Scientific analysis of the distinct eating habits of two societies in northern Peru 6,000 years ago has allowed a team of 91Ʋ researchers to draw new conclusions about how complex sociopolitical structures took shape in ancient Andean societies.
The article, “Early specialized maritime and maize economies on the north coast of Peru” wasinthe journalProceedings of the National Academy of Scienceson Dec. 7.



The researchers investigated food consumption of the Huaca Prieta andParedonespeoples, two neighboring groups who lived less than half a mile apart. Participating were, associate professor of anthropology,, associate professor of biological sciences and earth and environmental sciences and, senior research professor and University Distinguished Professor of anthropology and religion and culture emeritus and Rebeca Webb Wilson University Chair Emeritus.
Using carbon and nitrogen isotope ratios from dentin collagen—calcified tissue that is one of the four major components of teeth—and stable carbon isotope ratios from enamel carbonates of 21 individuals at Huaca Prieta and nine individuals fromParedones, the team concluded that the groups had distinct diets despite their proximity.
People at Huaca Prieta, less than 100 meters from the shoreline, consumed a marine-based diet. Living 400 meters inland, individuals atParedonesate a more agricultural diet that consisted mostly of meat and maize. The differences in diet confirm that they engaged in distinct subsistence practices, and that there was cooperation and exchange between these groups.

“The stable isotope data from teeth, which tell us about childhood diet and weaning practices, clarify that there were distinct foodways at these neighboring sites. These differences result from and reflect social and political distinctions of these two different groups,” Tung said. “Differences in food production, distribution and consumption generated opportunities for exchange, an interaction that bound them together in mutual benefit.”
The combined data from the researchers’ dental microwear and stable isotope analyses further reveals that there were economic and occupational specialties between and among communities. “There are clear differences in diet between individuals at HuacaPrietaandParedones, both between adults and children. Stable isotopes clarify what individuals ate as children, clearly demonstrating marine and maize consumption, respectively,” DeSantis said. “Similarly, as adults,Paredonesindividuals ate foods with more abrasives than individuals from HuacaPrieta,likely due to increased abrasives from the processing of maize on grinding stones. These data definitely document foods consumed by ancient Peruvians, with important and broad implications for understanding sociopolitical systems.”

The researchers posit that over hundreds of years, each societygrew its expertisein the seasonal availability and patterns of their food sources.With this expertise, people honedthe technologies they worked with, like fishhooks and blades, to process their food.This economic specialization and solidification of communal roles worked hand in hand with maturing sociopolitical structures and complexity between thePardeonesand HuacaPrieta,Dillehayexplained. “We know that communitiesmaturedand operated with distinct structures by lookingtocommunity identity markers,” he added. “Symbols, carvings and weaving techniques arethetelltale signs of social differentiationthat we know of.Scientific confirmation through dental microwear texture data further clarifies our understanding of these early societies.”
This collaborative work would not have been possible without each researcher’s efforts and contributions, DeSantis explained. Dillehay’s groundwork and excavations at sites in Peru laid the crucial foundation for this research. DeSantis contributed her expert analysis of isotope and microwear data. Tung’s expertise as abioarchaeologistanalyzing human skeletons from diverse regions in Peru, and her lab’s focus on stable isotope analysis, provided essential theoretical and thematic context. In addition to illuminating how society formed in this region, the researchers are keen to see more isotopic and dental microwear texture data analysis that reveals actual food consumption of a people in the exploration of ancient political economies.
The research was supported by the National Science Foundation grant EAR1053839, the National Geographic Society, the Rebecca Webb Wilson family, a 91Ʋ University Discovery Grant and a 91Ʋ University 91Ʋ 1220 Scholar Grant.