What is the difference between a whale, dolphin and porpoise?
The terms dolphin, porpoise and whale are confusing and do not relate well to the scientific classification of cetaceans. In general, whales are the largest cetaceans followed by dolphins and then porpoises. However, some ‘whales’ such as the Pilot Whale and Killer Whales are classified in the same family as dolphins (Family Delphinidae). The term ‘porpoise’ is sometimes used to refer to dolphins although it is now generally agreed that porpoise refers to toothed cetaceans with spade-like teeth and no beak belonging to the Family Phocoenidae (includes six species, one of which occurs in Australia).