Natural History, Reptiles/Testudinata
ORDER I. TESTUDINATA.
(Tortoises.)
The appearance of an animal of this Order will naturally recal to the mind the mailed Armadillos among the Edentate Mammalia, as the Sauria will remind us of the Pangolins. The Tortoises are readily distinguished from other Reptiles by their body being inclosed in a double buckler, which admits only of a partial protrusion of the head, tail, and limbs. The bones of the skeleton, though essentially the same as those found in the preceding classes, are strangely modified. If we remove the convex shield, called the carapace, that covers the upper part of a Tortoise, and turn it up, we shall find on the inner surface the vertebral column imbedded into an immovable piece, and the ribs flattened and widened so as to touch each other at their edges. The vertebrae of the neck and of the tail alone are free. The lower plate or plastron, in like manner, is composed of pieces representing the breastbone or sternum, united by sutures.
The external surface of these shields is covered with a series of plates of a horny (or sometimes leathery) texture, of regular but varied forms, united at their edges, but sometimes overlapping posteriorly. The shoulder-blade and all the muscles of the arm and neck, instead of being attached to the exterior of the ribs and spine, as in other vertebrate animals, are all within, as are also the bones of the pelvis, and even the muscles of the thighs; so that a Tortoise has been described as an animal turned inside out. The
SKELETON OF TORTOISE.
jaws are destitute of teeth, but are invested with horn like those of birds, and form in fact a powerful beak. The head, neck, tail, and limbs, are clothed with a tough skin, in which are imbedded plates, either connected or detached.
The sphere of action of the Testudinata is either the land or the water. Of those which are aquatic, some inhabit marshes, pools, and rivers; others are exclusively marine. The walk of the terrestrial species is slow, even to a proverb; the legs are short, restricted in motion, and being placed at a distance from the centre, they form a sort of short crutches, able to drag the unwieldy body along, but unable to restore the prone position if the animal be laid on its back. The feet seem like stumps abruptly cut off, armed around the edge with a set of blunt nails, which serve as a sort of grapplings to hold on the surface of the ground and drag the body forwards. To an animal which feeds on herbs, the power of pursuit is useless; nor is it necessary that swiftness in escape should be conferred on one which can draw in its head and limbs on the approach of danger, presenting only a solid case of mail, in which it may defy every enemy but man.
On the other hand, the marine species swim with great rapidity, rushing along beneath the surface like a bird on the wing. The feet take the form of powerful fins, and the form of the body is flattened, and thinned to an edge, both of these provisions facilitating progression through a dense medium. "But the well-developed flipper that enables the Marine Tortoise to oar its way with swiftness, is even a worse organ for land-progression than the clumsy foot of a Land Tortoise. Not but that they will shuffle back to the sea, which they have only occasion to leave in order to deposit their eggs, at a good pace, and they will deal heavy blows with their flippers to those who attempt to stop them, (for they, as well as the Land Tortoises, are very strong,) as those who have been foiled in turning Turtles have known to their cost."
The eggs are of an oval form, and are covered with a white calcareous shell, much resembling those of birds. Those of many of the species are eaten by man.
The food of the Testudinata is various: the terrestrial species are believed to subsist exclusively on vegetable diet; the marine species add to this the flesh of large shelled mollusks; the marsh and fresh-water kinds prey on fishes, young birds, insects, worms, and any other animals they can overcome.
About one hundred and twenty species are known to belong to the Order, of which twenty-eight are terrestrial, eighty-four are fluviatile, and eight are marine. They are confined to the warmer regions of the earth; none of them being properly inhabitants of the British Islands; but occasional occurrences of some of the marine species on our shores are recorded, and a terrestrial Tortoise is imported in some numbers from the south of Europe, and kept as a pet in gardens.
We shall consider the Tortoises as comprised in five Families; Testudinidæ, Emydidæ, Trionychidæ, Sphargidæ, and Cheloniadæ.
Family I. Testudinidæ.
(Land Tortoises.)
In this Family the carapace is very high and convex, solid in structure, and covered with a horny shell. The general form may be illustrated by the common Greek Tortoise (Testudo Græca), familiar to most of our readers. But the principal and most remarkable peculiarity, and that which most perfectly indicates the manner of life common to the group, is the conformation of the limbs: the feet are short and stumpy, nearly of equal length, with toes scarcely distinct, immovable, united by a thick skin, and forming a sort of truncated mass, "callous in its periphery, on the outside of which one distinguishes only horny cases, a sort of hoofs, which for the most part
FOOT OF TORTOISE.
correspond with the last phalanges [or joints] they incase, and consequently shew that these animals live only on the land, never in the water."[1]
The feet, as well as the head, are capable of being completely drawn within the bony shell. Some of the species have the hinder part of the carapace flexible, so that it can be brought down to the plastron; while others have the front plates of the plastron jointed to the rest by an actual hinge, so that they can shut up the head as in a sort of box.
The food of the members of this Family consists exclusively of vegetables: their motions are slow and awkward: they live to an immense age, individuals having been ascertained to be above two hundred years old. In temperate climates, they burrow into the earth on the approach of winter, where they remain inert.
Genus Testudo. (Linn.)
The technical characters of this genus are that the fore-feet are furnished with five toes each, the hind with four; the carapace is composed of a single piece; the anterior part of the plastron is not moveable. Above twenty species are described, principally inhabiting the tropical regions; many of these attain a gigantic size, to which our little European species present no approach.
One of the most interesting of these giant
INDIAN TORTOISE.
