Popular Science Monthly/Volume 20/March 1882/The Sirens of the Sea
THE sea is inhabited by three families of mammalian animals, which, though they may be so "very like a whale" as to have been sometimes spoken of together as cetaceans, are quite distinct in their structure and habits, and show evidences of distinct origin. They are the cetaceans, including the whales, dolphins, and porpoises; the pinnipeds, including the seals, sea-lions, and walruses; and the sirenians, including the manatees and dugongs. The affinities of the cetaceans are not exactly known, but it is certain that they are creatures of a very different sort from the animals of the other two classes; the pinnipeds are closely allied to the bears, dogs, and cats. Both these classes are carnivorous. The sirenians are herbivorous pachyderms, whose nearest analogies must be sought among the hogs, tapirs, and particularly in the hippopotamus.
The manatee, or sea-cow, is the most widely diffused of the sirenians, and, being American, has the first claim to consideration. Its various species are found along the coasts and in the rivers and inland lakes of tropical America; the length of the entire opposite coast of Africa, around the Cape; and as far north up the Mozambique coast as the Zambesi River; in the upper Niger River; in Lake Tchad; in the East African Lake Shirwa; and in the Tana Sea, in Abyssinia. Agassiz has termed the animal the modern representative of the dinotherium, and it is most probably the creature which Columbus mistook for a mermaid. It grows to be sometimes as long as seventeen or twenty feet, but generally, not more than from eight to twelve feet, and to weigh from one to three or four tons, having a body the shape of an elongated barrel, slightly flattened above and below, with two fore-limbs, but no sign of hinder extremities, and an horizontally flattened or spatulate tail of about one fourth the extent of the body. Its skin is much like that of the hippopotamus, and is very sparsely covered with hair. Its fore-limbs are set far forward, are more free in their motions than those of the cetaceans, and may be used as claspers, flexed over the chest, for swimming or dragging the animal along the bottoms, or up the banks of the rivers in which it feeds, and to assist in the prehension of food. The finger-bones may be felt through the skin, with which they are connected; but no evidence of digital organs is outwardly visible, except the rudimentary nails on the edges of the flippers. The flippers, flexible and possessing much of the power of the hand, have given the animal its name, from the Latin manus, a hand. The head is conical, with a fleshy nose,
like that of a cow, and large nostrils, and appears as if joined immediately on to the body, without visible neck. Anatomy furthermore shows that one of the cervical vertebræ, of which there are generally seven in mammals, including the dugong, is wanting. The mouth is small, and without front teeth, but is provided with two mobile, lateral, bristle-covered pads, with which it seizes its food quite dexterously. The mammæ are on the breast, and so resemble those of the human being as to make it easy to believe that the fable of the mermaid was derived from this animal.
The manatees feed in herds on the bottoms of rivers and the shallow waters along the shore, where they browse on algæ and aquatic herbs. They associate together in the most peaceable manner, and show a great community of feeling. They combine for defense when attacked, taking especial care of their young, by putting them in the center of the group, and, it is said, showing so much intelligent sympathy as to try to pull out the weapon from one of their companions which may have been struck with a harpoon. It is, indeed, a great shame to attack them wantonly, for no animal is more gentle and inoffensive, or more easily domesticated; but their flesh is excellent food, being much like pork, and is, moreover, allowed by the church to be eaten as fish on fast-days, and must, therefore, be considered legitimate prey for man. These animals are the most numerous inhabitants, after the turtles, of the waters around Greytown, Nicaragua, and are actively pursued by the Indians. The largest and best-known species is the Florida manatee, which inhabits the Gulf of Mexico and West Indian waters; the South American species is smaller, and the African the smallest of all.
