28 THE MYSTERIOUS BIPED

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    JUST BEFORE CHRISTMAS 1887, a young Dutch doctor with an un-Dutame, MarieEugène Fran?ois Thomas Dubois, arrived in Sumatra, ich East Indies, with theiion of finding the earliest human remains oh.

    1Several things were extraordinary about this. To begin with, no one had ever gone lookingfor a human bones before. Everything that had been found to this point had been foundactally, and nothing in Dubois’s background suggested that he was the ideal didate tomake the process iional. He was an anatomist by training with no background iology. Nor was there any special reason to suppose that the East Indies would holdearly human remains. Logic dictated that if a people were to be found at all, it would beon a large and long-populated landmass, not in the parative fastness of an archipelago.

    Dubois was driven to the East Indies on nothing strohan a hunch, the availability ofemployment, and the knowledge that Sumatra was full of caves, the enviro in whichmost of the important hominid fossils had so far been found. What is most extraordinary in allthis—nearly miraculous, really—is that he found what he was looking for.

    At the time Dubois ceived his plan to search for a missing link, the human fossil recordsisted of very little: five inplete Neaal skeletons, one partial jawbone of uainprovenance, and a half-dozen ice-age humaly found by railway workers in a cave at acliff called agnon near Les Eyzies, France. Of the Neaal spes, the bestpreserved was sitting unremarked on a shelf in London. It had been found by workers blastingrock from a quarry in Gibraltar in 1848, so its preservation was a wonder, but unfortunatelyno o appreciated what it was. After being briefly described at a meeting of the GibraltarStific Society, it had beeo the Hunterian Museum in London, where it remainedundisturbed but for an occasional light dusting for over half a tury. The first formaldescription of it wasn’t written until 1907, and then by a geologist named William Sollas“with only a passing peten anatomy.”

    So ihe name and credit for the discovery of the first early humao theNeander Valley in Germany—not unfittingly, as it happens, for by uny cid<q></q>eneander in Greek means “new man.” There in 1856 workmen at another quarry, in a cliff faceoverlooking the Düssel River, found some curious-looking bones, which they passed to alocal schoolteacher, knowing he had an i in all things natural. To his great credit theteacher, Johann Karl Fuhlrott, saw that he had some ype of human, though quite what itwas, and how special, would be matters of dispute for some time.

    Many people refused to accept that the Neaal bones were a at all. August Mayer,a professor at the Uy of Bonn and a man of influence, insisted that the bones were1Though Dutch, Dubois was from Eijsden, a town b the French-speaking part of Belgium.

    merely those of a Mongolian Cossack soldier who had been wounded while fighting inGermany in 1814 and had crawled into the cave to die. Hearing of this, T. H. Huxley inEngland drily observed how remarkable it was that the soldier, though mortally wounded, hadclimbed sixty feet up a cliff, divested himself of his clothing and personal effects, sealed thecave opening, and buried himself uwo feet of soil. Another anthropologist, puzzlihe Neaal’s heavy bre, suggested that it was the result of long-term frowningarising from a poorly healed forearm fracture. (In their eagero reject the idea of earlierhumans, authorities were often willing to embrace the most singular possibilities. At about thetime that Dubois was setting out for Sumatra, a skeleton found in Périgueux was fidentlydeclared to be that of an Eskimo. Quite what an a Eskimo was doing in southwestFrance was never fortably explained. It was actually an early agnon.)It was against this background that Dubois began his search for a human bones. Hedid no digging himself, but instead used fifty victs lent by the Dutch authorities. For a yearthey worked on Sumatra, then transferred to Java. And there in 1891, Dubois—or rather histeam, for Dubois himself seldom visited the sites—found a se of a human iumnow known as the Trinil skullcap. Though only part of a skull, it showed that the owner hadhad distinctly nonhumaures but a much larger brain than any ape. Dubois called itAnthropithecus erectus (later ged for teical reasons to Pithethropus erectus) anddeclared it the missing liween apes and humans. It quickly became popularized as “JavaMan.” Today we know it as Homo erectus.

