Sperm whales’ main source of food is medium-sized deep water squid, but they also feeds on species of fish, skate, octopus, and smaller squid. The diet of sperm whale populations in the open ocean includes more squid, while coastal populations mainly forage on fish. Stomach samples examined at whaling stations from whales caught in Alaska revealed that squid was an important food in the Western Aleutians and Bering Sea, but fish became progressively more important towards the eastern Aleutians and into the Gulf of Alaska. Fish eaten in northern latitudes commonly included sharks, sea devils, cod and hake.  A sperm whale consumes about one ton (907 kg) of food each day.

A sperm whale’s lower jaw contains 18-25 large teeth on each side of the jaw, 3-8 inches in length. The upper jaw may have tiny teeth but they rarely erupt. The upper jaw contains a series of sockets into which the lower teeth fit.