Dolphins belong to the subphylum Vertebrata, meaning that dolphins are animals with backbones. Oceanic dolphins are toothed whales within the family Delphinidae, while river dolphins are included in the family Platanistidae.
Dolphins are usually less than 10 feet in length. They have a beak-like snout called a rostrum and small teeth. The diet of the dolphin is strictly carnivorous and is largely composed of fish and squid, although orcas are capable of hunting large whales. Dolphins are found in oceanic bodies of water globally, save for the Caspian and Aral Seas. Dolphins produce a wide variety of vocalizations to communicate with other dolphins and incapacitate prey.