Virtually all fields of science are afflicted to some extent by hoaxes. Anthropology is no different, with each of its subfields having been subjected to at least a measure of intellectual dishonesty and fakery. Though the motives behind anthropological hoaxes have varied, the element underlying their success has always been the same: an audience predisposed to believe the implications of the fabricated data. There is, perhaps, no better example of this than the most notorious hoax in paleoanthropology—and, perhaps, in all of science—Piltdown Man.
Hoaxes in Biological Anthropology: Piltdown Man
The world first heard of the discovery of human fossil remains at Piltdown in a short announcement published in the British science weekly Nature. On December 5, 1912, that publication reported the discovery by Charles Dawson, a lawyer by trade but a collector of scientific specimens by avocation, of fragments of a human cranium and mandible in Sussex, in the south of England. The remains appeared to be greatly ancient, having been recovered from a stratigraphic layer in which the bones of extinct animals had already been found. A follow-up article in the same journal two weeks later provided sufficient detail to grab the attention of both the scientific community and the world at large.
The discovery of ancient human remains has long been newsworthy, but the initial and subsequent published descriptions of the bones found at Barcombe Mills Manor, in the Piltdown region of Sussex, indicated that they were more than simply newsworthy, they were revolutionary. The bones were perceived to be extraordinarily important precisely because they were so different from ancestral human remains discovered previously. Consisting of several humanlike cranial fragments and part of an apelike mandible, the fossils were given a new taxonomic name reflecting their unique characteristics: Eoanthropus dawsoni (Dawson’s Dawn Man).
The Intellectual Context of the Hoax
The supposed significance of the Piltdown remains is comprehensible only within the context of evolutionary thinking in the period of their discovery. Charles Darwin’s On The Origin of Species had been published in 1859. Though there was substantial resistance to the theory of evolution as espoused by Darwin, the book was a best seller, and many became convinced that Darwin had presented a viable mechanism, called by him “natural selection,” by which plant and animal species had originated and changed through time. Though Darwin avoided in Origin explicitly applying that mechanism to humanity, at the end of the book, he predicted that through the application of the concept of natural selection, “much light will be thrown on the origins of man and his history.”
If Darwin were correct, if all plant and animal species, including human beings, were the products of the evolutionary process of natural selection, there should be evidence of this process in the fossil record. In other words, fossil remains reflecting previous forms of humanity should be found. But what might previous forms of our species look like, and how would we recognize their bones when we find them?
By Darwin’s time, it had long been recognized that the contemporary animals most closely resembling human beings, both morphologically and behaviorally, were the great apes, in particular, chimpanzees. Creationists took this merely to be a reflection of God’s will, while evolutionists believed that this signified that human beings and apes were closely related, sharing in deep time a common evolutionary ancestor from which we had diverged. It was argued that the feature that most clearly and significantly demarcates and distinguishes modern people from modern apes was not seemingly trivial physical characteristics, like the morphology of our hands or feet, the size of our canine teeth, or nose shape. Instead, most thinkers reasonably concluded that the single most significant distinction between people and apes was our far greater level of intelligence made possible by our much larger brains—ours are 4 times larger than those of chimps.
Because we are most significantly different from our contemporary evolutionary cousins in terms of brain size and attendant intelligence, it was further concluded that brain size was our most developed or most evolved attribute, the physical feature most changed from an ancestral state and that, therefore, must have been evolving longest. This, in turn, was taken to mean that the initial characteristic to distinguish the human from the ape line in our evolutionary chronology must have been an expanding cranial volume necessitated by an enlarging brain. As a result, when perusing the fossil record to find the first human ancestors, scientists initially expected to find evidence of a creature with an apelike body but a cranium much larger than that of an ape. Grafton Eliot Smith, head of the Anatomy Department at University College, London, in the early 20th century, went so far as to predict that a hypothetical early human ancestor should be “merely an ape with an overgrown brain.” This view that the human brain had evolved before the features of the modern human body is labeled the brain-centered paradigm of human evolution.
