Part Il. THE HORSE UNDER DOMESTICATION ITS ORIGIN AND THE STRUCTURE AND GROWTH OF THE TEETH By S. H. Chubb HEN animals are living under perfectly natural conditions, \ \) their physical structure is slowly modified by climate, topography of habitats and food supply as well as by many other forces. In the struggle for self-preservation among the competitors by which they are surrounded, they develop weapons of defence, or acquire speed mechanism or other means of escape. Thus what we may call _natural, as opposed to artificial evolution, is controlled by a great variety of forces, while in a condition of domestication we have development directed in certain lines by man’s intelligence.
ORIGIN OF THE DOMESTIC HORSE Ewart, there seems to be little doubt that the domestic horse has been derived from several wild types which have since become extinct as wild species. Of two at least we may be reasonably sure: one of Europe or northwestern Asia, which has been called the Norseman’s horse; the other from northern Africa, which Professor Ridgeway has called Equus libycus.
There is abundant evidence to prove that in the late Quaternary, during and after the Glacial Period, but nevertheless many thousands of years ago, prehistoric man chased and killed wild horses, using their flesh for food and possibly their skins for raiment. This period was followed by a second, during which wild horses were captured, broken to rude harness and driven. The rearing action of the horse skeleton in the group on exhibition in the Museum (Frontispiece) is designed to express unwilling subjection, and the position of the man, as if holding a bridle, intellectual control. The period of domestication passed insensibly into a third, that of artificial development, during which the horse was modified, and is still being modified in various directions.
Under man’s protection and management, changes are brought about in domestic animals with considerable control and much more rapidly than under perfectly natural conditions. Through training and careful selection in breeding, speed has been greatly increased in the race horse, weight and strength have been developed in the draft horse, while the Shetland pony has been reduced to a most diminutive size. eB the light of researches made by Professors Ridgeway, Osborn and 39
Fig. 26. The draft horse pulling a heavy load. Gift of the late William C. Whitney. The sul ject from which the ske'eton was prepared was presented by Mr. George Ehret oi.
{ Aodersen Fhote ey Fig. 27. Arabian stallion ‘*Nimr.” Mounted in the position of watching a herd. Sul ject presented by Mr. Randolph Huntington 10
THE HORSE UNDER DOMESTICATION a The intimate relations which have thus existed between the horse and man have influenced both, and it is generally acknowledged by students of mankind that the subjugation of the horse and his adoption, both as a means of transportation and as an aid in agriculture, have been factors of the greatest importance in the later development of the human race.
COMPARISON OF THE SKELETON OF HORSE AND MAN HILE considering these two skeletons (Frontispiece), it will be worth while to look for a moment into their structure. They areso placed as to facilitate comparison. The one representing a typical or average type of horse, the other a man of about six feet in height and proportionately heavy. The limbs of the horse, moving only forward and backward, have much less freedom of motion than have those of man. Note the ball-and-socket joint of man at the shoulder and hip, the rotary motion of the forearm and the flexibility at the wrist and ankle, and compare with the restricted movement at the shoulder of the horse, the hingelike joint at the elbow, and the limited movement at the wrist (knee) and ankle (hock). The most pronounced differences however, are found in the head and feet. Compare the skull of man, which has an enormously developed brain and reduced facial portion, with that of the horse which has a comparatively small brain, the face, mouth, and teeth monopolizing almost the whole skull. The feet, instead of having five toes as in man, are reduced to a single digit! and they are very much elongated as a speed specialization. And yet a careful study will reveal a most striking similarity between the two subjects in general structure, the differences being simply modifications of a common plan. THE DRAFT HORSE HE Norseman’s horse of Europe seems to have been an animal with large head, convex forehead and rough coat, of rather clumsy appearance, and of little speed. It may have been a near relative of the Przewalsky horse which still lives as a wild species in northwestern Mongolia, the only true wild horse known at the present time. Among other evidences of this prehistoric type, are the many sketches found in the south of France and elsewhere, made by the very primitive cave-dwellers, which seem clearly to depict this type of horse, and it is no doubt this strain which predominates in our heavy draft horse of to-day although of course this horse has been greatly increased in size and strength by long and careful breeding.
iSee page 22.
Fig. 28. The draft horse. Rear view showingactionofpelvisandbackbone AMERICAN MUSEUM GUIDE LEAFLETS An attempt has been made to express the strength acquired in this breed in the mounted skeleton of the draft horse (Fig. 26). This skeleton has been so mounted as to show the action of the bones when the animal is drawing a heavy load. We must imagine that the shoulders rest against a collar upon which the horse is exerting its energy. Note that the head and body are lowered, the hind legs are doing the greater amount of work, the fore legs acting as supports, though a portion of the weight of the body has been thrown against the collar. From the rear view (Fig. 28) note that the right hip joint is much nearer the median line than is the left. The joint is also lower, and indeed, the entire right side of the pelvis has been lowered and thrown well to the left, so that when at the moment of greatest strain the right leg is extended, the pressure upon the anterior part of the body, and thence upon the collar, is applied in a line which coincides with the main axis of the body. At the next moment the left leg is supposed to be exerted, the right is released, the pelvis then swings to the right, the curve in the backbone becomes reversed and the pressure is again applied (this time from the left) along the main axis of the body as before; and so on from step to step.