|Fig. 2. Dugong.|
The dugong is the congener of the manatee in the Indian Ocean and the Australasian waters. It is as large as the manatee, and visibly different. Its head is small in proportion to the body, and is separated from it by a slight but distinct cervical depression; its skull is short, and its snout terminates abruptly in a large, thick upper lip, looking "something like the trunk of the elephant cut short across"; its tail, horizontally flattened, like that of the manatee, is forked or crescent-shaped, instead of being entire, as with its congener; and its flippers are destitute of any traces of nails. The eyes are small, and are furnished with a third eyelid or nictitating membrane. For the rest, we let an English writer, who examined one of the animals at the hunting-grounds in Moreton Bay, Australia, describe him:
"Now I could understand," he says, why one person had told me the dugong was like a whale; another, that it resembled a seal; a third, that it was not unlike a porpoise. The animal was in some sense a reminder of them all, but really not to be compared with either. It was, perhaps, likest a seal of elephantine proportions; and a baby dugong that had been taken from one of the prizes over which the carrion-birds were fighting and squabbling, and that had been kept for dispatch in spirits to England, would very well pass for a member of the seal family. A tour round the mature specimen had to be twice repeated before I could see my w r ay to a clear comprehension of its 'points.' Its dull-brown body was like a large cylinder, tapering off toward the head and great paddle-shaped tail. Ears there were none to speak of. The eyes were tiny, and three parts buried. The two flippers, considering the size of the animal, were remarkably small. The most prominent feature was the head, which terminated in a solid, square-cut upper lip, that warranted its comparison with a bullock. Being a female dugong, there were neither teeth nor tusks in the upper jaw, but a couple of small tusks of good ivory had been that morning taken from one of the bulls already operated upon. The inside of the mouth was lined with a rough apparatus, like a worn-down scrubbing-brush. The dugong, in short, is a vegetarian of the strictest order; and the stomach of our dead friend contained an immense quantity of vegetation cropped during the night from the bottom of the sea. It was the most curious example of a ruminating (herbivorous?) mammal I had ever seen. The skin was bare and slightly wrinkled, though at a distance it appeared to be quite smooth."
The dugong's nostrils are displayed upward; its lips have a horny edging which assists it in tearing sea-weeds from the bottom; and the forward part of its snout is covered with soft papillæ and a few stiff bristles. It often comes to the surface to breathe, and utters a peculiar cry, which our English writer, who heard it, describes as "a plaintive appeal, as if a child half awakened had softly moaned, and turned over to sleep again. I looked around," he adds, "in time to see a clumsy, grayish-brown head silently thrust above the surface, and, without leaving a sign, as silently disappear."
This animal has become the object of a thriving industry, the chief seat of which is at Moreton Bay, Queensland. Every part of the creature is marketable, and the pursuit and capture are easy and safe—too much so, probably, for the permanence of the trade. The flesh is eatable as beef, veal, or bacon, either of which it may be made to resemble; the head can be cooked into a delicious brawn; the flippers, a good deal boiled, make capital soup; the bones are dense, close grained, and capable of taking a high polish, hence adaptable to a variety of uses; the ivory tusks are in request for knife-handles; the skin is good to make a jelly "as acceptable and beneficial to invalids as calf's-foot," and for leather; and the fat is rendered at Moreton Bay into a palatable and wholesome oil.
