Pinniped Pinniped Pinnipeds, commonly known as seals, are a widely distributed and diverse clade of carnivorous, fin-footed, semiaquatic marine mammals. They comprise the extant families Odobenidae (whose only living member is the walrus), Otariidae (the eared seals: sea lions and fur seals), and Phocidae (the earless seals, or true seals). There are 33 extant species of pinnipeds, and more than 50 extinct species have been described from fossils. While seals were historically thought to have descended from two ancestral lines, molecular evidence supports them as a monophyletic lineage (descended from one ancestral line). Pinnipeds belong to the order Carnivora and their
Mammal Mammal Mammals ( from Latin "mamma" "breast") are vertebrate animals constituting the class Mammalia, and characterized by the presence of mammary glands, which in females produce milk for feeding (nursing) their young; a neocortex (a region of the brain); hair; and three middle ear bones. These characteristics distinguish them from reptiles and birds, from which they diverged in the late Triassic. There are around 5,450 species of mammals. The largest orders are the rodents, bats and Soricomorpha (shrews and allies). The next three are the Primates (apes, monkeys, and allies), the Cetartiodactyla (whales and even-toed ungulates), and the Carnivora (cats,