Prehistoric pinnipeds

Desmatophocidae is an extinct family of pinnipeds closely related to either the eared seals and walruses or to the earless seals. These animals were the first group of large-bodied pinnipeds to evolve, first appearing in the Early Miocene, with no direct modern descendants. Desmatophocids have only been found to live in the North Pacific, with fossils being found in Baja California, California, Oregon, Washington, and Japan.

Pinnipedimorpha is a clade of arctoid carnivorans that is defined to include the last common ancestor of Phoca and Enaliarctos, and all descendants of that ancestor. Scientists still debate on which lineage of arctoid carnivorans are the closest relatives to the pinnipedimorphs, being more closely related to musteloids.

Amphicynodon was an extinct genus of caniform carnivore. It has traditionally been considered an early bear, although recent evidence has suggested it may be a unique member linked to other pinnipeds. It was endemic to Europe and Asia during the Oligocene, from approximately 33.9—28.4 Mya and existing for approximately . It was similar in size to early mustelids.