Baby Seal

Fur seals have both blubber and a specially adapted fur coat, including outer guard hairs that repel water and a layer of insulating underfur. For this reason they were particularly prized by sealers. Many species were nearly hunted to extinction.
For most pinniped species molting is an annual process of replacing worn fur (and in some cases, skin) that temporarily grounds them. Molting can compromise thermoregulation, so some species, such as Elephant seals, fast and remain onshore for a month or more.
In many species, pups are born with a natal coat of a different length, texture and/or color than adults. This coat is adapted for the terrestrial, pre-weaning period, either a thick pelage to keep them warm in arctic environments, or a thin layer of fur to keep them cool on summer sands. During their first molt (about 11 days after birth for harp seals) the pups replace this with an adult coat better suited to life at sea. Until this age, pups risk hypothermia and drowning if they spend much time in the ocean.