Though it became the preferred view, mounting fossil evidence in the late 19th and early 20th centuries appeared to contradict the brain-centered paradigm. Scientists excavating for ancient human remains simply were not finding the bones of apes with overgrown brains. For example, just 3 years before the publication of On The Origin of Species, a discovery had been made in the Neander Valley of Germany that appeared to throw light on human antiquity. A calvarium (or “skullcap” consisting of the top of the cranium, lacking the face and lower jaw) had been found that although as large as that of a modern human being seemed otherwise apelike, with a flattened profile, a prognathous (jutting-out) lower face, and a large ridge of bone above the eyes. The caldarium also lacked the typically steep forehead of modern humans. Similar crania were found in Europe in the 19th century and together these fossils were assigned the name Neandertal.
The bones of the postcranial skeletons (the bones beneath the skull) of these Neandertals belied the prediction of the brain-centered paradigm. Though there was substantial controversy concerning the precise method of Neandertal locomotion, it was clear that they were, like modern human beings and unlike the apes, upright walkers. With their apelike cranial shape, the Neandertals seemed to be not the predicted apes with overgrown brains, but something quite different.
Later, in 1891, Dutch physician Eugene Dubois obtained a calvarium and femur from an ancient stratigraphic layer on the island of Java. The skull fragment was substantially smaller than that of a modern human—at about 940 cc, it was only 65% of the modern human mean (1450 cc). However, the femur found in association with the calvarium was indistinguishable from that of a modern human. Like the Neandertals, the so-called Java Man also was not an “ape with an overgrown brain,” but apparently the reverse, an upright human with a small, apelike brain.
Thus, before the discovery at Piltdown in 1912, the fossil evidence for human evolution implied, contrary to the preferred brain-centered view, that it had been an upright stance and bipedal locomotion, not the size of our brains and, therefore, not our great intelligence, that had early on distinguished our human ancestors from our evolutionary cousins.
The Key to Piltdown’s Success
Herein lies the key behind the significance of the discovery at Piltdown. Piltdown Man presented researchers with a very ancient human ancestor— perhaps at least as ancient as Java Man and far older than the Neandertals—with a very modern-looking, large braincase but a very primitive-looking, in fact very apelike, lower jaw. Though no postcranial remains of Piltdown Man were recovered, the humanlike cranium with an apelike jaw implied that Piltdown had possessed a humanlike brain but had been apelike from the lower jaw down, a compelling bit of evidence in apparent support of the brain-centered paradigm.
Thus, in this singularly dramatic discovery, the brain-centered paradigm had been revived, all other ancestral human fossils were displaced from the main line of human evolution, and, in addition, England, formerly devoid of any significant remains of ancient human beings, had found an ancestor.
Piltdown Unmasked
The discovery at Piltdown inspired a flood of paleoanthropological investigations, launched in the predictable attempt to confirm with additional evidence the existence in the human genealogy of a precociously large and humanly configured brain associated with a still unevolved, apelike body. However, no confirming evidence was forthcoming from any post-Piltdown investigations in Africa or Asia. In fact, the only investigator able to find an ostensibly confirming fossil was none other than Charles Dawson, the discoverer of the original, who claimed to have found a similar specimen just a few miles from where he had found the original.
Due to the scarcity of any convincing confirming evidence and the distinctly singular morphology of the Piltdown remains in the context of a growing sample in the 1920s, 1930s, and 1940s of small-brained bipeds deep in the human past, Eoanthropus was relegated to the status of a footnote in discussions of human evolution. When, finally, definitive dating tests were developed and then applied to the remains in the late 1940s and early 1950s, the hoax was definitively revealed. The cranial fragments of Piltdown
Man were those of a modern human being, ultimately radiocarbon dated to only about 600 years ago. The mandible, whose apelike morphology seemed to support the notion that early in the evolution of our species, our human ancestors retained their simian characteristics below the all-important brain, was apelike for the rather obvious reason that it had come from an ape, specifically, a modern orangutan, intentionally broken at exactly the right place to make it appear to belong to the Piltdown cranium. Filing marks on the teeth made by a metal tool clinched the diagnosis of fraud.
