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Animals of the Past

Chapter 16: REFERENCES
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This work surveys extinct animals and the evidence they left, beginning with the processes that create and destroy fossils and the methods used to interpret them. It examines early vertebrates and fishes, fossil footprints and their value for reconstructing movement and posture, and the dominant marine reptiles as well as extinct whales and large sharks of ancient seas. It describes the rise of birds, including toothed and flightless types, and treats the discovery, anatomy, habits, and likely diets of dinosaurs. Detailed restorations and references accompany paleontological descriptions throughout.

Fig. 27.—A Hint of Buried Treasures.

VIII

FEATHERED GIANTS

"There were giants in the earth in those days."

Nearly every group of animals has its giants, its species which tower above their fellows as Goliath of Gath stood head and shoulders above the Philistine hosts; and while some of these are giants only in comparison with their fellows, belonging to families whose members are short of stature, others are sufficiently great to be called giants under any circumstances. Some of these giants live to-day, some have but recently passed away, and some ceased to be long ages before man trod this earth. The most gigantic of mammals—the whales—still survive, and the elephant of to-day suffers but little in comparison with the mammoth of yesterday; the monstrous Dinosaurs, greatest of all reptiles—greatest, in fact, of all animals that have walked the earth—flourished thousands upon thousands of years ago. As for birds, some of the giants among them are still living, some existed long geologic periods ago, and a few have so recently vanished from the scene that their memory still lingers amid the haze of tradition. The best known among these, as well as the most recent in point of time, are the Moas of New Zealand, first brought to notice by the Rev. W. Colenso, later on Bishop of New Zealand, one of the many missionaries to whom Science is under obligations. Early in 1838, Bishop Colenso, while on a missionary visit to the East Cape region, heard from the natives of Waiapu tales of a monstrous bird, called Moa, having the head of a man, that inhabited the mountain-side some eighty miles away. This mighty bird, the last of his race, was said to be attended by two equally huge lizards that kept guard while he slept, and on the approach of man wakened the Moa, who immediately rushed upon the intruders and trampled them to death. None of the Maoris had seen this bird, but they had seen and somewhat irreverently used for making parts of their fishing tackle, bones of its extinct relatives, and these bones they declared to be as large as those of an ox.

About the same time another missionary, the Rev. Richard Taylor, found a bone ascribed to the Moa, and met with a very similar tradition among the natives of a near-by district, only, as the foot of the rainbow moves away as we move toward it, in his case the bird was said to dwell in quite a different locality from that given by the natives of East Cape. While, however, the Maoris were certain that the Moa still lived, and to doubt its existence was little short of a crime, no one had actually seen it, and as time went on and the bird still remained unseen by any explorer, hope became doubt and doubt certainty, until it even became a mooted question whether such a bird had existed within the past ten centuries, to say nothing of having lived within the memory of man.

But if we do not know the living birds, their remains are scattered broadcast over hillside and plain, concealed in caves, buried in the mud of swamps, and from these we gain a good idea of their size and structure, while chance has even made it possible to know something of their color and general appearance. This chance was the discovery of a few specimens, preserved in exceptionally dry caves on the South Island, which not only had some of the bones still united by ligaments, but patches of skin clinging to the bones, and bearing numerous feathers of a chestnut color tipped with white. These small, straggling, rusty feathers are not much to look at, but when we reflect that they have been preserved for centuries without any care whatever, while the buffalo bugs have devoured our best Smyrna rugs in spite of all possible precautions, our respect for them increases.

Fig. 28.—Relics of the Moa.

From the bones we learn that there were a great many kinds of Moas, twenty at least, ranging in size from those little larger than a turkey to that giant among giants, Dinornis maximus, which stood at least ten feet high,[10] or two feet higher than the largest ostrich, and may well claim the distinction of being the tallest of all known birds. We also learn from the bones that not only were the Moas flightless, but that many of them were absolutely wingless, being devoid even of such vestiges of wings as we find in the Cassowary or Apteryx. But if Nature deprived these birds of wings, she made ample amends in the matter of legs, those of some species, the Elephant-footed Moa, Pachyornis elephantopus, for example, being so massively built as to cause one to wonder what the owner used them for, although the generally accepted theory is that they were used for scratching up the roots of ferns on which the Moas are believed to have fed. And if a blow from an irate ostrich is sufficient to fell a man, what must have been the kicking power of an able-bodied Moa? Beside this bird the ostrich would appear as slim and graceful as a gazelle beside a prize ox.

[10] The height of the Moas, and even of some species of Æpyornis, is often stated to be twelve or fourteen feet, but such a height can only be obtained by placing the skeleton in a wholly unnatural attitude.

