"Despite the repeated tendency of s to evolve s for hypercarnivory, a canid has yet to appear that is completely catlike, that is, without any post- s. This possible constraint on morphological evolution in canids is argued to have resulted, paradoxically, in increased flexibility over evolutionary time and a great potential for rapid diversification and clade survivorship. Finally, it is suggested that the iterative pattern of specialization of the lower molars for meat-slicing that is seen in all families of carnivores, past and present, is probably a result of intraspecific competition for food, perhaps among s. This intraspecific selective force is countered by competition among species, since there are limits on the number of hypercarnivorous species within a single community."