Stable Isotopic Study on Horse Feeding Strategies in the Zhou Dynasty of Ancient China

Horses played a crucial role in military, ritual, and labor activities in ancient China, but our knowledge of their feeding practices is mostly limited to literature records. To investigate how this important livestock was fed in the Zhou Dynasty (1046–220 bce ), this study analyzed stable carbon and nitrogen isotopes of fifty bone and five tooth samples from horses discovered in Sanmenxia, Luoyang, and Zhengzhou of Henan Province. Bone isotope data from the Western Zhou period (1046–771 bce ) indicate a predominance of C 4 plants in the diet ( δ 13 C = −7.6‰ ± 0.6‰, δ 15 N = 6.6‰ ± 0.5‰; n = 4), with millet grain and straw likely serving as supplementary fodder alongside grass. In contrast, tooth isotopic values ( δ 13 C = −10.3‰ ± 2.9‰, δ 15 N = 6.2‰ ± 0.8‰; n = 5) suggest variable early‐life diets, implying that horses buried together may have originated from different pastures but were later gathered and fed a common diet at a single location for a relatively long time prior to burial. Feeding strategies shifted significantly during the following Eastern Zhou period (770–220 bce ). A marked decrease in bone carbon isotope values reflects a substantial increase in C 3 plant consumption ( δ 13 C = −13.7‰ ± 2.3‰, δ 15 N = 6.4‰ ± 0.8‰; n = 46). Considering the archaeological context of this time period, wheat, barley, and their straw were likely incorporated into horse fodder beside wild grass. Intersite isotopic variations likely reflect diverse horse origins. Individuals interred in large pits probably derived from multiple sources, while those in smaller pits likely came from single farms. These findings provide valuable insights into the scale of horse husbandry and shift in fodder management practices, as well as the influence of the agricultural shift from millet to wheat in central China during the Zhou Dynasty.