    The  year Dubois’s workers found a virtually plete thighbohat lookedsurprisingly modern. In fact, many anthropologists think itis modern, and has nothing to dowith Java Man. If it is aus bo is unlike any other found sinoheless Duboisused the thighboo deduce—correctly, as it turned out—that Pithethropus walkedupright. He also produced, with nothing but a scrap of ium and oooth, a model of theplete skull, which also proved unily accurate.

    In 1895, Dubois returo Europe, expeg a triumphal reception. In fact, he met nearlythe opposite reaost stists disliked both his clusions and the arrogant manner inwhich he presehem. The skullcap, they said, was that of an ape, probably a gibbon, andnot of any early human. Hoping to bolster his case, in 1897 Dubois allowed a respectedanatomist from the Uy of Strasbustav Schwalbe, to make a cast of the skullcap.

    To Dubois’s dismay, Schwalbe thereupon produced a monograph that received far moresympathetic attention than anything Dubois had written and followed with a lecture tour inwhich he was celebrated nearly as warmly as if he had dug up the skull himself. Appalled atered, Dubois withdrew into an undistinguished position as a professor of geology at theUy of Amsterdam and for the wo decades refused to let anyone examine hisprecious fossils again. He died in 1940 an unhappy man.

    Meanwhile, and half a world away, in late 1924 Raymond Dart, the Australian-born head ofanatomy at the Uy of the Witwatersrand in Johannesburg, was sent a small butremarkably plete skull of a child, with an intact face, a lower jaw, and what is known asan endocast—a natural cast of the brain—from a limestone quarry on the edge of the KalahariDesert at a dusty spot called Taung. Dart could see at ohat the Taung skull was not of aHomo erectus like Dubois’s Java Man, but from an earlier, more apelike creature. He placedits age at two million years and dubbed it Australopithecus afrius, or “southern ape man ofAfrica.” In a report to Nature, Dart called the Taung remains “amazingly human” andsuggested the need for airely new family, Homo simiadae (“the man-apes”), toaodate the find.

    The authorities were even less favorably disposed to Dart than they had been to Dubois.

    Nearly everything about his theory—indeed, nearly everything about Dart, it appears—ahem. First he had proved himself lamentably presumptuous by dug theanalysis himself rather than calling on the help of more worldly experts in Europe. Even hischosen name, Australopithecus, showed a lack of scholarly application, bining as it didGreek and Latin roots. Above all, his clusions flew in the face of accepted wisdom.

    Humans and apes, it was agreed, had split apart at least fifteen million years ago in Asia. Ifhumans had arisen in Africa, why, that would make us Negroid, foodness sake. It wasrather as if someone w today were to annouhat he had found the aral bones ofhumans in, say, Missouri. It just didn’t fit with what was known.

    Dart’s sole supporter of note was Robert Broom, a Scottish-born physi andpaleontologist of siderable intelled cherishably etriature. It was Broom’shabit, for instao do his fieldwork naked when the weather was warm, which was often.

    He was also known for dug dubious anatomical experiments on his poorer and moretractable patients. Wheients died, which was also often, he would sometimes burytheir bodies in his back garden to dig up for study later.

    Broom was an aplished paleontologist, and since he was also resident in South Africahe was able to exa?99ｌib.mihe Taung skull at first hand. He could see at ohat it ortant as Dart supposed and spoke out vigorously on Dart’s behalf, but to no effect. Forthe  fifty years the received wisdom was that the Taung child e and nothingmore. Most textbooks didn’t eveion it. Dart spent five years w up a monograph,but could find no oo publish it. Eventually he gave up the quest to publish altogether(though he did tinue hunting for fossils). For years, the skull—today reized as ohe supreme treasures of anthropology—sat as a paperweight on a colleague’s desk.

    At the time Dart made his annou in 1924, only four categories of a hominidwere known—Homo heidelbergensis, Homo rhodesiensis, Neaals, and Dubois’s JavaMan—but all that was about to ge in a very big way.

    First, in a, a gifted adian amateur named Davidson Black began to poke around ata place, Dragon Bone Hill, that was locally famous as a hunting ground for old bones.

