by Brian Switek
The growing unease between professional and amateur scientists was on full display during the excavation of a particularly important cave in southwest England. While out to quarry limestone in early 1858, the entrepreneur John Philp stumbled onto a cache of fossils in Brixham cave in Devonshire. He was sure that the strange bones could turn a profit, so he set up a little museum inside the cave, and word of the in situ exhibit grabbed the attention of amateur geologist William Pengelly. When Pengelly inquired if he and his fellows in the nearby Tourquay Natural History Society could study the cave, Philp was happy to oblige, but only if the price was right.
Unfortunately, the Tourquay Natural History Society had little hope of making the rent Philp required, but their luck changed. In April of 1858, Pengelly told the fossil mammal expert Hugh Falconer about the cave, and Falconer agreed that it had potential. This was a chance to study a fossil-bearing cave in detail. Falconer promised to mention the situation to his fellows at the Geological Society of London.
Upon hearing Falconer’s report the Geological Society agreed that the cave should be studied, and they set about securing funding. They also formed a cave committee consisting of Pengelly, Falconer, Charles Lyell, Richard Owen, Andrew Ramsay, and Joseph Prestwich. By May, excavations were ready to begin. The project was carried out by two teams. Members of the Tourquay Natural History Society supervised the digging carried out by hired help, and the fossils were sent back to the professional geologists in London for analysis. This was a precise enterprise, and Pengelly made careful geological notes as the strata were peeled back and the fossils removed. By August over 1,500 mammal bones were recovered, but the workers also turned up a few relics that were even more intriguing.
Before the summer ended, seven stone tools were found mingled with the remains of extinct cave bears, hyenas, and rhinoceros. At long last the elusive proof of “men among the mammoths” had been found, but most of the Geological Society experts were skeptical. Joseph Prestwich, in particular, worried that if the find was reported too soon religious outrage would overwhelm whatever scientific value the tools held. These fears put Falconer’s enthusiastic report on the artifacts through a month-long process of editing to make it less controversial.
The scientific censors overshot their mark. Despite the buzz surrounding Falconer’s report, it failed to elicit much of a response when it was finally read before a packed audience of London scientists. The evidence was too flimsy to push back the emergence of humans, and the fact that most London geologists had not even seen the tools made it easy to downplay their significance. Yet the excitement over the tools was not so much over their manufacture but their age, a point on which Pengelly’s notes were essential. This strained the relationship between Falconer and Pengelly, as the former began to lecture Pengelly on proper geological note-taking.
Tensions mounted over the unequal division of labor between the Torquay amateurs and the London theorists, too. This came to a head when Torquay Natural History Society member Edward Vivian published an article that attempted to reconcile Brixham cave with a literal reading of Genesis. The London academics were shocked and embarrassed. They ordered a halt to any publications about the cave, and even though it had previously been understood that the Brixham fossils would be returned to Torquay, the experts now insisted that the bones and artifacts stay in London.
As the London-Torquay association was suffering, so was Falconer’s health. He set off on a salutary trip to the Mediterranean intending to investigate a few interesting fossil sites along the way. One of his first stops was in Abbeville, France, the home of the controversial scientist Jacques Boucher de Perthes. During the 1830s the French naturalist Paul Tournal discovered stone tools alongside bones of extinct mammals, and Perthes made similar finds around Abbeville in 1838. He presented these finds in the first volume of his 1846 work Antiquités celtiques et antédiluviennes and boldly proclaimed that the “rude stones” mixed with the extinct fauna “prove[d] the existence of Man as surely as a whole Louvre would have done.” This assertion led to a barrage of jeering opposition and scientific criticism from his peers. Falconer, too, was skeptical of Perthes’ claims, but he recognized that a few of the French tools resembled those from Brixham.
