Ancient biomolecules suggest learned foraging strategy in extinct cave bears

Studying the behavioural ecology of long-extinct species is challenging due to the difficulty in measuring the behavioural phenotype and correlating this with genetic and environmental factors. However, a multidisciplinary approach integrating isotope analysis of diet and ancient DNA analysis of genetic relationships offers a potential framework to test the proximate causes of dietary preferences. Our study focuses on Late Pleistocene cave bears from the Romanian Carpathians. Stable isotope analysis of bone collagen reveals substantial lifetime variation in food plant preferences among individuals. We find that bears with similar diets do not cluster according to their population structure, sex, time period, climatic conditions, or location. This disconnect suggests that diet preference in cave bears is not genetically inherited, and instead that individuals adapted their diets based on foraging experience. This integrative approach opens new avenues for understanding Pleistocene animal behaviour, leveraging ancient biomolecules synergistically to reveal insights otherwise inaccessible.