Tortoises is that described by Mr. Darwin as inhabiting the Galapagos Islands. It is probably the Testudo nigra of Quoy and Gaimard. In these equinoctial islands it has been abundant from the time of Dampier, who observes, that five or six hundred men might subsist on them for several months without any other sort of provisions, adding, that they are so extraordinarily large and fat, and so sweet that no pullets eat more pleasantly.
The day on which Mr. Darwin visited the little craters in the Galapagos Archipelago was glowing hot, and the scrambling over the rough surface, and through the intricate thickets, was very fatiguing. "But," says Mr. Darwin, "I was well repaid by the Cyclopean scene. In my talk I met two large Tortoises, each of which must have weighed at least two hundred pounds. One was eating a piece of cactus, and when I approached it looked at me, and then quietly walked away; the other gave a deep hiss, and drew in his head. These huge reptiles, surrounded by the black lava, the leafless shrubs, and large cacti, appeared to my fancy like some antediluvian animals."
Mr. Darwin states his belief that these Tortoises are found in all the islands of the Archipelago; certainly in the greater number; and thus continues his description:—"They frequent, in preference, the high damp parts, but likewise inhabit the lower and arid districts. Some individuals grow to an immense size. Mr. Lawson, an Englishman, who had, at the time of our visit, charge of the colony, told us that he had seen several so large that it required six or eight men to lift them from the ground, and that some had afforded as much as two hundred pounds of meat. The old males are the largest, the females rarely growing to so great a size. The male can readily be distinguished from the female by the greater length of its tail. The Tortoises which live on those islands where there is no water, or in the lower and arid parts of the others, chiefly feed on the succulent cactus. Those which frequent the higher and damper regions eat the leaves of various trees, a kind of berry (called guayavita), which is acid and austere, and likewise a pale green filamentous lichen, that hangs in tresses from the boughs of the trees. The Tortoise is very fond of water, drinking large quantities, and wallowing in the mud. The larger islands alone possess springs, and these are always situated towards the central parts, and at a considerable elevation. The Tortoises therefore, which frequent the lower districts, when thirsty, are obliged to travel from a long distance. Hence, broad and well-beaten paths radiate off in every direction from the wells even down to the sea-coast; and the Spaniards, by following them up, first discovered the watering places. When I landed at Chatham Island, I could not imagine what animal travelled so methodically along the well-chosen tracts. Near the springs it was a curious spectacle to behold many of these great monsters; one set eagerly travelling onwards with outstretched necks, and another set returning, after having drunk their fill. When the Tortoise arrives at the spring, quite regardless of any spectator, it buries its head in the water, above its eyes, and greedily swallows great mouthfuls, at the rate of about ten in a minute. The inhabitants say that each animal stays three or four days in the neighbourhood of the water, and then returns to the lower country; but they differed in their accounts respecting the frequency of these visits. The animal probably regulates them according to the nature of the food which it has consumed. It is, however, certain, that Tortoises can subsist even on those islands where there is no other water than what falls during a few rainy days in the year.
"I believe it is well ascertained, that the bladder of the frog acts as a reservoir for the moisture necessary to its existence; such seems to be the case with the Tortoise. For some time after a visit to the springs, the bladder of these animals is distended with fluid, which is said gradually to decrease in volume and to become less pure. The inhabitants, when walking in the lower district, and overcome with thirst, often take advantage of this circumstance, by killing a Tortoise, and if the bladder is full, drinking its contents. In one I saw killed, the fluid was quite limpid, and had only a very slightly bitter taste. The inhabitants, however, always drink first the water in the pericardium, which is described as being best. The Tortoises, when moving towards any definite point, travel by night and by day, and arrive at their journey's end much sooner than would be expected. The inhabitants, from observation on marked individuals, consider that they can move a distance of about eight miles in two or three days. One large Tortoise which I watched, I found walked at the rate of sixty yards in ten minutes, that is, three hundred and sixty in the hour, or four miles a day—allowing also a little time for it to eat on the road. They were at this time (October) laying their eggs. The female, where the soil is sand, deposits them together, and covers them up with sand; but where the ground is rocky, she drops them indiscriminately in any hollow. Mr, Bynoe found seven placed in a line in a fissure. The egg is white and spherical; one which I measured was seven inches and three-eighths in circumference. The young animals, as soon as they are hatched, fall a prey in great numbers to the buzzard with the habits of the caracara. The old ones seem generally to die from accidents, as from falling down precipices: at least, several of the inhabitants told me they had never found one dead without some such apparent cause. The inhabitants believe that these animals are absolutely deaf; certainly they do not overhear a person walking close behind them. I was always amused, when, overtaking one of these great monsters as it was quietly pacing along, to see how suddenly, the instant I passed, it would draw in its head and legs, and uttering a deep hiss, fall to the ground with a heavy sound, as if struck dead. I frequently got on their backs, and then, upon giving a few raps on the hinder part of the shell, they would rise up and walk away; but I found it very difficult to keep my balance. The flesh of this animal is largely employed, both fresh and salted; and a beautifully clear oil is prepared from the fat. When a Tortoise is caught, the man makes a slit in the skin near its tail, so as to see, inside its body, whether the fat under the dorsal plate is thick. If it is not, the animal is liberated; and it is said to recover soon from this strange operation. In order to secure the Tortoises, it is not sufficient to turn them like Turtle, for they are often able to regain their upright position."[2]
Family II. Emydidæ.
(Marsh Tortoises.)
This is the most numerous in species of the Families of the Testudinata. MM. Duméril and Bibron observe, that America produces more Marsh Tortoises than all the rest of the world put together; for of the seventy-four species composing this family, forty-six are confined to that continent. The cause of this disproportion they attribute to the vast body of water in the form of immense lakes, marshes, and rivers with which the expanse of America is intersected. The continent of Africa, on the other hand, which offers in this respect so great a contrast to the former, presents us with but three species of Emydidæ, but is very rich in Testudinidæ.