Falconer wrote to Prestwich to suggest that further investigations of Abbeville might be worthwhile, and Prestwich soon visited the nearby gravel pits with his friend John Evans. The duo left Abbeville emptyhanded, but as soon as they returned home to England Prestwich received a message that a stone tool had been found and left in situ for him to examine. Prestwich and Evans dashed back across the English Channel and found precisely what they had been hoping for.
Whereas the age of the Brixham cave was difficult to determine, the stratigraphy of the French site in the Somme Valley was better known. As a result, Prestwich was able to convincingly show that the tool had been deposited at the same time as the extinct mammal fossils around it. Even so, Prestwich was cautious. He did not want to move the age of humanity backward in time any more than he wanted to move ancient mammals forward. He did note that the appearance of humans did not mark the beginning of a distinct geological period; our forebears had once inhabited a more ancient, unfamiliar, and dangerous world.
Prestwich encouraged his colleagues to visit the tool-bearing sites to see for themselves, and the geological community quickly reached a consensus. Fresh from the Somme Valley sites, Charles Lyell publicly announced the coexistence of human and ancient mammals before the 1859 meeting of the British Association for the Advancement of Science. “No subject has lately excited more curiosity and general interest among geologists and the public than the question of the antiquity of the human race,” Lyell said, and there was now compelling evidence that we had a more ancient origin than had been previously thought. It is no surprise that Lyell referred to On the Origin of Species (published that November) in the same speech, for the time had now come to more carefully examine the ancient history of our species.
This new understanding stirred up opposition, but eventually even critics like Thomas Wright and John Henslow were won over by the evidence. A new consensus had emerged almost overnight, though geologists still faced an old dilemma. Where were the bodies of the toolmakers? Human fossils that had been previously found (such as the Red Lady) were too poorly documented to be used as evidence. Outside of their geological context no one could be sure how old the fossils were.
Similar problems plagued the study of human fossils found in a Neander Valley limestone quarry near Düsseldorf, Germany. It was there that in 1856 laborers found a skull cap and portions of the limbs, ribs, hips, and shoulders of what they believed to be a cave bear. They presented the fossils to the local naturalist Johann Carl Fuhlrott, but he came to a different conclusion: the bones were human. Excited by this prospect, Fuhlrott brought the bones to the attention of the Bonn anatomist Hermann Schaffhausen, who agreed with Fuhlrott’s interpretation. They announced the discovery jointly in 1857 as the remains of a pre-modern human “of a barbarous and savage race.”76 The announcement was controversial from the start.
Like other human fossils, the Neander Valley bones had been exhumed by non-scientists, and no fossils useful for determining their age were found alongside them. Even more controversial was the question of what kind of human the skeleton represented. Although of a comparable stature to our species, the bones were more robust and the skull cap was low-domed with a heavy brow ridge. Was it one of our ancestors, an ancient “cousin,” or just an aberrant Homo sapiens?
FIGURE 87 - The first recognized Neanderthal skull as seen from the side, front, and top.
Numerous hypotheses were proposed during the following years. August Franz Mayer, a peer of Schaffhausen at Bonn, thought that the Neander Valley skeleton belonged to a Mongolian Cossack that had been driven into Germany during the Napoleonic Wars, the slouched posture and bowed legbones having been effected by a life spent on horseback; Pathologist Rudolf Virchow, by contrast, deemed the specimen a Homo
sapiens that had been distorted by disease; and their colleague Pruner Bey proposed that the skeleton was a dead ringer for “a powerfully organized Celt, somewhat resembling the skull of a modern Irishman with low mental organization.” Even T. H. Huxley thought that the bones fell within the range of variation of our species and at best represented a primitive throwback:In no sense, then, can the Neanderthal bones be regarded as the remains of a human being intermediate between Men and Apes. At most, they demonstrate the existence of a Man whose skull may be said to revert somewhat towards the pithecoid [ape] type—just as a Carrier, or a Pouter, or a Tumbler [breeds of pigeons], may sometimes put on the plumage of its primitive stock, the Columba livia.
