Geographer suggests Neanderthals were just Cretins
WASHINGTON - Recent research has renewed debate over the fate of Europe's Neanderthals, the beetle-browed hunter-gatherers who endured the rigors of the ice ages for 200 millennia, only to cede their territory to modern humans and dwindle to extinction in a relatively short time about 30,000 years ago.
In a controversial paper published in the Geographical Review, Jerome Dobson, a geographer at Tennessee's Oak Ridge National Laboratory, has suggested that the Neanderthals could have been a kind of modern human who suffered from chronic iodine deficiency and cretinism that caused the thick, curved bones, large heads, ridged eyebrows and heavy muscles that are typical Neanderthal characteristics.
Dobson noted that the map of sites where Neanderthal remains have been found corresponds fairly closely to a pattern of cretinism common in the "goiter belts" of Central and Alpine Europe until well into the 20th century, when iodized salt was introduced.
"Neanderthalism" may have ended only when modern humans figured out how to bring iodine inland, he said. Seaweed, marine fish and shellfish are nature's prime sources of iodine.
Anthropologists have greeted Dobson's work with considerable skepticism, noting that some Neanderthal remains have been found near the ocean, that key skeletal traits common in cretins are not found in Neanderthals, and that a single pathology cannot explain the extinction of an entire population that had survived in a hostile environment for thousands of years.
"It's an unfortunate case of people outside the field talking about something they don't know anything about," said Erik Trinkaus of Washington University in St. Louis, one of the nation's leading authorities on Neanderthals. "Cretinism leaves very distinctive marks on skeletons, and they're not there on Neanderthals."
Instead, Trinkaus said, his research on a 24,500-year-old skeleton recently discovered near Leiria, Portugal, lends weight to the theory that the Neanderthals "disappeared" only because they interbred with modern humans.
In an article being readied for publication this month in the Proceedings of the National Academy of Sciences, Trinkaus said the skeleton, that of a 4-year-old girl, displays a "mosaic" of Neanderthal and modern anatomical traits, and may be a hybrid that straddles the gap between the species.
Dobson disagrees. "Rather than a halfbreed, I believe the Leiria skeleton was in fact a (modern human) suffering from iodine deficiency," he said. "I think it validates my theory," he added, and for a skeleton so recent, "the burden of proof" is on Trinkaus "to show it is not a cretin."
The Neanderthals' fate has puzzled scientists ever since the first remains were discovered in 1856. Although there are sites in Gibraltar and Israel, most Neanderthal remains have been found in Central and Alpine Europe and parts of Western Asia, a cold, icy region throughout much of the Neanderthal period which began about 230,000 years ago.
Neanderthals and modern humans overlapped in Europe for about 10,000 years until the Neanderthals disappeared.
"The enduring question is, what happened to them?" said Richard Potts, director of the Smithsonian Institution's Human Origins Program. "How does one interpret the combination of features that distinguish them? Were they ancestral to modern man or simply a side branch?"
Two theories predominate. One suggests that modern humans bested the Neanderthals in competition for scarce resources and wiped them out. The second holds that as modern humans migrated out of Africa about 100,000 years ago, they mixed with other populations and eventually absorbed them.
Dobson's article, published in December, argues that Neanderthals were a species of modern humans who suffered from cretinism because they lived deep inland, where glacial meltwater leached the soil of iodine and other highly soluble minerals.
"Either they were genetically unable to process iodine" when they had it, Dobson said, or they suffered from a pathology caused by the absence of iodine in their diet.
Either way, many Neanderthals would have suffered from a list of abnormalities that go well beyond skeletal deformity to include goiter, mental retardation, sluggishness, deafness and retarded sexual maturity. Such afflictions, Dobson suggested, would have made Neanderthals easy marks in any competition with more modern immigrants.
Besides physical similarities and geographical distribution, Dobson also noted that the pendulous breasts and protruding abdomens of early modern humans' "Venus figurines" bear a significant resemblance to symptoms of cretinism, suggesting that the moderns were aware of the affliction and may have venerated women who suffered from it.
Finally, Dobson noted that there are still an estimated 1.5 billion people worldwide at risk of iodine deficiency and its effects, with cretinism widespread in some iodine-poor populations in remote areas.
Dobson's critics say his explanation is too facile. Potts pointed out that Neanderthals existed for 200,000 years in a variety of environments, "simply too long and too large a geographic area to say it's all explained by a single pathology." And Dobson's theory may pose as many new questions as answers: After modern humans supplanted the Neanderthals, where did the modern humans get their iodine? If the two competed for the same scarce resources, why is there little evidence of even random encounters, let alone warfare?
Trinkaus said the Leiria skeleton suggests that there was no war simply because modern humans trumped Neanderthals through interbreeding. The jaw, and teeth of the little girl's remains are similar to those of modern people, whereas the size of the femur and tibia suggests Neanderthals.
"The issue is not the Neanderthals themselves," Trinkaus said. "The issue is what the people looked like immediately afterwards, and within the period of 25,000 to 30,000 years ago."
Potts called Trinkaus' discovery "exciting" but said further excavation is needed, particularly to recover the child's skull, "key" in any analysis of Neanderthal characteristics.
And, like many other experts, Potts also wondered why, if interbreeding is the answer, no examples of it have been found until now. Although there is plenty of evidence the two species coexisted, there is no evidence that they cohabited.
NEANDERTHALS are thought of as robust European ice-age hunters (left, at the Neanderthal Museum in Mettmann, Germany), but geographer Jerome Dobson says their bones show deformities similar to those of modern people suffering from cretinism (right, at the Field Museum in Chicago) due to an iodine deficiency. WASHINGTON POST PHOTOS