Distinguishing millet and marine shellfish consumption by comparison of collagen and apatite in Prehistoric human teeth

Abstract

Collagen of human teeth excavated from Jomon and Yayoi sites in Gunma and Nagano was put to carbon and nitrogen stable isotope analysis. There was an average 3.9‰ δ¹³C increase in the δ¹³C of Terminal Jomon and Yayoi samples compared to Early-Late Jomon samples. The possible cause of this shift is the consumption of C4 plants with high δ¹³C such as foxtail and broomcorn millet (C4 millet). Another candidate is marine shellfish with a similarly high δ¹³C. We built a model to distinguish cereal and marine shellfish consumption based on the difference in the nutrients that collagen and apatite respectively reflect, and the contrasting nutrient makeup of C4 millet and marine shellfish. Carbon isotope values of collagen and the additionally measured apatite were consistent with the mixing model between C3 herbivores and C4 millet, where the contribution of the latter is 20-80%. These results support the archaeological deduction of millet agriculture.