The Moas were confined to New Zealand, some species inhabiting the North Island, some the South, very few being common to both, and from these peculiarities of distribution geologists deduce that at some early period in the history of the earth the two islands formed one, that later on the land subsided, leaving the islands separated by a strait, and that since this subsidence there has been sufficient time for the development of the species peculiar to each island. Although Moas were still numerous when man made his appearance in this part of the world, the large deposits of their bones indicate that they were on the wane, and that natural causes had already reduced the feathered population of these islands. A glacial period is believed to have wrought their destruction, and in one great morass, abounding in springs, their bones occur in such enormous numbers, layer upon layer, that it is thought the birds sought the place where the flowing springs might afford their feet at least some respite from the biting cold, and there perished miserably by thousands.

What Nature spared man finished, and legends of Moa hunts and Moa feasts still lingered among the Maoris when the white man came and began in turn the extermination of the Maori. The theory has been advanced, with much to support it, that the big birds were eaten off the face of the earth by an earlier race than the Maoris, and that after the extirpation of the Moas the craving for flesh naturally led to cannibalism. But by whomsoever the destruction was wrought, the result was the same, the habitat of these feathered giants knew them no longer, while multitudes of charred bones, interspersed with fragments of egg-shells, bear testimony to former barbaric feasts.

It is a far cry from New Zealand to Madagascar, but thither must we go, for that island was, pity we cannot say is, inhabited by a race of giant birds from whose eggs it has been thought may have been hatched the Roc of Sindbad. Arabian tales, as we all know, locate the Roc either in Madagascar or in some adjacent island to the north and east, and it is far from unlikely that legends of the Æpyornis, backed by the substantial proof of its enormous eggs, may have been the slight foundation of fact whereon the story-teller erected his structure of fiction. True, the Roc of fable was a gigantic bird of prey capable of bearing away an elephant in its talons, while the Æpyornis has shed its wings and shrunk to dimensions little larger than an ostrich, but this is the inevitable result of closer acquaintance and the application of a two-foot rule.

Like the Moa the Æpyornis seems to have lived in tradition long after it became extinct, for a French history of Madagascar, published as early as 1658 makes mention of a large bird, or kind of ostrich, said to inhabit the southern end of the island. Still, in spite of bones having been found that bear evident traces of the handiwork of man, it is possible that this and other reports were due to the obvious necessity of having some bird to account for the presence of the eggs.

The actual introduction of the Æpyornis to science took place in 1834, when a French traveller sent Jules Verreaux, the ornithologist, a sketch of a huge egg, saying that he had seen two of that size, one sawed in twain to make bowls, the other, traversed by a stick, serving in the preparation of rice uses somewhat in contrast with the proverbial fragility of egg-shells. A little later another traveller procured some fragments of egg-shells, but it was not until 1851 that any entire eggs were obtained, when two were secured, and with a few bones sent to France, where Geoffroy St. Hilaire bestowed upon them the name of Æpyornis maximus (the greatest lofty bird). Maximus the eggs remain, for they still hold the record for size; but so far as the bird that is supposed to have laid them is concerned, the name was a little premature, for other and larger species subsequently came to hand. Between the Æpyornithes and the Moas Science has had a hard time, for the supply of big words was not large enough to go around, and some had to do duty twice. In the way of generic names we have Dinornis, terrible bird; Æpyornis, high bird; Pachyornis, stout bird; and Brontornis, thunder bird, while for specific names there are robustus, maximus, titan; gravis, heavy; immanis, enormous; crassus, stout; ingens, great; and elephantopus, elephant-footed—truly a goodly array of large-sounding words. But to return to the big eggs! Usually we look upon those of the ostrich as pretty large, but an ostrich egg measures 4-1/2 by 6 inches, while that of the Æpyornis is 9 by 13 inches; or, to put it another way, it would hold the contents of six ostrichs' eggs, or one hundred and forty-eight hens' eggs, or thirty thousand humming birds' eggs; and while this is very much smaller than a waterbutt, it is still as large as a bucket, and one or two such eggs might suffice to make an omelet for Gargantua himself.

The size of an egg is no safe criterion of the size of the bird that laid it, for a large bird may lay a small egg, or a small bird a large one. Comparing the egg of the great Moa with that of our Æpyornis one might think the latter much the larger bird, say twelve feet in height, when the facts in the case are that while there was no great difference in the weight of the two, that difference, and a superiority of at least two feet in height, are in favor of the bird that laid the smaller egg. The record of large eggs, however, belongs to the Apteryx, a New Zealand bird smaller than a hen, though distantly related to the Moas, which lays an egg about one-third of its own weight, measuring 3 by 5 inches; perhaps it is not to be wondered at that the bird lays but two.

