A short history of nearly everything

thousands,” says Ian Tattersall. “There are some places in Africa where you literally can’t move without stepping on them. It’s strange because they are quite intensive objects to make. It was as if they made them for the sheer pleasure of it.”

From a shelf in his sunny workroom Tattersall took down an enormous cast, perhaps a foot and a half long and eight inches wide at its widest point, and handed it to me. It was shaped like a spearhead, but one the size of a stepping-stone. As a fiberglass cast it weighed only a few ounces, but the original, which was found in Tanzania, weighed twenty-five pounds. “It was completely useless as a tool,” Tattersall said. “It would have taken two people to lift it adequately, and even then it would have been exhausting to try to pound anything with it.”

“What was it used for then?”

Tattersall gave a genial shrug, pleased at the mystery of it. “No idea. It must have had some symbolic importance, but we can only guess what.”

The axes became known as Acheulean tools, after St. Acheul, a suburb of Amiens in northern France, where the first examples were found in the nineteenth century, and contrast with the older, simpler tools known as Oldowan, originally found at Olduvai Gorge in Tanzania. In older textbooks, Oldowan tools are usually shown as blunt, rounded, hand-sized stones. In fact, paleoanthropologists now tend to believe that the tool part of Oldowan rocks were the pieces flaked off these larger stones, which could then be used for cutting.

Now here’s the mystery. When early modern humans-the ones who would eventually become us-started to move out of Africa something over a hundred thousand years ago, Acheulean tools were the technology of choice. These early Homo sapiens loved their Acheulean tools, too. They carried them vast distances. Sometimes they even took unshaped rocks with them to make into tools later on. They were, in a word, devoted to the technology. But although Acheulean tools have been found throughout Africa, Europe, and western and central Asia, they have almost never been found in the Far East. This is deeply puzzling.

In the 1940s a Harvard paleontologist named Hallum Movius drew something called the Movius line, dividing the side with Acheulean tools from the one without. The line runs in a southeasterly direction across Europe and the Middle East to the vicinity of modern-day Calcutta and Bangladesh. Beyond the Movius line, across the whole of southeast Asia and into China, only the older, simpler Oldowan tools have been found. We know that Homo sapiens went far beyond this point, so why would they carry an advanced and treasured stone technology to the edge of the Far East and then just abandon it?

“That troubled me for a long time,” recalls Alan Thorne of the Australian National University in Canberra. “The whole of modern anthropology was built round the idea that humans came out of Africa in two waves-a first wave of Homo erectus, which became Java Man and Peking Man and the like, and a later, more advanced wave of Homo sapiens, which displaced the first lot. Yet to accept that you must believe that Homo sapiens got so far with their more modern technology and then, for whatever reason, gave it up. It was all very puzzling, to say the least.”

As it turned out, there would be a great deal else to be puzzled about, and one of the most puzzling findings of all would come from Thorne’s own part of the world, in the outback of Australia. In 1968, a geologist named Jim Bowler was poking around on a long-dried lakebed called Mungo in a parched and lonely corner of western New South Wales when something very unexpected caught his eye. Sticking out of a crescent-shaped sand ridge of a type known as a lunette were some human bones. At the time, it was believed that humans had been in Australia for no more than 8,000 years, but Mungo had been dry for 12,000 years. So what was anyone doing in such an inhospitable place?

The answer, provided by carbon dating, was that the bones’ owner had lived there when Lake Mungo was a much more agreeable habitat, a dozen miles long, full of water and fish, fringed by pleasant groves of casuarina trees. To everyone’s astonishment, the bones turned out to be 23,000 years old. Other bones found nearby were dated to as much as 60,000 years. This was unexpected to the point of seeming practically impossible. At no time since hominids first arose on Earth has Australia not been an island. Any human beings who arrived there must have come by sea, in large enough numbers to start a breeding population, after crossing sixty miles or more of open water without having any way of knowing that a convenient landfall awaited them. Having landed, the Mungo people had then found their way more than two thousand miles inland from Australia’s north coast-the presumed point of entry-which suggests, according to a report in the Proceedings of the National Academy of Sciences, “that people may have first arrived substantially earlier than 60,000 years ago.”