~ DEVELOPMENT OF GREAT SIZE IN THE DRAFT HORSE HE skeleton of a very large draft horse is exhibited to show*the extreme development of size in this breed. It has been photographed with the skeleton of a Shetland pony to show two extremes in domestic horses (Fig. 25). The following is a table of measurements of the two specimens.
GIANT Drarr Horse SHETLAND PONY Height at shoulders............. 6 ft. 1 in. (18% hands) 2 ft. 9° in. (84 hands) . ENG PSone le ne iors eT cL 2370 Ibs. 170 lbs.
REE MIE TIINOBUN c & ke Aig ic Ok bs ke ls 118%4 cu. in. 916 cu. in. USI aa? a an 188 cu. in. 1345 cu. in.
The pose chosen for the mounting of this specimen is one of inaction, designed to express quiet restfulness, in contrast to the running action of the race horse, to be mentioned later. It shows also a habit peculiar to horses, that of alternately resting the hind legs. Almost the entire weight of the hind quarters is supported on the extended left leg, while the right hind leg rests in a more flexed position and hangs perfectly lax. -The pelvis also seems to hang, as it were, from the left hip joint, tilting very much to the right and slightly twisting the vertebral column. A peculiar function of the patella (kneecap) in the horse is shown in the left knee joint or stifle. While the limb is extended and supports the animal’s weight, the patella rests on a projecting articulation of the femur, so that the knee is locked in an extended positicn by avery strong ligament which holds the patella at a fixed distance from the tibia below, thus sustaining the weight required of it with comparatively little muscular exertion.
An abnormal peculiarity of this specimen is a_pair of supernumerary molar teeth, which appear at the posterior end of the upper set. Having no opposing teeth in the lower Jaw upon which to wear, they have protruded down into the gum and must have caused the animal considerable discomfort.
THE SHETLAND PONY Tis highly probable that the Shetland pony is derived from practically the same wild stock as the very much larger draft horse, but has been reduced in size by adverse conditions to which it was subjected in the cold and barren Shetland Islands with their limited area, and also by having been systematically bred for the smallest possible size. Figure 25 shows the skeleton of an exceptionally small pony which was secured through the Whitney fund. This pony was bred in Scotland and obtained through the kindness of Professor J. C. Ewart of the University of Edinburgh. The skeleton represents the grazing action. It 43
tt AMERICAN MUSEUM GUIDE LEAFLETS will be seen that the downward reach of the head and the slow, lax step modify the position of almost every bone in the body. The vertebral column is considerably arched in the dorsal region, thus assisting in the downward curve of the neck and at the same time tilting the angle of the pelvis a few degrees toward the perpendicular, increasing the length of the hind limbs and tilting the body toward the head. The head being turned well to the right, there is a very slight curve toward the left in the anterior portion of the dorsal vertebra, and a slight curve to the right in the lumbar vertebre owing to the backward position of the right hind foot.
The weight of the body falls on the right front and the left hind foot, bringing them both very near the median line, and also modifying the position of the scapula and elevating the left side of the pelvis. A little below the knee a very small hairlike bone may be seen, which represents the shaft of the almost extinct fibula, a bone which was well developed in the ancestors of the horse.
THE ARABIAN HORSE F all the many types of horses probably the one most universally admired and loved is the Arabian, with its marvelous grace and beauty, great intelligence, perfection of anatomical mechanism, fleetness and endurance. The question may well be asked, whence comes this superiority?
The great fondness and care with which the Arabs have bred their horses for many hundreds of years have undoubtedly done much for the elevation of the stock; but more than this it is shown almost conclusively that the Arab was blessed with a wonderfully fine natural species on which to exercise his care. On this point Professor William Ridgeway of Cambridge University, has given us an immense mass of most convineing evidence.!
There are many reasons, traditional and historical, as well as zoélogical, for believing that the Arabian horse, or as Professor Ridgeway has called it, the Libyan horse, is in origin entirely separate from the very much inferior northern or Norseman’s horse, and that its native home was not in Arabia but northern Africa, where it was domesticated by the ancient Libyans, in all probability as early as 2000 B. c. The Egyptians also knew full well the value of domestic horses. ‘““Eeypt was, in fact, famous for its breed of horses which were not less excellent than numerous, and we find that they were even exported to other countries, Judea, Syria, and to the Kings of the Hittites.’’? It is IRipGeway, WiiiramM.
Origin and Influence of the Thoroughbred Horse.
Cambridge:
Univ.