The Marsh Tortoises, or Terrapins, have the body much flatter, the carapace being less arched, than the Land Tortoises. The toes are separated, or rather separately moveable, and are furnished with hooked claws; they are usually connected by a palmated membrane or web, and the hind feet are larger than the fore ones. They have twelve plates on the plastron; they withdraw the head and neck between the shields.
The habits of this Family differ much from those of other Tortoises. They swim with facility, and walk on land with a less slothful gait than the Testudinidæ. They inhabit marshes, stagnant ponds, lakes, and even small rivers whose course is gentle; feeding on small water-animals, such as frogs and newts, the young of web-footed fowl, fresh-water snails, and insects; nor does the flesh of larger creatures drowned in the lakes, or bogged in the marshes, come amiss to them. The eggs are rounded, with a hard, white, calcareous shell; they are deposited in shallow cavities scraped in the soft earth on the margins of the waters in which they reside, whence the young, hatched by the heat of the sun, readily find their way into their proper element.
Genus Emys. (Brongn.)
In this genus all the feet are furnished with five toes, but the inner toe of the hind foot is destitute of a nail: the plastron is wide, and oval, and is furnished with twelve plates; the marginal plates of the carapace are twenty-five. The jaws are strong and cutting, the mandibles notched, and toothed in a manner closely resembling the beak of a Falcon.
The most common European fresh-water Tortoise belongs to a genus allied to Emys, but distinguished by having the plastron attached to the buckler by a cartilage, allowing it some degree of mobility. It is named Cistudo Europæa, and is extended over the whole south-east of Europe, as far north as Prussia. It attains the length of nine or ten inches; the carapace is oval, of a blackish hue, marked with yellowish specks; the skin of the neck and breast is similarly spotted. It is a species of some elegance, but it is most esteemed for the excellence of its flesh, and is commonly sold in the markets of Germany. To improve its flavour, colonies of these animals, kept in ponds, are fattened upon lettuce and other leaves, bread, &c. "It may be even conveniently kept in a cellar, and fed on oats, which, being scattered on the floor, take root there, and as they begin to sprout up, afford a wholesome nutriment to this reptile." We are informed by Wolff that the peasants in Prussia keep numbers of these creatures in troughs for a year or two, and fatten them up.
EUROPEAN MARSH TORTOISE.
On approaching a pond where these reptiles abound, numbers of them may be seen of various sizes, from that of a penny upwards, sitting motionless on the twigs and branches of fallen trees, or the projecting points of any other substance that is partly submerged. They are very watchful, and on the slightest alarm they drop almost imperceptibly into the water, and sink to the bottom, whence they soon emerge if all is quiet. They are voracious: their living prey is taken, by stealing slowly towards it, and seizing it with a sudden snap.
It is a curious fact that whenever this Tortoise eats a fish, it rejects the air-bladder; and the peasants, who seek these animals for the market, judge of the number that are to be found in any pond, by the number of fish-bladders floating on the surface. Professor Bell has mentioned to us that he had a Tortoise of this species in his possession, to which he once threw six small living fishes; the next morning there was one fish remaining, and five air-bladders on the surface, told the fate of the rest.
Several genera of fresh-water Tortoises are distinguished by their not being able entirely to retract the head between the shields; but they obtain a partial protection by bending the long neck to one side. In general the head in this group is depressed, and the eyes are seated somewhat on the upper surface, so as to look obliquely upwards instead of sidewise. These Tortoises are, by some Naturalists, considered to form a distinct Family by the name of Hydraspidæ.
Family III. Trionychidæ.
(Soft Tortoises.)
These are large Tortoises which have no horny shell, but the carapace and plastron are covered with a soft skin. The ribs do not reach to the border of the carapace, nor are they united through the whole of their length, the parts analogous to sternal ribs being replaced by a simple cartilage; and the sternal pieces are partly dentelated as in the Turtles, and do not cover the whole inferior surface. The feet, like those of the preceding family, are webbed, but not lengthened; only three toes of each foot are furnished with nails. The horny beak is covered on the outside with fleshy lips, and the muzzle is produced into a short trunk. The tail is short, and the anal orifice of the body is situated near its extremity.
The Soft Tortoises inhabit great rivers and lakes, where they live upon aquatic animals; they are eminently carnivorous and voracious, and pursue with agility in the water, fishes, and especially young crocodiles. Notwithstanding the nature of their food, their flesh is esteemed for the table, and hence they are caught with a hook and line: it is necessary, however, as MM. Duméril and Bibron assert, that the hook should be baited with a living prey, or at least that the motion of apparent life should be communicated to it, if dead, as they are said never to touch a dead or immoveable prey. This does not apply, however, to the eggs of Crocodiles, which the Soft Tortoises devour greedily in the African and Indian rivers. In seizing their food, or defending themselves, they dart out their long neck with the sudden rapidity of an arrow. The grasp of their powerful and trenchant beak is sharp and deadly, nor is it relaxed until the piece is taken clean out; and as they are bold and ferocious, they are much dreaded even by those who fish for them.
Like the Emydes, the Soft Tortoises love to repose on the islets and points of rock, on the fallen trees at the rivers' margins, or on floating logs of timber, whence they drop into the water on the slightest alarm. They swim with ease and swiftness, both on and beneath the surface.
No species of this Family is found in any of the rivers of Europe. The Nile, the Niger, and the Senegal, the Euphrates, and the Ganges, the Mississippi, the Ohio, and their tributaries, and the great lakes of the St. Lawrence, are the localities known to be inhabited by various species of Trionychidæ.
