Sheep for the soldiers: Stable isotope evidence for sheep management at the Shichengzi fort, Xinjiang and its implications for Han frontier interaction

Abstract

The territorial expansion of the Han dynasty (202BC – 220AD) created sizeable borderlands, catalyzing interactions between Han military and indigenous communities. At the northwestern periphery of the empire in modern day Xinjiang, military economy reflects the interplay between Han agricultural and indigenous pastoral subsistence. In this study, we sequentially sampled sheep teeth enamel for carbon and oxygen analyses at Shichengzi, a Han dynasty military fort in Xinjiang, attempting to reconstruct the life history of these animals and hence investigate local herding strategies. The sheep isotopic profiles imply that these animals might have been transported to Shichengzi from various locations. Winter foddering and vertical transhumance were the two critical strategies employed to manage Shichengzi’s flocks. While most sheep grazed seasonally along the altitude, a portion of the sheep population were closely managed within the fort, provided with fodder all year round. Seasonal lambing concentrated births in the spring and autumn in an effort to increase livestock survivorship. The variation in sheep isotope profiles denotes an inter-dependent system of provisioning at Shichengzi, where a stable food source could be maintained and relations between border garrisons and local communities actively manipulated. This adaptive military economy was mostly the product of the complex interplay between military demand, the inherent advantages in the indigenous economy and the constraints of the local environment.