Stable isotope ratio analysis (C, N, S) of hair from modern humans in Ethiopia shows clear differences related to subsistence regimes

Abstract

We measured the stable isotope ratios (C, N, S) of modern human hair collected from 49 people in rural southern Ethiopia to characterize and compare the stable isotope signatures of interacting and ethnically distinct populations with differing economic practices (farmers, pastoralists, fishers) in order to determine if the dietary differences are visible and measurable in their hair isotope values. We found that there were significant differences in all three elements that can distinguish these economic practices (carbon: Χ2 = 8.523, p = 0.014; nitrogen: Χ2 = 35.372, p < 0.001; and sulfur: Χ2 = 30.887, p < 0.001). These results demonstrate the utility of isotopic methods as an indicator of dietary difference in living populations and shows that diverse dietary adaptations and economies even among interacting and neighboring peoples can be distinguished in this region of Ethiopia.