The identity of the perpetrator of the Piltdown hoax is still somewhat of a mystery. Dawson’s culpability seems clear, as he had much to gain (the fossil was named for him, and his fame grew as a result) and was present at every one of the discoveries at Piltdown as well as at the second site (labeled Piltdown II). Many others have been named, including highly respected scientists (Arthur Smith Woodward of the British Museum and Sir Arthur Keith, knighted for his contribution to science), a museum worker (Martin Hinton), a Jesuit priest (Teillard de Chardin), and even a world-famous author (Arthur Conan Doyle of Sherlock Holmes fame), but the evidence is not compelling that any one of these individuals contributed to the hoax. Each had a plausible motive, sufficient expertise, and, perhaps, adequate opportunity to produce and plant the false fossils, but ultimately, the identity of the guilty party is not all that important. The important lessons of the Piltdown hoax are these: (a) Piltdown was successful because it lent support to an expected, widely accepted view of evolution, the brain-centered paradigm; (b) scientists can be susceptible to hoaxes, especially when faked data conform to and support a preferred hypothesis; and (c) science is self-correcting, and when the implications and predictions drawn from evidence that turns out to be fabricated are not realized, the hoaxes themselves are debunked and relegated to the dustbin of history. It may have taken 40 years, but this is precisely what occurred in the case of Piltdown.
Hoaxes in Archaeology: A Mysterious American Past
Hoaxers have long been busy in archaeology as well, providing ostensible evidence supporting a representation of the past that conforms better to the desires of many. Consider, for example, the Newark Holy Stones, artifacts with Hebrew inscriptions found in 1860, immediately to the east of an authentically ancient earthwork in Newark, Ohio.
The Moundbuilder Myth
The mid-19th century was awash in speculation about who had built the thousands of earth mounds that dotted the landscape of the American Midwest. Some were massive tumuli, containing human remains buried along with an impressive and technologically sophisticated array of grave goods of stone, clay, and copper. Other earthworks had been made in the shape of animals. Serpent Mound in Ohio is one of the most impressive, a sinuous embankment of earth depicting a snake more than 405 meters (1,330 feet) in total length, from its gaping mouth to the tip of its coiled tail. Other mounds were extensive berms of earth enclosing the tops of hills. Still others had been constructed in the shape of huge, flat-topped pyramids, apparent platforms for temples or the conduct of ceremonies. Monks Mound, at the site of Cahokia, located in Collinsville, Illinois, looms 30 meters (100 feet) above the landscape and contains more than 560,000 cubic meters (20 million cubic feet) of earth, making it, by volume, the fifth-largest pyramid in the world. Monks Mound is the largest in a cluster of more than 100 found at the Cahokia site, a near-urban settlement at its peak more than 700 years ago.
Many naively believed that the native people of America could not have been responsible for the construction of these impressive earthworks because their culture was too primitive. These skeptics denied even the possibility that American Indians were capable of the methodical, coordinated labor necessary to have built the mounds. But if they had not constructed the mounds, someone else certainly must have. This led to rampant speculation in the 18th and 19th centuries concerning who that someone could have been. A host of possible ancient Old World visitors to the New World were suggested as having been responsible.
As seen in the case of Piltdown, the desire for material evidence in support of a preferred explanation fuels anthropological hoaxes. The desire to solve the “mystery” of who had built the mounds—and to solve it in a way that denied the involvement of native people—provided powerful inspiration for a number of archaeological fakes.
Moundbuilders From Israel? The Newark Holy Stones
The “Newark Holy Stones” were found in 1860 by professional land surveyor and ardent amateur archaeologist David Wyrick in Newark, Ohio. The first artifact discovered, the so-called Keystone, looks a bit like a plumb bob with Hebrew lettering on all four of its faces. Unable to read Hebrew, Wyrick brought the object to a local reverend that he knew, John W. McCarty, who translated it. On each of its four faces, the messages read, respectively: “the laws of Jehovah,” “the Word of the Lord,” “the Holy of Holies,” and “the King of the Earth.”
An artifact with Hebrew writing on it found in association with an ancient mound site seemed to lend support to the claim that a group other than Native Americans had built the mounds. Specifically, perhaps it had been ancient Hebrews who had had been responsible for the construction of at least some of these remarkable earthworks.
There was at least one significant problem with this interpretation. Scientists who examined the Keystone soon after it was discovered, the most important being geologist Charles Whittlesey, concluded that it could not have been a genuinely ancient Hebrew artifact. The inscription had been written in an essentially modern version of Hebrew. This represented a clear anachronism in an artifact that was supposed to date to the most active period of mound construction in Ohio, some 2,000 years earlier.
