The teeth of great apes help them survive times of food scarcity because they are diverse in type and material characteristics, allowing consumption of fallback foods.

"The teeth of some apes are formed primarily to handle the most stressful times when food is scarce, according to new research performed at the National Institute of Standards and Technology (NIST). The findings imply that if humanity is serious about protecting its close evolutionary cousins, the food apes eat during these tough periods—and where they find it—must be included in conservation efforts…

"…[N]atural selection in three ape species has favored individuals whose teeth can most easily handle the 'fallback foods' they choose when their preferred fare is less available. All of these apes—gorillas, orangutans and chimpanzees—favor a diet of fruit whenever possible. But when fruit disappears from their usual foraging grounds, each species responds in a different way—and has developed teeth formed to reflect the differences." (EurekAlert! 2009)


"Lucas and colleagues recently proposed a model based on fracture and deformation concepts to describe how mammalian tooth enamel may be adapted to the mechanical demands of diet (Lucas et al.: Bioessays 30 2008 374-385). Here we review the applicability of that model by examining existing data on the food mechanical properties and enamel morphology of great apes (Pan, Pongo, and Gorilla). Particular attention is paid to whether the consumption of fallback foods is likely to play a key role in influencing great ape enamel morphology. Our results suggest that this is indeed the case. We also consider the implications of this conclusion on the evolution of the dentition of extinct hominins." (Constantino et al. 2009:653)

Among apes, teeth are made for the toughest times

Journal article
The influence of fallback foods on great ape tooth enamelAm. J. Phys. Anthropol.April 11, 2009
Paul J. Constantino, Peter W. Lucas, James J.-W. Lee, Brian R. Lawn

Bornean OrangutanPongo pygmaeusSpecies