Inferences of social behavior in bone-cracking hyaenids (Carnivora, Hyaenidae) based on digital paleoneurological techniques. Implications for human–carnivoran interactions in the Pleistocene

The putative competition between large predators and humans during the Pleistocene, especially in cave environments, has been a hotly debated topic during the last decades. Here, with the aid of digital paleoneurological techniques, we study the brain morphology and proportions of two fossil hyenas from the Eurasian Pleistocene, Crocuta spelaea and Crocuta ultima. Our results show that the brain morphology of these extinct species closely resembles that of the extant Crocuta crocuta and differs from those of the other extant genera (Hyaena and Parahyaena). Our analysis of brain proportions, however, shows a lesser development of the anterior brain in the extinct taxa compared with C. crocuta, thus more closely resembling the condition of both Hyaena and Parahyaena. The latter fact indicates that the greater anterior brain development of C. crocuta is a derived and recently-acquired trait, and suggests that extinct species of Crocuta displayed less-developed social abilities and/or a more restricted adaptability to new environments compared to the former. These behavioral differences between extinct and extant spotted hyenas might contribute to a better understanding of the taphonomical evidence obtained from Eurasian Pleistocene sites in relation to the ecological role played by humans and hyenas in the taphocenosis.