    Unfortunately, rather than preserving the bones for study, the ese ground them up tomake medies. We  only guess horiceless Homo erectus bones ended up as asort of ese equivalent of bicarbonate of soda. The site had been much denuded by thetime Black arrived, but he found a single fossilized molar and on the basis of that alone quitebrilliantly annouhe discovery of Sinanthropus pekinensis, which quickly became knoeking Man.

    At Black’s urging, more determined excavations were uaken and many other bonesfound. Unfortunately all were lost the day after the Japaa Pearl Harbor in 1941when a ti of U.S. Marirying to spirit the bones (and themselves) out of thetry, was intercepted by the Japanese and imprisoned. Seeing that their crates held nothingbut bohe Japanese soldiers left them at the roadside. It was the last that was ever seen ofthem.

    In the meantime, ba Dubois’s old turf of Java, a team led by Ralph von Koenigswaldhad found anroup of early humans, which became known as the Solo People from thesite of their discovery on the Solo River at Ngandong. Koenigswald’s discoveries might havebeen more impressive still but for a tactical error that was realized too late. He had offeredlocals tes for every piece of hominid bohey could e up with, then discovered tohis horror that they had beehusiastically smashing large pieces into small oomaximize their ine.

    In the following years as more bones were found and identified there came a flood of newnames—Homnasis, Australopithecus transvaalensis, Paranthropus crassidens,Zinjanthropus boisei,and scores of others, nearly all involving a new genus type as well as anew species. By the 1950s, the number of named hominid types had risen to fortably overa huo add to the fusion, individual forms ofte by a succession of differentnames as paleoanthropologists refined, reworked, and squabbled over classifications. SoloPeople were known variously as Homo soloensis, Homenius asiaticus, Homoneahalensis soloensis, Homo sapiens soloensis, Homo erectus erectus, and, finally, plainHomo erectus .

    In an attempt to introdue order, in 1960 F. Clark Howell of the Uy ofChicago, following the suggestions of Ernst Mayr and others the previous decade, proposedcutting the number of geo just two—Australopithecus and Homo —and rationalizingmany of the species. The Java and Peking men both became Homo erectus. For a time orderprevailed in the world of the hominids.

    2It didn’t last.

    After about a decade of parative calm, paleoanthropology embarked on another periodof swift and prolific discovery, which hasn’t abated yet. The 1960s produced Homo habilis,thought by some to be the missing liween apes and humans, but thought by others not tobe a separate species at all. Then came (among many others) Homaster, Homolouisleakeyi, Homo rudolfensis, Homo microus, and Homo antecessor, as well as a raft ofaustralopithees: A.afarensis, A. praegens, A. ramidus, A. walkeri, A. anamensis, and stillothers. Altogether, some twenty types of hominid are reized ierature today.

    Unfortunately, almost no two experts reize the same twenty.

    Some tio observe the two hominid genera suggested by Howell in 1960, but othersplae of the australopithees in a separate genus called Paranthropus , and still othersadd an earlier group called Ardipithecus. Some put praegens into Australopithecus and someinto a new classification, Homo antiquus, but most don’t reize praegens as a separatespecies at all. There is ral authority that rules ohings. The only way a namebees accepted is by sensus, and there is often very little of that.

    A big part of the problem, paradoxically, is a she of evidence. Sihe dawn of time,several billion human (or humanlike) beings have lived, each tributing a little geicvariability to the total human stock. Out of this vast he whole of our uandingof humaory is based on the remains, often exceedingly fragmentary, of perhaps fivethousand individuals. “You could fit it all into the back of a pickup truck if you didn’t mind2Humans are put in the lamely Homimdae. Its members, traditionally called hominids, include any creatures(includiines) that are more closely related to us than to any surviving chimpahe apes,meanwhile, are lumped together in a family called Pongidae. Many authorities believe that chimps, gorillas, andutans should also be included in this family, with humans and chimps in a subfamily called Homininae.