Although most of the eggs of these big birds that have been found have literally been unearthed from the muck of swamps, now and then one comes to light in a more interesting manner as, for example, when a perfect egg of Æpyornis was found afloat after a hurricane, bobbing serenely up and down with the waves near St. Augustine's Bay, or when an egg of the Moa was exhumed from an ancient Maori grave, where for years it had lain unharmed, safely clasped between the skeleton fingers of the occupant. So far very few of these huge eggs have made their way to this country, and the only egg of Æpyornis now on this side of the water is the property of a private individual.

Most recent in point of discovery, but oldest in point of time, are the giant birds from Patagonia, which are burdened with the name of Phororhacidæ, a name that originated in an error, although the error may well be excused. The first fragment of one of these great birds to come to light was a portion of the lower jaw, and this was so massive, so un-bird-like, that the finder dubbed it Phororhacos, and so it must remain.

Fig. 29.—Eggs of Feathered Giants, Æpyornis, Ostrich, Moa, Compared with a Hen's Egg.

It is a pity that all the large names were used up before this group of birds was discovered, and it is particularly unfortunate that Dinornis, terrible bird, was applied to the root-eating Moas, for these Patagonian birds, with their massive limbs, huge heads and hooked beaks, were truly worthy of such a name; and although in nowise related to the eagles, they may in habit have been terrestrial birds of prey. Not all the members of this family are giants, for as in other groups, some are big and some little, but the largest among them might be styled the Daniel Lambert of the feathered race. Brontornis, for example, the thunder bird, or as the irreverent translate it, the thundering big bird, had leg-bones larger than those of an ox, the drumstick measuring 30 inches in length by 2-1/2 inches in diameter, or 4-1/4 inches across the ends, while the tarsus, or lower bone of the leg to which the toes are attached, was 16-1/2 inches long and 5-1/2 inches wide where the toes join on. Bear this in mind the next time you see a large turkey, or compare these bones with those of an ostrich: but lest you may forget, it may be said that the same bone of a fourteen-pound turkey is 5-1/2 inches long, and one inch wide at either end, while that of an ostrich measures 19 inches long and 2 inches across the toes, or 3 at the upper end.

If Brontornis was a heavy-limbed bird, he was not without near rivals among the Moas, while the great Phororhacos, one of his contemporaries, was not only nearly as large, but quite unique in build. Imagine a bird seven or eight feet in height from the sole of his big, sharp-clawed feet, to the top of his huge head, poise this head on a neck as thick as that of a horse, arm it with a beak as sharp as an icepick and almost as formidable, and you have a fair idea of this feathered giant of the ancient pampas. The head indeed was truly colossal for that of a bird, measuring 23 inches in length by 7 in depth, while that of the racehorse Lexington, and he was a good-sized horse, measures 22 inches long by 5-1/2 inches deep. The depth of the jaw is omitted because we wish to make as good a case as possible for the bird, and the jaw of a horse is so deep as to give him an undue advantage in that respect.

Fig. 30.—Skull of Phororhacos Compared with that of the Race-horse Lexington.

We can only speculate on the food of these great birds, and for aught we know to the contrary they may have caught fish, fed upon carrion, or used their powerful feet and huge beaks for grubbing roots; but if they were not more or less carnivorous, preying upon such reptiles, mammals and other birds as came within reach, then nature apparently made a mistake in giving them such a formidable equipment of beak and claw. So far as habits go we might be justified in calling them cursorial birds of prey.

Fig. 31.—Leg of a Horse Compared with that of the Giant Moa.

We really know very little about these Patagonian giants, but they are interesting not only from their great size and astounding skulls, but because of the early age (Miocene) at which they lived and because in spite of their bulk they are in nowise related to the ostriches, but belong near the heron family. As usual, we have no idea why they became extinct, but in this instance man is guiltless, for they lived and died long before he made his appearance, and the ever-convenient hypothesis "change of climate" may be responsible for their disappearance.

