It is vital for otters to keep their fur clean. A 50-pound otter must eat 11 to 16 pounds of food a day just to stay alive. When diving for food, sea otters have been known to go as deep as 330 feet, and to remain underwater for up to five minutes. A typical feeding dive lasts just a minute or two, in waters less than 60 feet deep. California sea otters eat a variety of marine invertebrates.
Sea otters are tool-users.
The use rocks to crack open hard-shelled prey on the surface, either setting a rock on their stomachs while floating on their backs, or holding rocks between their forepaws to pound their prey.