Medium Squid
The majority of the sperm whales' diet are squids of medium size, weighing about one pound. Traces of these squids are often present in sperm whale feces. Analysis of the stomach contents of sperm whales temporarily kept in captivity for research studies also found traces of medium squid.
Fish
A wide variety of fish are eaten by sperm whales daily. Researchers believe adult sperm whales consume several thousand pounds of fish daily. Sperm whales do not have a species preference, eating whatever type of fish is readily available.
Giant Squid
Sperm whales sometimes eat giant squid, which weigh over 1,000 pounds. No footage of whales fighting or eating giant squid exists, but the remains of giant squids have been found in the frozen stomachs of several deceased sperm whales. Further research led to the discovery of giant squid traces in the feces of other sperm whales. Researchers believe the scars of some larger sperm whales are the result of fights with giant squids.
Incidental Sea Life
Sperm whales also eat some sea life when attempting to consume food that is usually part of their diet. Mollusks, skate and other deep sea life is eaten by sperm whales as they pursue their primary food sources. Sperm whales will occasionally eat fish in nets or on lines set by commercial fishing companies.