There is some evidence that otters may learn their preferences and foraging strategies from their mothers. Sea otters eat 20-25 percent of their body weight each day. In the wild, sea otters are often seen chewing on kelp. Since kelp itself has little nutritional value for otters, one theory for this behavior is that the otters are actually eating the invertebrates that live in the kelp. However, otters in captivity have been observed eating kelp with apparent relish, and not necessarily for the invertebrates living there.
Sea otters are among only a handful of animals known to use tools on a regular basis while feeding.
A sea otter will carry a rock or other hard object up from the sea bottom, place the rock on its chest while floating on its back and use it as an anvil for breaking open hard-shelled food items While diving, sea otters make use of a pair of pouches formed by excess skin and fur just behind the forelimbs. As food items are found, they are stored in the pouches to maximize the length of each dive. The more food that can he gathered per dive, the less energy wasted. Grooming is an extremely important activity for sea otters, which depend on their fur coat for warmth instead of a layer of blubber. Their fur is the thickest of any animal in the world.