Researchers have increasingly recognized the need to quantify the material properties of primate food items, particularly hardness (H) and stiffness (E), which is measured as elastic modulus. Assessing E in the field is particularly difficult because the typical equipment needed to perform the requisite analyses is expensive and cumbersome. Alternatively, researchers can use hand-held, relatively inexpensive, portable durometers that measure H on Shore scales. Shore-D durometers show a reliable ability to characterize H in harder-stiffer materials, and Shore-D measures in these materials can be reliably converted to E. Shore-A durometers-employed in past field studies of food properties-do not accurately characterize the properties of harder-stiffer materials, which are likely to be those materials exerting the greatest mechanical demands on primate masticatory morphology. We offer recommendations for Shore-D durometer usage in the field.
2011 Wiley Periodicals, Inc.