for a very long time no one hadthought to look there。 it was only because richard leakey was on a flight that was divertedover the valley that he realized it might be more promising than had been thought。 a teamwas dispatched to investigate； but at first found nothing。 then late one afternoon kamoya kimeu； leakey’s most renowned fossil hunter； found a small piece of hominid brow on a hillwell away from the lake。 such a site was unlikely to yield much； but they dug anyway out ofrespect for kimeu’s instincts and to their astonishment found a nearly plete homo erectusskeleton。 it was from a boy aged between about nine and twelve who had died 1。54 millionyears ago。 the skeleton had “an entirely modern body structure；” says tattersall； in a way thatwas without precedent。 the turkana boy was “very emphatically one of us。”
also found at lake turkana by kimeu was knm…er 1808； a female 1。7 million years old；which gave scientists their first clue that homo erectus was more interesting and plexthan previously thought。 the woman’s bones were deformed and covered in coarse growths；the result of an agonizing condition called hypervitaminosis a； which can e only fromeating the liver of a carnivore。 this told us first of all that homo erectus was eating meat。
even more surprising was that the amount of growth showed that she had lived weeks or evenmonths with the disease。 someone had looked after her。 it was the first sign of tenderness inhominid evolution。
it was also discovered that homo erectus skulls contained （or； in the view of some； possiblycontained） a broca’s area； a region of the frontal lobe of the brain associated with speech。
chimps don’t have such a feature。 alan walker thinks the spinal canal didn’t have the sizeand plexity to enable speech； that they probably would have municated about as wellas modern chimps。 others； notably richard leakey； are convinced they could speak。
for a time； it appears； homo erectus was the only hominid species on earth。 it was hugelyadventurous and spread across the globe with what seems to have been breathtaking rapidity。
the fossil evidence； if taken literally； suggests that some members of the species reached javaat about the same time as； or even slightly before； they left africa。 this has led some hopefulscientists to suggest that perhaps modern people arose not in africa at all； but in asia—whichwould be remarkable； not to say miraculous； as no possible precursor species have ever beenfound anywhere outside africa。 the asian hominids would have had to appear； as it were；spontaneously。 and anyway an asian beginning would merely reverse the problem of theirspread； you would still have to explain how the java people then got to africa so quickly。
there are several more plausible alternative explanations for how homo erectus managedto turn up in asia so soon after its first appearance in africa。 first； a lot of plus…or…minusinggoes into the dating of early human remains。 if the actual age of the african bones is at thehigher end of the range of estimates or the javan ones at the lower end； or both； then there isplenty of time for african erects to find their way to asia。 it is also entirely possible that oldererectus bones await discovery in africa。 in addition； the javan dates could be wrongaltogether。
now for the doubts。 some authorities don’t believe that the turkana finds are homoerectus at all。 the snag； ironically； was that although the turkana skeletons were admirablyextensive； all othererectus fossils are inconclusively fragmentary。 as tattersall and jeffreyschwartz note in extinct humans； most of the turkana skeleton “couldn’t be pared withanything else closely related to it because the parable parts weren’t known！” the turkanaskeletons； they say； look nothing like any asian homo erectus and would never have beenconsidered the same species except that they were contemporaries。 some authorities insist oncalling the turkana specimens （and any others from the same period） homo ergaster。
tattersall and schwartz don’t believe that goes nearly far enough。 they believe it wasergaster“or a reasonably close relative” that spread to asia from africa； evolved intohomo erectus；and then died out。
what is certain is that sometime well over a million years ago； some new； parativelymodern； upright beings left africa and boldly spread out across much of the globe。 theypossibly did so quite rapidly； increasing their range by as much as twenty…five miles a year onaverage； all while dealing with mountain ranges； rivers； deserts； and other impediments andadapting to differences in climate and food sources。 a particular mystery is how they passedalong the west side of the red sea； an area of famously punishing aridity now； but even drierin the past。 it is a curious irony that the conditions that prompted them to leave africa wouldhave made it much more difficult to do so。 yet somehow they managed to find their wayaround every barrier and to thrive in the lands beyond。
and that； i’m afraid； is where all agreement ends。 what happened next in the history ofhuman development is a matter of long and rancorous debate； as we shall see in the nextchapter。
but it is worth remembering； before we move on； that all of these evolutionary jostlingsover five million years； from distant； puzzled australopithecine to fully modern human；produced a creature that is still 98。4 percent genetically indistinguishable from the modernchimpanzee。 there is more difference between a zebra and a horse； or between a dolphin anda porpoise； than there is between you and the furry creatures your distant ancestors left behindwhen they set out to take over the world。
29THE RESTLESS APESOME
：
time about a million and a half years ago； some forgotten genius of the hominidworld did an unexpected thing。 he （or very possibly she） took one stone and carefully used itto shape another。 the result was a simple teardrop…shaped hand axe； but it was the world’sfirst piece of advanced technology。
it was so superior to existing tools that soon others were following the inventor’s lead andmaking hand axes of their own。 eventually whole societies existed that seemed to do littleelse。 “they made them in the thousands；” says ian tattersall。 “there are some places inafrica where you literally can’t move without stepping on them。 it’s strange because they arequite 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 footand a half long and eight inches wide at its widest point； and handed it to me。 it was shapedlike a spearhead； but one the size of a stepping…stone。 as a fiberglass cast it weighed only afew ounces； but the original； which was found in tanzania； weighed twenty…five pounds。 “itwas pletely useless as a tool；” tattersall said。 “it would have taken two people to lift itadequately； 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 somesymbolic importance； but we can only guess what。”
the axes became known as acheulean tools； after st。 acheul； a suburb of amiens innorthern france； where the first examples were found in the nineteenth century； and contrastwith the older； simpler tools known as oldowan； originally found at olduvai gorge intanzania。 in older textbooks； oldowan tools are usually shown as blunt； rounded； hand…sizedstones。 in fact； paleoanthropologists now tend to believe that the tool part of oldowan rockswere 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 eventuallybee 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 theiracheulean tools； too。 they carried them vast distances。 sometimes they even took unshapedrocks 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 andcentral 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 themovius line； dividing the side with acheulean tools from the one without。 the line runs in asoutheasterly direction across europe and the middle east to the vicinity of modern…daycalcutta and bangladesh。 beyond the movius line； across the whole of southeast asia andinto china； only the older； simpler oldowan tools have been found。 we know that homosapiens went far beyond this point； so why would they carry an advanced and treasured stonetechnology 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 nationaluniversity in canberra。 “the whole of modern anthropology was built round the idea thathumans came out of africa in two waves—a first wave of homo erectus； which became javaman and peking man and the like； and a later； more advanced wave of h