Genus Trionyx. (Geoff.)
The species belonging to this genus, which includes the majority of those known, are distinguished by the following characters. The carapace is surrounded by a cartilaginous circumference, very wide, floating behind, and deprived of bone externally. The hinder part of the plastron is too narrow to hide the posterior limbs completely, when the animal draws them up under the carapace.
The common Soft Tortoise of North America (Trionyx spiniferus, Lesueur) inhabits the great lakes, and many of the rivers of that continent. It is a ferocious tyrant of the waters, devouring ducks and other fowl, the young of alligators, and fishes, with great voracity. It attains a large size.
SOFT TORTOISE.
Pennant mentions some which weighed seventy pounds; one which he kept for three months weighed twenty pounds, and the buckler or carapace of this specimen was twenty inches in length, while the neck and head measured thirteen inches and a half more. The upper parts vary in tint, being brown or grey of various shades, irregularly marbled, and frequently studded with dots: the under surface is whitish, or of the same tint as the human nails.
Towards the end of April or May, according to M. Lesueur, the females of this species crawl out of the rivers, for the purpose of seeking out places suitable for the deposition of their eggs. Sandy spots exposed to the sun are chosen, and to obtain these they will often scale a steep bank that is ten or fifteen feet above the water's edge. The eggs are deposited in hollows, to the number of fifty or sixty, the old Tortoises laying more than young ones. They are spherical in form; the shell is calcareous but in a slight degree, and is therefore more fragile than that of the eggs of the Emydes that inhabit the same waters. M. Lesueur counted in the ovary of a female twenty ready for laying, and an immense number of others, varying in their dimensions, from the size of a pin's head to the full volume attained when they become covered with the calcareous shell. They are caught by persons who angle for them with a hook and line, baited with a small fish; when drawn on shore they are dangerous, darting the head to the right and left with incredible velocity; they often inflict severe bites on their captors, so that the prudent chop off their heads as soon as they draw them out of the water; the flesh is very delicate in flavour.
It is believed that the Soft Tortoises pair, and that the male remains constantly attached to the same female, two individuals of different sexes being commonly seen together in any given locality.
Family IV. Sphargidæ.
(Leathery Turtles.)
In this and the following Family, the carapace is very much depressed, and their two pairs of feet, which are of unequal length, are flattened into the form of oars or solid fins, their toes being united so as to be scarcely distinguishable, and incased in the common integument. They all inhabit the ocean, which they never leave except for the purpose of depositing their eggs.
The Sphargidæ, or Leatherbacks, have the bony structure of the carapace and plastron invested with a leathery skin instead of horny plates. In the young animal this is tuberculous, but in adults it is smooth, though marked with several ridges, slightly serrated, which run down through the whole length of the carapace and plastron.
Genus Sphargis. (Illig.)
The one or two species which belong to this genus compose the whole Family. Their remaining characters may be thus summed up: the carapace has seven longitudinal ridges, the plastron live; the paddles have no distinct nails; the muzzle is pointed; the jaws are of great power; the upper has a sharp tooth on each side near the tip, behind which is a deep notch, and another triangular notch in front separates the two teeth, which receives the sharp up-turned point of the lower mandible; the opening of the eyelids is almost vertical, and when closed the edge of the posterior (answering to what is ordinarily the lower) overlaps that of the anterior; the fore limbs are much more developed than the hind, and are of great length and breadth.
The species that inhabits the Mediterranean (Sphargis coriacea, Linn.) has occasionally strayed to the shores of our own islands. Some of the specimens taken here have weighed seven hundred and eight hundred pounds. Pennant relates that one taken off the coast of Scarborough was purchased by a family, who invited several persons to partake of its flesh. A gentleman present told the guests that it was unwholesome, but one person persisting to eat of it was seized with violent
LEATHERY TURTLE.
purging and vomiting. This case, however, can hardly be considered conclusive as to its unwholesomeness, if what Pennant adds be correct, that the Carthusians are said to eat of the flesh of no other Turtle. The appearance of the meat is said to be coarse, and the flavour bad; though it is usually very fat.
There is a species common on the tropical shores of the Atlantic Ocean, by some thought to be identical with the above, though distinguished by other zoologists. It regularly visits the Tortugas, or low sandy islets that lie off the point of Florida, for the purpose of depositing its eggs, arriving, according to Audubon, later than the other Turtles, and manifesting less caution in selecting a place adapted for their concealment. The number laid by each female amounts to about three hundred and fifty, deposited in two parcels. Individuals of this species, when sorely wounded, or hampered in nets, have been heard to utter loud bellowing cries, audible at the distance of nearly a mile.
This is the largest of all the Testudinata known, sometimes attaining a length of nine or ten feet, and a weight of sixteen hundred pounds. Its carapace is of a dusky hue, and is marked over its surface into five or six-sided subdivisions, small and obscure, so as not to detract from its general smoothness.
Family V. Cheloniadæ.
(Turtles.)
The species of most importance to man are contained in this Family; one affording an abundant and esteemed article of diet, and another yielding a substance of much elegance, which, under the name of Tortoise-shell, is largely used in the arts. Their distinctive characters are, that the head, and particularly the feet, cannot be withdrawn between the carapace and plastron; that the feet are flattened into swimming-paddles, the toes being united, and enveloped in the same membrane: the anterior pair are greatly lengthened. Only the first two toes are furnished with claws, which are pointed; and one or other of these is apt to fall at a certain period of life. The pieces of which the plastron is composed do not form a continuous plate, but are variously dentelated, and leave wide
FOREFOOT OF HAWKSBILL TURTLE.
intervals filled only by cartilage. The ribs are narrowed, and separated from each other at their external portion, but the entire circumference of the carapace is occupied by a circle of pieces corresponding to sternal ribs. The plates of the carapace are horny, and for the most part continuous at their edges, as in the majority of other Testudinata, but in some species, as that from which the beautiful Tortoise-shell is obtained, the posterior edge of each plate is produced, and overlaps the one that succeeds it.
