Because of their hefty appetites, otters sometimes come into conflict with people who fish for sea urchins and abalone. They can dive as deep as 330 feet and stay under as long as five minutes. However, a typical feeding dive lasts just a minute or two, in waters less than 60 feet deep. A sea otter may use rocks to crack open hard-shelled prey at the surface, either setting a rock on its stomach while floating on its back, or holding rocks with its forepaws to pound its prey. Otters may also use rocks to pry up abalone and sea urchins.
Otters have unusual eyeballs, adapted to see both above and below the water.
But they use their sense of touch at least as much as their eyes. Their long whiskers help them detect vibrations in murky waters, and they use their sensitive paws to locate and capture prey under water. They seem to have an acute sense of smell and taste, but we don't really know how well they hear. They seem to be most sensitive to high-pitched sounds. An otter's fur keeps it alive in the icy water, so each otter spends up to four hours a day grooming to keep its coat in good shape.