The innovation of reindeer transport has transformed human societies across Northeast Asia. Tracing the prehistory of reindeer domestication and riding, however, has proven challenging. Recent cross-species archaeozoological research has developed an expanded paleopathological toolkit, but to date, there are few approaches to better understand the role of mounted reindeer riding, a key aspect of ancient Northeast Asian lifeways. Here, we present new osteological insights from contemporary domestic reindeer in northern Mongolia, where mounted riding remains an important mode of transport in the traditional pastoral lifeways of the Tsaatan community. Our study of modern skeletal material suggests that reindeer riding produces recognizable alterations to the skeleton, including left-biased asymmetry, pathological deformation to the vertebrae, and exostoses of the lower limbs. Comparison of reindeer tack and skeletal pathology with those from domestic horses shows unique features linked to the specific modality and equipment used in reindeer riding that may help trace the origins of this important innovation in archeological contexts across prehistory.
