Ponies in Prehistoric Times.—During the Pleistocene period some eight or more species of true horses and ponies inhabited North America. Apparently before Palæolithic man reached the New World all these American species had become extinct. About the American true horses which, like Hipparion, reached and found a home in Eastern Asia, very little is known. Some of their descendants found their way during Pliocene times into India; others reached south-eastern Europe.
One of the Indian Pleistocene species (E. namadicus) from the Narbada valley had large long-pillared molars like E. complicatus of North America and E. fossilis of England (fig. 22); another (E. sivalensis), well represented in Pliocene deposits of the Indian Siwaliks, is the oldest true horse about which we have definite information. Like Pliohippus, E. sivalensis had short-pillared molars, but instead of measuring, like Pliohippus, 12 hands at the withers, this Indian species reached, in some cases, a height of 15 hands.
Some of the Kirghiz breeds, in which the face is strongly bent downwards on the cranium, probably include this ancient Siwalik race amongst their ancestors. Some of the Eastern races which reached Europe[F15] in pre-glacial times found a congenial home in Tuscany and Umbria. Others, moving in a north-western direction, found their way into Britain, while others crossed by one or more land connections into North Africa. About the late Pleistocene descendants of the varieties and species which reached Europe before the Ice Age, a considerable amount of information has been gained from engravings and coloured drawings on the walls of caves occupied by Palæolithic man, and from fragments of skulls, teeth, and limb-bones found in Pleistocene deposits. Up to the end of last century naturalists, as a rule, assumed that the wild horses hunted during the Early Stone Age all belonged to the same species, the so-called (E. fossilis), and when about 1870 Prjevalsky discovered wild horses in Mongolia, it was further assumed that these wild herds were the descendants of E. fossilis, and hence represented the wild species from which all the modern domesticated breeds had sprung.
[F15] The horses which reached Europe in Pliocene times are usually said to belong to one species (E. stenonis).
Partly from fossil teeth and limb-bones, and partly from the engravings on the walls of caves and on pieces of horn, the conclusion was arrived at that E. fossilis, the assumed common ancestor of modern breeds, was characterised by a large coarse head, coarse limbs, and long-pillared molars (fig. 22). Prjevalsky’s horse when first discovered was said to be characterised by coarse limbs as well as by a large heavy head. As it was further assumed a generation ago that all domestic horses had long-pillared molars, and that the cannon-bones varied with the surroundings—being short and broad in some areas, long and narrow in others—there seemed no escape from the conclusion that all the horses now living under domestication are descended from one and the same wild Pleistocene ancestor.
But though in Prjevalsky’s horse the head is coarse, the limbs are nearly as fine as in thoroughbred race-horses, and though in horses of the Prjevalsky or steppe type the pillars of the molars are long, they are not long in all modern horses. Moreover, though there is evidence of the existence in Europe in prehistoric times of a species with a coarse head and relatively fine cannon-bones, there is no evidence of the existence of a species which combined a coarse head with short broad cannon-bones. On the other hand, it has been ascertained that since Miocene times there have been living side by side in Europe big-boned and fine-boned species, and that, except by dwarfing, long narrow cannon-bones are rarely if ever transformed into short, broad cannon-bones.
The skulls from the Roman military station at Newstead proved conclusively that there lived in Scotland during the first century large and small horses with short-pillared molars (fig. 23). This led to the discovery that in Shetland and other ponies of the Celtic type, and in Arabs and thoroughbreds of the Libyan or Siwalik type, some of the molars have as short pillars as in E. stenonis (fig. 21) of the Val d’Arno Pliocene deposits.
The investigations of the last decade having indicated that during the Ice Age in Europe, as in America, there were always several species of horses living contemporaneously, an attempt must be made to ascertain from which of the wild prehistoric species Shetland ponies are mainly descended. In addition to steppe horses of the Prjevalsky make and horses allied in skull, teeth, and limbs to E. sivalensis of India, there were in prehistoric times large and small varieties of browsing or forest horses, and “Celtic” and “Libyan” varieties of slender-limbed plateau or desert horses. Although trees and plateaus are conspicuous by their absence in the northern islands, the study of Shetland ponies makes it evident that they have mainly sprung from “forest” and “plateau” ancestors. Evidence of this we have in the limbs and skull as well as in the teeth. A fairly accurate estimate of the type to which a horse belongs, and also of its height, can often be gained from a study of the cannon-bones. For example, in 12-hands ponies of the “Celtic” variety the metacarpals are on an average 200 mm. long and 26·6 mm. wide at the middle of the shaft, whereas in 12-hands ponies of the “forest” type the length is on an average 193 mm. and the width 35 mm.—i.e., in the one case the length is 7·5 times the width, in the other only 5·5 times. In Preglacial times there were horses in Umbria with metacarpals 190 mm. by 32 mm., and horses with metacarpals 220 mm. by 30 mm. The 190 mm. metacarpals probably belonged to a long, low, broad-browed 12-hands “forest” pony, while the 220 mm. metacarpals doubtless belonged to a 13-hands fine-limbed pony of the “desert” type. During the Glacial period horses of the “forest” and “desert” as well as of the “steppe” type were common all over Europe.[F16] From the “Elephant-Bed” at Brighton bones of a 12-hands “forest” horse have been recovered. Kent’s Cavern, Torquay, in addition to the bones of a 12-hands “forest” horse, has produced cannon-bones of the same size and width as the fine-boned 13-hands Umbrian pony.
[F16] In the vicinity of an open-air settlement to the north of Lyons there are rubbish-heaps said to contain the remains of over 50,000 horses, which served as food during the Solutrian period of the Stone Age.
The “Elephant-Bed” and Kent’s Cavern small “forest” horses are best represented to-day by the long, low, broad-browed Iceland ponies, while the 13-hands small fine-boned race of Kent’s Cavern is best represented by Exmoor and other ponies of the “Celtic” type—i.e., by ponies with short-pillared molars, and only two of the eight callosities (chestnuts and ergots) invariably found on typical “forest” horses. Whether modern Shetland ponies are mainly descended from prehistoric British races or from a Norse race of the fjord type it is impossible to say. The Magdalenians, who occupied Kent’s Cavern while hunting the reindeer in the south of England towards the close of the Old Stone Age, had no domestic animals. Neither had their successors, the Azilians, who some 8000 years ago frequented the MacArthur and other caves near Oban. The Mediterranean race (now best represented by the Basques), which followed in the wake of the Azilians, perhaps brought sheep or cattle into Britain, but there is no evidence that they possessed horses. Professor Ridgeway believes “the use of the horse by man in the British Islands cannot be placed before the end of the Bronze or the beginning of the Iron Age.”[F17]