The dugong-hunting season at Moreton Bay, where the animals are supposed to resort from tropical seas to give birth to their young, lasts through the winter weather. The submarine pastures upon which they feed, says a writer in the "Gentleman's Magazine," "lie at a depth of from eight to fourteen feet, and the favorite grounds are banks protected from the sea, in bays and straits. They graze in company, and feed down the herbage so close that they leave a well-defined track to indicate their movements. The black fellows, who love occupation of this kind, if any, peer over the gunwale of the whaleboat into the clear water, and are unerring authorities, telling at once when the monsters passed that way though it were a week previously, and giving a shrewd guess as to their present whereabout." The animals are then tracked up, and strong nets, presenting a wall specified in one instance as fourteen feet high and a hundred and fifty yards long, are placed so as to intercept them as they go browsing up to their feeding-grounds. The dugong, in happy innocence, eats greedily of the succulent growths, clearing its way in the most workmanlike manner, when it is suddenly stopped by this strange barrier. Being a remarkably timid creature, it takes fright, loses its presence of mind, and gets hopelessly entangled. "Now and then a dugong is found wrapped round as with the folds of a hammock, and the net has to be cut away piecemeal. As often as not, the dugongs thus drown themselves by frantic efforts to escape, but where a partial entanglement permits them to follow their instinct and come to the surface, they are taken alive. In the morning the boat cruises round to see how the nets have fared and to secure the game. . . . The dugongs that are found alive in their captivity struggle desperately. As a rule 5 they are as harmless as vegetarians are usually supposed to be, the only known breakers of the peace being a couple of bulls fighting over a sweetheart, or a frantic mother maddened by danger to her offspring. Nevertheless, although the dugong is by nature mild-mannered, and innocent of the wiles by which a Greenland whale sends a boat spinning into the air with all bands, the men prefer to give the netted individual a wide berth. Nor would it be the correct thing to slaughter it on the ground, lest the blood should attract a legion of sanguinary sharks, whose attacks would cause a speedy loss of the booty. The dugong, still floundering, is therefore hauled ashore, and a long knife applied to the throat puts an end to its career." Harpooning has been practiced, and is much liked by the blacks, but is discountenanced because it tends to drive away the animals.
"When the dugong was hauled up on the sandy slope, a line was cut down the belly and the skin was taken off in one piece, and spread out to be used as a receptacle for the meat as it was hewn from the carcass. As it happened to be a fair-sized skin, it required two men to carry it. We were afterward shown a hide that was an inch and a half thick at the back, though the thickness bad gradually diminished toward the under part of the body." The hide is not, however, composed of gross material, but is really quite delicate.
The flesh "is cut off the carcass in flitches and slabs, and from the same animal is taken meat resembling beef, veal, and bacon. I have eaten it in each form, and can testify to its excellence, and to the way in which it has been palmed off upon knowing men as prime fillets of beef, cutlets of veal, and rashers of superior bacon. If the dugong is not properly fat, it is turned chiefly into bacon; should it, however, present a layer nearly two inches thick, the snow-white fat is used for a more important purpose. The lean flesh, beef-like in the mature and veal-like in the young animals, is eaten fresh or salted for food. The bacon-flitch in size, color, and streakiness, if hung in an English pork-butcher's shop, might easily be taken for a section of the side of a true Wiltshire hog; and the only difference detected in the eating would be, in the dugong, an absence of the strong flavor too often found in pork; and a mature dugong, twelve feet long, or thereabout, would weigh nearly a ton. It is worth mentioning, too, before passing from the flesh of this animal, that the meat from the calf is always the best, and that it is recommended by the faculty to consumptive persons, by reason of its undoubted strengthening qualities."
The oil, which is extensively manufactured at Moreton Bay, possesses all the medicinal qualities of cod-liver oil without its unpleasant taste. In its pure state it can be taken without disagreeing with the most sensitive stomach. "I have myself," says our English writer, "used it instead of butter with toast; have eaten delicate pastry made from dugong-lard; have fried fish with it; and, as a consequence, have never since ceased to wonder that some better effort is not attempted to make it more widely known. Consumption, the scourge of the old country, finds an unfriendly atmosphere in Queensland, where I have known consumptives, landing with the disease to all appearance hopelessly advanced, become in a few years healthy if not robust, yet, even there, the most marvelous effects are attributed to dugong-oil in cases of rheumatism, and wasting as well as ordinary consumption. . . . I have known ladies, who shuddered at the bare notion of swallowing oil, derive benefits from its adaptation to all manner of culinary purposes."
Dr. Hobbs, of Brisbane, who first introduced the oil, received a medal at the Paris Exhibition of 1855 for his product. The manufacture afterward fell into other hands, and the short-sighted managers, rather than admit that the supply could not be equal to the demand, adulterated the pure product with unsavory shark-oil. Then they were astonished and indignant that they received no more orders from the old country.
