caused by the environment, because the marks go across the breaks between the recovered pieces. The child's skull looks as though it has been fondled repeatedly."

Despite this evidence of ritualistic behavior, Homo sapiens still had a long way to go. What may be the earliest art, for example — pieces of red ocher engraved with abstract designs found in South Africa — would not appear for nearly 80,000 more years, while the spectacular cave paintings in Spain and France would not be created for another 40,000 years after that. Clearly, being like us physically was not enough by itself to trigger the cultural complexity — innovation, creativity, symbolism and perhaps spoken language — that distinguishes us from all other animals.

So what triggered those changes? Theories include hardships of the last Ice Age or random genetic mutations, but nobody really knows. Which is why paleontologists like White and Asfaw are going back to search for new clues in the ancient soil of eastern Africa.