The free-roaming horses that graze the Americas today descend from European stock brought over from the late 1400's onward. They are the progeny of animals that have been domesticated and selectively bred for thousands of years. They have lived wild, often untouched by man, for dozens of generations, even for centuries. They act wild, they think wild, and for generations, they have known nothing but a wild existence. These horses have been pushed by mankind to the most inhospitable habitats, such as desert, swamp, or mountain top. They are so successful in these places that they out-compete any livestock grazed there.

Today's wild horses have existed in America since the late fifteenth century, when the Spanish explorers "discovered" the new world (or, more accurately, invaded it). They crossed the sea with their Spanish Jennet horses -- compact animals with wide chests, muscular necks, and short, strong backs and legs. Spanish-bred horses were renowned for their intelligence, endurance, and tractability, making them excellent mounts for the purpose of conquering a continent.

This all changed in 711 A.D., when the North African Moors invaded Spain, mounted on small, agile, wiry Barbary horses. These little war horses were radically different from the mounts of the Spanish -- maneuverable, fleet and sure-footed.

It is unclear which come first, the Barb or the Arab, as many experts disagree on the origins, but the two distinct breeds are closely related. Barbs were thin-skinned desert horses bred for stamina, durable mounts capable of surviving on poor forage and little water, and were able to carry a rider great distances in the blistering heat. The Moors treated most of their livestock callously, but valued their horses highly, considering them partners. They preferred to ride mares, and sometimes held their horses in higher esteem than their wives!

These horses were bred for war and conquest. Barbs, along with many other fine horses, owe their very existence to the human desire to win wars. Barbary horses were indeed good war horses, and the slow-moving, heavy mounts of the Spanish were no match for them. The Moors enjoyed victory, and ruled for several hundred years.

The Spanish realized that they needed a different type of horse if they were to be successful in war, yet needed an efficient, good-natured mount for heavy farm work and transportation. They crossed their own heavy horses with the Barbs, including an infusion of Norse blood, and finally over the years, developed a short-coupled, stocky, docile breed with great versatility, capable as a war horse yet practical for draft and enviably handsome. The breed originated in the Spanish Province of Andalusia, which is why the horses of the conquistadors are often termed Andalusians. Originally, they were called Jinetas or Jennets, and earned the Spanish the reputation of raising fine horses.

These Jennets probably had more Barb blood than anything else, and had been bred carefully for centuries by the time the conquistadors took them to the Americas. Their characteristics were unmistakable. Jennets were on the small side, with a medium build, and fairly short-legged. The chest was so deep it usually accounted for half the height from withers to ground. The neck was short and muscular, the croup sloping. The mane and forelock were thick and long, as was the low-set tail. The head of a Spanish horse was distinctive, with a straight forehead, convex Roman nose, and a generally squared-off upper lip area, with the upper lip longer then the lower.

Besides the typical trot found in most other breeds, Iberian horses exhibited lateral gaits such as the pace, amble, running walk, and Paso gaits. The Spaniards also adopted a riding style more like that of the Moors, relying less on pulling the horse's head around and more on shifts of weight, leg pressure, and a light hand on the reins.

Horses evolved primarily in North America, but by the time the first Spanish explorers visited the New World, they had been extinct there for roughly 10,000 years. Columbus realized that many horses were needed to explore the New World, and brought 25 to the Caribbean Islands on his second voyage in 1493. Within a decade, horse breeding ranches were established on the islands of the West Indies.

Spain had just spent almost 800 years fighting a series of invaders, and horses were in short supply. Many of the Spanish stockmen who raised riding animals had turned to breeding mules due to public demand for a gentler mount with easy gaits. Crossing Jennets to asses produced calmer animals with smooth paces. Unfortunately, as a sterile hybrid, mules can not be used for breeding. To reduce the demand for mules, and thereby increase the Spanish horse population, the king finally forbade all people but women and clergy from riding mules.

It was difficult for Spain to part with large numbers of horses to explore the new world. Spanish horses were in great demand for many years on their native ground. They were needed for defense, conquests and exploration, domestic chores and travel, and were coveted by foreign breeders who sought to infuse their own stock with Spanish blood. Yet, the new world beckoned, and the importation of horses greatly improved Spain's chances for successful conquests.

