Seals have a thick blubber layer which combined with a thick fur coat protects them from the frigid climates in which they live. Seal have large eyes which enable them to see quite well both above and below the water. Seals have a well developed sense of hearing and sensitive whiskers. Their keen senses allow seals to be impressive predators.
Seals feed mainly on fish, crustaceans and shellfish.
Some, such as the leopard seal, feed on penguins, and the crabeater seal feeds almost exclusively on tiny shrimp-like animals called krill.