Whittlesey was a highly respected scholar with significant experience investigating and excavating mound sites in Ohio. His conclusion that the Keystone was a fake was accepted by many who, as a result, viewed it as a mere peculiarity, a prank perpetrated by someone who knew it would draw attention because of public fascination with the moundbuilder mystery. Then, just 5 months after the discovery of the Keystone and its rejection by most scholars, another anomalous artifact was found only about 6 miles from the Keystone find spot, by the same fellow who found the first one, David Wyrick. Called the “Decalogue” because it bore a version of the “Ten Commandments,” this second inscribed stone rather conveniently appeared to counter precisely the primary criticism leveled at the first. This artifacts inscription was far more convincing, bearing an archaic version of the Hebrew language dating to a time that seemed a much better fit for the period of mound construction. Rather than convincing scholars of its legitimacy, however, this feature of the Decalogue stone was interpreted by many as evidence of fakery. How likely was it, skeptics inquired, that a genuinely ancient Hebrew artifact would be found just a few miles from where a fake Hebrew artifact had been found 5 months previously by the same individual? It seemed far more likely that the hoaxer had learned from the criticisms leveled at the first artifact and used this knowledge to produce another, more convincing piece.
Researchers Brad Lepper and Jeff Gill have delved into the details of the Newark Holy Stones and present a convincing argument for the specific motives behind them. They discovered that the Keystone and Decalogue’s translator, Reverend McCarty, served under a bishop, Charles Petit Mcllvaine, who had already publicly predicted that artifacts linking the moundbuilders to the Bible would one day be found. In Lepper and Gill’s view, McCarty simply supplied the “proof” that fulfilled his bishop’s prediction. Lepper and Gill suggest that McCarty had the fake stones made, planted them in the ground, and, perhaps, directed the artifact collector Wyrick to them. McCarty’s motive may have been to lend support to his and McIlvaine’s belief in an intimate connection between the native inhabitants of the Old and New Worlds, both having descended from the people of the Old Testament.
Beginning in 1872, a team of researchers led by Cyrus Thomas of the Smithsonian Institution gathered data on 2,000 earthworks in 21 states, collecting 40,000 associated artifacts. This work led to the publication of an enormous volume in 1894, proving conclusively that the moundbuilders had not been a mysterious race of settlers of North America, but were the ancestors of the native people who Europeans had encountered in their expansion across the continent in the 18th century. Thomas discussed the Holy Stones and agreed with Whittlesey’s conclusion that they were fakes. The Keystone and Decalogue today are on display at the Johnson-Humrickhouse museum in Coshocton, Ohio. Though their authenticity is still championed by some, the vast majority of historians and archaeologists view them as little more than a historical curiosity.
Hoaxes in Cultural Anthropology: The Tasaday
In a short article appearing in the December 1971 issue of National Geographic titled “The Tasadays: Stone Age Cavemen of Mindanao,” the magazine revealed the discovery of a small group of native people living in caves on the island of Mindanao in the Philippines. These people captured the attention of National Geographic and were about to capture the attention of the Western world because they appeared to be the last human group on Earth untouched by modern civilization. The Tasaday seemed to represent the final remnant of a way of life that, perhaps, had characterized all of humanity for much of the history of our species. Social scientists and laypeople alike were intensely interested because, as National Geographic author and visitor to the Tasaday Kenneth MacLeish phrased it, the Tasaday were the equivalent of “time travelers in a time machine,” individuals plucked from an ancient period and deposited in the modern world, where we could gaze at the primitive innocence we, as a species, once had.
We All Want to Be Tasaday
Worldwide interest in the announcement of the existence of the Tasaday is understandable when we consider the context of the early 1970s. Americans were in the midst of an unpopular war and middle-class youth across Europe and America were actively questioning and rejecting the materialism that seemed to dominate and define the lives of their parents. Racism and sexism were being addressed, perhaps as never before, the deleterious impacts of 20th-century technology on the environment were being recognized and assessed, and repressive attitudes about sexuality were being questioned. Many were reconsidering Western civilization as a whole, viewing it not as the pinnacle of cultural evolution, but as a hopelessly sterile existence characterized by inequality, oppression, death, and destruction.
