The "Million-Dollar Pig's-Tooth Mystery"

I could see it coming from a mile away. As soon as I heard all the hype surrounding "Ida", the exceptionally preserved specimen of Darwinius announced last week, I knew creationists would soon be citing our old friends "Archeoraptor", "Piltdown Man", and "Nebraska Man" as reasons not to trust evolutionary scientists. Each was a public embarrassment to scientists, that is true, but there is no reason to sweep these mistakes under the rug. Each can tell us something valuable about the way science works and how scientists interact with the media, and the case of "Nebraska Man" in particular has some interesting similarities to the recent hubbub over Darwinius.

It all started in 1922, a time when Christian fundamentalism was on the rise and evangelical orators like William Jennings Bryan decried the dangers of evolution. Not only did it debase our special place in the universe, they argued, but religious leaders like Bryan believed that evolutionary science had a direct role in triggering World War I. They were convinced that the leaders of Germany had imbibed the Social Darwinian Kool-Aid and were simply weeding out the unfit through war and conquest.

Bryan did not go unchallenged, however. Henry Fairfield Osborn of the American Museum of Natural History saw no conflict between Christian faith and his vision of the internally-directed course of evolution. Osborn was as appalled by Bryan's call to make a choice between faith and science as he was about Bryan's misrepresentation of evolution. As Osborn stated in his polemic response, The Earth Speaks to Bryan, he thought that;

The moral principle inherent in evolution is that nothing can be gained in this world without an effort; the ethical principle inherent in evolution is that only the best has the right to survive; the spiritual principle in evolution is the evidence of beauty, of order, and of design in the daily myriad of miracles which we owe our existence.

These principles also echo Osborn's support for eugenics, and are a combination of his unconventional views on evolution and his religious zeal. Bryan, of course, did not agree with Osborn, and the two argued through the pages of periodicals like the New York Times. Indeed, in an February 26, 1922 article published in the New York Times Bryan famously declared "truth is truth and must prevail". Osborn might have chuckled to himself when he read these words. Just the day before Osborn had received a lead about a fossil find, from Bryan's home state of Nebraska no less, that had the potential to publicly embarrass the "Great Commoner."

The letter that arrived on February 25 was from Harold Cook, a fossil hunter from Nebraska who said he had found a tooth from beds bearing other fossil mammals (like horses and antelope) "that very closely approaches the human type." (Cook had earlier tried to contact the paleontologist Frederick Loomis, but had received no response.) Osborn could hardly believe his luck, and he replied that the tooth should be sent to him immediately. He received it on March 14, and he recorded his thoughts on opening the package in a letter to Cook;

The instant your package arrived, I sat down with the tooth, in my window, and I said to myself: "It looks one hundred per cent anthropoid." I then took the tooth into Doctor Matthew's room and we have been comparing it with all the books, all the casts and all the drawings, with the conclusion that it is the last right upper molar tooth of some higher Primate, but distinct from anything hitherto described. We await, however, Doctor Gregory's verdict tomorrow morning; he certainly has an eagle eye on Primate teeth. . . . We may cool down tomorrow, but it looks to me as if the first anthropoid ape of America had been found by the one man entitled to find it, namely, Harold J. Cook!

This was not a tooth from a human, but rather seemed to represent some kind of ape. This made it all the more interesting. All the fossil apes that had been discovered came from Europe and Asia; if Cook's tooth was from an ape it would be the first fossil ape to be found in North America. Although tempted to call it "Bryopithecus after the most distinguished Primate which the State of Nebraska has thus far produced", Osborn dubbed it Hesperopithecus haroldcookii, Harold Cook's ape of the western world. Even so, Osborn was tentative in his views on Hesperopithecus. The tooth Cook found and a similar one found in the AMNH's stores was little to go on, and as Osborn wrote in the American Museum Novitates;

...it would be misleading to speak of this Hesperopithecus at present as an anthropoid ape; it is a new and independent type of Primate, and we must seek more material before we can determine its relationships.

After his initial description, however, Osborn stepped away from the scientific study of Hesperopithecus. Instead he set some of his best paleontologists, W.K. Gregory, W.D. Matthew, and Milo Hellman, to the task of figuring out what Hesperopithecus was. The analysis by the three scientists supported the ape as an intermediate offshoot between Dryopithecus, the hypothesized ancestor of the living African apes, and Sivapithecus, a fossil ape from Asia close to our own lineage. It lived in a long-lost North American world populated by rhinos, camels, elephants, horses, antelope, and a fossil peccary called Prosthennops that would soon take on greater significance to the Hesperopithecus story.

Not everyone agreed about the identification of the teeth, however. In 1923 Gregory and Hellman wrote a second paper to defend the hypothesis that Hesperopithecus was truly a fossil ape. Other scientists who had read the earlier papers thought the teeth more likely belonged to a monkey, bear, rodent, or carnivore, and one scientist (who is not named) even proposed that Cook's tooth was truly "An incus bone [inner ear bone] of a gigantic mammal." None of these alternate interpretations seemed to hold up, though, and Gregory and Hellman upheld the status of Hesperopithecus as an ape.

