CHAPTER XX.

_THE DUGONG, MANATEES, WHALES, PORPOISES, AND DOLPHINS._

BY F. G. AFLALO, F.Z.S.

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THE DUGONG AND MANATEES.

These curious creatures, which seem to have been the basis of much of the old mermaid legend, have puzzled many eminent naturalists. Before they were placed in an order by themselves, Linnæus had classed them with the Walrus, Cuvier with the Whales, and another French zoologist with the Elephants. They are popularly regarded as the cows of the sea-pastures. Their habits justify this. I have often watched dugongs on the Queensland coast browsing on the long grasses, of which they tear up tussocks with sidelong twists of the head, coming to the surface to breathe at short intervals.

Omitting the extinct Rhytina, otherwise known as Steller's Sea-cow, which was exterminated in the Bering Strait not very long after civilised man had first learnt of its existence, we have to consider two distinct groups, or genera, of these sirenians. The DUGONG is the representative of the first, and the two MANATEES belong to the other.

The dugong is found on the coasts of Northern Australia, in many parts of the Indian Ocean (particularly off Ceylon), and in the Red Sea. It is easily distinguished, by even superficial observation, from the manatees. Its tail is slightly forked, somewhat like that of the whales: the tail of manatees, on the other hand, is rounded. The dugong's flippers, to which we also find a superficial resemblance in those of the whale, show no traces of external nails: in those of the manatees, which show projecting nails, there is a considerable power of free movement (the hands being, in fact, used in manipulating the food), which is not the case in the limbs of the whale. The body of the dugong is almost smooth, though there are bristles in the region of the mouth: that of the manatees is studded with short hairs. The male dugong has two large tusks: in neither sex of the manatees are such tusks developed. Finally, a more detailed examination of the skeletons would reveal the fact that, whereas the dugong has the usual seven bones in the neck, that of the manatees has only six.

When we come to the Whales, we shall encounter that very characteristic covering known as "blubber"; and, though it is present in smaller quantity, these sirenians have blubber as well. Complex stomachs they also have, like the whales, only in their case both the nature of the food and the structure of the teeth point clearly to a ruminating habit, which, for reasons that will be given in the right place, seems inadmissible in the whales. In both dugong and manatees the mouth is furnished with singular horny plates, the precise use of which does not appear to have been satisfactorily determined; and the upper lip of the manatee is cleft in two hairy pads that work laterally. This enables the animal to draw the grass into its mouth without using the lower lip at all.

In their mode of life the dugong and manatees differ as widely almost as in their appearance; for the former is a creature of open coasts, whereas the manatees hug river-estuaries and even travel many miles up the rivers. Of both it has been said that they leave the water at night, and the manatees have even been accused of plundering crops near the banks. The few, however, which have been under observation in captivity have always been manifestly uncomfortable whenever, by accident or otherwise, the water of their tank was run off, so that there is not sufficient reason for believing this assertion.

This group of animals cannot be regarded as possessing any high commercial value, though both natives and white men eat their flesh, and the afore-mentioned rhytina was, in fact, exterminated solely for the sake of its meat. There is also a limited use for the bones as ivory, and the leather is employed on a small scale,--a German writer has, in fact, been at great pains to prove that the Tabernacle, which was 300 cubits long, was roofed with dugong-skin, and the Red Sea is certainly well within the animal's range.

THE WHALES, PORPOISES, AND DOLPHINS.

Although anatomists have good reason for suspecting that all the members of the Whale Tribe are directly descended from river-dwelling forms, if not indeed, more remotely, from some land animal, there is something appropriate in the fact of the vast ocean, which covers something like three-quarters of the earth's surface, producing the mightiest creatures which have ever lived. There should also be some little satisfaction for ourselves in the thought that, their fish-like form notwithstanding, these enormous beings really belong to the highest, or mammalian, class of animal life.

One striking feature all these many-sized cetaceans have in common, and that is their similarity of form. Though they may vary in length from 70 to 7 feet, their outline shows a remarkable uniformity. Important internal and even external differences there may be. A whale may be toothed or toothless; a dolphin may be beaked or round-headed; either may be with or without a slight ridge on the back or a distinct dorsal fin; but no cetacean could well be mistaken for an animal of any other order. It is as well to appreciate as clearly as possible this close general resemblance between the largest whale and the smallest dolphin, as the similarity is one of some interest; and we may estimate it at its proper worth if we bear in mind that two species of cetaceans, outwardly alike, may not, perhaps, be more closely allied than such divergent ruminant types as the elephant, the giraffe, and the gazelle.

