Preliminary experiment into the effects of red ochre on decomposition rate and bone microstructure in stillborn/perinate Sus scrofa domesticus

Abstract

Abstract The use of red ochre in funerary rituals holds continued interest for archaeologists and anthropologists given its ubiquity and debates surrounding its function. Despite this, and efforts into distinguishing corpse treatments on a histological level, there has been no experimental attempt to identify the potential effects of ochre treatments on soft tissue decomposition or skeletal remains. Moreover, there remain questions concerning the susceptibility of stillborn, perinate, and neonate remains to bacterial bioerosion. To help fill these knowledge gaps an exploratory study was conducted to assess the effects of red ochre on decomposition rate and bone histology using minimally destructive microCT-based protocols. Five stillborn or perinate domestic piglets, a reliable proxy for human corpse decomposition due to their similar gut bacteria and thoracic size, were either left untreated or subjected to one of two ochre treatments (paste or powder), and then buried or left to decompose in an open-air environment. The preliminary results of this experiment suggest that red ochre does not inhibit, nor significantly increase bacterial bioerosion in stillborn/perinate bone. However, ochre paste, which delayed skeletonisation and inhibited fly activity, did contribute to skeletal disarray in the exposed piglet, which we hypothesise is due to mechanical effects. Moreover, the very limited and localised evidence of potential bioerosion manifested on the periosteal surface, providing evidence for an exogenous origin for osteolytic microbiota.