DOMESTICATION OF THE HORSE

Who was the first human to jump on the back of a wild horse? When did the first successful ride happen—that astonishing moment when some adolescent first hung on to a horse's mane and galloped through the village while everyone stared as if he (or she?) had begun to fly? That moment, irretrievably lost, changed history. Today horses are such an accepted part of the culture that all transportation technologies—even rocket engines—are still measured in horsepower. Horses, unlike other domesticated animals, are more important for transportation than as a source of milk, meat, or fibers. The domestication of the horse was both a zoological and a technological innovation, which is one reason the study of horse domestication is so complicated. Certain discoveries hold out the hope that we might eventually understand this seminal event much better.

WHERE WERE HORSES FIRST DOMESTICATED?

In 2001 geneticists at Uppsala University (Sweden) established that modern domestic horses have such wide variation in their mitochondrial DNA that they could not have descended from a single ancestor or small group of ancestors that lived in one place within the past ten thousand years. Similar studies conducted on modern domestic sheep (Ovis aries) and European/Near Eastern cattle (Bos taurus) had quite different results—these species are so homogeneous in their genetic makeup that they almost certainly are the descendants of single ancestors that lived recently. A single pair of wild sheep and only a few bull and cow pairs became the ancestors of almost all of our millions of modern domesticates—thus it is worthwhile investigating where those ancestral pairs were brought into a domesticated way of life.

Modern horses, though, are mongrels by comparison, probably because wild horses continued to interbreed with domesticated stock until modern times. Horse keepers encouraged the incorporation of new domesticates from previously isolated wild horse populations, whereas cattle and sheepherders did not. Breeding with wild horses was thought to enhance some of the qualities desired in domesticated horses—strength, speed, intelligence, and competitiveness—while most of these same qualities are undesirable in domesticated cattle and sheep. The contrast in character testifies to the very different demands humans have placed on horses, but it should not derail the search for the place where domestication took place. The earliest domesticated horses must have lived somewhere. One can accept that the genetic history of the modern horse is quite complicated without abandoning the search for the beginning of the story.

The first people to think seriously about the benefits of keeping, feeding, and raising tamed horses must have been familiar with wild horses. They had to have lived in a place where humans spent a lot of time hunting wild horses and studying their behavior. The geographic area where this was possible contracted significantly about ten thousand to fifteen thousand years ago, when the modern era of warm climate began and arctic steppe tundra—a favorable environment for Ice Age horses—was replaced by dense forest over much of the Northern Hemisphere. The horses of North America became extinct as the climate shifted, for reasons that are still poorly understood.

In Europe and Asia large herds of wild horses survived only in the steppes in the center of the Eurasian continent, leaving smaller populations isolated in pockets of naturally open pasture (marsh-grass meadows, alpine meadows, and arid mesetas) in Europe, Anatolia (modern Turkey), and the Caucasus Mountains. In these places, however, horses never became an important part of the human food quest over the long term—there were not enough wild horses left outside the steppe environment to make focusing on them worthwhile. In Anatolia, for example, small populations of wild horses survived long enough to be hunted occasionally by the Neolithic occupants of Çatal Hüyük and other farming villages in about 7400–6200 b.c., but they were hunted out during the Neolithic. In Western Europe horse bones account for more than 5 percent of the animals hunted at only a few early postglacial sites. Only in the Eurasian steppes were there large postglacial wild horse populations, and in steppe archaeological sites postglacial humans regularly hunted wild horses for more than half of their meat diet. For this reason alone one should look first to the Eurasian steppes for evidence of the earliest domestication.

Three equid species were hunted in the Ukrainian and Russian steppes north of the Black and Caspian Seas between 8,000 and 5,500 b.c. In the Caspian Depression, at such Mesolithic sites as Burovaya 53, Je-Kalgan, and Istai IV, garbage dumps dated before 5500 b.c. contain almost exclusively the bones of the horse and the onager, Equus hemionus. The latter is a fleet-footed animal smaller than a horse and larger than an ass, native to dry steppe and semidesert environments. Onagers were then very successful; their natural range extended from the Caspian steppes across Iran and into the Near East. Hunters in the arid Caspian steppes specialized in horse and onager hunting into the late sixth millennium b.c., at sites such as Dzhangar and Kair-Shak III. A second equid, Equus hydruntinus, was hunted in the slightly moister environment of the Black Sea steppes, where its bones are found in Mesolithic sites at Girzhevo and Matveev Kurgan, dated to the late seventh millennium b.c. This small, gracile animal, which then lived from the Black Sea steppes westward into Bulgaria and Romania, became extinct before 3000 b.c.

