Sometime within the last 100,000 years, say many anthropologists, Homo sapiens left Africa, traveled the world, and muscled aside all the other hominids on Earth. The "Out of Africa" theory makes a tidy story, but a new analysis of an ancient Australian skeleton suggests it may be wrong.
The skeleton, discovered in 1974 in a dry lake in New South Wales, was originally thought to be about 40,000 years old. But by combining three dating methods, Alan Thorne of Australian National University in Canberra found the bones are at least 60,000 years old. He estimates that the first humans actually reached the northern Australian coast no less than 70,000 years ago and then slowly dispersed across the continent.
The earliest Homo sapiens from Africa have a more robust build than the delicate Australian man. "But if the Out of Africa people are right, then the first Australians should look like those humans," says Thorne. He thinks the Australian skeleton supports a very different interpretation, in which ancestral humans emerged from Africa roughly 2 million years ago, and developed into separate races in widely dispersed locations.
The Australian colonists must have been bold adventurers. Their trip from Indonesia or the Philippines included long stretches with no land in sight. "Getting to Australia involves going beyond the horizon," says Thorne. "We're talking about the world's earliest ocean travel."