Press, 1905.
2WiLKInson,I.G.AncientEgyptians
THE HORSE UNDER DOMESTICATION by also clear, from Egyptian art, that these horses were of the North African, or as we would say to-day, Arabian type. It has been the constant infusion of this Libyan blood which has tended to improve our commoner horses for these many centuries. The skeleton of ‘* Nimr”’ (See Fig. 27, p. 40), a pure-blooded Arabian stallion, has been mounted to show some of the conspicuous characteristics of this species, which are as follows: 1. Head and tail carried high when the animal is animated; 2. Skull short, but broad between the eye sockets; 3. Eye sockets high and prominent, giving the eyes a wide range of vision; 4. Facial profile, or forehead, concave; 5. Muzzle slender, but jaw deep and wide-set above the throat ; 6. Round thorax, well “ribbed up” and short back with only five ribless, or lumbar vertebre; 7. Horizontally placed pelvis (a speed character) and very high tail region, few tailvertebra; 8. A complete shaft of the ulna, or small bone of the forearm; 9. Long and slender cannon bones and long sloping pasterns.! ‘“Nimr”’ was sired by the desert-bred Arabian “ Kismet,’ famous for an unbroken series of victories as a race horse in India. After his death at Oyster Bay, Long Island, in 1904, the subject was presented to the Museum by the owner, Mr. Randolph Huntington. THE RACE HORSE S for the earliest domestication of the horse in Britain, where the race horse or thoroughbred has since been developed, no definite statement can be made. We read that horsemen in large numbers opposed the landing of the Romans, and also that in 631 a. p. the English first began to saddle their horses. Again we find mention of “running’’ horses in the ninth century. But it is not until about 1689, when the famous “‘ Byerley Turk”’ was brought to England, that we learn anything definite concerning the origin of the present English stock, though horses of undoubted North African blood had been imported from Turkey a century or more earlier. The Darley Arabian, bred in the desert of Palmyra, was imported into England by Mr. Darley in 1705. About twenty years later the Godolphin Arabian? arrived on the scene, continuing to improve the English stock with infusion of North African or Libyan blood, to which the quality of the race horse is chiefly due. Touchstone states, ‘‘The thoroughbred, as soon as he ceases to be subjected to the special régime of training reverts to the Arab type with __Ossporn,H.F.PointsoftheSkeletonoftheArabHorse.Bull.Amer.Mus.Nat.Hist.,vol. Xxlll, art.
13, pp.
259-263, 1907.
2Richard Berenger, however, denies that this horse was an Arab, though his view is not generally accepted.
History and Art of Horsemanship, 1771.
46 AMERICAN MUSEUM GUIDE LEAFLETS such extraordinary rapidity that we cannot be blind to the fact that he descends, for at least seven parts out of eight, from the pure Arab,’”! which we would consider of Libyan origin, and indeed many admirers of the Arab would gladly eliminate the remaining eighth of non-Arabian blood. :
However the race horse of to-day is a very highly specialized animal, certainly vastly different in appearance from the Arab and yet still more widely separated from the draft-horse type.
In July, 1906, we were particularly fortunate in the gift from the late Mr. James R. Keene, of the remains of one of America’s most famous race horses, together with sufficient funds for the preparation of the skeleton. This remarkable horse, ‘‘Sysonby,’’ was foaled February 7, 1902, at Mr. Keene’s Castleton stud in Kentucky, a few months after the importation from England of his dam ‘‘Optime,”’ his sire being the English bred ‘““Melton.’’ His record is one of the most brilliant in the history of American horse-racing. He won a remarkable series of victories between his first race at Brighton Beach, July 14, 1904, as a two-year-old, and his untimely death at four years (July 17, 1906).
The skeleton (Fig. 29) has been mounted to show a phase in the stride of the running horse, and is based on studies made from direct observation and instantaneous photographs. The position is that of the moment after the right fore foot has left the ground, and the right “ knee’’ or carpus, is beginning to bend; the succeeding footfalls in order are the left hind, the right hind, the left fore and the right fore, the full length of one complete stride being about twenty-six feet.
At this instant the hind quarters are lifted perceptibly higher than the shoulders and from a rear view it will be seen that while the hind feet are thrust forward at this greater height from the ground, they are widely separated so as to avoid striking the fore. legs. A moment later the shoulders will be lifted by the push of the fore feet higher than the hind quarters, then the hind feet will move toward the median line and strike the ground, and the fore feet will have moved forward out of the way of the hind.
The backbone is slightly arched to help draw-together the fore and. hind limbs and feet, and thus lengthen the stride-and bring the back muscles into play. When viewed from above, the backbone is also observed to be curved a little to the right, owing to the forward position of the left side of the pelvis and of the left hind limb; this also lengthens: and gives power to the stride as the backbone is straightened. 1TovcusTONF,S.F.
Race Horses and Thoroughbred Stallions.