A critical re-evaluation of bone surface modification models for inferring fossil hominin and carnivore interactions through a multivariate approach: Application to the FLK Zinj archaeofaunal assemblage (Olduvai Gorge, Tanzania)

Abstract

Over the past three decades, controversial interpretations of the behavioral meaning of bone Surface modifications at FLK Zinj regarding primary or secondary access to carcasses by hominins have stemmed from the independent use of mark types (cut, percussion, and tooth marks) to evaluate opposing models. Such controversy has also been based on an over-reliance on tooth mark frequencies (mostly generated by non-hominin carnivores), which have been documented to be high when hyenids are primary bone modifiers, low when felids have primary access to carcasses, and high when suids feed primarily or secondarily on carcass parts. In addition, it has also been argued that the frequency of tooth marks on the FLK Zinj bones has been overidentified by some researchers, by mistaking tooth marks with biochemical marks created by plant roots. Some methodological approaches have hampered the use of cut marks to identify hominin behavior. Most of the reasons for purported equifinality of experimental scenarios are strictly methodological and are also caused by the separate rather than joint analysis of mark types. In the present work, for the first time cut marks, tooth marks, and percussion marks will be jointly analyzed, both experimentally and at FLK Zinj. Primary and secondary access to carcasses by hominins yields different frequency associations of all of these marks, which can be diagnostic of the type of access. Such mark-type relationships can only be detected when all mark types are analyzed simultaneously and not as separate sets. This multivariate approach provides a robust interpretation of primary access to carcasses by hominins at FLK Zinj.