Thanks to the application of the most advanced digital technologies, an international team analysed fossil remains from the San Teodoro Cave (Acquedolci, Sicily, southern Italy), bringing to light previously unknown aspects of the biology and behaviour of the spotted hyena (Crocuta crocuta), one of the great predators of the Pleistocene, and offering a unique perspective on the adaptation of carnivores in island contexts.

The study, led by the University of Milan in collaboration with Sapienza University of Rome, the Museum of Fauna at the University of Messina, Royal Holloway University of London and the University of Bristol, is published in the Rivista Italiana di Paleontologia e Stratigrafia and available in Open Access.

Through 3D imaging, researchers were able to decipher previously invisible details in the fossils, reconstructing not only the morphology of the animals, but also key elements of their social behaviour and ecology. The results highlight how geographical isolation profoundly influenced the development and adaptation of Sicilian hyenas, transforming Sicily into a veritable natural laboratory of fundamental importance for understanding certain specific evolutionary processes.

‘Thanks to the use of computerised tomography, we were able to explore the anatomy of the fossil skulls without damaging them, reconstructing highly accurate three-dimensional digital models of the brains of Sicilian hyenas and analysing the shape and development of different areas of the brain,’ says Dawid Iurino, professor in the Department of Earth Sciences ’Ardito Desio" at the University of Milan and lead author of the study.‘ Analysis of the brain revealed some differences compared to modern African hyenas. In particular, we found less development of the frontal cortex. In modern hyenas, these areas are associated with the management of complex social behaviours and life in large hierarchical clans. This suggests that Sicilian hyenas of the Pleistocene had a different social repertoire, probably living in smaller groups than modern forms,‘ explained Iurino.

‘Analysis of the teeth and bone remains,’ adds Alessio Iannucci, a researcher at Sapienza University, ‘shows that Sicilian hyenas were slightly smaller in size than continental Pleistocene hyenas, a clear sign of adaptation to an island environment where food resources are scarcer.’

‘This study allows us to view Sicily not only as a refuge, but as a veritable evolutionary laboratory,’ emphasises Raffaele Sardella, a palaeontologist at Sapienza University. ‘The remains of the hyenas of San Teodoro provide fundamental evidence of how large carnivores can respond flexibly to geographical isolation, modifying their physical dimensions and ecology over time.’

‘Grotta San Teodoro confirms its status as a site of international importance for the study of the Pleistocene,’ concludes Laura Bonfiglio, former curator of the Museum of Fauna at the University of Messina.