The language and phrasing of the articles announcing the discovery of the Tasaday were a perfect match for this period of social upheaval. The 26 (or 24, depending on who was doing the counting) Tasaday seemed to be living a natural, pristine, pure way of life, as MacLeish phrased it, “much as our ancestors did thousands of years ago.” The Tasaday were unpolluted by materialism, acquisitiveness, hatred, and war. They were living a way of life that many in the early 1970s wanted desperately to recapture for themselves. In her 1970 composition about the Woodstock music festival held in New York State in 1969, a cultural event that represents a coalescence of the political and social sea changes of the period, popular singer and songwriter Joni Mitchell plaintively cried out: “We’ve got to get ourselves back to the garden.” The Tasadays were, in a sense, the embodiment of the “Woodstock Nation.” Their homeland and way of life were, literally and figuratively, viewed as that Edenic “garden” that so many hoped existed and to which they hoped to return.
The Tasaday were, as one wag phrased it, “paleohippies.” In a time when materialism was being rejected in the West, the Tasaday didn’t even have a concept of private property. Desiring nothing, they had no unfulfilled desires. Though lacking in virtually any material comforts, they were described as being a truly “affluent society.” They shared everything, they recognized no leader, and all decisions were made by friendly consensus. The Tasaday didn’t hunt or grow crops, but subsisted almost entirely on the wild plants that grew abundantly in their small territory. Perhaps most significantly, in a time when those of us in the West lived in constant fear of imminent and utter nuclear annihilation and anthropologists wondered if territoriality, aggression, murder, and war had been inextricably etched into our genes, the existence of the Tasaday challenged this pessimism. They were a peaceful people who made no weapons and who did not even have a word in their language for war.
Writing for National Geographic, MacLeish’s characterization of his visit to the caves on Mindanao reflects the fundamental reason why the Tasaday so captivated the Western world. Describing this friendly confrontation between bearers of Western civilization and the simple, natural people of the Philippine forest, MacLeish put it this way: “Creatures of man’s most advanced and tormented society, and they [the Tasaday], perhaps the last of the world’s innocents, watched each other across the full span of cultural evolution. And they felt love for each other.” It was the perfect paradox. Proud bearers of Western civilization, with its complex technologies, innumerable material comforts, enormous scientific achievements, and great social and political sophistication, were the pitiable element in this equation, facing off against the simple innocence and blissful happiness of the primitive Tasaday, a people who had nothing—except bliss and happiness. With all of our material advancements and comforts, it was we who envied them.
Upon their “discovery,” the Philippine government moved to protect the Tasaday from the depredations of the modern world. Their champion was found in Philippine official Manuel Elizalde, who held the governmental post “Presidential Assistant on National
Minorities.” Elizalde had the ear of the dictatorial ruler of his country, Ferdinand Marcos. With Marcos’s blessing, Elizalde created a 46,299-acre preserve— this, for 26 people—that was to be off-limits to loggers, miners, developers, and the vast majority of anthropologists. This was done, ostensibly, to protect the Tasaday, to allow them to continue to live their way of life unobstructed by the interference of those who might exploit them. This policy, not coincidentally, also served to isolate them from those whose only agenda was to study them. Elizalde also initiated a fundraising campaign, establishing a foundation whose purpose was to help protect the Tasaday from the outside world. It is estimated that the foundation collected more than $35 million for this ostensible purpose.
Paradise Lost: Revelation of a Hoax
During the period of 1974 to 1986, the Tasaday remained an ensconced and insulated people, an icon of paradise lost, a living fossil reflecting the idyllic way of life abandoned by our ancestors in the devil’s bargain offered by the evolution of cultural complexity.
Then, in 1986, this neat little scenario came crashing to earth. The dictatorial regime of Ferdinand Marcos was overturned. Cronies of the regime, including Elizalde, ultimately fled, and the tens of millions of dollars he oversaw to protect the Tasaday disappeared along with him. More important, the forest preserve of the Tasaday was reopened, not to those bent on despoiling the habitat of Mindanao, but to scientists who wished to revisit the Tasaday and take the metaphorical time machine once more.
There was only one problem. In 1986, no one was living in the caves that were purported to have been the homes of the Tasaday. When surviving individuals in the original cohort of 26 were tracked down, they were found living in houses in villages, planting crops, wearing T-shirts and jeans, smoking cigarettes, and living a lifeway that was indistinguishable from other native residents of the forests of Mindanao. Most damning of all, when questioned about what had happened in the 15 or so years since the announcement of their existence in 1971 and the renewed contact in 1986, some stated that nothing at all had happened—and that, in fact, their lives as simple, primitive, nearly naked cave people had been nothing more than a bit of theater they had been coerced into by none other than Manuel Elizalde. As one Tasaday reported:
We didn’t live in caves, only near them, until we met Elizalde…. Elizalde forced us to live in the caves so that we’d be better cavemen. Before he came, we lived in huts on the other side of the mountain and we farmed. We took off our clothes because Elizalde told us to do so and promised if we looked poor that we would get assistance. He gave us money to pose as Tasaday and promised us security from counter-insurgency and tribal fighting.
