There are over 260 species of carnivorans, the majority of which feed primarily on meat. They have a characteristic skull shape and dentition. South America is notable for its diversity of canids, having in spite of their relatively brief history there. South America's felid diversity is also greater than that of North America north of Mexico, while its mustelid diversity is comparable and its mephitid and ursid diversities are lower. Its procyonid diversity is somewhat less than , the center of the family's recent evolution. The diversification of canids and felids in South America was partly a consequence of the inability of the continent's native avian and metatherian predators to compete effectively following the Great American Interchange.