Reference has already been made to the fact that the whales are true mammals, and we must now clearly set before us the justification for separating them from the Fishes--to which any one with a superficial knowledge of their habits and appearance would unhesitatingly assign them--and raising them to the company of other mammals. Let us first separate them from the Fishes. The vast majority of fishes, with some familiar exceptions like the conger-eel, are covered with scales: whales have no scales. The tail of fishes, often forked like that of whales, is set vertically: in whales the tail is set laterally, and for this a good reason will presently be shown. Fishes have anal fins: whales not only have no anal fins, but their so-called pectoral fins differ radically from the fins of fishes. Fishes breathe with the aid of gills: whales have no gills. Fishes, in the vast majority of cases, reproduce their young by spawning, the eggs being left to hatch out either in gravel-beds or among the water-plants, lying on the bottom (as in the case of the herring), or floating near the surface (as in that of the plaice): whales do not lay eggs, but bear the young alive. This brings us to the simple points of resemblance between them and other mammals. When the young whale is born, it is nourished on its mother's milk. This alone would constitute its claim to a place among the highest class. Whales breathe atmospheric air by means of lungs. Hair is peculiarly the covering of mammals, just as scales are characteristic of fishes and feathers of birds. Many whales, it is true, have no hair; but others, if only in the embryonic stage, have traces of this characteristic mammalian covering. It must, moreover, be remembered that in some other orders of mammals the amount of hair varies considerably--as, for instance, between the camel and rhinoceros.

Having, then, shown that whales are mammals, we must now determine the chief features of the more typical members of the order. The extremities of whales are characteristic: a large head, occupying in some species as much as one-third of the total length; and the afore-mentioned forked, or lobed, tail set laterally. The flippers, which bear only a slight resemblance to the pectoral fins in fishes, are in reality hands encased in swimming-gloves. In some whales these hands are five-fingered, in others the fingers number only four, but many of the fingers contain more bones than the fingers of man. In some whales we find a dorsal fin, and this, as also the flippers, acts as a balancer. In no whale or porpoise is there any external trace of hind limbs, but the skeleton of some kinds shows in varying stages of degradation a rudimentary bone answering to this description. Perhaps however, the most distinctive feature of whales is the blow-hole, situated, like the nostrils of the hippopotamus, on the upper surface of the head, and similarly enabling the animal to breathe the air without exposing much of its head above the surface of the water. The blow-hole (or blow-holes, for whalebone-whales have two) may be said to take the place of nostrils as regards the breathing, though perhaps no sense of smell is included in its functions. In the Sperm-whale, or Cachalot, there is a single S-shaped blow-hole near the end of the snout. The well-known spouting of whales is merely the breathing out of warm vapour, which, on coming in contact with the colder air--and it should be remembered that most whaling is carried on in the neighbourhood of icebergs--condenses in a cloud above the animal's head. I have seen many a sperm-whale spout, and the cloud of spray, often mixed with a varying volume of water if the whale commences to blow before its blow-hole is clear of the surface, drifts forward over the forehead. This is due to the forward position of the blow-hole. I never to my knowledge saw a whalebone-whale spouting, but its double jet is said to ascend vertically over its back, and this would in like manner be accounted for by the more posterior position of the blow-holes. Having filled its lungs, which are long and of simple structure, with fresh air, in enormous draughts that fill the great cavities of its chest, the whale sinks to the depths. There, in ordinary circumstances, it will lie for a quarter of an hour or more, but the pain of the harpoon and the knowledge that there is danger at the surface may keep it below for as much as an hour. When it has to breathe again, a few powerful strokes from the laterally set tail suffice to bring it quickly to the surface. This is not the place for a detailed anatomy of the whale, but no one can fail to notice with admiration such parts of its equipment for the battle of life as the structure of its windpipe, which enables it to breathe with comfort with its mouth full of water, the complicated network of blood-vessels that ensures the slow and thorough utilising of all the oxygen in its lungs while it remains at the bottom, and the elastic cushion of blubber that makes this gigantic animal indifferent to extremes of pressure and temperature. Thanks mainly to its coat of blubber, the whale exists with equal comfort at the surface or hundreds of fathoms below it; in the arctic or in tropical seas.

