Classical Stories From WSMR

A lock of hair could rewrite assumptions about the Inca Empire

NPR | By Regina G. Barber,

Nell Greenfieldboyce, Rachel Carlson, Rebecca Ramirez

Published February 16, 2026 at 9:05 AM EST

A khipu was used to record statistical information, such as taxes, census data and storehouse inventories.

The Inca Empire in South America was one of the most powerful pre-Columbian societies. It was known for the architecture of Machu Picchu, an extensive road network and a system of terraces for agriculture. The society also kept records known as khipu, which involved a system of tying knots to encode sophisticated information.

Literacy in this form of writing was assumed to be something that only the highest levels of Inca society could do. But NPR science correspondent Nell Greenfieldboyce shares how a new analysis of a cord made out of human hair may change that assumption.

Curious about science history? Email us at shortwave@npr.org.

Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave.

The Inca Empire in South America was one of the most powerful pre-Columbian societies. It was known for the architecture of Machu Picchu, an extensive road network and a system of terraces for agriculture. The society also kept records known as khipu, which involved a system of tying knots to encode sophisticated information.

Literacy in this form of writing was assumed to be something that only the highest levels of Inca society could do. But NPR science correspondent Nell Greenfieldboyce shares how a new analysis of a cord made out of human hair may change that assumption.

Curious about science history? Email us at shortwave@npr.org.

Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave.

Listen to Short Wave on Spotify and Apple Podcasts.

This episode was produced by Rachel Carlson, edited by Rebecca Ramirez and fact-checked by Nell and Tyler Jones. Maggie Luthar was the audio engineer.