Most dolphins eat fish, squid, shrimp and other crustaceans, though the diet of dolphins varies by species and by what is available to them in their part of the ocean. Some dolphins eat herring, cod and mackerel.
Dolphins belong to a group of marine mammals that have teeth but do not chew their food. They swallow their prey whole and have a compartmentalized stomach that makes it possible for them to digest whole fish rapidly.
Dolphins hunt in groups called pods. They use echolocation to hunt for prey by bouncing high-pitched sounds through the water and listening for echoes. They compress or herd fish into compact groups and take turns diving through the school of fish to eat. Dolphins also herd fish toward shallow waters near the shore, corraling them so they cannot escape, and then feed on the captured fish.