Distinguishing hominin and brown hyena (Parahyaena brunnea) bone accumulations from the Middle Stone Age in South Africa

Brown hyenas (Parahyaena brunnea) are often implicated as either contributing to or scavenging faunal remains at archaeological sites in southern Africa. Various criteria have been established to distinguish between anthropogenic and brown hyena accumulations. Brown hyenas regularly feed on other carnivores. It is expected that such hyena assemblages will have a greater diversity of carnivore species, compared to accumulations of humans. We test this notion using anthropogenic accumulations dating to the Middle Stone Age from the Eastern and Western Cape of South Africa, as well as (nearly) contemporaneous fossil brown hyena accumulations from the same region, using a Carnivore Richness Index (CRI). This index measures the richness of carnivore taxa in samples against the richness of ungulate taxa. The results show that CRI values are generally low for faunas from layers and whole assemblages accumulated by hominins. The range is between 0.13 and 0.42 when all the layers are considered together as a whole for individual sites. For fossil brown hyena samples, the CRI values are consistently higher relative to hominin-induced samples with values ranging between 0.40 and 0.52. The results indicate that quantification using the CRI effectively discriminates layers and sites with higher probabilities of brown hyena activity from those of anthropogenic accumulations. Thus, if used in conjunction with other methods such as the carnivore-ungulate ratio, taphonomic modifications and the presence of juvenile hyena remains and coprolites, it will allow for better identification of the agents involved in the accumulation process.