Twenty two species of cetacean have been recorded in Shetland although a handful of these have occurred very rarely or only as stranded corpses.

WHALES
There are two types of whale - toothed whales and baleen whales. Toothed whales (including porpoises and dolphins) may have as many as 120 teeth, as in white sided dolphin, or as few as 4 in Risso's dolphin. The number is related to diet.

All toothed whales use echo-location to locate their prey, eyes are of limited use except in the sunlit surface layers of the sea.

Baleen whales feed by trawling through the sea, forcing large quantities of water through dense fibrous baleen plates that line their jaws like brushes. The fibres trap small organisms which the animal scrapes off with its tongue and swallows.

DOLPHINS
Dolphins are larger than porpoises and have taller dorsal fins that are distinctly hooked back. White-beaked dolphins are the most commonly encountered and are identified by the diagnostic white beak and pale saddle behind the dorsal fin. They are often seen in late summer from the MV Good Shepherd as it plies between Grutness and Fair Isle.

SEALS
Two species of selkie or seal breed in Shetland, the common or harbour seal and the grey seal. The population of both is stable with about 6,000 commons and 3,500 greys now found in the islands.

Shetland's common seal population is internationally important and represents 20% of the British population. Both species were hunted for their fur in the recent past. In the late 1960's as many as 7,000 common seal pups a year were being taken. This proved unsustainable. The population went into steep decline and in 1973 legislation was introduced ban hunting of common seals in Shetland. Grey seals continued to be exploited into the 1980's but at much lower levels.