Farmers or Nomads: Isotopic Evidence of Human-Animal Interactions (770BCE to 221BCE) in Northern Shaanxi, China

Chinese history is composed of the contest, war, and admixture between the nomads in the north plateau and the farmers in central China. During the Eastern Zhou Period (770-221 BCE), nomadic groups, such as Rong ((sic)) and Di ((sic)), occupied the Eurasian Steppes and had frequent contact with the farmer group in Central China according historic records. This created a geographic boundary between the two groups named the agro-pastoral interweaving belt. To explore the impact of ethnic integration and human-animal interaction during the Eastern Zhou Dynasty, carbon and nitrogen stable isotope analysis of humans and animals at the Chongpingyuan site, Shaanxi, was undertaken. The delta C-13 (mean: -7.9 +/- 0.5 parts per thousand, n = 17) and delta N-15 values (mean: 8.8 +/- 0.6 parts per thousand, n = 17) for human and pigs (mean delta C-13: -8.1 +/- 0.5 parts per thousand; mean delta N-15:7.5 +/- 0.5 parts per thousand, n = 2) revealed that they consumed C(4-)based foods mainly while the delta C-13 and delta N-15 values of cattle (-17.6 parts per thousand, 4.3 parts per thousand, n = 1), horse (-17.1 parts per thousand, 4.1 parts per thousand, n = 1), and sheep (mean: -17.4 +/- 1.5 parts per thousand, 6.0 +/- 0.8 parts per thousand, n = 7) suggest that they relied on C-3 plants supplemented with minor C-4 plants. Based on the archaeological and historic contexts, we infer that humans at Chongpingyuan survived on an agro-pastoral economy with millet agriculture as the economic foundation. Given the isotopic spacing between humans and animals, we found that pigs contributed to the main sources of animal protein, whereas other animals might have been provisioned for other purposes, such as rituals or properties. In general, no significantly dietary differences between genders and funeral customs are found, but people with abundant burial objects seem to have consumed more animal protein, possibly related to social heterogeneity.