A Lock of Braided Human Hair Could Change How We Think About Inca Society and Record-Keeping

The khipu knot-tying system was thought to have only been used by elites, but one artifact suggests commoners, too, knew how to use it

Sara Hashemi | Daily Correspondent

August 15, 2025

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A single lock of 500-year-old hair could upend what researchers have long thought about class and literacy in the Inca Empire, according to a new study.

Spanning across western South America, the Inca Empire was the largest pre-Columbian empire in the Americas. The Incas used intricate knotted cords, known as khipus, to store information. These cords were used to record events, contracts and even, potentially, stories and myths.

The Inca Empire is often cited as a rare example of an empire without a written language, but Kit Lee, an anthropologist at East China Normal University and one of the study co-authors, tells Nell Greenfieldboyce at NPR that khipus are frequently “overlooked as a form of writing.” Much of what’s known about the production of khipus comes from the accounts of Spanish colonizers, which claimed they were made exclusively by elites. But now, a closer look at one of these artifacts suggests otherwise.

At the center of the study, published in the journal Science Advances on August 13, is a khipu that scientists radiocarbon dated to 1498 C.E. It consists of a primary cord of braided hair, with knotted pendants tied to it. The artifact was found at an auction in Germany and eventually made its way to Scotland, where it was acquired by the University of St. Andrews.

“I was amazed at how beautiful it was,” Sabine Hyland, a social anthropologist at the university whose work focuses on khipus, tells Humberto Basilio at Science.

Hyland initially assumed that, like most other khipus she’s seen, this one was primarily made of animal fibers. But, she says, “Kit looked at me and said, ‘Sabine, this primary cord is human hair,’” Hyland recalls to NPR. The researchers concluded that the hair in the khipu belonged to its maker, because human hair carried a person’s essence in Incan culture and was often used as a kind of signature in khipu production. At nearly three and a half feet long, the lock likely represents more than eight years of growth.

A chemical analysis of the carbon, nitrogen and sulfur in the hair offered insights into the diet and location of the person it belonged to. The analysis revealed that the owner of the hair ate few things with marine origins, suggesting they lived in the highlands. Additionally, their diet consisted mainly of tubers and greens. These results, the study authors say, suggest the person was low class.

“It was a complete shock,” Hyland says to Javier Barbuzano at Science News. Until now, researchers thought that khipus were not used by commoners but by the ruling elites—who had diets that primarily consisted of meat and maize. This lock, therefore, suggests khipu literacy could have been more widespread than previously thought.

Andrew Wilson, a forensic anthropologist at the University of Bradford in England who was not involved in the study, warns that while the paper unlocks the potential for further research on khipu, it’s not enough to draw conclusions about all of Inca society. “A small portion of hair doesn’t tell the whole story,” he says to Science.

Still, the study suggests there’s a lot that researchers could learn from the hundreds of khipus held in museum collections, even ones that have been studied before. Further analysis of these overlooked artifacts could help researchers understand Inca society in its own words, rather than through the narratives of Spanish colonizers.

“Ultimately, this gets us closer to being able to tell Inca histories using Inca sources,” Manny Medrano, a historian and khipu researcher at Harvard University who was not involved in the work, says to NPR. “We need to tell a story of literacy and of writing and of recordkeeping in the Inca Empire that is way more plural, that includes folks who have not been included in the standard narrative.”

Sara Hashemi | Read More

Sara Hashemi is a science writer and fact-checker currently based in New York City. Her work has appeared in Sierra, The Body, Maisonneuve magazine and more.