    The upshot is that the creatures traditionally called hominids bee, uhis arra, hominins. (Leakeyand others insist on that designation.) Hominoidea is the name of the aue sunerfamily whicludes us.

    how much you jumbled everything up,” Ian Tattersall, the bearded and friendly curator ofanthropology at the Ameri Museum of Natural History in New York, replied when I askedhim the size of the total world archive of hominid and early human bones.

    The she wouldn’t be so bad if the bones were distributed evenly through time andspace, but of course they are not. They appear randomly, often in the most tantalizing fashion.

    Homo erectus walked the Earth for well over a million years and inhabited territory from theAtlantic edge of Europe to the Pacific side of a, yet if yht back to life everyHomo erectus individual whose existence we  vouch for, they wouldn’t fill a school bus.

    Homo habilis sists of even less: just two partial skeletons and a number of isolated limbbones. Something as short-lived as our own civilization would almost certainly not be knownfrom the fossil record at all.

    “In Europe,” Tattersall offers by way of illustration, “you’ve got hominid skulls in Geiadated to about 1.7 million years ago, but then you have a gap of almost a million years beforethe  remains turn up in Spain, right oher side of the ti, and then you’ve gotanother 300,000-year gap before you get a Homo heidelbergensis in Germany—and none of<bdi>.</bdi>them looks terribly much like any of the others.” He smiled. “It’s from these kinds mentary pieces that you’re trying to work out the histories of entire species. It’s quite atall order. We really have very little idea of the relationships between many a species—which led to us and which were evolutionary dead ends. Some probably don’t deserve tarded as separate species at all.”

    It is the patess of the record that makes eaew find look so sudden and distinct fromall the others. If we had tens of thousands of skeletons distributed at regular intervals throughthe historical record, there would be appreciably more degrees of shading. Whole new speciesdon’t emerge instantaneously, as the fossil record implies, but gradually out of other, existingspecies. The closer you go back to a point of divergehe closer the similarities are, so thatit bees exceedingly difficult, and sometimes impossible, to distinguish a late Homoerectus from an early Homo sapiens, si is likely to be both aher. Similardisagreements  often arise over questions of identification frmentary remains—deg, for instance, whether a particular bone represents a female Australopithecus boiseior a male Homo habilis.

    With so little to be certain about, stists often have to make assumptions based on otherobjects found nearby, and these may be little more than valiant guesses. As Alan Walker andPat Shipman have drily observed, if you correlate tool discovery with the species of creaturemost often found nearby, you would have to clude that early hand tools were mostly madeby antelopes.

    Perhaps nothier typifies the fusion than the fragmentary bundle of tradisthat was Homo habilis. Simply put, habilis bones make no sense. When arranged in sequehey show males and females evolving at different rates and in different dires—the malesbeing less apelike and more human with time, while females from the same period appearto be moving away from humareater apeness. Some authorities don’t believehabilis is a valid category at all. Tattersall and his colleague Jeffrey Schwartz dismiss it as amere “wastebasket species”—oo whirelated fossils “could be vely swept.”

    Even those who see habilis as an indepe species don’t agree oher it is of the samegenus as us or is from a side branch that never came to anything.

    Finally, but perhaps above all, human nature is a factor in all this. Stists have a naturaltendency to interpret finds in the way that most flatters their stature. It is a rare paleontologistindeed who annouhat he has found a cache of bones but that they are nothing to getexcited about. Or as John Reader uatedly observes in the book Missing Links, “It isremarkable how often the first interpretations of new evidence have firmed thepreceptions of its discoverer.”

    All this leaves ample room fuments, of course, and nobody likes tue more thahropologists. “And of all the disciplines in sce, paleoanthropology boasts perhapsthe largest share of egos,” say the authors of the ret Java Man —a book, it may be hat itself devotes long, wonderfully unselfscious passages to attacks on the inadequaciesof others, in particular the authors’ former close colleague Donald Johanson. Here is a smallsampling:

    In our years of collaboration at the institute he [Johanson] developed a well-deserved, if unfortunate, reputation for uable and high-decibel personalverbal assaults, sometimes apanied by the tossing around of books orwhatever else came vely to hand.

