Direct evidence for scavenging as a primary feeding strategy in Pliocrocuta, an extinct genus of bone-cracking hyaenas

Abstract

Abstract The carnivoran family Hyaenidae exhibits a complex evolutionary history of diverse trophic adaptations, including the consumption of almost entire carcasses, either predated or scavenged. The associated durophagy peaked within the subfamily Hyaeninae in a clade of ‘fully developed bone crackers’, enabling a specialisation towards a scavenging niche. Coprolites (fossilised faeces) are increasingly valuable source of palaeoecological information, including the feeding habits of their producers. While coprolites are well documented for Quaternary bone-cracking hyenas, those from the Neogene members of this group remain poorly known. Here we present an investigation of bone-cracking hyaenid coprolites recovered from the Early Pliocene locality of Odessa Catacombs in Ukraine. These coprolites are attributable to an early representative of the genus Pliocrocuta , which is abundantly recorded at the locality. Morphologically, the examined coprolites are similar to those of later bone-crackers, particularly the extant brown and striped hyaenas ( Parahyaena brunnea and Hyaena hyaena ). Geochemical analyses corroborate a bone-rich diet in Pliocrocuta , as indicated by the high calcium and phosphate content and the prevalence of heavily digested bone inclusions that are taxonomically indeterminate. Numerous hairs and occasional culm-like plant fragments were revealed as surface imprints and internal hollow channels indicating their ingestion. The abundance of hair in the Pliocrocuta coprolites suggests non-regurgitative consumption of skin, a behavioural trait observed in the predominantly scavenging bone-crackers, brown and striped hyaenas. The study provides the earliest direct evidence for extensive bone consumption combined with the hair processing that is typical of behaviourally specialised scavengers within the durophagous hyaenid clade. This supports a primary reliance on scavenging in the genus Pliocrocuta and demonstrates that this feeding strategy was established in the true bone-cracking hyaenids by at least 3.6 million years ago.