The sea otter, of course. Though related to skunks and weasels, otters spend most of their time in the water. Their sleek, streamlined bodies and webbed feet make them excellent swimmers. Sea otters have the densest fur of any animal, and they have two layers of it that help them stay warm in cold water.
Sea otters are mammals, and therefore breathe air.
However, otters can hold their breath for deep dives to the ocean floor. Their favorite foods are often found buried in the sand or nestled in rocks. They eat shellfish, spiny sea urchins, crabs, shrimp and small fishes. Otters eat a lot because their body burns energy quickly. Sea otters are known for their unique style of eating.