Carnivora: Fossil Record
The first carnivores evolved, probably from insectivore-like ancestors, in the late Paleocene, about 55 million years ago. These early carnivores, classified in the extinct familes Miacidae and Viverravidae,
The jaw depicted here is from one of these early carnivores, Viverravus, from the Eocene of North America.
By the early Oligocene, the first members of the Canidae, Felidae, Mustelidae, and Viverridae (that is, the dog, cat, weasel, and mongoose families) had evolved. Later in the Oligocene, the first bears appeared; by the end of the Oligocene, the earliest pinnipeds had evolved from a bear-like ancestor. The Miocene saw the appearance of the first hyaenas, as well as further diversification of the pinnipeds.
For more information on some of the most famous extinct carnivores of all, take a look at Sabretooths!, a UCMP special exhibit.