The roots of the Piltdown Man hoax can be traced back to another international sensation: the publication of Charles Darwin’s “On the Origin of Species” in 1859. According to Darwin’s theory of evolution by natural selection, fossils must exist that would clearly link apes with modern humans. For the latter half of the 19th century and beyond, the search for the so-called “missing link” dominated the European archaeological community.
Discoveries made in France, Belgium and Germany—including the outstanding jaw fossil identified as hominid species Homo heidelbergensis, uncovered in 1907—stirred up envy in Britain, where archaeologists were desperate to come up with their own big finds. Scientists identified the Pleistocene-era gravel pits in southern England as the most likely location of such early-man fossils. As the story goes, Charles Dawson saw some gravel excavated to build a pond in Piltdown, Sussex, and decided to set up his own investigations at the spot.
According to Isabelle De Groote, a professor at the Research Centre in Evolutionary Anthropology and Palaeoecology and School of Natural Sciences and Psychology at Liverpool John Moores University and lead author of the new study published by Royal Society Open Science in August, Dawson’s early letters reveal that he was obsessed with gaining entrance to the archaeological Royal Society by making a “big” discovery. A solicitor and amateur archaeologist, Dawson had previously donated a collection of fossils to the British Museum.
After several years of excavations, Dawson reached out to Arthur Smith Woodward of the British Museum. According to De Groote, he wrote Smith Woodward that he had discovered a “thick portion of a human skull which will rival H. heidelbergensis in solidity.” Thrilled by the find, Woodward began excavating with Dawson; they found a mandible (jawbone), several teeth, more skull fragments and primitive tools buried in the same Pleistocene- or Pliocene-era gravel pits.
On December 18, 1912, Dawson and Woodward announced at a meeting of the U.K. Geological Society that they had unearthed fossils belonging to a primitive hominid that lived between 500,000 and 1 million years ago. Taken together, the ape-like mandible and parts of a human-like skull seemed to suggest that the individual had characteristics of both apes and humans. They called the discovery Eoanthropus dawsoni (or “Dawson’s dawn man”), but it quickly became known as Piltdown Man.
Dawson and Woodward kept working together at the Sussex site until the beginning of World War I. By that time, Dawson’s health was declining (he would die in 1916) but he wrote to Woodward in 1915 saying he had found a second set of remains, which was dubbed Piltdown Man II. This reported discovery helped quiet any doubts about authenticity, and Smith Woodward continued to promote Piltdown Man in the decades to come.
But in the 1920s and ‘30s, doubts began surfacing as other early human remains were found around the world, none of which showed the same large brain and ape-like jaw as Piltdown Man. Instead, the evidence indicated that hominids’ jaws and teeth became human-like before a large brain evolved. In the late 1940s, the Piltdown fossils were tested using new fluoride-based dating technology, which revealed they were closer to 50,000 years old, not 500,000. Later carbon-dating technology would show the skull was actually no more than 600 years old.
Further close examination revealed Piltdown Man’s jaw actually came from an orangutan, while the skull fragments were medieval human bones and the teeth had been filed down to make them more human. Moreover, the remains appeared to have been stained reddish-brown to match each other, as well as the color of gravel in the pits. In 1953, the British Natural History Museum publicly declared Piltdown Man a hoax.
In addition to the obvious suspect (Dawson), a number of possible forgers were blamed over the years, from Smith Woodward and Pierre Teilhard de Chardin, a Jesuit who teamed up with Dawson for the Piltdown digs, to famed mystery author Sir Arthur Conan Doyle and Martin Hinton, a disgruntled volunteer on the Piltdown dig who supposedly sought revenge against Smith Woodward.
But according to De Groote’s study, all the Piltdown Man fossils were most likely made by a single forger. Her team used cutting-edge techniques such as microCT scanning, ancient DNA analysis and 3-D microscopy on the human and ape remains found at Piltdown, and determined that the jaw and teeth of Piltdown Man actually belonged to the same ape. Their findings suggest the forger likely found the fossils in a curiosity shop or a museum collection, both of which Dawson would have had access to. The cranial bones, meanwhile, came from two or three medieval humans.
De Groote told LiveScience that the bones were “evidently purposely selected for their cranial thickness.”
The researchers also found that some of the bones and teeth were loaded with gravel that was held in place by pebble plugs; both cemented with putty, which had also been stained reddish brown. The gravel and the pebbles all came from sediment similar to that found at the Piltdown site. De Groote believes the gravel was added to weigh down the more modern bones, which are lighter than older fossils.
While the forger showed strong technique, De Groote believes he could not have been a trained conservator (like Smith Woodward). In addition, she argues, “The consistency in the modus operandi and the use of a limited number of specimens to create both the Piltdown I and Piltdown II material are indicative of a single forger.” As the only person with a direct association with the Piltdown II site, Dawson is clearly the most plausible culprit. Along with worldwide fame, the discovery of Piltdown Man finally brought the amateur archaeologist the honor he had so long been seeking, in the form of nomination to the Royal Society.
In finding a solution to the mystery behind the more-than-century-old Piltdown Man hoax, De Groote hopes to offer a lesson for modern scientists. In the new study, she writes of the hoax as a cautionary tale “not to see what [the scientists] want to see, but to remain objective and to subject even their own findings to the strongest scientific scrutiny.”