They must come ashore to molt, rest, breed and give birth. Most species do this once a year. Sea lions are found further south than most species. They have a sleek body that is covered with fine hair. The closely related fur seals have even finer hair, called fur, which allows them to live further north or south.
Seals rely less on hair for warmth then do the sea lions and fur seals.
True seals have a layer of thick blubber that helps insulate them from cold arctic waters. They live further north and south than any sea lions of fur seals do. Sea lions and fur seals have small, slim external ear flaps. Seals have tiny ear holes and no visible ear flaps. Sea lions have front flippers that are long and usually hairless.