It is not perhaps in keeping with the plan of this work that we should consider in detail the soft parts of the whale's inside. One or two parts of its feeding and digestive mechanism may, however, offer some points of passing interest. The complex stomach, which is divided into chambers, like that of the ruminants already described, has suggested that the latter function may in a modified process be performed by whales. It is, however, evident that the teeth of toothed whales are in no way adapted to the act of mastication, which is inseparable from any conception of ruminating, while the toothless whales have as complicated a stomach as the rest. Mr. Beddard, writing on the subject in his interesting "Book of Whales," takes the more reasonable view that the first chamber of the stomach of whales should be regarded rather as a storehouse in which the food is crushed and softened. The teeth of whales, the survival of which in the adult animal offers the simplest basis of its classification under one or other of the two existing groups, or sub-orders, are essentially different from the teeth of many other kinds of mammals. It cannot, perhaps, be insisted that the distinctive terms employed for these two categories of whales are wholly satisfactory. For instance, the so-called "toothless" whales have distinct teeth before birth, thus claiming descent from toothed kinds. On the other hand, the so-called "toothed" whales are by no means uniformly equipped in this respect, some of the porpoises having as many as twenty-six teeth, distributed over both jaws, while the bottlenoses have no more than two, or at most four, and these in the lower jaw only. Only the lower jaw, in fact, of the great sperm-whale bears teeth that are of any use, though there are smaller and functionless teeth in the gums of the upper. The teeth of whales, by the way, are not differentiated like our canines and molars, but are all of one character. Although, in "toothless" whales, the foetal teeth disappear with the coming of the baleen, or whalebone, the latter must not, in either structure or uses, be thought to take their place. The plates of whalebone act rather as a hairy strainer. Unless we seek a possible analogy at the other end of the mammalian scale, in the Australian duckbill, the feeding of the whalebone-whales is unique. They gulp in the water, full of _plankton_, swimming open-mouthed through the streaks of that substance. Then the huge jaws are closed, and the massive tongue is moved slowly, so as to drive the water from the angles of the mouth through the straining-plates of baleen, the food remaining stranded on these and on the tongue. The size and number of the baleen-plates appear to vary in a degree not yet definitely established; but there may, in a large whale, be as many as between 300 and 400 on either side of the cavernous mouth, and they may measure as much as 10 or 12 feet in length and 7 or 8 feet in width.

An enumeration of such whales and porpoises and dolphins as have at one time or other been stranded on the shores of the British Isles may serve as an epitome of the whole order. Only one interesting group, in fact--the River-dolphins of the Ganges and Amazons--is unrepresented in the British list. Whales, either exhausted or dead, are periodically thrown up on our coasts, even on the less-exposed portions--one of the most recent examples in the writer's memory being that of a large specimen, over 60 feet long, stranded on the sands near Boscombe, in Hampshire, and the skeleton of which at present adorns Boscombe Pier. It was one of the rorquals, or finbacks, probably of the species called after Rudolphi; but the skeleton is imperfect, though its owner, Dr. Spencer Simpson, appears to have preserved some details of its earlier appearance. It should be remembered that many of the following can only be regarded as "British" with considerable latitude, the records of their visits being in some cases as rare as those of the rustic bunting and red-necked nightjar among birds, or of the derbio and spotted dragonet among fishes.

British zoologists, however, usually include the following:--WHALEBONE-WHALES: Southern Right-whale; Humpback; Finbacks, or Rorquals. TOOTHED WHALES: Sperm-whale, or Cachalot; Narwhal; Beluga, or White Whale; Grampuses; Beaked Whale; Broad-fronted Whale; Cuvier's Whale; Sowerby's Whale; Pilot-whale; Porpoise; Dolphin; White-sided Dolphin; White-beaked Dolphin; Bottlenose.

A selection may therefore be made of five of the most representative of these species--the SOUTHERN WHALE, the CACHALOT, the NARWHAL, the PORPOISE, and the DOLPHIN.

The SOUTHERN WHALE, which, in common with the closely allied polar species, whaling-crews call "right," seeing that all other kinds are, from their point of view, "wrong," is probably the only right-whale which has ever found its way to our shores. Some writers include the Greenland Right-whale, but their authority for this is doubtful. It is said to grow to a length of at any rate 70 feet, though 55 feet would perhaps be more common for even large specimens. In colour it is said to be dark above, with a varying amount of white or grey on the flippers and under-surface. The head and mouth are very large, occupying in some cases one-third of the total length, and the baleen-plates measure as much as 8 or 10 feet in length and 5 or 6 feet in width. The species has no back-fin, but there is a protuberance on the snout, known technically as the "bonnet." This whale appears to give birth to its single calf some time in the spring months, and the mother shows great affection for her offspring. The HUMPBACK is distinguished from the right-whales externally by its longer flippers and the prominence on its back, and internally by the fluted skin of the throat. The FINNERS, or RORQUALS, have a distinct back-fin. They feed on fishes and cuttles, and I have more than once known a rorqual, which looked fully 50 feet long (comparing it roughly with my 24-foot boat), to swim slowly round and round my lugger, down on the Cornish coast, puffing and hissing like a torpedo-boat on its trial trip, rounding up the pilchards in a mass, and every now and then dashing through them open-mouthed with a terrific roar, after several of which helpings it would sink out of sight and not again put in an appearance.