The food of the Turtles consists chiefly of various kinds of sea-weeds, such as the Zostera or sea-grass, which grows in immense submerged fields at the bottom of the tropical seas. It has been stated that some species will crawl up the shores of desert islands during the night, and clamber up the cliffs of lone and isolated rocks far out at sea, for the purpose of browsing on certain favourite plants. But some species, such as the great Loggerhead Turtle (Chelone caouana), which diffuse a rank odour, feed largely on cuttles, and other mollusca, their powerful jaws crushing even such stony shells as those of the great Strombi and Cassides, as a man would crack a nut. The robust form of the jaws in these animals, their trenchant and frequently notched or toothed edges, the mode in which the lower mandible shuts into the upper, and the great strength of the muscles which move them, manifested in the force with which they snap together,—while they remind the beholder of the beak of a bird of prey, yet constitute an instrument of far greater power, and seem to intimate that it must be something more than grass that requires an apparatus so formidable.
The flattened form of the Marine Turtles presents little resistance to the fluid in which they move, and their broad oar-like feet enable them to swim and dive with great velocity and grace. Mr. Audubon speaks of some species shooting through the element with the arrowy fleetness of a bird on the wing. Except when they come on shore to lay their eggs on the sand, or clamber on the rocks, as intimated above, to browse on herbage, the Turtles never leave the sea; they may often be seen in fair weather in the tropics, floating motionless on the calm surface of the ocean, many hundred miles from land. They are supposed on such occasions to be asleep, but they are very vigilant, and will rarely allow a near approach without disappearing by diving. They remain a long time under water, as might be expected from the volume of their arbitrary lungs, enabling them to retain a sufficient quantity of air, while submerged.
The very peculiarities of conformation, however, which adapt them for swift progression in their own element, render them awkward and almost helpless when out of it. It is only with laborious efforts that they are enabled to shuffle along on land; and if once turned over on their backs, their great width and flattened form prevent their ever being able to regain their natural position.
The flesh of the herbivorous kinds is well known as an article of luxury in this country: to voyagers, however, it fills a much more important position, as it affords a most valuable resource in tropical climates, being abundant, easily kept fresh, and as nutritious as it is agreeable. The eggs of all the species are excellent, and are procured in immense numbers; the albumen, or that part which answers to the white, does not grow hard by the application of heat.
The various species seem to have no settled habitat, but are widely scattered over the whole ocean of the warmer regions of the globe. There are, however, favourite resorts, where they are procured in greater abundance, as low sandy coasts of uninhabited islands, or lonely spots on other shores. Thus in the Atlantic, the Cape Verd Isles, Ascension, and the Isles of the West Indies; in the Indian Ocean, the Isle of France, Madagascar, Rodriguez, and the Seychelles; in the Pacific, the Galapagos, and the Sandwich Isles, are noted resorts of Turtle.
The reason of some shores being more frequented by Turtles than others, is their suitability for breeding-places. To reach the destined spot for the deposition of the eggs, "the females have often to traverse the sea for more than fifty leagues, and the males accompany them to the sandy beaches of those desert islands selected for the places of nidification. Arrived at the end of their voyage, they timidly come forth from the sea after sunset; and, as it is necessary to leave the eggs above high-water mark, they have often to drag themselves to a considerable distance before they can hollow out their nests (about two feet in diameter) during the night, and there lay at one sitting to the number of one hundred eggs. This laying is repeated thrice, at intervals of two or three weeks. The eggs vary in size, but are spherical, like tennis-balls; and when they are laid, their investing membrane is slightly flexible, although covered with a delicate calcareous layer. After slightly covering the nest with light sand, the parent returns to the sea, leaving the eggs to the fostering influence of a tropical sun. The eggs are said to be hatched from the fifteenth to the twenty-ninth day; and when the young Turtles come out, their shells are not yet formed, and they are white as if blanched. They instinctively make for the sea; but on their road, and as they pause before entering the water, the birds of prey that have been watching for the moment of their appearance hasten to devour them; whilst those that have escaped their terrestrial persecutors by getting into the sea, have to encounter a host of voracious fishes and legions of ambushed crocodiles."[3]
Genus Chelone. (Brongn.)
If we consider the Green Turtle, the Loggerhead, and the Hawksbill, as constituting but so
HEAD OF GREEN TURTLE.
many species of a single genus, the characters of that genus will be the same as those already enumerated as marking the Family: but if, with some zoologists, we treat the differences between these animals as generic and not specific, restricting the term Chelone to the Green Turtle and its allies (C. mydas, maculosa, marmorata, &c.), we may give the following (from Duméril and Bibron) as the distinctive characteristics of this genus. The plates which compose the disk of the carapace are thirteen, not overlapping; the muzzle is short and rounded; the upper jaw has a slight notch in front, and small dentelations on the sides; the horny case of the lower jaw is formed of three pieces, and has its sides deeply dentelated; the first toe of each foot is furnished with a nail.
