Arctoidea is a superfamily of extinct and extant mostly carnivorous mammals which include the extinct group Hemicyonidae (dog-bears), and extant groups Musteloidea (weasels), Nothocyon, Pinnipedia (seals, sea lions), and Ursidae (bears), found in all continents from the Eocene, 46 Ma ago, to the present, approximately 46 million years.
Canoidea (literally "dog-like"), is a suborder within the order Carnivora. They typically possess a long snout and non-retractile claws (in contrast to the cat-like carnivores, the Feliformia). The Pinnipedia (seals, sea lions and walruses) evolved from caniform ancestors and are accordingly assigned to this group. Most members of this group have non-retractile claws (the fisher, marten, red panda and ringtail have retractile or semi-retractile claws) and tend to be plantigrade (with the exception of Canidae). Other traits that separate Caniformia from Feliformia is that caniforms have longer jaws and have more teeth, with less specialized carnassial teeth. They also tend more towards omnivorous and opportunistic feeding, while the feliforms are more specialized for eating meat. Caniforms have single-chambered or partially divided auditory bullae, composed of a single bone, while in feliforms the auditory bullae are double-chambered, composed of two bones joined by a septum.