Towards an interpretive framework for heated ostrich eggshell: An actualistic study

Abstract

Cooking is one way that hunter gatherers maximize the energetic and nutritional outputs of their diets, and the benefits of cooking are clear for many foods, but cooking is labor intensive, and most foods can be consumed raw. Nutritional studies show that cooking eggs dramatically increases the bioavailability of the protein they contain, thus once humans had the ability to control fire, they would be incentivized to cook eggs. To understand when humans started to cook eggs, quantitative approaches for recognizing thermally altered ostrich eggshell (OES) are necessary. Furthermore, techniques are required for recognizing intentional heat alternation versus alteration caused by wildfires. This study reviews the lengthy history of ostrich egg exploitation in the archaeological and ethnographic records, as well as previous taphonomic studies of thermally altered eggshell, and presents the results of actualistic studies utilizing various heating strategies and documenting the resultant changes in color and morphology of OES. The results demonstrate that anthropogenic and non-anthropogenic fires produce distinct patterns of changes, as well as potential diagnostics for identifying cooking.