The SPERM-WHALE, or CACHALOT, may serve as our type of the toothed whales. It attains to the same great dimensions as the largest of the whalebone group. A more active animal for its size could scarcely be conceived; and I have seen one, in the Indian Ocean, fling itself three or four times in succession out of water like a salmon, striking the surface each time as it fell back with a report like that of a gun. No one appears to have explained whether performances of this sort are due to mere playfulness, or, as seems more probable, to the attacks of parasites or such larger enemies as sharks or "killers." I have also seen four thresher-sharks leaping out of water, and falling with a loud blow on the whale's back; but the victim lay quite still in this case, and may in fact have been worn out before we came upon the scene. I wish to add that I took the word of the skipper, himself an old whaling-captain, for their identity as threshers. The dazzling sun shone full on them, and on the sea between, and it was impossible, even with the ship's telescope, to recognise them with any accuracy. The cachalot has a very different profile from what any one who had seen only its skull in a museum would be led to expect, for the sperm-cavity in the forehead is not indicated in the bones. The structure of the head enables the animal to drop the lower jaw almost at right angles to the upper; and Mr. Frank Bullen quotes, in his fascinating "Cruise of the Cachalot," the current belief that it does so to attract its prey by the whiteness of its teeth and palate. Although both fishes and cephalopods are very curious, even to their own destruction, it is doubtful whether the whale could not catch its food more rapidly by swimming open-mouthed through the acres of floating squid encountered all over the warmer waters of the ocean.

The NARWHAL, an arctic type, may be distinguished from all other cetaceans by the single spiral tusk in the left side of the head of the male. Sometimes the right tusk grows as well, and either may attain a length of as much as 8 feet; but in the female both teeth remain undeveloped.

The COMMON PORPOISE of our own seas, distinguished by its rounded head from the equally common beaked dolphin, is too familiar to need much description. It grows to a length of 5 or 6 feet, and is dark in colour on the back and white beneath. Its conspicuous back-fin is always recognisable when it gambols with a herd of its fellows; and a line of these sea-pigs, a mile or so in length, is no uncommon sight, their presence inshore being indicative on some parts of the coast of the coming of east wind. The porpoise, which has, like many of its group, teeth in either jaw, is a voracious feeder, preying in estuaries on salmon and flounders, and on more open parts of the coast on pilchards and mackerel. It is occasionally a serious nuisance in the Mediterranean sardine-fisheries, and I have known of the fishermen of Collioure, in the Gulf of Lyons, appealing to the French Government to send a gunboat from Toulon that might steam after the marauders and frighten them away. One of the most remarkable cases of a feeding porpoise that I can recall was that of one which played with a conger-eel in a Cornish harbour as a cat might play with a mouse, blowing the fish 20 or 30 feet through the air, and swimming after it so rapidly as to catch it again almost as it touched the water.

The DOLPHIN, which is in some seasons as common in the British Channel as the more familiar porpoise, is distinguished by its small head and long beak, the lower jaw always carrying more teeth than the upper. It feeds on pilchards and mackerel, and, like the porpoises, gambols, particularly after an east wind, with its fellows close inshore. There are many other marine mammals somewhat loosely bracketed as dolphins. RISSO'S DOLPHIN, for instance, a rare visitor to our coasts, has a striped skin, and its jaws are without teeth, which distinguish it from the common dolphin and most of the others. It cannot therefore feed on fishes, and most probably eats squid and cuttle-fish. The BOTTLE-NOSED DOLPHIN, a species occurring in the greatest numbers on the Atlantic coast of North America, is regularly hunted for its oil. HEAVYSIDE'S DOLPHIN, which hails from South African waters, is a smaller kind, chiefly remarkable for the curious distribution of black and white on its back and sides.

A word must, in conclusion, be said on the economic value of the whales. Fortunately, as they are getting rarer, substitutes for their once invaluable products are being from time to time discovered, and much of the regret at their extermination by wasteful slaughter is sentimental and not economic. For whalebone it is not probable that a perfect substitute will ever be found. It therefore maintains a high price, though the former highest market value of over £2,000 per ton has fallen to something nearer the half. The sperm-oil from the sperm-whale, and the train-oil from that of the right-whales, the spermaceti out of the cachalot's forehead and the ambergris secreted in its stomach, are the other valuable products. Ambergris is a greyish, fatty secretion, caused by the irritation set up in the whale's inside by the undigested beaks of cuttle-fish. Its market price is about £5 per ounce. A lump of 240 lbs. sold for nearly £20,000.

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