Something, perhaps, remains to be said concerning the causes which seem to have led to the development of these giant birds, as well as the reasons for their flightless condition and peculiar distribution, for it will be noticed that, with the exception of the African and South American ostriches the great flightless birds as a rule are, and were, confined to uninhabited or sparsely populated islands, and this is equally true of the many small, but equally flightless birds. It is a seemingly harsh law of nature that all living beings shall live in a more or less active struggle with each other and with their surroundings, and that those creatures which possess some slight advantage over their fellows in the matter of speed, or strength, or ability to adapt themselves to surrounding conditions, shall prosper at the expense of the others. In the power of flight, birds have a great safeguard against changes of climate with their accompanying variations in the supply of food, and, to a lesser extent, against their various enemies, including man. This power of flight, acquired early in their geological history, has enabled birds to spread over the length and breadth of the globe as no other group of animals has done, and to thrive under the most varying conditions, and it would seem that if this power were lost it must sooner or later work harm. Now to-day we find no great wingless birds in thickly populated regions, or where beasts of prey abound; the ostriches roam the desert wastes of Arabia, Africa and South America where men are few and savage beasts scarce, and against these is placed a fleetness of foot inherited from ancestors who acquired it before man was. The heavy cassowaries dwell in the thinly inhabited, thickly wooded islands of Malaysia, where again there are no large carnivores and where the dense vegetation is some safeguard against man; the emu comes from the Australian plains, where also there are no four-footed enemies[11] and where his ancestors dwelt in peace before the advent of man. And the same things are true of the Moas, the Æpyornithes, the flightless birds of Patagonia, the recent dodo of Mauritius and the solitaire of Rodriguez, each and all of which flourished in places where there were no men and practically no other enemies. Hence we deduce that absence of enemies is the prime factor in the existence of flightless birds,[12] although presence of food is an essential, while isolation, or restriction to a limited area, plays an important part by keeping together those birds, or that race of birds, whose members show a tendency to disuse their wings. It will be seen that such combinations of circumstances will most naturally be found on islands whose geological history is such that they have had no connection with adjacent continents, or such a very ancient connection that they were not then peopled with beasts of prey, while subsequently their distance from other countries has prevented them from receiving such population by accident in recent times and has also retarded the arrival of man.

[11] The dingo, or native dog, is not forgotten, but, like man, it is a comparatively recent animal.

[12] Note that in Tasmania, which is very near Australia, both in space and in the character of its animals, there are two carnivorous mammals, the Tasmanian "Wolf" and the Tasmanian Devil, and no flightless birds.

Once established, flightlessness and size play into one another's hands; the flightless bird has no limit placed on its size[13] while granted a food supply and immunity from man; the larger the bird the less the necessity for wings to escape from four-footed foes. So long as the climate was favorable and man absent, the big, clumsy bird might thrive, but upon the coming of man, or in the face of any unfavorable change of climate, he would be at a serious disadvantage and hence whenever either of these two factors has been brought to bear against them the feathered giants have vanished.

[13] While we do not know the limit of size to a flying creature, none has as yet been found whose wings would spread over twenty feet from tip to tip, and it is evident that wings larger than this would demand great strength for their manipulation.

REFERENCES

There is a fine collection of mounted skeletons of various species of Moas in the Museum of Comparative Zoology at Cambridge, Mass., and another in the American Museum of Natural History, New York. A few other skeletons and numerous bones are to be found in other institutions, but the author is not aware of any egg being in this country. Specimens of the Æpyornis are rare in this country, but Mr. Robert Gilfort, of Orange, N.J., is the possessor of a very fine egg. A number of eggs have been sold in London, the prices ranging from £200 down to £42, this last being much less than prices paid for eggs of the great auk. But then, the great auk is somewhat of a fad, and there are just enough eggs in existence to bring one into the market every little while. Besides, the number of eggs of the great auk is a fixed quantity, while no one knows how many more of Æpyornis remain to be discovered in the swamps of Madagascar. No specimens of the gigantic Patagonian birds are now in this country, but a fine example of one of the smaller forms, Pelycornis, including the only breast-bone yet found, is in the Museum of Princeton University.

The largest known tibia of a Moa, the longest bird-bone known, is in the collection of the Canterbury Museum, Christchurch, New Zealand; it is 3 feet 3 inches long. This, however, is exceptional, the measurements of the leg-bones of an ordinary Dinornis maximus being as follows: Femur, 18 inches; tibia, 32 inches; tarsus, 19 inches, a total of 5 feet 9 inches. The egg measures 10-1/2 by 6-1/2 inches.

There is plenty of literature, and very interesting literature, about the Moas, but, unfortunately, the best of it is not always accessible, being contained in the "New Zealand Journal of Science" and the "Transactions of the New Zealand Institute." The volume of "Transactions" for 1893, being vol. xxvi., contains a very full list of articles relating to the Moas, compiled by Mr. A. Hamilton; it will be found to commence on page 229. There is a good article on Moa in Newton's "Dictionary of Birds," a book that should be in every library.

Fig. 32.—The Three Giants, Phororhacos, Moa, Ostrich.

IX

THE ANCESTRY OF THE HORSE

"Said the little Eohippus
I am going to be a horse
And on my middle finger-nails
To run my earthly course."

