Functional discrimination in the masticatory apparatus of juvenile and adult cougars (Puma concolor) and spotted hyenas (Crocuta crocuta)

Abstract

Functional analyses of the teeth and jaws of juvenile and adult cougars (Puma concolor) and spotted hyenas (Crocuta crocuta) indicate several key differences and similarities in the design of the masticatory apparatus between species and age groups. Data from adults indicate preferential use of the precarnassial premolars in C. crocuta for durophagy (feeding on hard foods), and in P. concolor are suggestive of the need to use their carnassials during durophagy. In juveniles, powerful biting is limited to the caudalmost corpus (i.e., excluding the deciduous precarnassial premolars in P. concolor and many specimens of C. crocuta); however, dental replacement patterns determine how many and which teeth are available for use in this function. The most limiting scenario is one in which dP4 has been shed but eruption of P4 is incomplete, leaving only dP3 and the minute M1 to deliver strong bite forces. This condition occurs well after weaning in P. concolor but coincides more closely with the age of weaning in C. crocuta. It is during this period of masticatory compromise that juvenile C. crocuta must begin to join adult clan members at carcasses and thus must be able to feed aggressively with a masticatory apparatus that is poorly equipped to do so.