The true horse, Equus caballus, was more adaptable; it ranged across both the Caspian Depression and the Black Sea steppes, and it survived in both environments long after both E. hemionus and E. hydruntinus were hunted out. Horse bones were more than 50 percent of the identified animal bones at Girzhevo and Matveev Kurgan, a pattern that was repeated at Ivanovskaya on the Samara River, an eastern tributary of the Volga, and in Neolithic sites in the southern foothills of the Ural Mountains. All these sites were relatively small. Small camps imply that the hunters lived and hunted in small groups, probably using ambush techniques rather than large communal drives. Their taste for the flesh of wild equids created a familiarity with them and their habits that later would make the domestication of the horse possible.

WHY WERE HORSES DOMESTICATED?

The first domesticated animals north of the Black and Caspian Seas were introduced by farmers of the Criş culture who migrated from the broad Lower Danube Valley into the forested eastern Carpathian foothills, spilling into the Seret and Prut River valleys about 5800–5600 b.c. The ownership of cattle and sheep made possible an entirely new political economy in the region. Domesticated animals constituted capital that could be loaned, offered at public ceremonies, and given as gifts. The connection between animals and power would become the foundation on which new forms of ritual and politics would develop among steppe societies. Between 5400 and 5200 b.c. cattle and sheep were adopted by the Dnieper-Donets culture (also known as the Mariupol culture, after the cemetery of Mariupol) in the steppe valleys of the Dnieper and Donets Rivers north of the Black Sea. By 5200–5000 b.c. the people of the Volga-Ural steppes, far to the east, had begun raising cattle and sheep as well. An economic boundary formed at the eastern and northern edges of the Volga-Ural steppes; beyond this frontier, the native foragers rejected domesticated animals for another 2,500 years.

The techniques of cattle herding would have suggested obvious possibilities to anyone familiar with horses. Both cattle and horse bands follow the lead of a dominant female. The cowherd needs only to control that female to control the whole herd—a technique easily applied to horses. A dominant male, the bull or the stallion, normally guards the wild band, a job taken by a human in a domestic herd. Thus, males present a similar management problem in both species, and they have the same iconic status as symbols of virility and strength. When people who depended on equid hunting began to keep domesticated cattle, it would not have been long before someone tried to apply cattle management techniques to horses.

What was the incentive to tame horses if the people who did it already had cattle and sheep? The first horse tamers would not have been able to predict the ultimate advantages of leaping onto the back of a fast, powerful, and aggressive creature naturally more inclined to fight or run from humans than to carry them. Horses, however, are easier to feed through the winter than cattle or sheep. Cattle and sheep push snow aside with their noses, whereas horses use their hooves. In deep or continuous snow the noses of cattle and sheep become bloody and sore, and if they are not provided with fodder they will stand and starve in a field where there is ample winter forage just beneath their feet. Horses will paw ice and snow away with their hard hooves and feed themselves. They are supremely well adapted to the cold grasslands of our planet, where they evolved. People who lived in cold grasslands with domesticated cattle and sheep soon would have seen the advantage in keeping horses, if just for a cheap supply of winter-season meat. It is possible that this phase of horse keeping, when horses were primarily a source of meat, began as early as 5000 b.c. in the Pontic-Caspian steppes.

WHEN WERE HORSES DOMESTICATED?

The cemetery of Khvalynsk, located in the Russian steppes on the west bank of the Volga River, between Saratov and Samara, contained the graves of more than two hundred people and dated to about 5000–4500 b.c. During this first period of stockbreeding in the steppes, domesticated animals were sacrificed to accompany the dead. Animal sacrifices were placed in graves, at the edges of grave openings, and on the ground above filled-in graves at Khvalynsk. Igor Vasiliev, the excavator, reported a minimum of sixty-one sheep, twenty-one cattle, and eleven horses as sacrifices. Most of these animals were represented by just the leg bones, but seventeen sheep and nine cattle still had parts of both the head and the lower leg bones—probably the remains of hides with the head and feet still attached. Only cattle, sheep, and horses were offered in the Khvalynsk funeral sacrifices—except for one deposit, containing a single bird. Three graves held the bones of horses combined with cattle or sheep or both.

