Sea otters are one of the smallest marine mammals. The sea otters are part of the weasel family. They are known for their very rich fur, which is richest in the animal kingdom at 850,000 to 1 million hairs per square inch. They are the largest of the weasel family and the adults can reach 5 feet and 70lbs! Sea Otters are found near shore in kelp beds and feed on mostly shellfish, crabs, urchins and other crustaceans. They are also known for their use of tools to break open the hard shells of some of their catch. The otters are very social and are often seen with many of their friends rafting in the kelp beds.