Porpoise

Neophocaena - Finless porpoise
Phocoena - Harbour porpoise et al.
Phocoenoides - Dall's porpoise

The porpoises are small cetaceans of the family Phocoenidae; they are related to whales and dolphins. They are distinct from dolphins, although the word "porpoise" has been used to refer to any small dolphin, especially by sailors and fishermen. The most obvious visible difference between the two groups is that porpoises have flattened, spade-shaped teeth distinct from the conical teeth of dolphins.

The name derives from French pourpois, originally from Medieval Latin porcopiscus (porcus pig + piscus fish).

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.