Because the sirenians live in the sea, the first inclination of naturalists, before they had become fully acquainted with the family, was to classify them with the whales. A better knowledge of them has proved that this arrangement, unless it is safely qualified, is misleading. Professor Owen says on this subject: "The whole of the internal structure in the herbivorous cetacea differs as widely from that of the carnivorous cetacea as do their habits; 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 manatees with the true whales can not, therefore, be admitted in a distribution of animals according to their organization. With much superficial resemblance, they have little real organic resemblance to the walrus, which exhibits an extreme modification of the amphibious carnivorous type. I conclude, therefore, that the dugong and its congeners must either form a group apart or be joined with the pachyderms, with which the herbivorous cetacea have most affinity."
Professor H. C. Chapman, of Philadelphia, who has dissected a male and a female hippopotamus, has discovered several analogies in structure between the manatee and that animal. He remarks that in observing the manatee that lived for several months in the Philadelphia Zoölogical Garden, the manner in which it rose to the surface of the water to breathe reminded him often of the hippopotami that he had watched in the Zoölogical Garden of London and the Jardin des Plantes in Paris. The slow way in which the animals rose to the surface, the motionless poise of the almost sunken body, the nostrils often just appearing at the surface, were very much alike in both animals. The stomach cf the manatee resembles that of the hippopotamus in an atrophied condition; the sexual vesicles are found in both the hippopotamus and the manatee; the placenta of the hippopotamus offers points of resemblance with that of the dugong; and the brain of the hippopotamus, besides its typical relations to those of the pachyderms and ruminants, has also affinities with that of the manatee. "Beginning with the pig, we pass by an easy transition to the peccary, which leads to the hippopotamus, and thence, in diverging lines, to the ruminantia on the one hand and the manatee on the other. Paleontologists have not discovered a form which bridges over the gap between the hippopotamus and the manatee, but it will be remembered that certain fossil bones, considered by Cuvier to have belonged to an extinct species of hippopotamus (H. medius), are regarded by Gervais as the remains of the Halitherium fossili, an extinct sirenian, of which order the manatee is a living representative. . . . I do not mean to imply that the manatee has necessarily descended direct from the hippopotamus, though extinct intermediate forms may in the future show this to be so, for possibly they may be the descendants of a common ancestor. . . . It seems to me, however, that the only explanation of the structure of the living forms, and of the petrified remains of the animals referred to in these observations, is the hypothesis of there being some generic connection between them." Some writers have regarded the dugong as the behemoth of the Scriptures, which ate grass like the ox, and whose bones were as bars of iron, although the identity is more frequently ascribed to the hippopotamus. Since they are both so much alike, either animal will do. "It is true," says our English writer, "that the dugong does graze on submarine pastures, and that his bones ring as hard as steel when struck; but the reference might be held to apply equally well to the Halicore tabernaculi of the Red Sea, which bears a rough resemblance to its Australian relative."
Rüppel has suggested that the curtain with which the Israelites were ordered to veil the tabernacle was made of the skin of the dugong; but it is hard to imagine how a hide an inch thick could be adapted to such a purpose.
Another member of the family of the sirenians (Rhytina stelleri) was found by the Russians in Behring Strait in 1771. The mariners of Behring's second expedition, who were shipwrecked there, lived principally off its flesh for nearly a year. It is said that the animal was so hotly pursued afterward by hunters that it was exterminated in seventeen years, and no specimen has been seen since. Baron Nordenskiold, however, in his "Voyage of the Vega," adduces evidence to prove that a specimen of this animal was seen twenty-seven years ago, although there is little doubt that it is now extinct. The Baron, moreover, does not believe that its extinction was due to destruction by the hunters, but that it was a survival from a past age, doomed to
extinction, which overtook it when it was driven from its pastures on the shore of Behring Island. It attained a length of twenty-five feet, and had a skin composed of horny tubes, sometimes an inch long, wrinkled like the bark of a tree, which served to protect it from the ice and rocks on which it fed. It had no teeth, but its jaws were covered with an undulating surface of horny, tubular matter; and it was a vegetable-feeder, resembling in habits and qualities the other members of the family.