The ritual grouping of horses with cattle and sheep would be explained most easily if horses weremanaged like cattle and sheep, tamed and controlled by human herders. At the related cemetery of S'yezzhe on the Samara River, an above-grave ritual deposit contained red ochre, broken pottery, shell beads, a bone harpoon, and the skulls and lower leg bones of two horses. Two figurines of horses carved on flat pieces of bone were placed near this red-ochre-stained deposit. Similar funeral deposits of horse bones and carved horse images have been found at other contemporary cemeteries in the western steppes (Varfolomievka and Lipovi Ovrag). Symbolically, horses were treated in the burials like domesticated cattle and sheep—they occupied the same ritual category as livestock. It thus seems likely that horses already were domesticated or on the way to domestication by about 5000–4500 b.c. in the steppes north of the Black and Caspian Seas.

the origin of horseback riding

It is difficult to distinguish the bones of early domesticated horses from those of their wild cousins. Contemporary feral populations differ in bodily form in different environments—Chincoteague ponies are smaller than Nevada mustangs, for example. The leg bones of postglacial horses from southeastern Europe or Germany tended to be a little thicker than those of typical steppe horses, but the whole range in leg thickness can be found in one archaeological site, as at La Adam cave in the Dobruja region of Romania. It is thus difficult to identify a morphological variant that clearly indicates domestication and that cannot be ascribed to the regional environment or interregional movement of wild horse populations.

It has been doubly difficult to distinguish the bones of a mount from those of a horse merely eaten for dinner. Riding leaves few traces on horse bones—only six thoracic vertebrae are known to show riding-related pathologic features, and these bones rarely are preserved at archaeological sites. A bit, however, leaves marks on the teeth, and teeth usually survive very well. Bits are used only to guide horses from behind, to drive or to ride. They are not useful if the horse is pulled from the front, as packhorses are, so evidence for bit use implies riding or driving.

Most horses that have been ridden or driven frequently with a bit—90 percent in a study of modern bitted horses—show bit wear on their lower second premolars (P2s). A well-positioned bit is supposed to sit on the tongue and gums in the space between the front and back teeth, called the "bars" of the mouth. But X-ray photographs taken at the University of Saskatchewan (Canada) show that a horse can use its tongue to elevate and retract the bit, pushing it back into the grip of its premolars. The horse has to force the bit back into its cheeks, which prevent the bit from moving back farther than the front half of the P2. Thus, all wear from bit chewing is concentrated on one part of one tooth (the P2), unlike the wear from chewing anything else.

A metal bit creates distinctive abrasions on the enamel of the P2, usually concentrated on the first cusp; it also wears down a bevel or facet on the front (mesial) corner of the tooth, also usually on the first cusp. Horses that chew on a rope or leather mouthpiece, like those probably used for the oldest bits, show the same wear facet in the same place, but its surface is smooth and polished, not abraded. Measurement of the depth of the wear facet easily distinguishes populations of bitted horses from horses who have never worn bits. Horses that have not been bitted do not have a wear facet on the mesial corner of the P2. In our study of such horses, the median measurement of the dip on the mesial corner of the tooth was only 0.5 millimeters. We regard a 3-millimeter-deep facet as the threshold for identifying bit wear in archaeological cases. If several mature horses, three years old or older, from a single archaeological site have mesial bevels of 3 millimeters or more on their P2s, it is evidence either for numerous cases of a very rare natural pathological condition or for the use of bits.

