Dolphin This term has often been misused in the US, mainly in the fishing industry, where all small cetaceans (dolphins and porpoises) are considered porpoises, while the fish "dorado" is called dolphin fish. In common usage the term 'whale' is used only for the larger cetacean species, while the smaller ones with a beaked or longer nose are considered 'dolphins'. The name 'dolphin' is used casually as a synonym for bottlenose dolphin, the most common and familiar species of dolphin. There are six species of dolphins commonly thought of as whales, collectively known as blackfish: the killer whale, the melon-headed whale,
Whale of fat, and the skull of any such creature containing a melon will have a large depression. The melon size varies between species, the bigger the more dependent they are of it. A beaked whale for example has a small bulge sitting on top of its skull, whereas a sperm whale's head is filled up mainly with the melon. The whale eye is relatively small for its size, yet they do retain a good degree of eyesight. As well as this, the eyes of a whale are placed on the sides of its head, so their vision consists of two