Experiments in ancient Maya bloodletting: quantification of surface wear on obsidian blades

Abstract

It is widely accepted that the ancient Maya practiced sacrificial bloodletting to communicate with their dead ancestors and the gods. Implements to draw blood included a variety of tools, including stone blades made of obsidian. Evidence for bloodletting is based on ethnohistoric accounts provided by the Spaniards, ethnographic observation of modern Maya rituals, iconography depicting bloodletting, hieroglyphic references, and the recovery of artifacts from ritual contexts. However, evidence for bloodletting based on the surface wear on the obsidian blades themselves is inconclusive and difficult to identify. Recent work for quantifying use-wear on stone tools using laser scanning confocal microscopy (LSCM) and scale-sensitive fractal analysis, based on relative area (RelA), has led to an experimental program to quantitatively document wear patterns on replicated obsidian tools. Three obsidian blade segments were used to cut raw beef as a proxy for bloodletting. Our results demonstrate that surface roughness on the blade segments can be documented using RelA, but discrimination of the used from the previously unused surface was only possible in one of the three cases; the original surface structure of an obsidian blade plays a role in wear formation and its subsequent documentation based on RelA.