The conclusion of the Anglo-Irish geologist William King, however, was closer to that of Fuhlrott and Schaffhausen. He thought that the bones belonged to a different species of human, which he named Homo neanderthalensis in 1864. (American paleontologist E. D. Cope, presumably unaware of King’s work, proposed the same name for the species after more remains were recovered from Spy, Belgium.) That the Neanderthals were different was apparent when they were compared to our own Stone Age precursors, the Cro Magnons, who had been described in 1868 by the French geologist Louis Lartet. Still, the Neanderthals were too similar to us to shed much light on our ape ancestry. True fossil “ape-men” that filled the chasm between us and our earlier primate ancestors had yet to be found.
The dearth of transitional human fossils must have frustrated Darwin. He certainly could have used them when he wrote his 1871 book devoted to human evolution, The Descent of Man, and Selection in Relation to Sex. As things were, Darwin could only restate the fortuitous nature of the fossil record and assure his readers that the place where the bones of our ancestors were most likely to be found had not yet been searched. Appealing to the “law of fossil succession” he had identified as a youth in South America, Darwin proposed that Africa might yield the remains of the earliest humans.
In each great region of the world the living mammals are closely related to the extinct species of the same region. It is therefore probable that Africa was formerly inhabited by extinct apes closely allied to the gorilla and chimpanzee; and as these two species are now man’s nearest allies, it is somewhat more probable that our early progenitors lived on the African Continent than elsewhere.
But this was anything but a certainty. Just below this famous passage Darwin remarked:But it is useless to speculate on this subject, for an ape nearly as large as a man, namely, the Dryopithecus of Lartet, which was closely allied to the anthropomorphous Hylobates [gibbons], existed in Europe during the Upper Miocene period; and since so remote a period the earth has certainly undergone many great revolutions, and there has been ample time for migration on the largest scale.
Nor did Darwin believe that we shared a recent common ancestor with chimpanzees or gorillas. Of all the apes they were the most similar to us on a superficial level, but in an 1868 sketch of the human family tree Darwin drew in a notebook, he placed a deep divide between them and us. Chimpanzees, gorillas, orangutans, and gibbons all shared a relatively recent common ancestor, but humans had arisen from some earlier ape stock before the later branches diverged. Humans were on their own divergent branch that had split off early, or in Darwin’s words, it seemed “that some ancient member of the anthropomorphous sub-group gave birth to man.”
The young Dutch anatomist Eugène Dubois thought he had a good idea of where to look for the fossils of such creatures. For him the Asian orangutans and gibbons were much more like us than the African apes, and the discovery of a fossil ape from the Siwalik Hills of India reinforced his hunch that our origins lay in the East. The Indonesian island of Sumatra contained limestone deposits of about the same age as the Indian site, making it a promising place to look for human ancestors. To get there Dubois enlisted as a medical officer in the Dutch army. In 1887, he left home, family in tow, to begin his search.
Soon after he arrived at Sumatra, Dubois found enough fossil mammals to convince the Dutch government that his expedition was worthwhile. They provided him with two engineers and fifty forced laborers to continue his work, but one engineer proved incompetent, the other fell ill, and many of the laborers deserted. This was just as well. The fossils the crew exhumed were too recent, and there was little hope of finding an “ape-man” among them. In 1890, to start over again Dubois transferred to Java where he put a new crew to work in the vicinity of the Solo River. Piece by piece, parts of a humanlike skeleton were culled from the sediment: a jaw in 1890, a molar and skullcap in 1891, and a left femur in 1892.
FIGURE 88 - A photograph of the Pithecanthropus skullcap and the associated femur and tooth.
Dubois called his find Anthropithecus erectus, or the “erect man-ape.” This was a fitting name for a creature with a femur fit for upright walking and a brain size about 1.75 times that of a chimpanzee, but Dubois had made an error in his calculations. In December of 1892, Dubois discovered his mistake and realized that the brain of Anthropithecus was 200 cubic centimeters larger than he had first surmised. This placed it closer to humans than to apes, and Dubois did a little taxonomic rearranging to rechristen his find Pithecanthropus erectus , the “erect ape-man.” (Ernst Haeckel had informally proposed a hypothetical human ancestor he called Pithecanthropus alaulus, or “speechless ape-man,” some years earlier.) Excited by his find Dubois began sending reports of his discovery to colleagues back home.
