By Danny Freedman
It’s a dentist’s nightmare. But a lifetime of plaque build-up on the teeth of Neanderthals proved to be a goldmine for a team of researchers whose findings suggest a need to rethink one theory for how these ancient human cousins went extinct.
In a recent study, researchers from GW and the Smithsonian Institution said their dental digging uncovered plant microfossils and starch granules that indicate Neanderthals consumed a variety of plants, such as palm dates, grains and legumes—and even cooked some of them, demonstrating a previously unknown level of plant-food prep for their species. The cooking process can make plants more nutritious and easier to digest.
The findings refute some researchers’ speculations that the Neanderthal menu consisted mostly of meat, especially big-game, while early modern humans out-competed—and outlived—them thanks to a more diverse diet.
Instead, Neanderthals perhaps “had a little bit more complex dietary behavior than some people had given them credit for,” says Amanda Henry, PhD ’10, who conducted the research as part of her dissertation work at GW.
“Now that we have this new evidence that they were also consuming plant foods, maybe we need to revisit that theory and try to come up with a slightly more nuanced explanation that better fits the data that we have,” she says.
The findings were published online Dec. 27 in the Proceedings of the National Academy of Sciences.
Dr. Henry conducted her research along with GW professor Alison Brooks, of the university’s Center for the Advanced Study of Hominid Paleobiology, and Dolores Piperno, a GW research professor and a scientist with the Smithsonian’s National Museum of Natural History, in D.C., and its Tropical Research Institute, in Panama.
(Drs. Henry and Brooks also were among the GW faculty, students and alumni who recently helped the Smithsonian create its new Hall of Human Origins.)
Neanderthals emerged some 200,000 years ago and lived until roughly 28,000 years ago. For part of that time, they co-existed with a handful of other human species, including our own (Homo sapiens).
For the current study, Dr. Henry took a dental pick to a total of seven teeth belonging to three Neanderthals: one that is perhaps 50,000 years old, excavated at Shanidar Cave in northwestern Iraq in the 1950s; and two individuals, around 36,000 years old, uncovered in 1885 from the Spy Cave in central Belgium.
Until now, the authors write in the study, there had been suggestions that Neanderthals consumed plants but the evidence was “not always unequivocally linked to diet.” Evidence that they cooked plant foods was similarly lacking, according to the researchers.
But dental plaque, it turns out, is “one of the few, really good secure places” to look for archaeological evidence of diet, says Dr. Henry.
Since plaque—which comprises repeating layers of bacteria and minerals from saliva—accumulates only while an individual is alive, chipping into it and analyzing the contents offers a reliable look at items Neanderthals actually put into their mouths, the researchers said.
The team’s findings of starch granules in the plaque are the oldest such examples to date. Damage to the granules was recognized as being consistent with cooking based on previous research by Dr. Henry.
Doing dental work on teeth from the Paleolithic period “took a little bit of practice,” says Dr. Henry, who last month finished a post-doctoral stint at GW and has recently arrived in Germany to lead her own research group at the Max Planck Institute for Evolutionary Anthropology.
“There’s no ‘ick’ factor,” she says; the end result is merely a bit of powder. But the work did stir some strong emotions. Examining the plaque under a microscope, says Dr. Henry, “I couldn’t help thinking, ‘God! I’m the only person who’s ever seen this.’”
And though one Neanderthal was at the Smithsonian, in D.C., the other two were in Belgium—and the feeling of traveling with such precious cargo was less exhilarating. “I think I was most the anxious I’ve ever been about not losing my luggage,” she says.