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The article discusses a study which investigated the association between tooth chipping and the diet and bite forces of fossil hominins. The researchers applied a simple fracture equation to estimate peak bite forces directly from chip size as many fossil hominins had antemortem chips on their posterior teeth. Photographs of hominin, ape, monkey and peccary enamel chips were obtained from original specimens or casts of museum specimens.

A number of living primates feed partyear on seemingly hard food objects as a failback. We ask here how hardness can be quantified and how this can help understand primate feeding ecology. We report a simple indentation methodology for quantifying hardness, elastic modulus, and toughness in the sense that materials scientists would define them. Suggested categories of fallback foods-nuts, seeds, and root vegetables-were tested, with accuracy checked on standard materials with known properties by the same means. Results were generally consistent, but the moduli of root vegetables were overestimated here. All these properties are important components of what fleidworkers mean by hardness and help understand how food properties influence primate behavior. Hardness sensu stricto determines whether foods leave permanent marks on tooth tissues when they are bitten on. The force at which a food plastically deforms can be estimated from hardness and modulus. When fallback foods are bilayered, consisting of a nutritious core protected by a hard outer coat, it is possible to predict their failure force from the toughness and modulus of the outer coat, and the modulus of the enclosed core. These forces can be high and bite forces may be maximized in fallback food consumption. Expanding the context, the same equation for the failure force for a bilayered solid can be applied to teeth. This analysis predicts that blunt cusps and thick enamel, will indeed help to sustain the integrity of teeth against contacts with these foods up to high loads. [ABSTRACT FROM AUTHOR]