When Dubois returned to Europe in 1894 he was hit by a wave of controversy. Experts disagreed on what type of creature Pithecanthropus was, if indeed the bones represented just one creature. The femur was very humanlike and clearly from a bipedal animal, but the low-domed skull was more apelike. This led some experts to argue that the bones of a human and an ape had become mixed together, but Dubois remained firm in his interpretation:The more I myself have studied these fragments the more firmly I have been convinced of this unity of origin; and at the same time it has become ever clearer to me that they are really parts of a form intermediate between men and apes, which was the ancestral stock from which man was derived.
Even though Dubois received accolades for his achievements, the identity of “Java Man” remained contentious. The refusal of some of his peers to agree with him frustrated Dubois, and he was aghast when an unauthorized description of Pithecanthropus was made by the German anatomist Gustav Schwalbe in 1899. It seemed that the argument over his discovery was slipping out of his hands. Without warning Dubois closed off all access to the bones in 1900, but he had a plan that would ultimately establish Pithecanthropus in its rightful place between human and ape.77
Using the femur and skullcap as guides, Dubois wrangled with the relationship between brain and body size. Based upon the femur, it appeared that Pithecanthropus would have closely matched our species in stature, but the calculated brain size was only about two-thirds of our own. This did not match Dubois’ expectations. Dubois believed that there was an internal driving mechanism in evolution that caused brain size to double in respect to body size in each advancing stage of evolution. If Pithecanthropus had a body like ours, this ratio would be thrown off, but Dubois reasoned that if it had the proportions of a large gibbon then it would fall halfway between human and ape.
Dubois took his time with Pithecanthropus, but after more than two decades of secrecy his colleagues had grown impatient with him. It was unfair that important fossils collected during a government-sponsored expedition were held under lock and key. Under threats and formal complaints, Dubois relented and restored access to the fossils in 1923. Even though many of his peers did not accept his new conclusion that Pithecanthropus looked like a giant gibbon, and it could still not be determined whether it was truly one of our ancestors, Java Man was generally welcomed as an early fossil human. It was the first of the fossil ape-men to be scientifically described, but it was no longer the only one.
In 1908, the English archaeologist Charles Dawson was given some scraps of bone found in a gravel
pit in Uckfield, East Sussex. A collector of stone tools and other artifacts, Dawson scoured the site for more bone fragments, and eventually he showed what he had found to geologist Arthur Smith Woodward. In September 1912, Woodward and Dawson recovered even more bone fragments from the gravel pit. When they were all put together the pieces represented a partial skull and the lower jaw of an ancient human they decided to call Eoanthropus dawsoni, popularly known as “Piltdown Man.”
FIGURE 89 - The reconstructed skull of “Piltdown Man.”
The reconstructed skull of Eoanthropus showed a strange combination of features. The lower jaw was similar to that of a juvenile ape, but the skull was reminiscent of Homo sapiens. Indeed, the high-domed head confirmed that an increase in brain size led the way in human evolution, for this creature had evolved a large brain before all the ape traits were lost. The French anthropologist Marcellin Boule thought that the jaw seemed so “ape-like” because it was actually from an ape, and his American colleague G. S. Miller came to a similar conclusion.
These concerns echoed the Pithecanthropus debate from decades before, and for much the same reasons. The fragmentary nature of the bones and the span of time it took to recover them cast doubt on whether all the pieces belonged to only one individual. It was an osteological jigsaw puzzle that led Miller to write, tongue-in-cheek, “deliberate malice could hardly have been more successful than the hazards of deposition in so breaking the fossils as to give free scope to individual judgment in fitting the parts together.”