Investigating diet and dietary change using the stable isotopes of carbon and nitrogen in mummified tissues from Puruchuco-Huaquerones, Peru

Puruchuco-Huaquerones is one of the largest cemeteries ever discovered in South America. Between 2200 and 2400 individuals have been recovered, most dating to the Late Horizon (A.D. 1476--1532). Five tissues (bone, hair, nail, skin and muscle) were sampled from 72 partially mummified individuals and analyzed for the stable isotopes of carbon and nitrogen. Soft tissues record short term diet, in the months antemortem; whereas bone records long term diet, 10--25 years antemortem. Isotope data from all tissues indicated the diet included primarily maize and lower trophic level animals (e.g., guinea pig, camelid) but also included some C3 resources. Although the site was close to the sea, isotope data, for most individuals, were not consistent with the consumption of marine foods. The isotopic composition of soft tissues demonstrated that C3 resources (e.g., tubers) were cyclically incorporated into the diet. Tubers are a wet season crop harvested during the coastal winter. As such, their consumption was likely limited to the winter months. This cyclical variation enabled the determination of season of death by comparing the carbon isotope data from sequential samples of hair and nail. Approximately 60% to 70% of individuals died during the winter. There were dietary differences between males and females; males had greater access to maize, perhaps as chicha beer, and animal protein relative to females. Isotope data from all tissues indicated that individuals buried in rope-encased bundles, assumed to be high status, and individuals interred without weaving tools, consumed a diet enriched in 13C and 15N relative to the rest of the population. Marine foods are enriched in 13C and 15N relative to maize and lower trophic level animals; consequently, isotope data for high status individuals are consistent with preferential access to marine foods. When isotope data from soft tissues were compared against isotope data from bone, the average values were similar. As such, although short term diet varied in the months before death, foods consumed in the short term were isotopically similar to the foods consumed in the last 10--25 years of life. This indicates that the individuals interred at Puruchuco-Huaquerones were native to the coast.