Porpoises; harbour porpoises

Harbour porpoises are often mistaken for dolphins, and vice-versa. Both are cetaceans - that is "mammals" - not fish! However, there are major differences. Dolphins grow to about 12 feet in length, especially the bottle-nosed variety found in Cardigan Bay. The nose is shaped, as the name suggests, like the neck of a bottle, whereas a porpoise has a far stubbier, flatter snout. The dolphins dorsal fin is also longer and it points backwards, whereas the porpoise has a smaller, triangular dorsal fin. The major difference, however, is that the porpoise only grows to five feet in length. The dolphin also rolls higher out of the water as it moves, whilst the porpoise hardly breaks the surface. Many sightings of "porpoises" are actually of dolphins. Some people, even experienced fishermen, have got in the habit of referring to the dolphins by the wrong name.