porpoise family WIKIPEDIA:Porpoise) The porpoises are small cetaceans of the family *Phocoenidae*; they are related to whales and dolphins. They are however distinct from dolphins, although the word "porpoise"is often used to refer to any small dolphin, especially in North America. A key difference is the shape of the teeth and of the head. Porpoises, divided into six species, live in all oceans, mostly near the shore. Probably best known is the Harbour Porpoise, which can be found across the Northern Hemisphere. ( phocoenidae porpoise cetacean marine mammal requires discussion