["International Journal of Osteoarchaeology, EarlyView. ", "\nABSTRACT\nThe Cova Eirós archaeopaleontological site preserves the most comprehensive archaeostratigraphic sequence in the northwestern Iberian Peninsula, with an exceptionally rich record spanning from the Mousterian to the Upper Paleolithic. The extensive fragmentation of the faunal record and the rich taxonomic diversity at this site have limited the identifiability of the remains and led to an overrepresentation of the main taxa (Ursus spelaeus and Cervus elaphus). To refine our understanding of the site's faunal composition and to explore the subsistence strategies of both Neanderthal and Anatomically Modern Human (AMH) groups, we compared the results of traditional morphological analyses with those obtained through the application of Zooarchaeology by Mass Spectrometry (ZooMS) to the indeterminate fraction of the assemblage. While overall congruent with morphological identifications, the ZooMS data reveal two significant trends: firstly, a marked decrease in the relative abundance of Ursus spelaeus, previously overrepresented due to the prevalence of deciduous teeth; and secondly, an increased representation of large ungulates compared to that identified through conventional methods. The inclusion of specimens showing clear evidence of anthropogenic modification reduces the apparent dominance of C. elaphus, suggesting a more diversified subsistence strategy. The integration of paleoproteomic and morphological approaches thus provides a more nuanced reconstruction of the paleoenvironment and dietary patterns of the hunter‐gatherer groups occupying the Eastern Mountains of Galicia during the middle to late phases of MIS 3.\n"]