To help prove that cliff dwellers of Mesa Verde National Park migrated south to the Rio Grande pueblos in New Mexico during the late 13th century, researchers turned to an unlikely source: ancient domesticated turkeys.
In a recently published study, researchers found that when DNA from turkey bones stored in museums from both ancient cultures was compared, it revealed a correlation supporting the migration.
“It appears they took their turkeys with them when they left Mesa Verde, perhaps carrying the chicks in baskets with some feed for the journey,” said Scott Ortman, an assistant professor of archaeology at the University of Colorado Boulder, and a lead author of the study.
The study showed that the genetic composition of the turkey population in the northern Rio Grande pueblos changed substantially before and after the Mesa Verde exodus.
“What we found was good evidence of a substantial influx of turkeys into the northern Rio Grande region that had the same genetic composition as turkeys from the Mesa Verde region,” said Ortman, a former Cortez resident and former director of research at Crow Canyon Archaeological Center. “This is a new line of evidence suggesting a strong connection between contemporary Tewa Pueblo people in New Mexico and the Pueblo people who lived in Mesa Verde country before its collapse.”
The study was published in a recent issue of the journal PLOS ONE. The study included co-authors from Washington State University, the University of California, Davis and a molecular anthropologist from the University of Oklahoma.
The Mesa Verde region was a hub of Southwest Puebloan society, populated by as many as 30,000 people in the middle of the 13th century. A severe drought in 1277, coupled with resource depletion and social upheaval, is thought to have triggered a massive migration south to New Mexico and Arizona by the end of the 13th century.
For the study, Ortman and his colleagues used mitochondrial DNA – which is passed down from mother to offspring – extracted from turkey bones buried in the Mesa Verde region before the migration, and mitochondrial DNA collected from the northern Rio Grande region before and after Mesa Verde was abandoned.
Use of DNA from domesticated animals as a proxy to show human migration patterns has been used before, but this is the first time it has been used to study the Mesa Verde migration, Ortman said.
“It’s cool, and sharing the results has raised the intrigue of the public. People are fascinated by this historical mystery and the use of DNA to investigate it,” he said during an interview Friday with The Journal from his CU office. “The paper has generated more media calls than anything else I’ve done.”
He added that the study also showed the importance of curated collections from old excavations.
“The people who excavated the turkey bones we examined had no idea people would be able to get DNA out of them. They saved them recognizing that they were interesting and had value,” he said.
The bones analyzed were from the Museum of Indian Arts and Culture and the School of Advanced Research, both in Santa Fe, New Mexico, as well as from the Maxwell Museum of Anthropology at the University of New Mexico in Albuquerque.
The study casts light on a long-running debate between archaeologists on the migration patterns of the Mesa Verde people. A main criticism of the migration theory to the Rio Grande pueblos is that Mesa Verde pottery and building styles don’t show up there after 1280.
The turkey DNA supports the case that they did migrate to the Rio Grande pueblos, Ortman said, but why they did not continue making the pots and buildings the way they had been is another archaeological question.
“That has been the big issue. The turkey DNA results support the argument we are making that a sizable chunk of the Mesa Verde culture moved to the northern Rio Grande region and stimulated the formation of the Tewa Pueblo people that live in the area,” he said.
Previously, Ortman and his colleagues used biological, linguistic, oral tradition and material culture evidence to suggest that the ancestors of the Tewa-speaking Pueblo people in New Mexico lived in the Mesa Verde region.
Ortman said researchers considered using DNA from ancient human remains, but when the idea failed to garner tribal support, they received permission from Pueblo leaders to use the turkey bones.
Turkeys had been kept as a source of feathers to make blankets and other goods by the Mesa Verde inhabitants before A.D. 1000, Ortman said. The archaeological record shows that the Mesa Verde people later raised the turkeys as a meat source, causing turkey bones to become a more common and an improved research tool.
Ortman said the team first tried using DNA from ancient domesticated dogs to document the migration. That approach did not pan out, and the reason revealed a new mystery.
Ancient canid remains in museums unearthed from Mesa Verde were domesticated dogs. But when researchers looked at DNA from what were traditionally thought to be domestic dogs buried in the northern Rio Grande, they discovered they were actually coyotes.
“It’s an interesting puzzle as to why the northern Rio Grande people buried so many coyotes,” he said. “We looked at whether they were domesticated, but the isotopes showed they were eating wild game, indicating they were wild.”
jmimiaga@the-journal.com