How they got there and why they came are questions that can’t be answered. According to most anthropology texts, there’s no evidence that people could even speak 60,000 years ago, much less engage in the sorts of cooperative efforts necessary to build ocean-worthy craft and colonize island continents.

“There’s just a whole lot we don’t know about the movements of people before recorded history,” Alan Thorne told me when I met him in Canberra. “Do you know that when nineteenth-century anthropologists first got to Papua New Guinea, they found people in the highlands of the interior, in some of the most inaccessible terrain on earth, growing sweet potatoes. Sweet potatoes are native to South America. So how did they get to Papua New Guinea? We don’t know. Don’t have the faintest idea. But what is certain is that people have been moving around with considerable assuredness for longer than traditionally thought, and almost certainly sharing genes as well as information.”

The problem, as ever, is the fossil record. “Very few parts of the world are even vaguely amenable to the long-term preservation of human remains,” says Thorne, a sharp-eyed man with a white goatee and an intent but friendly manner. “If it weren’t for a few productive areas like Hadar and Olduvai in east Africa we’d know frighteningly little. And when you look elsewhere, often we do know frighteningly little. The whole of India has yielded just one ancient human fossil, from about 300,000 years ago. Between Iraq and Vietnam-that’s a distance of some 5,000 kilometers-there have been just two: the one in India and a Neandertal in Uzbekistan.” He grinned. “That’s not a whole hell of a lot to work with. You’re left with the position that you’ve got a few productive areas for human fossils, like the Great Rift Valley in Africa and Mungo here in Australia, and very little in between. It’s not surprising that paleontologists have trouble connecting the dots.”

The traditional theory to explain human movements-and the one still accepted by the majority of people in the field-is that humans dispersed across Eurasia in two waves. The first wave consisted of Homo erectus, who left Africa remarkably quickly-almost as soon as they emerged as a species-beginning nearly two million years ago. Over time, as they settled in different regions, these early erects further evolved into distinctive types-into Java Man and Peking Man in Asia, and Homo heidelbergensis and finally Homo neanderthalensis in Europe.

Then, something over a hundred thousand years ago, a smarter, lither species of creature-the ancestors of every one of us alive today-arose on the African plains and began radiating outward in a second wave. Wherever they went, according to this theory, these new Homo sapiens displaced their duller, less adept predecessors. Quite how they did this has always been a matter of disputation. No signs of slaughter have ever been found, so most authorities believe the newer hominids simply outcompeted the older ones, though other factors may also have contributed. “Perhaps we gave them smallpox,” suggests Tattersall. “There’s no real way of telling. The one certainty is that we are here now and they aren’t.”

These first modern humans are surprisingly shadowy. We know less about ourselves, curiously enough, than about almost any other line of hominids. It is odd indeed, as Tattersall notes, “that the most recent major event in human evolution-the emergence of our own species-is perhaps the most obscure of all.” Nobody can even quite agree where truly modern humans first appear in the fossil record. Many books place their debut at about 120,000 years ago in the form of remains found at the Klasies River Mouth in South Africa, but not everyone accepts that these were fully modern people. Tattersall and Schwartz maintain that “whether any or all of them actually represent our species still awaits definitive clarification.”

The first undisputed appearance of Homo sapiens is in the eastern Mediterranean, around modern-day Israel, where they begin to show up about 100,000 years ago-but even there they are described (by Trinkaus and Shipman) as “odd, difficult-to-classify and poorly known.” Neandertals were already well established in the region and had a type of tool kit known as Mousterian, which the modern humans evidently found worthy enough to borrow. No Neandertal remains have ever been found in north Africa, but their tool kits turn up all over the place. Somebody must have taken them there: modern humans are the only candidate. It is also known that Neandertals and modern humans coexisted in some fashion for tens of thousands of years in the Middle East. “We don’t know if they time-shared the same space or actually lived side by side,” Tattersall says, but the moderns continued happily to use Neandertal tools-hardly convincing evidence of overwhelming superiority.