To confirm this hypothesis, however, the rest of the skeleton of Hesperopithecus would have to be found. This was especially important since the original tooth was nearly destroyed. In an interview Gregory later gave to Popular Science in 1931 the anthropologist referred to the whole event as the "million-dollar pig-tooth mystery", the "million-dollar" aspect coming from when the tooth was going to be x-rayed. When Gregory handed the tooth to the x-ray operator he jokingly told him to be careful for the specimen was worth a million dollars. The man became so nervous that he dropped it, and it shattered into bits which Gregory had to collect and later glue together.

Hence the search for more Hesperopithecus fossils became more important than before. The area from which Cook found the first tooth were searched but no more of Hesperopithecus turned up. Instead Gregory and the other workers who picked over the site found more remains of Prosthennops, and Gregory was shocked to find that the teeth of this ancient pig-like animal matched those of Hesperopithecus perfectly. In 1927 Gregory published a letter in Science in which he announced the downfall of the "western ape";

Last summer (1927) Mr. Thomson made further excavations in the exact locality where the type of Hesperopithecus haroldcookii was discovered. A number of scattered upper and lower premolar and molar teeth were found in different spots, but every one of them appears to me to pertain to Prosthennops, and some of these also resemble the type of Hesperopithecus, except that the crown is less worn. Thus it seems to me far more probable that we were formerly deceived by the resemblances of the much worn type to equally worn chimpanzee molars than that the type is really a unique token of the presence of anthropoids in North America.

This was a very embarrassing situation, but sometimes hypotheses turn out to be wrong. Within the space of five years scientists formed a hypothesis about a tooth, knew they required more information to fully understand it, and sent out field workers to find more bones to test their idea. This is how science works. Also, as Gregory would later state, it was probably just as well that they were wrong. If they had found an ape closely related to humans from North America it would have confused efforts to understand our ancestry; it would have thrown anthropologists off the track and have them searching North America in vain. Why, then, do creationists continue to mention "Hesperopithecus" as a case of science gone awry?

Much like the present controversy over "Ida", the scientific statements about "Hesperopithecus" did not match how the creature was presented to the public. First, Osborn could not contain his excitement over finding what he thought was a fossil ape from Nebraska. How could Bryan deny evolution when one of our relatives used to inhabit his home state? It was such a fortuitous find that Osborn could hardly control his enthusiasm and in The Earth Speaks to Bryan he wrote;

It is noteworthy that shortly after his pledge to accept the Truth appeared in 1922 ["truth is truth and must prevail." - Bryan in the New York Times, Feb. 26, 1922], the Earth spoke to Bryan and spoke from his own native State of Nebraska, in the message of a diminutive tooth, the herald of our knowledge of anthropoid apes in America. This Hesperopithecus tooth is like the "still small voice"; its sound is by no means easy to hear. Like the hieroglyphics of Egypt, it requires a Rosetta Stone to give the key to interpretation. Our Rosette Stone is comparison with all the similar grinding teeth known, collected from all parts of the world, and described or figured in learned books and illustrations. By these means this little tooth speaks volumes of truth-truth consistent with all we have known before, with all that we have found elsewhere. [emphasis mine]

Unfortunately the right "Rosetta Stone" to understand "Hesperopithecus" was a fossil peccary, and Osborn was so abashed by his blunder that he never mentioned "Hesperopithecus" again. Yet this does not explain why creationists still go on and on about "Nebraska Man." Osborn never applied the title to the teeth and he had maintained that "Hesperopithecus" was a non-human ape from the very start. Where did "Nebraska Man" come from?

Shortly after the announcement of "Hesperopithecus" in 1922 the Illustrated London News ran an article about the find by Grafton Elliot Smith. Included with it was a restoration of what "Hesperopithecus" might have been like by Amedee Forestier, but it was a far cry from what Osborn, Gregory, Matthew, and Hellman envisioned. Forestier, taking inspiration from depictions of "Java Man" (known as Homo erectus today), turned "Hesperopithecus" into "Nebraska Man." He is seen walking, club in hand and "wife" by his side, through a landscape inhabited by camels and other prehistoric mammals.

Osborn was not happy about this. So little was known of "Hesperopithecus" at the time that "such a drawing or 'reconstruction' would doubtless be only a figment of the imagination of no scientific value, and undoubtedly inaccurate." Smith, though, thought that Forestier's painting hit pretty close to the mark. Contrary to the findings of the AMNH team Smith thought that "Hesperopithecus" might have been "a primitive member of the Human Family." Smith's thoughts on "Hesperopithecus" aside, "Nebraska Man" was never a scientific idea, only a speculation of what might be by Forestier.

The rise and fall of "Hesperopithecus", then, cannot be represented by a single thread. It is a complex story where there was little agreement about the tooth from Nebraska until the issue was finally settled in 1927. The scientists who first described the teeth thought that it was a North American ape, not a fossil human, but the Illustrated London News painting stuck more firmly in the minds of people than the actual scientific discussions about the fossil. Will it be the same with "Ida"? Will the media hype overshadow scientific discussions about her exquisitely-preserved bones? Only time will tell, but at least in this case Darwinius is represented by a nearly-complete fossil. "Ida" is most definitely a fossil primate, and I look forward to the forthcoming debates over where she fits in the primate family tree.