Quinoa, potatoes and llamas fueled emerging social complexity in the Lake Titicaca basin of the Andes


Food production systems are essential elements for the emergence of complex socio-ecological systems. In the Andes, societal complexity has often been linked to the increased production and consumption of maize by elites, but the importance of highland crops, such as potatoes, one of the most important crops. most cultivated in the world, and quinoa, currently recognized as a “superfood” remains largely underestimated. Using stable isotopes, including compound-specific amino acids, we are reconstructing the diets of people living in southern Lake Titicaca, where the state of Tiwanaku emerged. Over time, locally produced potatoes, quinoa and llamas, through increasingly intensive practices, have facilitated long-term food security, which has supported population growth, contributed to increased complexity. socio-political and facilitated resilience through episodes of significant climatic variations.


The Lake Titicaca basin was one of the main centers of cultural development in the ancient world. This lakeside environment is unique in the high dry Andes altiplano, and its aquatic and terrestrial resources would have contributed to the flowering of complex societies in this region. However, it is not yet clear to what extent local aquatic resources, especially fish, and the introduced crop, maize, which can be grown in areas along the lake shores, have helped facilitate sustained food production. and population growth, which underpinned increasing social political complexity from the formative period (1400 BCE to 500 CE) and culminated with the state of Tiwanaku (500 to 1100 CE) . Here, we present direct dietary evidence from stable isotope analysis of human skeletal remains spanning over two millennia, as well as faunal and floral reference materials, to reconstruct food pathways and ecological interactions in southern Lake Titicaca. over time. Bulk stable isotope analysis, together with stable isotope analysis of compound-specific amino acids, enables better discrimination between resources consumed in aquatic and terrestrial environments. Taken together, this evidence shows that the human diet relied primarily on C3 plants, especially quinoa and tubers, as well as terrestrial animals, especially domestic camels. Surprisingly, fish was not a major source of animal protein, but a slight increase in C4 plant consumption attests to the growing importance of corn in the Middle Horizon. These results underscore the primary role of local terrestrial food resources in obtaining a nutritious diet that has enabled sustained population growth, even in the face of the climate and policy changes documented during these periods.


    • Accepted October 4, 2021.
  • Author contributions: research designed by MJM, RPE and CAH; MJM, IK, JMC and MCB carried out research; IK and RPE contributed new reagents / analytical tools; MJM, IK and JMC analyzed the data; and MJM, IK, JMC, MCB, RPE and CAH wrote the article.

  • The authors declare no competing interests.

  • This article is a direct PNAS submission.

  • This article contains additional information online at https://www.pnas.org/lookup/suppl/doi:10.1073/pnas.2113395118/-/DCSupplemental.

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