Enhancing the reconstruction of the Gabasa Neandertal's diet using Ca and Sr stable isotopes

Neandertals are known to have occupied Eurasia for over 250,000 years and were well adapted to the environmental conditions of the last ice ages. However, the dietary habits of these ancient humans remain debated, with conflicting evidence suggesting that they may have been primarily carnivorous, omnivorous, or even herbivorous. Traditional isotope analyses have provided some insights into Neandertal diets, but their limitations (preservation and baseline effect) have sparked the need for new approaches. These limitations are well known on the Iberian Peninsula, and while recent results of carbon, oxygen, radiogenic strontium, and zinc isotopes and trace element ratios allow the reconstruction of the Gabasa (Spain) Neandertal diet, some questions still remain unanswered. Our study explores the potential of using calcium and stable strontium isotopes (δ⁴⁴Ca and δ⁸⁸Sr, respectively) to supplement previous analyses performed on the Gabasa Neandertal. Based on the low δ⁴⁴Ca and δ⁸⁸Sr values observed for the Neandertal specimen, our results suggest a hypercarnivorous diet that included low but non-negligible quantities of bone, although it is not possible to rule out the possible impact of milk consumption. Overall, our work argues that Ca, Sr, and Zn stable isotopes can supplement conventional isotope studies and offer a more comprehensive picture of human diets, including that of Neandertals.