Most dolphins feed on cod, herring and mackerel. They consume small prey, including small fish, crustaceans and small animals. Aside from fish, they also hunt various small and large squids, octopus, plankton, sea turtles, krill and cephalopods.

Dolphins consume different types of foods, depending on their species, habitat and availability of food sources. Larger dolphins, such as the killer whale, prey on marine mammals, marine birds and large animals when fish and other smaller prey are not available. Some marine mammals consumed by large dolphins include large whales, seabirds, penguins, sharks, seals, walruses and sea lions.

Dolphins generally form groups, called pods, to hunt for food. They communicate with each other and use echolocation, which enables them to produce sound waves, to detect prey. Bait balling is a common technique used by dolphins to capture prey. They use this technique to capture a school of fish by swimming around in a circle to surround the group of fish. The fish become easier to capture as they are forced to flock together with no way to escape. Dolphins also use corralling, a technique that involves chasing fish into shallow waters or pushing them into a narrow area.