Sea otters search for food using their front paws and highly sensitive noses. Whiskers, in the nose act like fingers; they can move individually and sense where their prey is.
Prey can include a multitude of different foods, including sea snails, mussels, crabs, clams, abalone, sea urchins, and many other animals. The sea otter’s teeth are ideal for crushing and grinding, but for prey that are more difficult to crack open, sea otters have been observed to use rocks as tools.
Otters dive to obtain a variety of invertebrate animals. The most common prey of Sea Otters is sea urchins, mussels, abalone, clams, scallops, crabs, seasnails, chitons, octopus, and squid. An acute sense of touch, using paws, nose, and whiskers, is very important for finding prey in crevices or bottom sediments, and during a dim light.
Items such as crabs and urchins are broken open with paws and teeth; the teeth are modified for crushing hard foods. Hard-shelled mussels and clams are bashed repeatedly against a stone on the otter’s chest. Their rock tools range from 6 to 15 cm across, and favorite rocks may be carried in the armpit pouch on several successive dives.
It is the only mammal other than the primates formed (monkeys, apes, humans) known to use tools. While eating, Sea Otters float on their backs, using their chest as a dinner table, and are often accompanied by gulls and small fish which scavenge on leftovers.
Food is usually squeezed between the leathery pads of the two front legs and brought to the surface to be eaten. Several food items are often stored in a loose pocket of skin in the armpit area for transportation and while feeding.
Most foraging takes place at depths less than 30m, but one dive to 100m has been recorded. Research on the west coast of Vancouver island found that food dives varied from 45 to 127 seconds, the longest interval between food dives was 180 seconds and individuals may spend up to two hours diving for one kind of food.