Dolphins Dolphins are mammals closely related to whales and porpoises. Dolphins have a powerful and streamlined body. They are found in all seas and oceans. Dolphins can be told apart from porpoises by their nose, which is beaklike, and also their conical teeth. Porpoises have a flatter nose, sharper teeth, and a more solid body. There are 32 known species of dolphins. The bottle-nosed dolphin is often the species used in aquatic shows. The common dolphin inspired many Mediterranean folk lores. Both of the dolphins above appear in open waters, usually around cruise ships. They like to show off around the boat. There are also freshwater dolphins that live in rivers of Asia and South America