The American whose ancestors came over in the "Mayflower" has a proper pride in the length of the line of his descent. The Englishman whose genealogical tree sprang up at the time of William the Conqueror has, in its eight centuries of growth, still larger occasion for pluming himself on the antiquity of his family. But the pedigree of even the latter is a thing of yesterday when compared with that of the horse, whose family records, according to Professor Osborn, reach backward for something like 2,000,000 years. And if, as we have been told, "it is a good thing to have ancestors, but sometimes a little hard on the ancestor," in this instance at least the founders of the family have every reason to regard their descendants with undisguised pride. For the horse family started in life in a small way, and the first of the line, the Hyracotherium, was "a little animal no bigger than a fox, and on five[14] toes he scampered over Tertiary rocks," in the age called Eocene, because it was the morning of life for the great group of mammals whose culminating point was man. At that time, western North America was a country of many lakes, for the most part comparatively shallow, around the reedy margins of which moved a host of animals, quite unlike those of to-day, and yet foreshadowing them, the forerunners of the rhinoceros, tapir, and the horse.

[14] Four, to be exact; but we prefer to sacrifice the foot of the Hyracothere rather than to take liberties with one of the feet of Mrs. Stetson's poem.

The early horse—we may call him so by courtesy, although he was then very far from being a true horse—was an insignificant little creature, apparently far less likely to succeed in life's race than his bulky competitors, and yet, by making the most of their opportunities, his descendants have survived, while most of theirs have dropped by the wayside; and finally, by the aid of man, the horse has become spread over the length and breadth of the habitable globe.

Fig. 33.—Skeleton of the Modern Horse and of His Eocene Ancestor.

Now right here it may be asked, How do we know that the little Hyracothere was the progenitor of the horse, and how can it be shown that there is any bond of kinship between him and, for example, the great French Percheron? There is only one way in which we can obtain this knowledge, and but one method by which the relationship can be shown, and that is by collecting the fossil remains of animals long extinct and comparing them with the bones of the recent horse, a branch of science known as Palæontology. It has taken a very long time to gather the necessary evidence, and it has taken a vast amount of hard work in our western Territories, for "the country that is as hot as Hades, watered by stagnant alkali pools, is almost invariably the richest in fossils." Likewise it has called for the expenditure of much time and more patience to put together some of this petrified evidence, fragmentary in every sense of the word, and get it into such shape that it could be handled by the anatomist. Still, the work has been done, and, link by link, the chain has been constructed that unites the horse of to-day with the horse of very many yesterdays.

The very first links in this chain are the remains of the bronze age and those found among the ruins of the ancient Swiss lake dwellings; but earlier still than these are the bones of horses found abundantly in northern Europe, Asia, and America. The individual bones and teeth of some of these horses are scarcely distinguishable from those of to-day, a fact noted in the name, Equus fraternus, applied to one species; and when teeth alone are found, it is at times practically impossible to say whether they belong to a fossil horse or to a modern animal. But when enough scattered bones are gathered to make a fairly complete skeleton, it becomes evident that the fossil horse had a proportionately larger head and smaller feet than his existing relative, and that he was a little more like an ass or zebra, for the latter, spite of his gay coat, is a near relative of the lowly ass. Moreover, primitive man made sketches of the primitive horse, just as he did of the mammoth, and these indicate that the horse of those days was something like an overgrown Shetland pony, low and heavily built, large-headed and rough-coated. For the old cave-dwellers of Europe were intimately acquainted with the prehistoric horses, using them for food, as they did almost every animal that fell beneath their flint arrows and stone axes. And if one may judge from the abundance of bones, the horses must have roamed about in bands, just as the horses escaped from civilization roam, or have roamed, over the pampas of South America and the prairies of the West.

The horse was just as abundant in North America in Pleistocene time as in Europe; but there is no evidence to show that it was contemporary with early man in North America, and, even were this the case, it is generally believed that long before the discovery of America the horse had disappeared. And yet, so plentiful and so fresh are his remains, and so much like those of the mustang, that the late Professor Cope was wont to say that it almost seemed as if the horse might have lingered in Texas until the coming of the white man. And Sir William Flower wrote: "There is a possibility of the animal having still existed, in a wild state, in some parts of the continent remote from that which was first visited by the Spaniards, where they were certainly unknown. It has been suggested that the horses which were found by Cabot in La Plata in 1530 cannot have been introduced."

Still we have not the least little bit of positive proof that such was the case, and although the site of many an ancient Indian village has been carefully explored, no bones of the horse have come to light, or if they have been found, bones of the ox or sheep were also present to tell that the village was occupied long after the advent of the whites. It is also a curious fact that within historic times there have been no wild horses, in the true sense of the word, unless indeed those found on the steppes north of the Sea of Azof be wild, and this is very doubtful. But long before the dawn of history the horse was domesticated in Europe, and Cæsar found the Germans, and even the old Britons, using war chariots drawn by horses—for the first use man seems to have made of the horse was to aid him in killing off his fellow-man, and not until comparatively modern times was the animal employed in the peaceful arts of agriculture. The immediate predecessors of these horses were considerably smaller, being about the size and build of a pony, but they were very much like a horse in structure, save that the teeth were shorter. As they lived during Pliocene times, they have been named "Pliohippus."

