Very small squid eat plankton. As they grow larger, they hunt and eat other marine creatures. Common food sources for small squid include small fish, crabs and shrimp.

Squid hunt by stalking. They have eight arms for locomotion and two tentacles for hunting. They sneak up on their prey and capture it with their tentacles, which draw the prey into their mouths. Their tentacles are equipped with sharp barbs to seize prey animals. Once the squid grab their prey, they bring it into their beaks, which tear apart food. Squid also have rough tongues that further rip prey apart before the squid swallow it.

The exact species and types of food squid choose vary by season, location and size of the squid. Squid are opportunistic and generally eat whatever is available. If no other food sources are around, they sometimes resort to eating other squid. Large squid eat large fish and sharks. Vampire squid eat dead and decaying organisms.

Squid have excellent eyesight. They can see in all directions at once and can see well in both light and dark environments. They have an excellent sense of smell, too. Organs located near their eyes are used for smelling. Their skin is very sensitive to touch and can "taste" the water around them. They use this adept range of senses to help locate prey and avoid predators.