The role of climate change in the extinction of the last wild equids of Europe. Palaeoecology of Equus ferus and Equus hydruntinus during the Last Glacial Period

The last European wild equids —Equus ferus and Equus hydruntinus— were among the large mammals (or megafauna) that became extinct during the Late Quaternary Extinction Event disappearing from Europe during the Holocene. The role that the combined action of the major climatic changes of the Pleistocene/Holocene Transition and the human activities played in their extinction is not fully understood. The reduction of steppe-like biomes in Europe following the increase of mean global temperatures during the Holocene is usually regarded as the main event that triggered their disappearance, as both equids display typical morphological adaptations for open grasslands and grass eating. However, E. ferus and E. hydruntinus are found, often even co-occurring, in both warm and cold phases of the Late Pleistocene. Thus, the investigation of their niche occupation can help decipher whether their ecology and specialised dietary adaptations were the main reason of their decline following the early Holocene global warming. Here we investigate the feeding strategies of the two equids by studying their long- and short-term dietary adaptations through examination of their patterns of dental wear. As expected, dental mesowear points to a highly abrasive diet concordant with a grazing feeding behaviour for both E. ferus and E. hydruntinus which is consistent with their specialised morphological adaptations for open habitats. In contrast, dental microwear suggests a somewhat degree of plasticity in diets, as both species display microscopic features commonly recorded in modern mixed feeders. Such a flexibility may be the reason for which they could have persisted even when open grasslands were not the dominant landscape. Our findings provide a new line of evidence supporting the idea that human activities (e.g., competition with the first domestic forms brought from Eurasia and Africa) may have played a larger role in the extinction of some megafauna groups than climate change per se.