Going back into the past a step farther, though a pretty long step if we reckon by years, we come upon a number of animals very much like horses, save for certain cranial peculiarities and the fact that they had three toes on each foot, while the horse, as every one knows, has but one toe. Now, if we glance at the skeleton of a horse, we will see on either side of the canon-bone, in the same situation as the upper part of the little toes of the Hippotherium, as these three-toed horses are called, a long slender bone, termed by veterinarians the splint bone; and it requires no anatomical training to see that the bones in the two animals are the same. The horse lacks the lower part of his side toes, that is all, just as man will very probably some day lack the last bones of his little toe. We find an approach to this condition in some of the Hippotheres even, known as Protohippus, in which the side toes are quite small, foreshadowing the time when they shall have disappeared entirely. It may also be noted here that the splint bones of the horses of the bronze age are a little longer than those of existing horses, and that they are never united with the large central toe, while nowadays there is something of a tendency for the three bones to fuse into one, although part of this tendency the writer believes to be due to inflammation set up by the strain of the pulling and hauling the animal is now called upon to do. Some of these three-toed Hippotheres are not in the direct line of ancestry of the horse, but are side branches on the family tree, having become so highly specialized in certain directions that no further progress horseward was possible.

Backward still, and the bones we find in the Miocene strata of the West, belonging to those ancestors of the horse to which the name of Mesohippus has been given because they are midway in time and structure between the horse of the past and present, tell us that then all horses were small and that all had three toes on a foot, while the fore feet bore even the suggestion of a fourth toe. From this to our Eocene Hyracothere with four toes is only another long-time step. We may go even beyond this in time and structure, and carry back the line of the horse to animals which only remotely resembled him and had five good toes to a foot; but while these contained the possibility of a horse, they made no show of it.

Fig. 34.—The Development of the Horse.

Increase in size and decrease in number of the toes were not the only changes that were required to transform the progeny of the Hyracothere into a horse. These are the most evident; but the increased complexity in the structure of the teeth was quite as important. The teeth of gnawing animals have often been compared to a chisel which is made of a steel plate with soft iron backing, and the teeth of a horse, or of other grass-eating animals, are simply an elaboration of this idea. The hard enamel, which represents the steel, is set in soft dentine, which represents the iron, and in use the dentine wears away the faster of the two, so that the enamel stands up in ridges, each tooth becoming, as it is correctly termed, "a grinder." In a horse the plates of enamel form curved, complex, irregular patterns; but as we go back in time, the patterns become less and less elaborate, until in the Hyracothere, standing at the foot of the family tree, the teeth are very simple in structure. Moreover, his teeth were of limited growth, while those of the horse grow for a considerable time, thus compensating for the wear to which they are subjected.

We have, then, this direct evidence as to the genealogy of the horse, that between the little Eocene Hyracothere and the modern horse we can place a series of animals by which we can pass by gradual stages from one to the other, and that as we come upward there is an increase in stature, in the complexity of the teeth, and in the size of the brain. At the same time, the number of toes decreases, which tells that the animals were developing more and more speed; for it is a rule that the fewer the toes the faster the animal: the fastest of birds, the ostrich, has but two toes, and one of these is mostly ornamental; and the fastest of mammals, the horse, has but one.

All breeders of fancy stock, particularly of pigeons and poultry, recognize the tendency of animals to revert to the forms whence they were derived and reproduce some character of a distant ancestor; to "throw back," as the breeders term it. If now, instead of reproducing a trait or feature possessed by some ancestor a score, a hundred, or perhaps a thousand years ago, there should reappear a characteristic of some ancestor that flourished 100,000 years back, we should have a seeming abnormality, but really a case of reversion; and the more we become acquainted with the structure of extinct animals and the development of those now living, the better able are we to explain these apparent abnormalities.

