They are protected by the federal government's Canada Fisheries Act. The California population is protected by the Marine Mammal Act and the U.S. Endangered Species Act. Sea otters are found only in the ocean and are rarely seen on land. River otters swim in rivers, streams and the ocean. They often come on shore.
Sea otters have paddle-shaped hind limbs, whereas the river otter's are webbed.
River otters don't. Sea otters usually have a single pup, born in the water. They have poor underwater vision. Sea otters dine floating on their backs, using their stomachs as a table to spread out the food they have gathered. They may use rocks to crush hard-shelled food, like clams.