Dolphins are marine mammals related to whales and porpoises. There are almost forty species of dolphins. Dolphins eat a variety of fish like mackerel, herring and cod, as well as squid. They live in the northern and southern oceans and can also live with trainers or people. The document provides diagrams of a dolphin's inside and outside parts and includes an interesting poem and facts about dolphins, such as their ability to jump 20 feet in the air. It also describes different types of dolphins, like bottlenose dolphins.