Natural History: Mammalia/Manatidæ
Family I. Manatidæ.
(Manatees.)
We find here a group of aquatic animals, the forms of which differ so greatly from those that we are about to notice, and are so obviously modelled on that of the Whales, that they have ordinarily been ranked under the Order Cetacea. In their aquatic habits, their fishlike form, their smooth bodies, gradually tapering and terminating in a broad horizontal fin, their total want of posterior limbs, and the contraction of the anterior into flippers or swimming paws, the resemblance to the last named animals is very manifest. But the resemblance is almost confined to external characters; the whole internal structure, as Professor Owen has shewn, differing very widely from that of the carnivorous Cetacea; so that, to use the words of this eminent physiologist, "the amount of variation is as great as well could be in animals of the same class, existing in the same great deep. The junction of the Dugongs and the Manatees with the true Whales cannot therefore be admitted in a distribution of animals according to their organization. With much superficial resemblance, they have little real or organic resemblance to the Walrus, [with which they were associated by Linnæus,] which exhibits an extreme modification of the amphibous carnivorous type. I conclude, therefore, that the Dugong and its congeners must either form a group apart, or be joined, as in the classification of M. de Blainville, with the Pachyderms, with which they have the nearest affinities, and to which they seem to have been more immediately linked by the now lost genus Dinotherium."
The food of the Manatidæ consists of sea-weeds, the grass of rivers, and other aquatic herbage: for the digestion of which they are furnished with a stomach divided into several sacs. They have no canine teeth: the molars are compound or semi-compound, with plain or furrowed crowns: the genus Rytina has no molars, but their place is supplied by a horny plate in the middle of each jaw. The mammæ are two, situated upon the breast, as are those of the Elephant. The lips are set with thick wiry bristles: the nostrils are placed at the extremity of the muzzle, which is obtuse and truncated; the eyes are protected by an inner membrane, which can be drawn over the iris: the bones of the skeleton are dense and solid in texture, and not filled with oil, as in the Cetacea.
Genus Manatus. (Cuv.)
The form of the Manatee has been compared to that of the leathern bottles used in the south of Europe. The body is oblong, terminated by an oval tail-fin; the head is somewhat conical, with a broad, tumid muzzle; beset with stiff, but very short bristles; no perceptible depression marks the situation of the neck. There are eight molars in each jaw, which are ridged doubly or trebly, and have the root distinct from the crown; strongly resembling those of the Hippopotamus and Tapir: there are no canines, nor incisors in the adult. The swimming paws have vestiges of nails at their edge. The skin is rough and coarse, like that of an elephant.
The best known species is the Manatee of America, (Manatus Americanus, Cuv.) which frequents the mouths of rivers, and quiet secluded bays and inlets in the islands of the West Indies, and the coasts of Guiana and Brazil. It is said to attain nearly twenty feet in length, and is of a dull bluish-black hue, with the inferior parts rather lighter. It is gregarious in its habits, capable of strong attachment to its species, which is especially manifest in the females towards their offspring. It has been stated that if one of a herd has been harpooned, its companions will assemble round, and attempt to drag out the weapon; and if the cub be taken, the mother will fall an easy prey, her maternal affection being more powerful than her instinctive fear of man.
From personal experience we can confirm Hernandez's statement of the excellence of the flesh of the Manatee: he truly compares it to well-
MANATEE.
fatted pork of pleasant flavour. The pursuit of it on this account, has rendered it scarce in many localities where it was formerly numerous: in the vicinity of Cayenne, it was at one time so common, that a large boat might be filled with them in a day, and the flesh was sold at threepence per pound. About the middle of the last century it fetched at Port Royal, in Jamaica, fifteen-pence (currency) per pound.
The Manatee is captured by means of the harpoon. At St. Domingo, the hunters approached them in a small boat, and struck them with a harpoon attached to a stout cord. The wounded animal made violent efforts to escape, but its movements were impeded, as well as revealed, by means of a buoy of cork or similar material fastened to the end of the line. At length, the animal exhausted with its efforts, was towed to the shore, and there killed. The sport was considered as peculiarly diverting, though not unattended with danger from the capsizing of the boat in the struggles of the Manatee in the shoals.
Specimens of this species have been cast on the shores of the British Isles; but they were dead, and in an advanced stage of decomposition.
An enormous extinct animal (Dinotherium), known as yet exclusively by its skull, seems to have been intermediate between the aquatic and the terrestrial Pachydermata. The incisors of the lower jaw form two immense tusks, with their roots encased in enormous sockets, which project downward and backward, in the same manner as those proceeding from the upper jaw of the Morse. The size and situation of the nasal orifice have led to the presumption that it was furnished with a proboscis; and Professor Kaup conjectures its general appearance to have resembled the accompanying representation.
Dr. Buckland considers it as nearly allied to the Tapirs, but still more aquatic, inhabiting freshwater lakes and rivers. "To an animal of such habits, the weight of the tusks sustained in water would have been no source of inconvenience; and if we suppose them to have been employed as instruments for raking and grubbing up by the roots large aquatic vegetables from the bottom, they would under such service, combine
SUPPOSED FORM OF DINOTHERIUM.
the mechanical powers of the pick-axe with those of the horse-harrow of modern husbandry. The weight of the head, placed above these downward tusks, would add to their efficiency for the service here supposed, as the power of the harrow is increased by loading it with weights. The tusks of the Dinotherium may also have been applied with mechanical advantage to hook on the head of the animal to the bank with the nostrils sustained above the water, so as to breathe securely during sleep, whilst the body remained floating at perfect ease beneath the surface: the animal might thus repose, moored to the margin of a lake or river without the slightest muscular exertion, the weight of the head and body tending to fix and keep the tusks fast anchored in the
SKULL OF DINOTHERIUM.
substance of the bank; as the weight of the body of a sleeping bird keeps the claws clasped firmly around its perch. These tusks might have been further used, like those in the upper jaw of the Walrus, to assist in dragging the body out of the water; and also as formidable instruments of defence. The structure of the scapula [or shoulder-blade] seems to shew that the fore-leg was adapted to co-operate with the tusks and teeth in digging and separating large vegetables from the bottom."[1]
M. de Blainville, however, and some other of the French zoologists, contend that the Dinotherium approached still nearer to the Manatide; that it was, in fact, "a Dugong with tusk-incisors." And they judge that the magnitude of the nasal opening, and the enlargement of the surrounding surfaces, would agree as well with an immense and overspreading upper lip, as with a proboscis. There is, however, no reason to doubt that this singular form supplied a connecting link between the Dugongs and the Elephants.
This animal is believed to have measured eighteen feet in length: the lower jaw, exclusive of the tusks, measures four feet in length and three in breadth. The character of the molar teeth shews that its food was exclusively vegetable.
- ↑ Bridgewater Treatise.