Figure 3

Carbon and nitrogen values from bone collagen with ellipses showing ranges at 95% confidence. (A) Individuals included in this study as well as humans and faunal values from previously published data³¹ (B) Humans included in this study showing the variation between those in the “Dry” and “Steppe” zones. “Dry” sites have less than 250 mm of annual precipitation, “Steppe” sites have over 250 mm of precipitation per year. (C) δ¹⁵N from bone collagen versus δ¹³C values from dental enamel demonstrating the shift from primarily C₃ reliant diets in the Early period to a wider range of carbon and nitrogen values, indicating an increase in the diversity of diets in the later three periods. (D) δ¹⁸O from dental enamel versus δ¹⁵N from bone collagen showing the values in “Dry” and “Steppe” areas.