Younger Dryas reindeer in northwest Europe: A multi-isotope study of the palaeoecology and mobility of Chelm’s Combe fauna, Britain.

Reindeer ( Rangifer tarandus ) played a central role in the subsistence strategies of Late and Final Palaeolithic populations across northern Europe, particularly during the Younger Dryas (c. 12,850–11,650 cal BP). However, while reindeer are known from securely dated Younger Dryas faunal contexts in Britain, they are not associated with archaeological assemblages, and there is currently no conclusive evidence for human presence in Britain at the height of the Younger Dryas stadial. This absence raises important questions about local environmental conditions and the ecology and movements of animal populations in Britain compared to those elsewhere in northwest Europe. In this study, we present the first detailed multi-tissue, multi-isotope analysis of Younger Dryas reindeer from Britain, based on the faunal assemblage from Chelm’s Combe, southwest England. To investigate climate, environment, and reindeer mobility during this period, we analysed oxygen and carbon isotope values from reindeer and red deer ( Cervus elaphus ) tooth enamel, strontium isotopes from reindeer enamel, and carbon, nitrogen, and sulfur isotope values from the bone collagen of reindeer, red deer, and horse ( Equus ferus ). The strontium isotope results indicate that, while some reindeer were likely locally resident, others were non-local and possibly migratory, with potential movement routes extending into northern Britain or across the Channel into northern France. Comparative collagen isotope analysis reveals a pronounced east–west gradient in reindeer δ¹³C and δ¹⁵N values, echoed in the δ¹⁵N values of horse, with British specimens exhibiting higher δ¹⁵N and lower δ¹³C values than their continental counterparts. These isotopic differences likely reflect regional variations in temperature, moisture, and lichen availability. Together with the strontium isotope results, these data point to limited connectivity between British and continental reindeer populations. Our findings contribute to a more nuanced understanding of reindeer biogeography and palaeoecology during the Younger Dryas and offer critical context for interpreting the apparent absence of human activity in stadial Britain.