    So, bearing in mind that there is little you  say about humaory that won’t bedisputed by someone somewhere, other than that we most certainly had one, what we thinkwe know about who we are and where we e from is roughly this:

    For the first 99.99999 pert of our history as anisms, we were in the same aralline as chimpanzees. Virtually nothing is known about the prehistory of chimpanzees, butwhatever they were, we were. Then about seven million years ago something major happened.

    A group of new beings emerged from the tropical forests of Afrid began to move abouton the open savanna.

    These were the australopithees, and for the  five million years they would be theworld’s dominant hominid species. (Austral is from the Latin for “southern” and has noe in this text to Australia.) Australopithees came in several varieties, someslender and gracile, like Raymond Dart’s Taung child, others more sturdy and robust, but allwere capable of walking upright. Some of these species existed for well over a million years,others for a more modest few huhousand, but it is worth bearing in mind that even theleast successful had histories many times lohan we have yet achieved.

    The most famous hominid remains in the world are those of a 3.18-million-year-oldaustralopithee found at Hadar ihiopia in 1974 by a team led by Donald Johanson.

    Formally known as A.L. (for “Afar Locality”) 288–1, the skeleton became more familiarlyknown as Lucy, after the Beatles song “Lu the Sky with Diamonds.” Johanson has neverdoubted her importance. “She is our earliest aor, the missing liween ape andhuman,” he has said.

    Lucy was tiny—just three and a half feet tall. She could walk, though how well is a matterof some dispute. She was evidently a good climber, too. Much else is unknown. Her skull wasalmost entirely missing, so little could be said with fidence about her brain size, thoughskull fragments suggested it was small. Most books describe Lucy’s skeleton as being 40pert plete, though some put it closer to half, and one produced by the AmeriMuseum of Natural History describes Lucy as two-thirds plete. The BBC television seriesApe Man actually called it “a plete skeleton,” even while showing that it was anythingbut.

    A human body has 206 bones, but many of these are repeated. If you have the left femurfrom a spe, you don’t he right to know its dimensions. Strip out all the redundantbones, and the total you are left with is 120—what is called a half skeleton. Even by this fairlyaodating standard, and even ting the slightest fragment as a full bone, Lustituted only 28 pert of a half skeleton (and only about 20 pert of a full one).

    In The Wisdom of the Bones, Alan Walker rets how he once asked Johanson how hehad e up with a figure of 40 pert. Johanson breezily replied that he had disted the106 bones of the hands a—more than half the body’s total, and a fairly important half,too, one would have thought, since Lucy’s principal defining attribute was the use of thosehands ao deal with a ging world. At all events, rather less is known about Lucythan is generally supposed. It isn’t even actually known that she was a female. Her sex ismerely presumed from her diminutive size.

    Two years after Lucy’s discovery, at Laetoli in Tanzania Mary Leakey found footprints leftby two individuals from—it is thought—the same family of hominids. The prints had beenmade when two australopithees had walked through muddy ash following a voliceruption. The ash had later hardened, preserving the impressions of their feet for a distance ofover twenty-three meters.

    The Ameri Museum of Natural History in New York has an abs diorama thatrecords the moment of their passing. It depicts life-sized re-creations of a male and a femalewalking side by side across the a Afri plain. They are hairy and chimplike indimensions, but have a bearing and gait that suggest humanness. The most strikiure ofthe display is that the male holds his left arm protectively around the female’s shoulder. It is atender and affeg gesture, suggestive of close bonding.

    The tableau is doh such vi that it is easy to overlook the sideration thatvirtually everything above the footprints is imaginary. Almost every external aspect of thetwo figures—degree of hairiness, facial appendages (whether they had human noses or chimpnoses), expressions, skin color, size and shape of the female’s breasts—is necessarilysuppositional. We ’t even say that they were a couple. The female figure may in fact havebeen a child. Nor  we be certain that they were australopithees. They are assumed to beaustralopithees because there are no other known didates.

