Piltdown man: Hunting a hoaxer

One hundred years on, the search continues for the perpetrators of the ‘Piltdown man’ scam, one of science’s most successful frauds. Catherine de Lange investigates.

Replica Model Of The 'Piltdown Man' Hoax Skull Bone fragments consisting of parts of a skull and jawbone collected in 1912 from a gravel pit at Piltdown, East Sussex, England. – Sabena Jane Blackbird / Alamy

Like all good detective stories, this one begins with a body. On a cold winter’s day, two men take the stage in front of an excited crowd at the Geological Society of London to speak publicly for the first time about an incredible discovery. In a gravel pit near the south coast of Britain, the men have unearthed the fossilised remains of what they think is an early human ancestor. It is one of just a handful of early human fossil finds in these early days of anthropology, and seems to provide the missing link in the story of human evolution. The announcement makes waves in the scientific community, painting a new picture of what it means to be human.

The year was 1912; 12 months later, the discovery was published in The Quarterly Journal of the Geological Society. It’s now 100 years since this first publication, and these fragments of fossilised bone are laid out on a table in front of me at London’s Natural History Museum. What was regarded in 1912 as one of the most significant palaeontological discoveries of the time is now recognised as one of the world’s greatest scientific hoaxes. We now know these fossil fragments are a disparate assemblage – part human, part animal – made to look like pieces of a whole creature that never really existed.

This so-called Piltdown man, nicknamed after the village in which he was seemingly dug up, was an elaborate and artificial construction. But who created it, and why? What motivated them to try and fool some of the greatest scientific minds of the time? Where did these fragments really come from, and can they tell us anything useful about the history of human evolution? After a century of mystery, a group of scientists are once again on the hunt for answers.

As hoaxes go, Piltdown man was a good one. “It was a very clever fraud that fooled a lot of senior scientists for a long time,” says archaeologist Darren Curnoe, from the University of New South Wales in Sydney. “It had a profound impact on the history of our discipline for almost 50 years.”

One of the two men who made the spectacular announcement of the discovery in 1912 was solicitor and amateur archaeologist Charles Dawson. Dawson claimed he had found pieces of what looked like a thick-boned human skull in a gravel bed. Being well-connected in palaeontological circles, he enlisted the help of Arthur Smith Woodward, then Keeper of Geology at the Natural History Museum in London, to help him make sense of this find.

The duo appeared convinced that what they had found was
an early human, dating back around 500,000 years.

Along with the skull fragments and a jawbone containing teeth, Dawson had also found some ancient-looking stone tools as well as tooth and bone fossils from several animals, including mastodon, elephant, horse, rhinoceros, hippopotamus, deer and beaver.

By the time they stood in front of the crowds in London, the duo appeared convinced that what they had found was an early human, dating back around 500,000 years. They named it Eoanthropus dawsoni (Dawson’s dawn man). In case there was any doubt, Dawson later claimed to have found more fragments in a second nearby site, named Piltdown 2, which seemed to fit neatly with his initial finds.

Most of the British scientists working in the field embraced the find. “Darwin was British. And then along comes Piltdown [man], and that provides pretty strong evidence for evolution. I suspect that a lot of British scientists accepted it partly due to nationalism,” says Curnoe.

A few, however, had their doubts, especially those working outside Britain. For a start, not everyone was convinced that the jawbone and the skull fragments matched. “There were several people who said from the beginning: these don’t belong together. They didn’t suggest it was a hoax, just that nature had played a cruel trick and had washed together a genuine ancient fossil ape specimen into the Piltdown gravels with some genuinely human fossils,” says Chris Stringer, an anthropologist at London’s Natural History Museum, as he holds up a reconstruction of the Piltdown man skull for me to see how the fragments might have fit together.

Stringer believes this detective story can benefit from a modern examination, and described the thrust of his new investigations in a commentary in the journal Nature in December 2012.

Although the real skull fragments are on display downstairs in the Museum’s public gallery, Stringer has brought all the other specimens from the Piltdown story to one of the museum’s back offices. I’m not allowed to touch the fossils, but as Stringer talks me through the Piltdown claims he shows me how each item fits into the old story, and points to subtle details which first sounded alarm bells for the 20th-century palaeontologists.

Back in 1912, there were limited ways to test the true nature of the specimens.

Today, we know the sceptics were right to doubt the find – the jawbone did belong to an ape, probably an orangutan, and while the skull fragments are human, they are much younger than originally thought, and were artificially aged through staining.

Back in 1912, there were limited ways to test the true nature of the specimens. But by the late 1940s, British palaeontologist Kenneth Oakley had developed a test for relative dating of fossils based on their fluorine content. When objects are buried they exchange material with the groundwater around them, losing nitrogen and picking up fluorine and uranium. When this test was applied to the Piltdown fossils in 1949 it became obvious that the jawbone in particular was much younger than some of the mammal fossils.

