( Originally Published 1936 )
This is the most numerous family of the Cetacea, but contains species of moderate or comparatively small size. There are generally teeth in both upper and under jaws.
Narwhal (Monodon monoceros)
An inhabitant of the northern, and especially the Arctic, seas, where it is met with in small shoals, or " schools," the Narwhal attains a length, in the males, of fourteen or fifteen feet. It is light greenish-grey in colour, irregularly blotched with white, and a distinguishing feature of the males is the possession of two spiral tusks, of which the left only is usually developed, and projects to a distance of from six to eight feet from the end of the nose. See Plate 37, Fig. 156. The use of this formidable weapon is hard to conjecture, for the Narwhal, like most of the Cetacea, is a rather inoffensive animal.
Porpoise (Phocoena communis)
Probably the best known of all the whale family is the Porpoise, common to our shores and also found in various other parts of the world, sometimes ascending rivers to a considerable distance. It is a small animal, measuring perhaps as much as six to eight feet in length, blackish above and white below.
The head is short and rounded and near the middle of the back is a large fin. See Plate 38, Fig. 159. Porpoises swim in schools, and have a habit of turning slowly over and over in the water, one following another in single file, and their antics are often very amusing.
Dolphin (Delphinus delphis)
This animal is similar to the one above mentioned in size and colour, but differs from it in having a long pointed muzzle and numerous sharp-pointed teeth in both upper and lower jaws. It is found in nearly all the seas of the world, and many species are known, but it does not come so near shore as the porpoise. As a rule those seen in crossing the Atlantic are a dull greenish or yellowish on the back, striped with white below. They are terrible foes to shoals of small fish, devouring them in great numbers. The Dolphin is a swifter creature than the porpoise, and makes long and graceful leaps over the waves with the greatest agility. See Plate 37, Fig. 157.
The term " Dolphin " is often improperly applied by sailors to a large and brilliantly metallic fish, (Coryphaena hippuris), which is. found in the warmer parts of the Atlantic, in the Mediterranean, and the Indian Ocean, and feeds chiefly on flying-fish.
Gangetic Dolphin (Plantanista gangetica)
This species inhabits the Ganges and other large rivers of India, and is usually about seven or eight feet long, but occasionally reaches a greater length.
It differs from the dolphin in having a short neck, and in the ribs not being connected together, but free, as in land animals. The colour is blackish, the back fin is rudimental, and the tiny eye is useless, the animal being blind. There is a long beak, containing about thirty teeth on each side in each jaw, which are sharp in the young but wear down in old specimens. See Plate 37, Fig. 158. The Gangetic Dolphin feeds on fish and crustacea.
Grampus (Orca gladiator)
A species of cetacean found in many parts of the world is the Killer, or Grampus, reputed to be the most savage and bloodthirsty of the order to which it belongs. Rushing through the water in schools of six or eight individuals, they devour everything that comes in their way, and several seals have been found in the stomach of a single specimen. The Killer is at once distinguished by the gigantic backfin, which stands upright to a height of several feet and has a small hook at the tip. They are large animals, attaining a length of twenty feet or more; the upper parts are black, the under part is white, and a white streak runs over the eye. Although the head is small in proportion to the size of the body, it is armed with strong and powerful teeth. Stories are told by sea-men of fights between Killers and the large Green-land whales, several of them combining and attacking the larger animal; and there is no doubt that they are extremely aggressive, destructive, and voracious creatures.