The Green Turtle (Chelone mydas, Linn.) is of an olive or greenish-brown hue above, and yellowish-white below. The carapace consists of twenty-five marginal plates, surrounding a disk of thirteen; the medial plates of the latter form almost perfect hexagons; the whole shell is somewhat heart-shaped, being pointed at the posterior extremity. Its length is sometimes above six feet, and its weight six or seven hundred pounds. Dampier mentions one that was captured in the Bay of Campeachy, which was nearly six feet wide, and four feet thick. A son of Captain Roche, a boy of ten years old, went in the shell as a boat, from the shore to his father's ship, lying about a quarter of a mile distant. Pliny speaks of the Chelonophagi, dwelling on the shores of the Red Sea and the Indian Ocean, who not only subsisted on Turtles, but converted their enormous shells into roofs for their huts, and boats for their little voyages; and the inhabitants of some of the tropical islands at this day make these shells serve the same purposes, and others,
GREEN TURTLE.
such as drinking-troughs for their cattle, and baths for their children.
The West Indian Isles, particularly the Bahamas, and those little sandy spots off the end of Cuba, known as the Caymanas, the Isle of Ascension, and most of the islands of the Pacific, are favourite resorts of the Green Turtle. Specimens have been occasionally caught on the shores of Europe, driven hither by stress of weather. "In the year 1752," says Mr. Bingley, "one, six feet long and four feet broad, weighing betwixt eight and nine hundred pounds, was caught in the harbour of Dieppe after a storm. In 1754, a still larger one, upwards of eight feet long, was caught near Antioche, and was carried to the Abbey of Long-veau, near Vannes in Britany; and in the year 1810, I saw a small one which had been caught amongst the submarine rocks near Christchurch, Hants."[4]
This is the species the flesh of which is so highly esteemed, that it forms no unimportant article of commerce. Great numbers are imported every season for the supply of the London hotels and eating-houses, and these are chiefly brought from the West Indies and from Ascension Island. Ships proceeding on long voyages through the tropical seas always endeavour to recruit their supplies of fresh provisions, by calling at the islands where these animals are known to abound, and taking in a large number of living Turtle, as they are readily preserved in health for a long time with little trouble and without food.
The mode of taking Turtle is thus graphically described by Sir J. E. Alexander, as he witnessed it at Ascension, which island he calls the head-quarters of the finest Turtle in the world:—
"We walked down to the Turtle ponds, two large enclosures near the sea, which flowed in and out through a breakwater of large stones. A gallows was erected between the two ponds, where the Turtle are slaughtered for shipping, by suspending them by the hind flippers, and then cutting their throats. About three hundred Turtle, of four or five hundred pounds each, lay on the sand, or swam about in the ponds; a sight to set an alderman mad with delight.
"In the hot months of January, February, March, and April, the females land at night; and waddling over the sands in the various bays of
TURNING TURTLE.
the island far above high-water mark,—for by a pole in the ponds, the tide only rises here two feet,—they scrape up, by alternate scoops of their flippers, a hole deep enough to cover their bodies. Into this they get, sighing heavily, and deposit from one hundred and fifty to two hundred eggs; cover them up, leave them to the sun to hatch, and then waddle again towards the sea. Two stout hands are, meanwhile, on the look out, watching the movements of the unfortunate Turtle; and running up to her after the completion of her task, one seizes a fore-flipper, and dexterously shoves it under her belly, to serve as a purchase, whilst the other, avoiding a stroke which might lame him, casts the Turtle over on her back, where she lies helpless. From fifteen to thirty are thus turned in a night; and six hundred had been so captured in the season of 1834. In the bays, where the surf, or heavy rollers, prevent the boats being beached to take on board the Turtle when caught, they are hauled out to them by ropes.
"No ships' crews are now allowed to turn Turtle, which is converted into a government monopoly; and two pounds ten shillings is the price for each. Strange to say, from the time that the young Turtle, the size of a dollar, are observed scuttling down to the water, they are never seen again here until they are four or five hundred pounds weight; and how long they take to attain this great size, and where they spend the intermediate time, is as yet a mystery. I was surprised to hear that Turtle are kept in the ponds for a year and upwards, without a morsel of food of any kind. They sometimes deposit their eggs in the sand, on the sides of the ponds; and in due time the little animals are allowed to make their escape to the sea. One old female, called 'Nelson,' because one of her flippers had been carried off by a shark, was kept, out of respect, for two or three years in the ponds. She contrived, however, one night to crawl round the enclosure, and make her escape; but she was turned next year in Clarence Bay. Another Turtle was also turned there, a short time since, on the back shell of which was carved the name of a mate of a British vessel, who had bought it and sailed with it three weeks before; it is probable that, imagining it to be dead, he had thrown it overboard. The best way to send home Turtle from Ascension, is to 'head them up' in a sealed cask, and have the water changed daily by the bung-hole and a cock. Turtle, though the extremes of heat and cold are injurious to them, should always arrive in hot weather in England. Thus, an unfortunate captain, on one occasion, took from Ascension two hundred Turtle, and timing his arrival badly, brought only four alive to Bristol!"
Catesby mentions a mode of capturing these animals besides turning them on the sands. The inhabitants of the Bahamas are very expert at the latter, and go in boats to the neighbouring coast of Cuba, where on moonlight nights they watch the passing of the female Turtles to and from their nests, and intercepting them, turn them on their backs. Leaving each as it is turned, they proceed along the shore, turning every one they meet with; knowing that they will find each on their return in the position in which it was left; for the Turtle, lying on its back, can never recover its feet by any efforts of its own. Some are so large, as to require three men to turn them. But the way in which these creatures are most commonly taken at the Bahamas, is by striking them with a sharp iron peg or spear-head of two inches long, set in a socket at the end of a staff twelve feet long. Two men set out on this employment in a light canoe, one to paddle noiselessly in the stern, while the other stands watchful in the bow, ready to strike. As soon as a Turtle is perceived, either swimming at the surface with the back exposed, or else crawling at the bottom in shoal water among the thick sea grass, the spear is darted at it. The sharp point enters the shell, and pierces the body, but is dislodged from the staff in the act; a slender line, however, fastened to the peg, is in the hand of the spearman, and though the Turtle speeds away, the canoe is enabled to keep up with him; his strength is soon spent, and he is hauled to the surface, and lifted into the boat.
