Arctoidea is an infraorder of extinct and extant mostly carnivorous mammals which include the extinct group Hemicyonidae (dog-bears), and extant groups Musteloidea (weasels, raccoons, skunks, red pandas), Pinnipedia (seals, sea lions), and Ursidae (bears), found in all continents from the Eocene, 46 million years ago, to the present.Arctoids are caniforms, along with dogs (canids) and extinct bear dogs (Amphicyonidae).The earliest caniforms were superficially similar to martens, which are tree-dwelling mustelids.Together with cats, caniforms comprise the order Carnivora.