No. 216 - THE PENNY MAGAZINE - Aug. 15, 1835

THE PORPOISE.

THE cetacea (an order of mammalia comprising the whale, the grampus, the porpoise, &c.,) were formerly classed with fishes, and in common language still bear that ill-applied title. Hence we read of the "whale-fishery," and of the number of "fish" taken upon any occasion. The cetacea are not "fish" in any sense of the word. They breathe the atmospheric air by means of lungs; their heart consists of two auricles and two ventricles; their blood is warm; they bring forth living young, and manifest towards them great attachment, nursing and protecting them with remarkable assiduity. As it respects the general form of their body and the construction of their limbs, the cetacea differ considerably from all terrestrial mammalia; and the reason is evident--their exclusive destination to acquatic habits. Terrestrial mammalia are covered with hair, wool, spines, scales, or plates of mail: in the cetacea, we find the skin naked and smooth,--a circumstance in strict harmony with their structure and habits. In its general outline, the body has considerable resemblance to that of a fish, being of an oblong form, and terminating in a thick, muscular tail, furnished, at the extremity, with a horizontal cartilaginous paddle. There are no posterior limbs, and the anterior are modified into the form of short broad oars, which they resemble also in their use. But the great muscular force resides in the tail; its action is not, however, from side to side, as we see in the fish, but up and down, and the reason of this arrangement is very evident;--the cetacea breathe air, and are obliged to inspire every few minutes, hence, plunging as they do into great depths, they are enabled to raise themselves, by a succession of vigorous strokes, with great rapidity to the surface. What is termed "blowing" by the whale-fishers is nothing more than the forcible expiration of the breath before the animal has reached the surface. Having retained his breath as long as possible, as he ascends, he gins to force out, through his nostrils, the pent-up air, which throws aloft the water in a jet or column. The position of the nostrils in the cetacea is well worthy consideration. Of little use as olfactory organs, they are the exclusive apertures through which the process of breathing takes place. In other mammalia, the nostrils are placed at the extremity of the muzzle, but in the cetacea the muzzle or snout is always immersed beneath the surface, and cannot well be elevated. Where, then, can these organs be conveniently situated?--On that part which, as the animal floats, rises naturally above the surface. They open on the top of the head, and lead, in the whales, into a large sack, where the air, before being expired, is pent up, and whence it is violently expelled by the compression of powerful muscles. The larynx or windpipe is prolonged into the posterior nares, or back of the nostrils, in the form of a cone, so that the air is immediately conducted to the lungs through an uninterrupted channel. As it regards the organs of sight and hearing, we may observe that, as in fish, the eye is adapted to the density of the surrounding medium, the cornea being lat, and the crystalline lens globular. The external aperture of the ear is very small, and capable of being closed.

There are two other points, of especial interest, which we cannot pass over, general as we intend our remarks to be,--we allude to the deposition of a layer of oil or blubber between the skin and muscles, and to the construction of the vertebrae of the neck. There are several uses connected with the mode of life of the cetacea, which the layer of blubber between the skin and muscles appears to serve. In the first place, it tends to render their specific gravity lighter,--a circumstance of some importance when we consider the immense mass of muscle and bone of which these animals are compacted. it is, however, in the true whales that we find the layer of blubber the thickest. These are animals exposed to the rigours of the Polar circle, and it would appear to be a means of preserving the vital heat of the body, which might perhaps be otherwise unable to withstand the intensity of the cold. This coating is as bad a conductor of caloric as the fur of the white bear. But the blubber has most probably another use also. It is well known that the whale plunges to an amazing depth, where it has to sustain an extraordinary pressure. Now, to prevent this pressure from paralyzing the muscles and disturbing the functions of the internal organs, must be one of the ends to be kept in view in the economy of this gigantic animal. Such a purpose the thick layer of blubber will well subserve, and such is, no doubt, one of its appointed uses.

The cetacea appear to have no neck. They have no distinct interval of separation between the head and the trunk, yet, if we examine their skeleton, we shall find that they possess the number of cervical vertebrae common to all mammalia, namely, seven. The neck of the giraffe also consists of seven vertebrae. But, in the one case, we find the vertebrae elongated to the utmost, in the other case, the whole seven are compacted closely together, and so compressed as to lose the usual appearance of such bones;--they scarcely occupy the space, in length, of a single vertebra of the giraffe. Hence the neck of the cetacea is immovable and solid.

The cetacea are divided into several groups. Some are herbivorous, as the dugong, feeding on the submarine vegetables which grow in shallows or near shore; most, however, are carnivorous, preying on the fish and other tenants of the ocean. To this latter family must be referred that common native of the shores of our island, the porpoise (Phocaena communis, CUVIER).

The porpoise is the smallest of the cetacea, seldom exceeding five feet in length. It frequents, in troops, the bays and inlets of our coast, and especially the mouths of rivers, not unfrequently advancing to a considerable distance up their stream. In such places it is often taken in nets by the fishermen, becoming entrapped while eagerly pursuing its prey. When the shoals of herring and other fish which periodically visit our coast make their appearance, they are harassed, among other enemies, by this active and voracious animal, which revels in the luxury of a perpetual feast; and, as its appetite is enormous and its digestion rapid, the slaughter in which it appears incessantly occupied must be very great. The porpoise is common at the Nore, and few have sailed to Margate or Ramsgate who have not seen these animals, tumbling along, as they appear to do, in the rushing waves. The peculiarity of their motion results from the horizontal position of the tail-paddle, and the up-and-down stroke which it gives; and their momentary appearance is for the purpose of breathing, which accomplished, they plunge down in search of their food. In former days, the flesh of the porpoise was highly esteemed as a delicacy for the table, and was served at public feasts; indeed, it is but lately that it has fallen into disrepute, and been omitted at city entertainments, where the turtle usurps its place. Our forefathers must have had a different notion about table delicacies from ourselves; for few, we believe, would now relish the rank, oily, fishy flesh of this animal.