Sea-serpent, the name given to gigantic animals, presumably of serpentine form, which have been frequently described by sailors and others, and which are believed by many naturalists to exist in the sea-depths, especially in tropical oceans. The question of the existence of a sea-serpent has long formed one of the knotty problems of zoological science. But it seems reasonable to conclude that there exists a certain basis for the supposition that huge undescribed marine forms do exist in the sea-depths, and that the most reliable tales of sea-serpents take origin from appearances of such animals. Of such tales possessing a warrantable basis of fact, and emanating from authoritative sources, that of Captain M'Quhae is one of the best known. This account was published in 1848. Captain M'Quhae commanded H.M.S. Dedalus, and encountered the serpentine form in 24° 44' S. lat. and 9° 20' E. long., and therefore in the South Atlantic Ocean, near the Tropic of Capricorn, and not very far from the coast of Africa. It was not, as in other cases, in bright and fine weather, but in dark and cloudy weather, and with a long ocean swell. The animal was swimming rapidly, and with its head and neck above water. Captain M'Quhae in his report to the Admiralty describes it with confidence as 'an enormous serpent, with head and shoulders kept about 4 feet constantly above the surface of the sea;' and he adds: 'As nearly as we could approximate by comparing it with the length of what our maintopsail-yard would show in the water, there was at the very least 60 feet of the animal à fleur d'eau, no portion of which was, to our perception, used in propelling it through the water, either by vertical or horizontal undulation. It passed rapidly, but so close under our lee-quarter that had it been a man of my acquaintance I should have easily recognised his features with the naked eye: and it did not, either in approaching the ship or after it had passed our wake, deviate in the slightest degree from its course to the south-west, which it held on at the pace of from 12 to 15 miles per hour, apparently on some determined purpose. The diameter of the serpent was about 15 or 16 inches behind the head, which was without any doubt that of a snake; and it was never during the twenty minutes that it continued in sight of our glasses once below the surface of the water; its colour a dark brown, with yellowish white about the throat. It had no fins, but something like the mane of a horse, or rather a bunch of seaweed, washed about its back.' Regret has been very naturally expressed that Captain M'Quhae did not bestow a shot on it. Figures prepared from a sketch by him were published in the Illustrated London News of 28th October 1848. About the same time the testimony of another witness, Lieutenant Drummond, appeared, and was found to differ in some important points from the account of the animal given by Captain M'Quhae and the figures published with his approbation, particularly in ascribing a more elongated form to the head, in the mention of a back-fin, whereas Captain M'Quhae expressly says that no fins were seen, and in a lower estimate of the length of the portion of the animal visible. Lieutenant Drummond's words are: 'The appearance of its head, which with the back-fin was the only portion of the animal visible, was long, pointed, and flattened at the top, perhaps 10 feet in length; the upper jaw projecting considerably; the fin was perhaps 20 feet in the rear of the head, and visible occasionally; the captain also asserted that he saw the tail, or another fin about the same distance behind it; the upper part of the head and shoulders appeared of a dark-brown colour, and beneath the under jaw a brownish white. It pursued a steady and undeviating course, keeping its head horizontal with the water, and in rather a raised position, disappearing occasionally beneath a wave for a very brief interval, and not apparently for the purposes of respiration. It was going at the rate of perhaps from 12 to 14 miles an hour, and when nearest was perhaps 100 yards distant. In fact, it gave one quite the idea of a large snake or eel.' Lieutenant Drummond's account is the more worthy of regard, as it is derived from his log-book, and so gives the exact impressions of the hour, whilst Captain M'Quhae's was written from memory after his arrival in England. Sir Richard Owen thought the animal was a gigantic seal; a supposition, however, which does not at all agree with the description given.
In 1875 a battle between a sea-serpent and a whale was viewed from the deck of the Pauline of London, Captain Drevar, when proceeding with a cargo of coals from Shields to Zanzibar. When the Pauline reached the region of the trade-winds and equatorial currents she was carried out of her course, and after a severe storm found herself off Cape San Roque, where several sperm-whales were seen playing about her. While the crew were watching them they suddenly beheld a sight that filled every man on board with terror. Starting straight from the bosom of the deep, a gigantic serpent rose and wound itself twice in two mighty coils round the largest of the whales, which it proceeded to crush in genuine boa-constrictor fashion. In vain did the hapless whale struggle, lash the water into foam, and even bellow, for all its efforts were as nothing against the supernatural powers of its dreadful adversary; whose strength may be further imagined from the fact that the ribs of the ill-fated cetacean were distinctly heard cracking one after the other with a report like that of a small cannon.