The oldest archaeological collection of numerous horse P2s with wear facets in excess of 3 millimeters is from the site of Botai in northern Kazakhstan. Botai was a settlement of specialized horse hunters who seem to have ridden horses to hunt horses, a peculiar practice that existed only in northern Kazakhstan during the period 3500–3000 b.c. Sites of the Botai type and of the related Tersek type contain 65–99.9 percent horse bones, indicating that the meat diet came almost exclusively from horses. Five of the nineteen measurable P2s studied at Botai, representing at least three different horses, had significant bevel measurements: two of 3 millimeters, one of 3.5 millimeters, one of 4 millimeters, and one of 6 millimeters. A 3-millimeter wear facet was also found on one P2 from a Tersek site very much like Botai, Kozhai 1, in the steppes just west of Botai, dated to the same period. One can be reasonably certain that some Botai and Tersek horses were bitted and ridden.

Dogs and horses were the only domesticated animals these people had—the Botai-Tersek communities essentially were mounted foragers. They possessed no cattle or sheep, no wheeled vehicles, and no bronze metallurgy—all things that their Yamnaya culture neighbors in the Volga-Ural steppes to the west had during the same period. Botai-Tersek sites have large and well-studied collections of horse bones, but that does not mean that riding actually began there. It is likely that Botai-Tersek people acquired domesticated horses and the idea of riding them from their western neighbors, who had been managing domesticated cattle and sheep, and probably horses, for fifteen hundred years before 3500 b.c.

The appearance of riding at Botai suggests that other cultures of the Eurasian steppes were riding horses by about 3500–3000 b.c.—and probably earlier. A man on foot can herd about two hundred sheep with a good herding dog. A man on horseback can herd about five hundred. Riding greatly increased the efficiency and productivity of herding economies and probably was used also in tribal raiding, long before riders were organized and armed in a way that finally made them effective against urban armies.

the spread of horseback riding

Riding was not a sport of kings before 1000 b.c. In fact, an adviser to one Near Eastern king, Zimri-Lim of Mari, warned him in about 1770 b.c. that he should not dishonor his kingship by riding horses; instead, he should ride in a chariot. Teams of elegantly outfitted horses drew chariots into battle as early as 1800–1900 b.c. in the Near East and Anatolia, and it was in this capacity that horses first were used widely by royalty. Horses initially appeared in small numbers in Anatolia and Iran around 3000 b.c., perhaps imported to breed with asses to produce mules, which were stronger than asses and better suited than horses to the hot Near Eastern climate. The earliest artistic images of horses appeared in about 2300–2000 b.c.; they showed horses alone or men riding on horseback. The identity of these riders or their function is not known, but riding was not adopted by Near Eastern elites, and it was not used in state-level warfare.

Between about 2800 and 2000 b.c. ponderous four-wheeled battlewagons were used in Near Eastern warfare. They were pulled by asses (Equus asinus) or onagers (E. hemionus), native equids but smaller and weaker than horses. The chariot was a light, two-wheeled vehicle designed specifically for speed, made possible by the invention of the spoked wheel, which greatly reduced its weight. Chariots could take advantage of the superior speed of horses, which began to be imported in large numbers when the chariot was invented, about 2000 b.c. It is not clear where chariots were invented—they appeared in graves in the Eurasian steppes around 2000 b.c. and could have spread from there through the Iranian Elamites into Mesopotamia during the Third Dynasty of Ur. Alternatively, they might have been invented in the Near East and spread northward into the steppes. Regardless of their origin, chariots were expensive to make, the horses that pulled them were exotic foreign beasts, and both chariot teams and drivers needed long training, so horse-drawn chariots were automatic signals of status and wealth. Once they appeared, elite chariot corps dominated warfare between the kings of the Near East for centuries.

The effective use of cavalry in urban, state-level warfare depended on three tactical and technical innovations: the organization of large bodies of riders into units that attacked and retreated on command; the invention of the short, recurved compound bow, which made it easier to shoot from a moving horse; and the development of molds to cast metal arrowheads of standard weight and size, which made archery more accurate. These three innovations came together in the western Eurasian steppes in about 1000 b.c., perhaps as a result of contact between tribal steppe riders and state-level military organizations in the Near East or the Caucasus Mountains. Within a few centuries cavalry replaced chariots on the battlefields of the Near East and the western Eurasian steppes. Warfare and world history were changed forever.

See alsoWarfare and Conquest (vol. 1, part 1); Milk, Wool, and Traction: Secondary Animal Products (vol. 1, part 3); Late Neolithic/Copper Age Eastern Europe (vol. 1, part 4).

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David W. Anthony