How large was the daily hunting range of prehistoric high-altitude populations in hypoxic environments? — evidence from 87Sr/86Sr, δ13C, and δ18O analyses of archaeological animal teeth

Limited archaeological evidence from low-altitude settings suggests terrestrial prey-procurement and hunting ranges of approximately 15–20 km. Whether this range changed under high-altitude hypoxic conditions, however, remains unclear. The Mabu Co site, a lakeside site in the southern Tibetan Plateau dating to 5000–2000 BP, is located at an altitude of 4420–4465 m. Wild faunal remains recovered from the site indicate that hunting was practiced throughout the period of occupation. In this study, we first constructed a bioavailable 87 Sr/ 86 Sr isoscape extending up to approximately 50 km from the site and then conducted bulk 87 Sr/ 86 Sr, δ 13 C, and δ 18 O analyses on terrestrial small-mammal and ungulate teeth recovered from the site. In addition, high-resolution sequential 87 Sr/ 86 Sr analyses were conducted on selected tooth enamel samples of ungulates. The bulk 87 Sr/ 86 Sr results show that the 87 Sr/ 86 Sr values of small-mammals are tightly clustered near the site, approximately 4–6 km, whereas those of ungulates exhibit greater variation, with all values falling within a 20-km radius. The δ 13 C and δ 18 O data, together with sequential 87 Sr/ 86 Sr profiles, indicate periodic back-and-forth movements of red deer ( Cervus elaphus ) and blue sheep/argali ( Pseudois nayaur/Ovis ammon ) within their respective ecological niche spaces. Taken together, multiple lines of evidence suggest that the daily hunting range of ancient humans in an ultra-high-altitude hypoxic environment was approximately 20 km, within the range documented in comparable low-altitude archaeological case studies, indicating remarkable behavioral adaptability under extreme environmental conditions. Our study provides the first estimate of the daily hunting range of ancient humans in an ultra-high-altitude region, offering a new perspective for understanding human behavior and survival strategies in extreme environments.