Of no less a ship than H.M. yacht Osborne the captain and officers in June 1877 forwarded an official report to the Admiralty containing an account of a sea-serpent's appearance off the coast of Sicily on the 2d of that month. 'The time was five o'clock in the afternoon. The sea was exceptionally smooth, and the officers were provided with good telescopes. The monster had a smooth skin, devoid of scales, a bullet-shaped head, and a face like an alligator. It was of immense length, and along the back was a ridge of fins about fifteen feet in length and six feet apart. It moved slowly, and was seen by all the ship's officers.' This account was further supplemented by a sketch from the pencil of Lieutenant W. P. Hynes of the Osborne, who to the above description adds that the fins were of irregular height, and about 40 feet in extent; but, 'as we were passing through the water at 10½ knots, I could only get a view of it "end on." It was about 15 or 20 feet broad at the shoulders, with flappers or fins that seemed to have a semi-revolving motion. 'From the top of the head to the part of the back where it became immersed I should consider about 50 feet, and that seemed about a third of the whole length. All this part was smooth, resembling a seal.' These instances are but examples of the many cases in which narratives of the most circumstantial character have been recorded regarding the appearance of serpentine animals, usually in tropical seas.
As will readily be admitted, the chief point at issue is that of the zoological determination of the forms reported to have been seen. Gigantic cuttle-fishes, now proved to have a veritable existence, might in many cases imitate an elongated marine form, swimming near the surface of the sea. It is by far the most plausible theory of sea-serpent existence to suppose that most of the animals described are really giant cuttle-fishes of the Loligo or squid type. These creatures may attain a length of 40 feet or more inclusive of their tentacles, and as they swim along the surface of the sea backwards the tail-fin might well be mistaken for a serpentine head and its fin or ridge, while the tentacles and wash produced by the animal's movements would impart an exaggerated length to the body. Even the incident already described in the case of the Pauline might be explicable on the theory that giant cuttle-fishes attacked the whales, and that the so-called serpents were really the arms or tentacles of the squids. As regards the Pauline case, it may be remarked that the latitude in which the incident occurred was one most unlikely for any sea-snakes to be found. Certain fishes, too, such as the Basking Shark (Selache maxima), would also under certain circumstances appear as unusual marine forms; and, as the present writer has pointed out, the well-known Tape-fishes (Gymnetrus banksii) and other Ribbon-fishes would very accurately reproduce the features of a marine snake, especially when these fishes, as sometimes happens, have grown to an immense size. The marine snakes or Hydrophidae of the Indian Ocean would also serve to personate the 'great unknown' if unusually large. It seems certain that in the immense development of ordinary marine animals may be found a probable clue to the sea-serpent mystery. Mr P. H. Gosse entertained the notion that it might be possible to explain certain sea-serpent stories on the theory that some of the gigantic marine reptiles with whose fossils we are well acquainted might still be in existence in the sea-depths, and occasionally make their appearance at the surface of the ocean. Cases of mere serpentine appearances assumed by certain animals are not to be confused with cases in which a single animal has presented a serpentine aspect. Flocks of the birds known as shags swimming close to the water's edge might personate a sea-serpent swimming along the top of the water; but a flock of birds would have been readily detected by Captain M'Quhae, and by many other observers who have beheld the unknown form from a relatively near distance.
Apart altogether from these historical or semi-historical examples, the sea-serpent has had continuous existence in folklore everywhere, whether among the Eskimo, Fijians, Japanese, Icelanders, Basques, Red Indians, or Chinese. The notion is natural and easy of belief, and the human desire for wonders is sufficient to account for any belief.
See C. Gould, Mythical Monsters (1886); F. S. Bassett, Legends and Superstitions of the Sea (Chicago, 1886); J. Gibson, Monsters of the Sea (1886); an article in the present writer's Leisure-time Studies (1884); and Oudemans, The Great Sea-Serpent (1893).