Bearing in mind that the two splint bones of the horse correspond to the upper portions of the side toes of the Hippotherium and Mesohippus, it is easy to see that if for any reason these should develop into toes, they would make the foot of a modern horse appear like that of his distant ancestor. While such a thing rarely happens, yet now and then nature apparently does attempt to reproduce a horse's foot after the ancient pattern, for occasionally we meet with a horse having, instead of the single toe with which the average horse is satisfied, one or possibly two extra toes. Sometimes the toe is extra in every sense of the word, being a mere duplication of the central toe; but sometimes it is an actual development of one of the splint bones. No less a personage than Julius Cæsar possessed one of these polydactyl horses, and the reporters of the Daily Roman and the Tiberian Gazette doubtless wrote it up in good journalistic Latin, for we find the horse described as having feet that were almost human, and as being looked upon with great awe. While this is the most celebrated of extra-toed horses, other and more plebeian individuals have been much more widely known through having been exhibited throughout the country under such titles as "Clique, the horse with six feet," "the eight-footed Cuban horse," and so on; and possibly some of these are familiar to readers of this page.

So the collateral evidence, though scanty, bears out the circumstantial proof, derived from fossil bones, that the horse has developed from a many-toed ancestor; and the evidence points toward the little Hyracothere as being that ancestor. It remains only to show some good reason why this development should have taken place, or to indicate the forces by which it was brought about. We have heard much about "the survival of the fittest," a phrase which simply means that those animals best adapted to their surroundings will survive, while those ill adapted will perish. But it should be added that it means also that the animals must be able to adapt themselves to changes in their environment, or to change with it. Living beings cannot stand still indefinitely; they must progress or perish. And this seems to have been the cause for the extinction of the huge quadrupeds that flourished at the time of the three-toed Miocene horse. They were adapted to their environment as it was; but when the western mountains were thrust upward, cutting off the moist winds from the Pacific, making great changes in the rainfall and climate to the eastward of the Rocky Mountains, these big beasts, slow of foot and dull of brain, could not keep pace with the change, and their race vanished from the face of the earth. The day of the little Hyracothere was at the beginning of the great series of changes by which the lake country of the West, with its marshy flats and rank vegetation, became transformed into dry uplands sparsely clad with fine grasses. On these dry plains the more nimble-footed animals would have the advantage in the struggle for existence; and while the four-toed foot would keep its owner from sinking in soft ground, he was handicapped when it became a question of speed, for not only is a fleet animal better able to flee from danger than his slower fellows, but in time of drouth he can cover the greater extent of territory in search of food or water. So, too, as the rank rushes gave place to fine grasses, often browned and withered beneath the summer's sun, the complex tooth had an advantage over that of simpler structure, while the cutting-teeth, so completely developed in the horse family, enabled their possessors to crop the grass as closely as one could do it with scissors. Likewise, up to a certain point, the largest, most powerful animal will not only conquer, or escape from, his enemies, but prevail over rivals of his own kind as well, and thus it came to pass that those early members of the horse family who were preëminent in speed and stature, and harmonized best with their surroundings, outstripped their fellows and transmitted these qualities to their progeny, until, as a result of long ages of natural selection, there was developed the modern horse. The rest man has done: the heavy, slow-paced dray horse, the fleet trotter, the huge Percheron, and the diminutive pony are one and all the recent products of artificial selection.

REFERENCES

The best collection of fossil horses, and one specially arranged to illustrate the line of descent of the modern horse, is to be found in the American Museum of Natural History, New York, but some good specimens, of particular interest because they were described by Professor Marsh and studied by Huxley are in the Yale University Museum. They are referred to in Huxley's "American Addresses; Lectures on Evolution." "The Horse," by Sir W. H. Flower, discusses the horse in a popular manner from various points of view and contains numerous references to books and articles on the subject from which anyone wishing for further information could obtain it.

Fig. 35.—The Mammoth.
From a drawing by Charles R. Knight.

X

THE MAMMOTH

"His legs were as thick as the bole of the beech,
His tusks as the buttonwood white,
While his lithe trunk wound like a sapling around
An oak in the whirlwind's might."

In the October number of McClure's Magazine for 1899 was published a short story, "The Killing of the Mammoth," by "H. Tukeman," which, to the amazement of the editors, was taken by many readers not as fiction, but as a contribution to natural history. Immediately after the appearance of that number of the magazine, the authorities of the Smithsonian Institution, in which the author had located the remains of the beast of his fancy, were beset with visitors to see the stuffed mammoth, and the daily mail of the Magazine, as well as that of the Smithsonian Institution, was filled with inquiries for more information and for requests to settle wagers as to whether it was a true story or not. The contribution in question was printed purely as fiction, with no idea of misleading the public, and was entitled a story in the table of contents. We doubt if any writer of realistic fiction ever had a more general and convincing proof of success.

