erectus did not distinguish themselves in brain size, brain structure is more telling. They were the first of our ancestors to have an asymmetric brain, as modern humans do; Australopithecus species do not. Asymmetry is a mark of increasing specialization and therefore complex cognitive ability. Erectus used it to, among other things, discover and tame fire. What they did not use it for is technology. Tools found with the Dmanisi fossils include cutting flakes, rock "cores" from which flakes were made and a chopper, all primitive even for their time. "The old idea that you needed a master's degree in stone tools to leave Africa is crazy," says Bernard Wood.

Republic of Georgia at a site called Dmanisi, scientists have unearthed 1.8 million-year-old fossils of erectus, "the first outpost we know of beyond Africa," says G. Philip Rightmire of Binghamton University. "It looks like these people got out and materialized everywhere in Eurasia," showing up as Java man and Peking man, among others. (None of the original fossils of Peking man survived World War II. Packed for shipment to the United States for safekeeping, they disappeared in transit; only casts remain.) Ancient humans didn't just walk: they reached Australia 60,000 years ago, across miles of open ocean.