    I had been told that they were posed like that because during the building of the dioramathe female figure kept toppling over, but Ian Tattersall insists with a laugh that the story isuntrue. “Obviously we don’t know whether the male had his arm around the female or not,but we do know from the stride measurements that they were walking side by side and closetogether—close enough to be toug. It was quite an exposed area, so they were probablyfeeling vulnerable. That’s why we tried to give them slightly worried expressions.”

    I asked him if he was troubled about the amount of lise that was taken in restrugthe figures. “It’s always a problem in making re-creations,” he agreed readily enough. “Youwouldn’t believe how much discussion  go into deg details like whether Neaalshad eyebrows or not. It was just the same for the Laetoli figures. We simply ’t know thedetails of what they looked like, but we  vey their size and posture and make somereasonable assumptions about their probable appearance. If I had it to do again, I think I mighthave made them just slightly more apelike and less human. These creatures weren’t humans.

    They were bipedal apes.”

    Until very retly it was assumed that we were desded from Lud the Laetolicreatures, but now many authorities aren’t so sure. Although certain physical features (theteeth, for instance) suggest a possible liween us, other parts of the australopitheeanatomy are more troubling. In their book Extinct Humans, Tattersall and Schwartz point outthat the upper portion of the human femur is very like that of the apes but not of theaustralopithees; so if Lucy is in a direct liween apes and modern humans, it meanswe must have adopted an australopithee femur for a million years or so, then gone back toan ape femur when we moved on to the  phase of our development. They believe, in fact,that not only was Luot our aor, she wasn’t even much of a walker.

    “Lud her kind did not loote in anything like the modern human fashion,” insistsTattersall. “Only when these hominids had to travel between arboreal habitats would they findthemselves walking bipedally, ‘forced’ to do so by their own anatomies.” Johansoaccept this. “Lucy’s hips and the muscular arra of her pelvis,” he has written, “wouldhave made it as hard for her to climb trees as it is for modern humans.”

    Matters grew murkier still in 2001 and 2002 when four exceptional new spes werefound. One, discovered by Meave Leakey of the famous fossil-hunting family at LakeTurkana in Kenya and called Kenyanthropus platyops (“Kenyan flat-face”), is from about thesame time as Lud raises the possibility that it was our aor and Lucy was anunsuccessful side branch. Also found in 2001 were Ardipithecus ramidus kadabba, dated atbetween 5.2 million and 5.8 million years old, and Orrorin tugenensis, thought to be 6 millionyears old, making it the oldest hominid yet found—but only for a brief while. In the summerof 2002 a French team w in the Djurab Desert of Chad (ahat had never beforeyielded a bones) found a hominid almost 7 million years old, which they labeledSahelanthropus tchadensis. (Some critics believe that it was not human, but an early ape andtherefore should be called Sahelpithecus.) All these were early creatures and quite primitivebut they walked upright, and they were doing so far earlier than previously thought.

    Bipedalism is a demanding and risky strategy. It means refashioning the pelvis into a fullload-bearing instrument. To preserve the required strength, the birth al must beparatively narrow. This has two very signifit immediate sequences and one loerm one. First, it means a lot of pain for any birthing mother and a greatly increased dangerof fatality to mother and baby both. Moreover to get the baby’s head through such a tightspace it must be born while its brain is still small—and while the baby, therefore, is stillhelpless. This means long-term infant care, whi turn implies solid male–female bonding.

    All this is problematiough when you are the intellectual master of the pla, but whenyou are a small, vulnerable australopithee, with a brain about the size of an e,3therisk must have been enormous.

    3Absolute brain size does not tell you everything-or possibly sometimes even much. Elephants and whales bothhave brains larger than ours, but you wouldnt have much trouble outwitting them in traegotiations. It isrelative size that matters, a point that is often overlooked. As Gould notes, A. afrius had a brain of only 450cubitimeters, smaller than that of a gorilla. But a typical afrius male weighed less than a hundredpounds, and a female much less still, whereas gorillas  easily top out at 600 pounds (Gould pp. 181-83).

