RORQUAL, a whale of a long and elongated shape, with a small back-fin and a number of longitudinal pleatings or folds on the throat (see Cetacea). The name rorqual refers to these folds, while the alternative title of finner, or fin-whale, marks an important difference between these whales (for there are several species) and right-whales. The furrows on the throat are numerous and close-set, the flipper is comparatively small, and the dorsal fin distinct. The head is relatively small, flat and pointed in front, the whalebone short and coarse, the body long and slender, and the tail much compressed before it expands into the “flukes.” Rorquals are the most abundant and widely distributed of all whales, being found in all seas, except the extreme Arctic and Antarctic regions. There are four distinct species of this genus in British seas. Firstly, Sibbald’s rorqual, or blue whale (Balaenoptera sibbaldi), the largest of all animals, attaining a length of 80 or even sometimes 85 ft. Its colour is dark bluish grey, with small whitish spots on the breast; the whalebone is black; the flippers are larger proportionally than in other rorquals, measuring one-seventh of the total length of the body; and the dorsal fin is small and placed far back. This whale has usually 64 vertebrae, of which 16 bear ribs. Like the others, this species seems to pass the winter in the open seas, and approaches the coast of Norway at the end of April or beginning of May. At this time its sole food is a small crustacean (Euphausia inermis), which swarms in the fjords. Secondly, we have the common rorqual (B. musculus, or B. physalus) with a length of from 65 ft. to 70 ft., and of a greyish slate-colour above and white underneath, and the whalebone slate-colour, variegated with yellow or brown. It has usually 62 vertebrae, of which 15 bear ribs. This is the commonest of all the large whales on the British coasts; scarcely a winter passing without the body of one being washed ashore, usually after stormy weather, and frequently on the south coast, as this species has a more southern range than the last, and enters the Mediterranean. It feeds largely on fish, and is frequently seen feasting among shoals of herrings. Thirdly comes Rudolphi's rorqual (B. borealis), a smaller species, scarcely attaining a length of 50 ft. It is bluish black above, with oblong light-coloured spots, whilst the under-parts are more or less white; the whole of the tail and both sides of the flippers are black; the whalebone is black, and the bristly ends fine, curling and white; the flippers are very small, measuring one-eleventh of the total length of the body. There are 56 vertebrae, with 14 pairs of ribs. This species, according to Dr. C. Collett, feeds chiefly on minute crustaceans, mainly Calanus finmarchicus and Euphausia inermis, and not on fish. Down to the last quarter of the 19th century it was considered the rarest of the whales of European seas, and was only known from a few individuals stranded on the coasts of northern Europe at long intervals. The most southern point at which it has been met with is Biarritz. Since the establishment of the whaling station near the North Cape it has been shown to be a regular summer visitor. Lastly, the lesser rorqual, B. rostrata, the sharp-nosed finner of American whalers, is the smallest species found in the northern seas, rarely exceeding 30 ft. in length. Its colour is greyish black above, whilst the under-side is white, including the whole of the lower side of the tail; the inner side of the flippers is also white, and there is a broad white band across the outer side, which is a very characteristic mark of the species; the whalebone is yellowish white. The dorsal fin in this and the preceding species is comparatively high, and placed far forwards on the body. This whale has usually 48 vertebrae, of which 11 bear ribs. It is common in summer in the fjords of Norway, and is often seen around the British Isles. It has been taken, though rarely, in the Mediterranean, and ranges as far north as Davis Strait.
Common Rorqual (Balaenoptera musculus).
Rorquals are met with in almost all seas, and nearly all the individuals carefully examined, whether from the North Pacific, the Australian seas or the Indian Ocean, come very near in structure to one or the other of the Atlantic forms described above, so much so that some zoologists believe that there are but four species, with an almost cosmopolitan range. Other naturalists, on the contrary, have described and named almost every individual specimen captured as belonging to a different species. See Whale and Hump-back Whale. (R. L.*)