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In the Teeth of the Inca: A Georgia State anthropologist uses dental remains to explore class structures at Machu Picchu

Monday, April 20, 2009 – Jeremy Craig, University Relations

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When assistant professor of anthropology Bethany Turner first visited the awe-inspiring Inca site of Machu Picchu in 2005, the journey through the Peruvian region of Cusco in the Andean highlands revealed a cold and windy environment.

But as she traveled farther toward her destination, stunning terraces and verdant vistas roofed by descending clouds dominated her view.

“It’s an architectural wonder,” she said of the ancient place, which has intrigued anthropologists for centuries.

Beyond the beauty and marvels of the site, however, endless questions remain about the people who lived and worked at what is believed to have been an estate for the Inca emperor Patchacuti.

Now, by using slivers of tooth enamel no larger than a grain of rice, Turner has helped to reveal more about the people who served the government and religious figures of Machu Picchu.

People on a chessboard

Imagine a government moving you and your family, involuntarily, from one place to another to maintain facilities that were part of the operations of the state.

Moving people from place to place in this manner was key for Inca expansion and control — for reasons such as providing labor to needed areas, placing loyal settlers in troubled areas or as punishment if they resisted.

“It was almost like moving people around on a chessboard,” Turner said. “There were a lot of different motivations for moving people around, and people would be moved around differently due to their social class.”

Within the span of a century, the Inca grew from a small state existing in the Cusco region of Peru, in the southern Andean highlands, to an empire which, at the time of contact with the Spanish in 1532, controlled about 12 million people in western South America, encompassing present-day Ecuador, parts of Colombia, most of Peru, most of Bolivia and southward into Chile.

In relocating people, the Inca moved entire families and villages, but sometimes, they would put together strangers from different villages to serve the elites as long-term professional servants called yanacona.

Turner has studied samples of 74 skeletons found mostly in burial caves, but were the remains at Machu Picchu those of yanacona? Did they represent an entire group of people transplanted from one place to another to serve on a royal estate? The answers would be found in the molecules locked in their teeth.

Revelations in enamel

When you eat certain foods, drink water, or inhale dust from a particular place, molecules from these elements are incorporated into tooth enamel.

And teeth, which do not regenerate or change, preserve chemical signatures from elements consumed in childhood in ways that other parts of the skeletal system do not.

“Tooth enamel forms at a stable rate that’s more genetically controlled than almost anything on the skeleton,” Turner explained. “And once your tooth crowns form, they don’t remodel. A broken tooth isn’t going to heal like a broken arm would. So no matter how old someone was when they died, if we are able to analyze their first molar, we can essentially reconstruct patterns of diet and relocation in the first four years of life.”

Turner took small portions of tooth enamel from a collection of Incan skeletal remains held at Yale University and performed isotopic analyses at Yale, Emory University and the University of Florida.
Analyzing isotopes of strontium, oxygen and lead, Turner found that the skeletons buried at Machu Picchu were not local to the area, nor were they from the same places — indicating that they were indeed yanacona and giving further credence to the consensus that Machu Picchu served as a royal estate.

“All of them matched the pattern we would expect from yanacona — everyone was foreign to Machu Picchu, and everyone came from a variety of different places,” Turner explained.

At Machu Picchu, the yanacona would likely have engaged in agricultural work and maintained the site in a constant state of readiness for the emperor, his entourage and guests.

“For all of its visual beauty, the site would have been even more colorful to see with people, especially with a lot of activity that occurred when the emperor arrived,” Turner said.

More mysteries

Turner’s findings contribute yet another piece to the puzzle that researchers have been putting together about the Inca. And she hopes that the method of studying teeth to reveal social class can be applied to other areas of the empire.

“I feel like this study is a first step,” Turner said. “It doesn’t close the book in investigating social status in the Inca state.”

Future research will involve examining other locations where the Inca held power to see if people buried there were most likely locals, or if they were imported as labor colonists.

“Whether or not you had yanacona could speak to the function that a particular site served in the empire,” Turner said.

And by learning a site’s functions, more light can be shed on how the Inca managed to control and conquer such a vast territory.

“I hope that we can reconstruct the way Inca administered regions differently,” Turner said. “It suggests a flexible kind of statecraft where if you didn’t resist, did what you were told and produced what you were supposed to, life might not change that much. But if you fought, you could be uprooted, or they would transplant a large number of colonists in your area to keep an eye on you.”

Respecting the past

The samples Turner used to help reveal more about the people who lived and worked at Machu Picchu came from the remains of skeletons held by Yale University.

The collection of remains was excavated in the 1910s by Hiram Bingham III, a U.S. Senator from Connecticut, who undertook one of the first scientific archaeological excavations in the Andes region.
Yale and the Peruvian government are debating as to whether the collection should be divided up, with some remains staying at Yale, or whether all of the remains should be returned to Peru. The Peruvian government recently filed a lawsuit in federal court to have the remains returned.

In any case, researchers take great care in handling human remains. They must always be treated respectfully, Turner said, and careful controls now exist at Machu Picchu, requiring the permission of Peru’s government to undertake excavations.

There are also concerns about the site itself and its ability to handle the masses who visit the site every year.

“Some people have raised concerns because it is built along a ridge connected to two mountains,” Turner said. “That’s a whole lot of body weight to be on it every day.”