    So why did Lud her kind e down from the trees and out of the forests? Probablythey had no choice. The slow rise of the Isthmus of Panama had cut the flow of waters fromthe Pacifito the Atlantic, diverting warming currents away from the Arctid leading tothe o of an exceedingly sharp ice age in northern latitudes. In Africa, this would haveproduced seasonal drying and cooling, gradually turning juo savanna. “It was not somuch that Lud her like left the forests,” John Gribbin has written, “but that the forestsleft them.”

    But stepping out onto the open savanna also clearly left the early hominids much moreexposed. An upright hominid could see better, but could also be seeer. Even now as aspecies, we are almost preposterously vulnerable in the wild. Nearly every large animal you care to name is stronger, faster, and toothier than us. Faced with attack, modern humanshave only two advantages. We have a good brain, with which we  devise strategies, andwe have hands with which we  fling or brandish hurtful objects. We are the only creaturethat  harm at a distance. We  thus afford to be physically vulnerable.

    All the elements would appear to have been in place for the rapid evolution of a potentbrain, ahat seems not to have happened. For over three million years, Lud herfellow australopithees scarcely ged at all. Their brain didn’t grow and there is no signthat they used even the simplest tools. What is straill is that we now know that forabout a million years they lived alongside other early hominids who did use tools, yet theaustralopithees ook advantage of this useful teology that was all around them.

    At one poiween three and two million years ago, it appears there may have been asmany as six hominid types coexisting in Africa. Only one, however, was fated to last: Homo,which emerged from the mists beginning about two million years ago. No one knows quitewhat the relationship was between australopithees and Homo, but what is known is thatthey coexisted for something over a million years before all the australopithees, robust andgracile alike, vanished mysteriously, and possibly abruptly, over a million years ago. No oneknows why they disappeared. “Perhaps,” suggests Matt Ridley, “we ate them.”

    ventionally, the Homo line begins with Homo habilis, a creature about whom we knowalmost nothing, and cludes with us, Homo sapiens (literally “mahinker”). Iween, and depending on which opinions you value, there have been half a dozen otherHomo species: Homaster, Homo neahalensis, Homo rudolfensis, Homoheidelbergensis, Homo erectus, and Homo antecessor.

    Homo habilis (“handy man”) was named by Louis Leakey and colleagues in 1964 and wasso called because it was the first hominid to use tools, albeit very simple ones. It was a fairlyprimitive creature, much more chimpahan human, but its brain was about 50 pertlarger than that of Lu gross terms and not much less large proportionally, so it was theEinstein of its day. No persuasive reason has ever been adduced for why hominid brainssuddenly began to grow two million years ago. For a long time it was assumed that big brainsand upright walking were directly related—that the movement out of the forests atedirategies that fed off of or promoted braininess—so it was something of asurprise, after the repeated discoveries of so many bipedal dullards, to realize that there wasno apparent e betwee all.

    “There is simply no pelling reason we know of to explain why human brains ge,” says Tattersall. Huge brains are demanding ans: they make up only 2 pert of thebody’s mass, but devour 20 pert of its energy. They are also paratively picky in whatthey use as fuel. If you e another morsel of fat, your brain would not plainbecause it won’t touch the stuff. It wants glucose instead, and lots of it, even if it means short-ging ans. As Guy Brown notes: “The body is in stant danger of></a> beied by a greedy brain, but ot afford to let the brain go hungry as that would rapidlylead to death.” A big brain needs more food and more food means increased risk.

    Tattersall thinks the rise of a big brain may simply have been an evolutionary act. Hebelieves with Stephen Jay Gould that if you replayed the tape of life—even if you ran it baly a relatively short way to the dawn of hominids—the ces are “quite unlikely” thatmodern humans or anything like them would be here now.

    “One of the hardest ideas for humans to accept,” he says, “is that we are not theculmination of anything. There is nothing iable about our being here. It is part of ourvanity as humans that we tend to think of evolution as a process that, in effect, rogrammed to produce us. Even anthropologists teo think this way right up until the1970s.” Indeed, as retly as 1991, in the popular textbook The Stages of Evolution, C.

