Sen Otters off the Coast of California 
sea otters off the coast of Californiahave an unusual method of getting food．They dive to the floor of the sea to find the shell－fish they like． 
When an otter brings a shellfish to the surface of the water，he floats on his back and puts the shellfish on his chest．Then the otter digs the meat out of the shell with his teeth． 
Sea otters are especially fond of shellfish with a very hard shell．When the otter brings up one of these，he also brings a stone．He puts the stone on his chest，holding the shellfish in his front paws．He takes a wide swing and smashes the hard shell on the stone．Then he has no trouble getting at the meat in the shell． 
加利福尼亚近海的海獭 
生活在加利福尼亚近海的海獭，其取食方法很不寻常，它们潜入海底去寻找它们喜欢的甲壳动物。 
当海獭把一只甲壳动物挟持到水面时，就背朝下浮在水面上，把甲壳动物抱在胸前，然后用牙把肉从壳中剔出。 
海獭尤喜食长有坚壳的甲壳动物。当海獭把这样一只甲壳动物带到水面时，同时也带上来一块石头。它把石头放在胸前，用前爪抓住这只甲壳动物。它大幅度地摆动一下身体，对着石头猛击坚硬的甲壳，然后，取壳中肉就没有麻烦了。