In some of the isles of the Pacific, where the natives are almost as much at home in the sea as the Turtles themselves, a peculiarly dexterous method of capturing these animals is adopted. Two or three men go out in a canoe in smooth water, when the Turtles delight to sleep on the surface, basking in the sun. No sooner is one discovered, than the ready diver plunges into the sea, and coming up silently behind the animal, suddenly seizes the hinder edge of the carapace before it awakes, and pressing down the posterior part of the body in the water, obliges the fore parts to remain upright. Thus the terrified Turtle, now thoroughly awakened, is prevented from diving until the canoe coming up, the bold fisherman and his prey are both taken on board.
Mr. Darwin, in his very interesting Journal, describes a method of Turtle-catching not very dissimilar to the above, but superior in spirit and boldness. Keeling Island is the scene of his graphic description. He observes,
"I accompanied Captain Fitzroy to an island at the head of the lagoon; the channel was exceedingly intricate, winding through fields of delicately branched corals. We saw several Turtles, and two boats were then employed in catching them. The method is rather curious; the water is so clear and shallow, that although at first a Turtle quickly dives out of sight, yet in a canoe or boat under sail, the pursuers after no long chase come up to it. A man standing ready in the bows at this moment dashes through the water upon the Turtle's back, then clinging with both hands by the shell of the neck, he is carried away till the animal becomes exhausted and is secured. It was quite an interesting sight to see the two boats thus doubling about, and the men dashing into the water, trying to seize their prey."
But there is a mode of fishing for these animals, said to be practised on the coasts of China and Mozambique, which is still more remarkable; living fishes being trained for the purpose of capturing the Turtles. Columbus seems to have been aware of this fact, which has since been noticed by Commerson, as cited by Middleton and Salt. The fish used is a species of Echeneis or Remora, and the following is the method used by the natives of those parts. Their little boat is provided with tubs, in which are a number of these fishes, the top of whose head is covered with an oval plate, soft and fleshy at the circumference, but furnished in the middle with an apparatus of bony pieces, very complicated in its structure, arranged in two regular rows, somewhat resembling the laths of venetian blinds. In different species the number of these plates is varied, some not containing above fifteen, others as many as thirty-six. By muscular action, they are turned on their axis at the pleasure of the fish, and their free edges are provided with small hooks, which are raised all together like the points of a wool card. The tail of each of the trained fishes in the tubs is furnished with a ring, and to this is fastened a cord of fine texture but strong, and of considerable length. When the fishermen discover the Turtles basking on the surface of the water, not daring to disturb their intended prey, by making the least noise, they slip overboard one of their Remoras, secured by the long cord, and pay out the line according to their distance. The fish soon perceives the Turtle, and hastening to it, fixes itself so firmly on the floating reptile, that the fishermen can draw both together into their boat, where there is no difficulty in detaching the fish by pushing forwards its head from behind.
The deposition of eggs by the female of this species has been carefully watched and minutely recorded by an accurate observer of nature, who thus describes the process. “On nearing the shore,” says Mr. Audubon, “and mostly on fine calm moonlight nights, the Turtle raises her head above the water, being still distant thirty or forty yards from the beach, looks around her, and attentively examines the objects on shore. Should she observe nothing likely to disturb her intended operations, she emits a loud hissing sound, by which such of her many enemies as are accustomed to it are startled, and so are apt to remove to another place, although unseen by her. Should she hear any more noise, or perceive any indications of danger, she instantly sinks and goes off to a considerable distance; but should everything be quiet, she advances slowly towards the beach, crawls over it, her head raised to the full stretch of her neck, and when she has reached a place fitted for her purpose, she gazes all round in silence. Finding all well, she proceeds to form a hole in the sand, which she effects by removing it from under her body with her hind flappers, scooping it out with so much dexterity that the sides seldom if ever fall in. The sand is raised alternately with each flapper, as with a large ladle, until it has accumulated behind her, when supporting herself with her head and forepart on the ground, she, with a spring from each flapper, sends the sand around her, scattering it to the distance of several feet. In this manner the hole is dug to the depth of eighteen inches, or sometimes more than two feet. This labour I have seen performed in the short period of nine minutes. The eggs are then dropped one by one, and disposed in regular layers, to the number of one hundred and fifty, or sometimes nearly two hundred. The whole time spent in this operation may be about twenty minutes. She now scrapes the loose sand back over the eggs, and so levels and smooths the surface, that few persons seeing the spot would imagine that anything had been done to it. This accomplished to her mind, she retreats to the water with all possible dispatch, leaving the hatching of the eggs to the heat of the sand. When a Turtle, a Loggerhead for example, is in the act of dropping her eggs, she will not move, although one should go up to her, or even seat himself on her back; but the moment it is finished, off she starts, nor would it then be possible for one, unless he were as strong as Hercules, to turn her over and secure her."[5]
The group to which the Hawksbill (Chelone
HAWKSBILL TURTLE.
imbricata, Linn.) belongs, with its ally C. virgata, Cuv., whether we regard it as of generic or sub-generic rank, may be thus characterised. The carapace is large, flat, and heart-shaped, composed of thirteen discal plates, and twenty-five marginal ones; the hinder margins of these are free, and overlap the succeeding plates, for nearly a third of their length; the muzzle is long and somewhat compressed; the jaws have straight edges, neither notched nor toothed, but curving towards each other at the extremities, where the lower shuts within the upper; each fin is furnished with two nails.