These were estimated to be at least a million years old, yet the jawbone seemed to be much younger. “That really raised the doubts,” Stringer says. By the mid 1950s, further tests had shown that the jawbone was not human and, thanks also to further discoveries outside Europe (see ‘Evidence for early humans’, right), Piltdown man was declared a hoax.
Yet numerous questions still remain. “Those early tests were not sufficient to say what the actual age of the fragments are, and this is something we still badly need to know,” says Colin Groves, a biological anthropologist at the Australian National University in Canberra. Using modern tools, this is what Stringer and his team are now trying to find out.

“We started this project doing state-of-the-art analysis to try and get to the bottom of fundamental issues, such as what species was used to make the ape fake, how many human bones were used, where did the bones come from, and does it look like there were multiple people involved or just one person?” Stringer says.

The question of who conjured up the hoax is perhaps the most intriguing. It seems pretty clear that Dawson played a crucial role; he was the one who ‘discovered’ the fossils at Piltdown, and later on at a secondary site also ‘found’ some more human bone fragments and a tooth. His motives? Dawson, so the story goes, was chasing recognition and wanted to become a Fellow of the Royal Society. “To become a fellow of the Royal Society as an amateur you’ve got to make big discoveries,” Stringer says. “You could say he’d been working up to this. This was like his great achievement.”
One way in which Stringer hopes to shed light on the whodunit is by close examination of the staining on the tools and bones. He points to one of the stone tools where a drop of acid has washed away the dark stains, revealing the true colour. To find out what the stain is made of, the team is using a highly sensitive technique called Raman spectroscopy.

This builds a chemical profile of the stain by bombarding the surface of the specimen with light rays, and analysing the way the light is scattered, which is specific to each chemical element. This method is super-precise and non-destructive.
Destroying the samples in order to understand their origins was one of the biggest setbacks when the fakery began to be exposed 60 years ago. In particular, back in those days radiocarbon dating (using the differing ratio of radioactive carbon-14 isotopes to carbon-12 isotopes) involved taking large chunks from the specimen.

“If you’re looking at a single tooth you’re going to destroy the whole thing,” Stringer says. Today, the tiniest of samples can be used, and dating is much more precise. DNA sampling is also being used to help explain where the samples came from and what species they belong to. Stringer says the results of the DNA tests are coming in soon, and should be published later in 2013.

If all goes to plan, these tests should help reveal who was to blame. “We may never know of course, but it would be interesting nonetheless to bring some of these new ideas and new techniques to the question,” Curnoe says.
For a start, DNA tests and radiocarbon dating will show whether some of the bone and tooth fragments at both the Piltdown 1 and Piltdown 2 sites came from the same individual. That finding would point firmly to Dawson, as he was the only person to be at both sites.

We may never find out who was involved in each detail of the hoax, but
a much clearer picture should soon emerge.

But even if the prime suspect is Dawson, it’s unlikely he acted alone. For one thing, he would have needed to get his hands on some pretty rare specimens. Then, there’s the expert knowledge that went behind the preparation of the fakes.

That accomplice may have been Arthur Smith Woodward. As Keeper of Geology at the Natural History Museum in London, he certainly had the know-how. Another suspect is Martin Hinton, who was then in a junior role at the Museum. Hinton would have had access to the fossil collections and, what’s more, a whole batch of stained materials was later found among his possessions. Could he have been the one to prepare the stains for Dawson? By comparing these materials to the stains on the Piltdown fossils, Stringer’s team should be able to determine whether or not that was the case.

I, for one, favour another theory. What if Hinton was really trying to test out staining techniques in his free time to do a bit of detective work of his own? This is Stringer’s pet theory and one that has some evidential basis, thanks to a very striking object that was also discovered at Piltdown. Of all the specimens laid out before me, this is a real anomaly. All the other pieces are small fragments of fossil tucked into protective padded cases, but this one by comparison is a hulking slab of what looks like wood. It is, in fact, a piece of elephant bone, carved to look like a digging implement, but also strangely similar to a cricket bat. “To me, this is such a crude thing compared to the other stuff,” says Stringer.

“Even at the time people said this looks like it’s been cut with a steel knife; it looks like a cricket bat.”
Stringer suggests the ‘cricket bat’ could have been planted at the site by somebody – possibly Hinton – who suspected the whole thing to be a hoax, and wanted to expose the truth. According to Stringer, Hinton would have been too junior to go to Smith Woodward and say: “You idiots, it’s all a fake!” Instead he may have thought: “I’ll just do something really absurd that puts an end to it.” What’s more absurd than setting up early humans as cricket players? But because Dawson couldn’t draw attention to a single item being a fake, says Stringer, “it gets published as one of the oldest bone artefacts in the world. Even though it’s ridiculous.”

We may never find out who was involved in each detail of the hoax, but a much clearer picture should soon emerge. Whether it was Dawson’s craving for recognition that motivated him to commit the forgery, a joke that got out of hand, or even a misplaced desire to provide evidence on the theory of evolution, the Piltdown hoax also serves another purpose, however unpleasant, which is to remind us of flaws in the scientific method.

The ultimate litmus test that comes from Piltdown, says Curnoe, is that it was probably too good to be true because it fit too closely to the status quo. “What we’ve learned is that palaeoanthropology is a discipline of surprises. So many new finds that are unexpected overturn the prevailing view. When something looks too good to be true and it makes us feel that we’re right, we’re probably wrong.”

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