Appalled by the apparent humbug that had taken in so many, including most anthropologists, the American Anthropological Association asked linguist Thomas Headland to organize a symposium on the Tasaday for their 1989 annual meeting. Contributions to the symposium were published in 1992 in a book edited by Headland and titled The Tasaday Controversy: Assessing the Evidence. Scholars involved with investigating the Tasaday in the early 1970s as well as other specialists with crucial insights about the controversy participated. Though some raised to the defense of the claim that the Tasaday at least were an isolated, distinct cultural group, most concluded from the evidence that the Tasaday had been manipulated to play the role of a primeval cave people as part of a cynical hoax.
For example, the Tasaday had been presented as a people completely isolated from their neighbors on Mindanao, whose villages, by the way, had been a mere 3-hour walk from the Tasaday caves. However, a careful reexamination of their language by linguist Clay Johnston indicated that it was virtually identical to that of their neighbors, people with whom Johnston had lived for 10 years, sharing in common 90% of their words. The claim that the Tasaday were nonagricultural and nearly completely vegetarian, lacking even simple weapons for hunting, was shown by Thomas Headland, the symposium organizer, to be improbable at best. A careful analysis showed that they could not have survived on what they were actually seen eating in the early 1970s. That they were a “Stone Age” people whose simple toolmaking was a model for the technology that characterized ancient humanity was shown to be farcical by anthropologist Robert Carniero. He pointed out that the few stone tools the Tasaday used were childish and nonfunctional. These supposed tools were further characterized by another symposium participant, anthropologist Gerald D. Berreman, as “amateurish tools such as seventh graders might be expected to invent in response to a classroom assignment.”
Finally, even if one could argue that the Tasaday had abandoned the caves only recently, there should have been in 1986 physical evidence of the kind archaeologists find reflecting past habitation, things like middens, living surfaces littered with broken bits of stone, and trash accumulations. But, as Berreman pointed out, the caves where the Tasaday were supposed to have lived for generations lacked any physical sign of human habitation. No human group is that assiduously neat, and the lack of any physical evidence of occupation of the caves seems definitive in showing that the Tasaday had never lived in them.
Elizalde ultimately absconded to Costa Rica with the Tasaday foundation money, squandering it there and dying of drug abuse in 1997. His motivation for the hoax, likely with the approval of Marcos, had been to create a situation in which a large swath of valuable forest lands could be set aside for him to control and to profit from, and a gullible world would fund his lifestyle by supplying huge sums of money for what was thought to be the worthwhile and valuable effort to protect and preserve a fascinating lifeway on the brink of extinction.
Self-Correction in Science
That the Tasaday hoax worked for 15 years is a sad testament to the shamelessness of its perpetrators. The success of the Tasaday hoax, like the success of Piltdown and the Newark Holy Stones, is emblematic, showing that hoaxes in anthropology have been successful when they gave an audience what they wanted, whether it was a preferred evolutionary ancestor, Old World visitors to the New World in antiquity, or the existence of a paradisial way of life that reflects the essential goodness of the human species. Fortunately, the success of these hoaxes was relatively short-lived. Science is self-corrective, and the irony is clear. The hoaxes discussed here each inspired additional research, as new data with revolutionary implications always do, and this is precisely what led to their unmasking.
References:
- Feder, K. L. (2005). Frauds, myths, and mysteries: Science and pseudoscience in archaeology. New York: McGraw-Hill.
- Headland, T. N. (Ed.). (1992). The Tasaday controversy: Assessing the evidence. Washington DC: American Anthropological Association.
- Lepper, B. T., & Gill, J. (2000). The Newark Holy Stones. Timeline, 17(3), 16-25.
- MacLeish, K. (1972, August). The Tasaday: Stone Age cavemen of Mindanao. National Geographic, pp. 219-248.
- Russell, M. (2003). Piltdown Man: The secret life of Charles Dawson & the world’s greatest archaeological hoax. Gloucestershire, UK: Tempus.
