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
Pinniped Pups of most species are born precocial. Unlike terrestrial mammals, pinniped milk has little to no lactose. Mother pinnipeds have different strategies for maternal care and lactation. Phocids such as elephant seals, grey seals and hooded seals remain on land or ice and fast during their relatively short lactation period–four days for the hooded seal and five weeks for elephant seals. The milk of these species consist of up to 60% fat, allowing the young to grow fairly quickly. In particular, northern elephant seal pups gain each day before they are weaned. Some pups may try to steal extra milk