About three centuries ago, in 1696, a Russian, one Ludloff by name, described some bones belonging to what the Tartars called "Mamantu"; later on, Blumenbach pressed the common name into scientific use as "Mammut," and Cuvier gallicized this into "Mammouth," whence by an easy transition we get our familiar mammoth. We are so accustomed to use the word to describe anything of remarkable size that it would be only natural to suppose that the name Mammoth was given to the extinct elephant because of its extraordinary bulk. Exactly the reverse of this is true, however, for the word came to have its present meaning because the original possessor of the name was a huge animal. The Siberian peasants called the creature "Mamantu," or "ground-dweller," because they believed it to be a gigantic mole, passing its life beneath the ground and perishing when by any accident it saw the light. The reasoning that led to this belief was very simple and the logic very good; no one had ever seen a live Mamantu, but there were plenty of its bones lying at or near the surface; consequently if the animal did not live above the ground, it must dwell below.

To-day, nearly every one knows that the mammoth was a sort of big, hairy elephant, now extinct, and nearly every one has a general idea that it lived in the North. There is some uncertainty as to whether the mammoth was a mastodon, or the mastodon a mammoth, and there is a great deal of misconception as to the size and abundance of this big beast. It may be said in passing that the mastodon is only a second or third cousin of the mammoth, but that the existing elephant of Asia is a very near relative, certainly as near as a first cousin, possibly a very great grandson. Popularly, the mammoth is supposed to have been a colossus somewhere from twelve to twenty feet in height, beside whom modern elephants would seem insignificant; but as "trout lose much in dressing," so mammoths shrink in measuring, and while there were doubtless Jumbos among them in the way of individuals of exceptional magnitude, the majority were decidedly under Jumbo's size. The only mounted mammoth skeleton in this country, that in the Chicago Academy of Sciences, is one of the largest, the thigh-bone measuring five feet one inch in length, or a foot more than that of Jumbo; and as Jumbo stood eleven feet high, the rule of three applied to this thigh-bone would give the living animal a height of thirteen feet eight inches. The height of this specimen is given as thirteen feet in its bones, with an estimate of fourteen feet in its clothes; but as the skeleton is obviously mounted altogether too high, it is pretty safe to say that thirteen feet is a good, fair allowance for the height of this animal when alive. As for the majority of mammoths, they would not average more than nine or ten feet high. Sir Samuel Baker tells us that he has seen plenty of wild African elephants that would exceed Jumbo by a foot or more, and while this must be accepted with caution, since unfortunately he neglected to put a tape-line on them, yet Mr. Thomas Baines did measure a specimen twelve feet high. This, coupled with Sir Samuel's statement, indicates that there is not so much difference between the mammoth and the elephant as there might be. This applies to the mammoth par excellence, the species known scientifically as Elephas primigenius, whose remains are found in many parts of the Northern Hemisphere and occur abundantly in Siberia and Alaska. There were other elephants than the mammoth, and some that exceeded him in size, notably Elephas meridionalis of southern Europe, and Elephas columbi of our Southern and Western States, but even the largest cannot positively be asserted to have exceeded a height of thirteen feet. Tusks offer convenient terms of comparison, and those of an average fully grown mammoth are from eight to ten feet in length; those of the famous St. Petersburg specimen and those of the huge specimen in Chicago measuring respectively nine feet three inches, and nine feet eight inches. So far as the writer is aware, the largest tusks actually measured are two from Alaska, one twelve feet ten inches long, weighing 190 pounds, reported by Mr. Jay Beach; and another eleven feet long, weighing 200 pounds, noted by Mr. T. L. Brevig. Compared with these we have the big tusk that used to stand on Fulton Street, New York, just an inch under nine feet long, and weighing 184 pounds, or the largest shown at Chicago in 1893, which was seven feet six inches long, and weighed 176 pounds. The largest, most beautiful tusks, probably, ever seen in this country were a pair brought from Zanzibar and displayed by Messrs. Tiffany & Company in 1900. The measurements and weights of these were as follows: length along outer curve, ten feet and three-fourths of an inch, circumference one foot, eleven inches, weight, 224 pounds; length along outer curve, ten feet, three and one-half inches, circumference two feet and one-fourth of an inch, weight, 239 pounds.

For our knowledge of the external appearance of the mammoth we are indebted to the more or less entire examples which have been found at various times in Siberia, but mainly to the noted specimen found in 1799 near the Lena, embedded in the ice, where it had been reposing, so geologists tell us, anywhere from 10,000 to 50,000 years. How the creature gradually thawed out of its icy tomb, and the tusks were taken by the discoverer and sold for ivory; how the dogs fed upon the flesh in summer, while bears and wolves feasted upon it in winter; how the animal was within an ace of being utterly lost to science when, at the last moment, the mutilated remains were rescued by Mr. Adams, is an old story, often told and retold. Suffice it to say that, besides the bones, enough of the beast was preserved to tell us exactly what was the covering of this ancient elephant, and to show that it was a creature adapted to withstand the northern cold and fitted for living on the branches of the birch and hemlock.