A beach full of sea lions is a noisy place, full of barks and roars. In contrast, true seals, unless mating or disturbed, are usually very quiet except f or underwater trills and calls. In the water, a seal is a graceful and powerful swimmer. Webbed back flippers move from side to side while small front flippers steer and help the seal haul out on land or ice. Their bullet-shaped bodies are streamlined, and they spend much of their ti me in the water, swimming, napping, or just sitting with their heads bobbing above the surface.
Sea lions prefer to stay near shore.
They swim with their large front flippers, using their back end to steer. It is hard for a mammal to live in water, because cold water conducts heat away from a warm body better than air. Seals often live in very cold water and have several specializations that help them survive. A layer of fat, called blubber, lies just und er the skin, surrounding the main body. The fat near the skin may be very cold, but it forms an insulating barrier that keeps the inner body, like the heart and other major organs, warm.