Identifying the Impact of Soil Ingestion on Dental Microwear Textures Using a Wild Boar Experimental Model

Abstract

Dental microwear has been widely used to reconstruct mammals' past diet and to understand their dental evolution. In archaeology, it can help reconstruct anthropogenic herd-feeding systems. However, deciphering the impact of exogenous mineral particles on dental wear is an ongoing challenge since studies have shown that soil ingestion can generates microwear traces that interfere with the dietary signals. To bridge this gap, this study relies on the first large-scale controlled-food experiment on wild boars (Sus scrofa) to test how soil ingestion can affect the dietary signal recorded in dental microwear. It provides the opportunity to investigate the impact of natural soil ingestion over microwear traces by comparing penned boars that were able to root with stalled boars that were not. We performed 3D Dental microwear texture analysis (DMTA) on 22 controlled-fed boars kept captive either in an indoor stall with no soil ingestion, or in a wooded pen with natural soil ingestion. We analysed shearing and crushing facets on upper and lower first and second molars using standard texture parameters. We also conducted particle size distribution analyses of the ingested soil. In line with previous works, the consumption of exogenous abrasives in rooting boars leads to less rough, less complex and more anisotropic wear surfaces than in stall-fed boars, even though they received the same diet. Thus, we highly recommend studying DMT when investigating ancient pig husbandry systems, particularly local changes in food management. Overall, this study contributes to a better comprehension of how exogenous abrasives impact DMT among mammals.