Smithsonian.com

A replica of Piltdown Man. Image: Anrie/Wikicommons

One-hundred years ago, on December 18, 1912, British paleontologist Arthur Smith Woodward introduced the world to a tantalizing fossil: England’s most ancient human ancestor, perhaps one of the world’s oldest hominids. Best known as Piltdown Man, the “discovery” turned out to be the biggest hoax in the history of paleoanthropology. It’s a scientific crime that researchers are still trying to solve.

Piltdown Man consists of five skull fragments, a lower jaw with two teeth and an isolated canine.  The first fossil fragment was allegedly unearthed by a man digging in gravel beds in Piltdown in East Sussex, England. The man gave the skull fragment to Charles Dawson, an amateur archaeologist and fossil collector. In 1911, Dawson did his own digging in the gravel and found additional skull fragments, as well as stone tools and the bones of extinct animals such as hippos and mastodons, which suggested the human-like skull bones were of a great antiquity. In 1912, Dawson wrote to Smith Woodward about his finds. The two of them—along with Pierre Teilhard de Chardin, a Jesuit priest and paleontologist—returned to the Piltdown gravels to continue excavating. They found additional skull fragments and the lower jaw. The following year Teilhard de Chardin discovered the lone canine tooth.

Smith Woodward reconstructed the Piltdown man skull based on the available fossil evidence. His work indicated the hominid had a human-like skull with a big brain but a very primitive ape-like jaw. Smith Woodward named the species Eoanthropus dawsoni (Dawson’s Dawn Man). It was the first hominid found in England, and other anatomists took Piltdown as evidence that the evolution of a big brain was probably one of the first traits that distinguished hominids from other apes.

At the time of the discoveries, the field of paleoanthropology was still in its infancy. The only other hominid fossils that had been found by 1912 were Neanderthals in continental Europe and the even older Homo erectus of Indonesia. As additional fossils were discovered elsewhere, such as Africa and China, it became harder to see how Piltdown fit with the rest of the fossil record. The growing collection of hominid bones suggested upright walking was the first major adaptation to evolve in hominids with increases in brain size coming millions of years later after the emergence of the genus Homo. Finally, in the 1950s, it became clear why Piltdown was so odd: It was a fake.

In 1949, physical anthropologist Kenneth Oakley conducted fluorine tests on the Piltdown Man bones to estimate how old they were. The test measures how much fluoride bones have absorbed from the soil in which they’re buried. By comparing the fluoride levels to those of other buried objects with known ages, scientists can establish a relative age of the bones. With this method, Oakley determined Piltodwn Man wasn’t so ancient; the fossils were less than 50,000 years old. In 1959, anatomist Wilfrid Le Gros Clark and anthropologist Joseph Weiner took a closer look at Piltdown Man’s anatomy and realized the jaw and skull fragments belonged to two different species. The skull was most likely human while the jaw resembled an orangutan. Microscopic scratches on the jaw’s teeth revealed someone had filed them down to make them appear more like human teeth. And all of the bones had been stained to make them look old.

Since the truth about Piltdown Man was revealed, there have been many suspects implicated in the forgery. Dawson was the prime suspect. But he died in 1916, so scientists never had the chance to question his possible role in the hoax. Teilhard de Chardin, who found the isolated canine tooth on his own, is another possibility. One of Smith Woodward’s colleagues, Martin Hinton, may have also played a role. In 1978, workers found an old trunk of Hinton’s at the Natural History Museum in London. The trunk held teeth and bones stained in a similar way as the Piltodwn Man fossils. Despite much interest and speculation, no one has ever definitively tied any of these men to the hoax.

And now, a century after the announcement of Piltdown Man, scientists are still intrigued by the fake hominid’s origins. A team of 15 British researchers are using new methods to investigate the mystery. Radiocarbon dating and DNA testing will help identify exactly how old the bones are and confirm the jaw belongs to an orangutan. Chemical tests will also help the team pinpoint where the bones came from and whether they were all stained in the same way.

It will be several months before the analyses are complete. But if it turns out all the material was stained in the same way, or came from the same location, then it’s more likely that just one person was responsible for the scientific fraud. And that person is likely to be Dawson. It turns out that Dawson was responsible for at least 38 fake finds during his amateur fossil-hunting career, the Telegraph reports. Chris Stringer, an anthropologist at the Natural History Museum in London and one of the scientists investigating Piltdown, speculates in a commentary in Nature that Dawson may have committed such hoaxes in an effort to achieve scientific glory.

Stringer writes that Piltdown Man serves as a good reminder for scientists to “keep their guard up.” I think it also highlights the importance of open science in the field of paleoanthropology. The hoax wasn’t uncovered until scientists unconnected to the discovery analyzed the evidence. Today, numerous hominid species are known based on just a handful of fossils that only a handful of scientists have ever had the chance to study. In no way do I think some of these fossils might be fake. But giving other scientists greater access to the complete hominid fossil record will not only allow more errors to be detected but will also stimulate new interpretations and explanations of how our ancestors evolved.

And with that sentiment, I end my last Hominid Hunting post as I head off to a new job with Science News. I’ve enjoyed sharing my love of all things hominid with my readers, and I’ve appreciated all of the spirited feedback.

Ed. Note: Thanks, Erin, for all of your blogging the past couple of years! It’s been a thrill and best of luck to you going forward. — BW