    L Brace stuck doggedly to the linear cept, aowledging just one evolutionary deadend, the robust australopithees. Everything else represented a straightforrogression—each species of hominid carrying the baton of development so far, then handingit on to a younger, fresher runner. Now, however, it seems certain that many of these earlyforms followed side trails that didn’t e to anything.

    Luckily for us, one did—a group of tool users, which seemed to arise from out of nowhereand overlapped with the shadowy and much disputed Homo habilis. This is Homo erectus, thespecies discovered by Eugène Dubois in Java in 1891. Depending on which sources yousult, it existed from about 1.8 million years ago to possibly as retly as twenty thousandor so years ago.

    Acc to the Java Man authors, Homo erectus is the dividing line: everything thatcame before him elike in character; everything that came after was humanlike. Homoerectus was the first to hunt, the first to use fire, the first to fashion plex tools, the first toleave evidence of campsites, the first to look after the weak and frail. pared with all thathad gone before, Homo erectus was extremely human in form as well as behavior, itsmembers long-limbed and lean, very strong (much strohan modern humans), and withthe drive and intelligeo spread successfully e areas. To other hominids, Homoerectus must have seemed terrifyingly powerful, fleet, and gifted.

    Erectus was “the velociraptor of its day,” acc to Alan Walker of Penn StateUy and one of the world’s leading authorities. If you were to look one in the eyes, itmight appear superficially to be human, but “you wouldn’t ect. You’d be prey.”

    Acc to Walker, it had the body of an adult human but the brain of a baby.

    Although erectus had been known about for almost a tury it was known only fromscattered fragments—not enough to e even close to making one full skeleton. So it wasn’tuntil araordinary discovery in Afri the 1980s that its importance—or, at the veryleast, possible importance—as a precursor species for modern humans was fully appreciated.

    The remote valley of Lake Turkana (formerly Lake Rudolf) in Kenya is now one of theworld’s most productive sites for early human remains, but 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 iigate, but at first found nothing. Then late oernoon KamoyaKimeu, Leakey’s most renowned fossil hunter, found a small piece of hominid brow on a hillwell away from the lake. Such a site was uo 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 “airely modern body structure,” says Tattersall, in a way thatwas without pret. 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 stists their first clue that Homo erectus was more iing and plexthan previously thought. The woman’s bones were deformed and covered in crowths,the result of an agonizing dition called hypervitaminosis A, which  e only fromeating the liver of a ivore. This told us first of all that Homo erectus was eati.

    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 tained (or, in the view of some, possiblytained) 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 al didn’t have the sizeand plexity to enable speech, that they probably would have unicated about as wellas modern chimps. Others, notably Richard Leakey, are vihey could speak.

    For a time, it appears, Homo erectus was the only hominid species oh. It was hugelyadventurous and spread across the globe with what seems to have beeaking 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 hopefulstists 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 mao turn up in Asia so soon after its first appearan Africa. First, a lot of plus-or-minusinggoes into the dating of early human remains. If the actual age of the Afri bones is at thehigher end of the range of estimates or the Java the lower end, or both, then there isplenty of time for Afri 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 inclusively fragmentary. As Tattersall and JeffreySchwartz note iinct Humans, most of the Turkana skeleton “couldn’t be pared withanything else closely related to it because the parable parts weren’t known!” The Turkaons, they say, look nothing like any Asian Homo erectus and would never have beensidered the same species except that they were poraries. Some authorities insist oncalling the Turkana spes (and any others from the same period) Homaster.

    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 Afrid boldly spread out auch 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 ditions that prompted them to leave Africa wouldhave made it much more difficult to do so. Yet somehow they mao find their wayaround every barrier and to thrive in the lands beyond.

    And that, I’m afraid, is where all agreement ends. What happened  in the history ofhuman development is a matter of long and rancorous debate, as we shall see in the chapter.

    But it is worth remembering, before we move on, that all of these evolutionary jostlingsover five million years, from distant, puzzled australopithee to fully modern human,produced a creature that is still 98.4 pert geically indistinguishable from the modernchimpahere is more differeween a zebra and a horse, or between a dolphin anda porpoise, than there is between you and the furry creatures your distant aors left behihey set out to take over the world.

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