The fore-feet or paddles are larger in these species than in the rest of the Family, and it is said that the Hawksbill, unlike the Green Turtle, which is helpless when turned over on its back, can, by means of its long feet, recover its proper position.
The Hawksbill commonly grows to the length of three feet, and the width of two, but specimens are reported to have been seen of much greater size. Its flesh is of no estimation as food, being both ill-flavoured and unwholesome; its eggs, however, are highly valued. The species is not unimportant notwithstanding, for it produces almost exclusively that well known and beautiful material, so much used in the arts, called Tortoise-shell. In the luxurious ages of ancient Grecian and Roman art, this elegant substance was employed in embellishing articles of use and ornament, perhaps more copiously than with us; for they decorated their doors, the pillars of their houses, their beds, and the statues of their gods with it. Velleius Paterculus relates that when the city of Alexandria in Egypt was taken by Julius Cæsar, the warehouses were found to contain so large a quantity of this material, that he proposed to make it the principal ornament of his triumph, as he did subsequently with ivory, in his triumph at the close of the African war. In the present day the demand for it in the more costly sorts of cabinet work, in inlaying, in articles of virtù, and especially in the manufacture of combs, renders this substance an important article of commerce.
The plates of the carapace in this species are stronger, thicker, and clearer than in any other; they are nearly transparent, and most beautifully variegated with yellow, red, and dark brown clouds, often proceeding in radiations; and, being susceptible of a high polish, are well adapted for ornamental purposes. The comparative value of tortoise-shell is said to depend mainly on the thickness and size of the scales, and, but in a subordinate degree, on the clearness and brilliancy of the varying hues. The Indian Archipelago, and particularly the coasts of New Guinea, and the Spice Islands, are reputed to afford the best and finest specimens. A shell is considered of little value, if the animal from which it is taken, does not weigh at least a hundred and fifty pounds.
The ancients were not aware of any mode by which the layers of which the plates are composed could be separated from each other; they therefore had recourse to the tedious and wasteful plan of sawing them into thin leaves or veneers. A better method is now pursued; the whole carapace being taken from the animal, is filled with live coals, or placed with the inner part downwards, over a fire; when thoroughly heated, the plates start from the bony shield, and the constituent layers also gape apart at the edges, so as to be easily detached from each other. A plate varies in thickness from an eighth to a quarter of an inch, according to the size and age of the animal.
For the following account of the manner in which this beautiful material is rendered available to the many purposes of use and ornament which it subserves, we are indebted to the history of British Reptiles by Professor Bell.
"The scales, or plates, are in the first place separated by the application of heat. They are sold to the manufacturers in the rough state, in which they are uneven, fragile, opaque, and dirty; and it is the first object of the artificer to obviate these defects. The uneven surface, the irregular curvature, the unequal thickness of different parts, have all to be corrected: and not only can these objects be readily effected, but the substance can be rendered ductile, compressible, capable of receiving any impression, of being carved, moulded, and polished, and even extended by soldering pieces together by means of their own substance reduced to powder. The whole of these processes are performed by means of heat.
"The uneven curvature is first of all to be removed, and the plate rendered perfectly flat. This is effected by immersing it in hot water, and then allowing it to cool under heavy pressure, between smooth blocks of wood, or metallic plates. The surface is then rendered smooth, and the thickness equal, by scraping and filing away the rough and prominent parts. In this way each plate receives an equal and smooth surface. But it is in many cases desirable to employ larger pieces than can be obtained from single plates, and two pieces are then united together in the following manner:—The edges are bevelled off to the space of two or three lines, and the margins, when placed together, overlap each other to that extent. They are then pressed together by a metallic press, and the whole is submitted to the action of boiling water; and by this means the two pieces are so perfectly soldered together, as to leave no indication of the line of union. By the application of heat, also, the tortoise-shell may be made to receive any impression, by being pressed between metallic moulds.
"No portion of this precious substance is lost or useless. The filings and powder, which remain after these and the other processes to which the shell is submitted, are placed with any small fragments in metallic moulds, and by means of pressure, exercised whilst they are exposed to the heat of boiling water, they are formed into plates of any thickness which may be required."
COMB-CUTTING.
The shell of the Turtle being so valuable, some ingenuity is well bestowed in the endeavour to avoid any waste of it. Accordingly, in manufacturing combs, a curious invention has been resorted to for this end. To make a comb six inches long, and one inch wide, one would naturally suppose that it would be needful to have a piece of shell of that size; and such is indeed the case. But two combs may be formed out of a piece of shell very little larger, by merely resorting to a very simple plan, which the accompanying diagram will clearly illustrate. The shell is cut by a circular saw, in the manner represented in the zigzag lines; thus, when the sawing is completed, the shell can be pulled in two, and the teeth of the combs will be cut out of one another, while the solid margins are left to form the backs.
Besides the localities already named as the resorts of the Hawksbill Turtle, we may mention the West Indian Isles, those of Bourbon and Mauritius, the Seychelles, and most of the situations enumerated in the notice of the Green Turtle. On three occasions it has occurred on the shores of our own country. Sibbald received the shell of one which came into Orkney. Fleming records its having been taken at Papa Stour, one of the West Zetland Isles; and Dr. Turton mentions one which was taken in the Severn in the year 1774, and placed in his father's fishponds, where it lived till the following winter.
