Porpoise, the common name of the small cetacean mammals of the genus phocama (Cuv.). The snout is short, uniformly rounded, wide from the breadth of the more horizontal inter-maxillaries and maxillaries, without the prolonged beak, separated from the forehead by a distinct furrow, which characterizes the dolphin, to which family it also belongs. The name is evidently a corruption of the French porc-poisson (hog fish); it is called Meerschwein by the Germans, marsouin by the French, and sea hog and puffing pig by the English and Americans. Though it is an air-breathing mammal and not a fish, the shape of the body is fish-like and adapted for progression in the water; the jaws are armed with minute conical teeth; the blow-hole, on the top of the head, is transverse, crescentic, with the concavity forward. (For its anatomy see Dolphin.) There are several species in different parts of the world, some of which have a very wide geographical distribution; they are very active, living in shoals or flocks, and are frequently seen swimming and playing about vessels, running races with them, and leaping out of water.
Their food consists chiefly of fishes and cephalopod mollusks; their flesh, dark-colored and gorged with blood, was once considered a delicacy, and is now often eaten by sailors; their blubber yields a very fine oil, and their skin makes an excellent leather. The common porpoise (P. communis, Cuv.) is from 4 to 6 ft. long, bluish black above with violet or greenish reflections, and white beneath; a little behind the middle of the back is a triangular cutaneous fold or dorsal fin; teeth 20 to 24 on each side in both jaws, compressed laterally, and curved somewhat backward; the lower jaw the longer; the pupil is V-shaped reversed, and the tongue festooned all round; the skin is smooth, perfectly destitute of hair and even of eyelashes, and beneath it is a layer of fat about an inch thick; there are no lips, and the small eyes are nearly in a line with the opening of the mouth; the opening of the ear is exceedingly small; neither the dorsal fin nor the tail has any internal bones, and the former consists of fat and is incapable of motion; the pectorals are brownish, though arising from a white part of the body; the brain is large, with numerous and deep convolutions over the cerebellum.
There are four stomachs, and even six if all the constricted portions be counted as such; the walls of the first are strongly wrinkled, of the second very thick with longitudinal wrinkles of a pulpy consistence, the third membranous with numerous small pores, and the fourth wrinkled like the first; the intestine grows smaller to the anus, and the caecum is absent. Gestation continues six months, and a single young one is produced at a birth, about 20 in. long, which is suckled and protected by the mother, as in other mammals; it can provide for itself at a year old. This species is common all about the coasts of Europe, extending even to the icy seas; they generally keep near the shores, where they root about with their snouts like hogs; they are often seen rolling and tumbling in the water, as they rise to the surface to breathe with a puffing sound; they look in the water like large black pigs, whence their common names. They pursue herrings, mackerel, salmon, and other fishes which swim in shoals, sometimes going far up rivers in their pursuit; they have been seen in the Thames at London, and in the Seine at Rouen, and even at Paris. The common porpoise of the American coast, formerly considered the same as the P. communis of Europe, was described as distinct by Prof. Agassiz in 1850, under the name of P. Americana. In size and color the two species are very much alike; the general -form of the skull is different, the posterior surface in the European species being nearly vertical, but in the American much curved; the teeth of the latter are divided on the broad faces near the summit by grooves almost into three lobes, those of the former being smooth; the dorsal fin in the American is serrated and furnished with very characteristic tubercles, which are not mentioned in the descriptions of the European; the temporal groove of the skull is as wide as long in P. Americana, but narrower and oblong in P. communis.
This species is common on our coast, chiefly in spring and summer, appearing in pursuit of the herring and other migratory fish; it should not be confounded with the cetacean called the sea porpoise, a true dolphin, and only seen off soundings. In former years it was captured in great numbers near the E. end of Long Island, in large seines from which they were harpooned and dragged on shore; from the blubber of each animal about six gallons of oil are obtained. - See " Marine Mammals of the Northwest Coast," by Charles M. Scammon (New York, 1874).
Common Porpoise (Phocaena communis).