Trans-Atlantic voyages were difficult for horses. Sometimes they were crowded into the dark hold of the ship, supported by a sling to hold them on their feet, with no exercise, helpless to do anything but endure the relentless rolling of the ship over often stormy seas. Alternately, they were tied on an open deck for a month or more, without shade or protection from the storms. Food and water were often in short supply. If the ship was becalmed, and sat in the tropics unmoving, for days at a time, the horses often died of dehydration, and were pushed overboard into the ocean. In fact, so many met this fate, that a section of the Atlantic is called the Horse Latitudes, for the multitude that ended up in this watery equine graveyard. (An area north of the Canary islands is called "Golfo de Yegues", gulf of the mares, from Spanish expeditions a century earlier, beset with similar problems.)

It made sense to bring a number of broodmares to the West Indies and allow them to produce the horses needed for the expeditions. Spain even sanctioned free transport for broodmares to encourage the development of horse ranches. New World horse breeders enjoyed great success, and by the early 1500's had established ranches on Puerto Rico, Jamaica, Santo Domingo, Cuba, and later on the continent itself, in Mexico and Peru. There were no predators on these islands, grazing was excellent, and the climate was ideal. Cattle were also raised successfully, along with other livestock.

These ranches supplied the invaders of Mexico, Central America, and Peru with thousands of mounts of fine quality. The island horses were bought by explorers who paid with gold. Much of the breeder's profits were reinvested to import the finest breeding stock from Spain, to further improve the quality of the horses bred on the islands. At one point the demand for riding horses was so great, the farms were hard pressed to satisfy the demand. Fine quality Barbs were imported from North Africa and bred into the island lines, flavoring the genetic soup further.

In 1519, Hernando Cortez, set sail from Cuba to conquer Mexico, with 600 men and sixteen horses of chestnut, bay, overo pinto, sorrel and roan. The Spanish conquistadors preferred to ride stallions into battle and on journeys, so only 6 of his mounts were mares, one of which gave birth to a foal en-route to the mainland, bringing the total to seventeen.

The native Aztecs of Mexico had never seen horses before, and were initially terrified, mistaking the mounted soldiers as one creature, half-man, half-horse, a supernatural beast, or perhaps even a God! And, Horrors! This creature could divide into man and beast, then rejoin to form a single entity, unharmed by the separation! Or perhaps the horse was a magical deer, or a medicine dog, that only Man-Gods could ride!

Cortez was quick to use this misconception to his advantage. During one strategic encounter, he had a fine stallion named El Arriero tied to a tree. A soldier was instructed to lead a mare in heat slowly past the stud. El Arriero pranced and squealed, arched his neck, stamped, and fought the tie. "You and your people have angered the horses!" admonished Cortez. The Indians were frightened, not recognizing this display as frustrated lust. After the mare had passed, Cortez said he would calm the animal, gently stroked him and whispered into his ear. The stallion, no longer aroused, relaxed and nuzzled Cortez. The Indians were reverent. This Cortez must be a powerful man to have such influence over the mighty stallion!

To further frighten the Indians, he separated a mare from her new foal. The mare began whinnying frantically. "The horses are crying out in anger against the Indians!" proclaimed Cortez. To placate the horses, the Aztec leaders brought cloths for the horses to lie on, and chicken for them to eat! Perhaps Cortez perpetuated the idea that horses ate poultry so that he could himself dine on chicken, but the idea backfired in the end.

Subsequently, Cortez's stallion was stolen by the Indians. They treated the animal in a manner befitting a God, adorned him with flowers, attended to his every desire - until he starved because they were trying to feed him chicken!

Montezuma, the ruler of the Aztecs, proclaimed Cortez the prophesied incarnation of their God, Quetzalcoatl, and presented him with gold and silver gifts. But Cortez wanted to conquer, not co-exist. He sought treasures and riches. Other tribes, tired of being ruled by the Aztecs, joined forces with Cortez, and the Aztecs fell. Cortez looted their gold and gemstones, and his success inspired further conquests.

Because Mexico was such a successful venture, Spanish explorers worked their way into South America, and set sail north as well, to establish settlements and hoping to find a north passage to the Pacific. A Spaniard named de Ayllon ventured further up the coast and established a settlement that is thought to have been located at the mouth of the Cape Fear river in North Carolina.

The Spaniards were abusive to the natives, believing them to be stupid and inferior beings. Wherever they encountered Indians, they fought bloody battles, and stole Indian children to sell as slaves in the West Indies. Before long, the natives hated white men on sight, and strenuously resisted any that intruded. Primarily for this reason, most Florida settlements failed. Horses were stolen from these expeditions by Indians who eventually realized that riding horses conferred more advantages than eating them. Natives didn't fence livestock, and were not skilled in herding. As a result, increasing numbers of horses escaped and proliferated on the beckoning grassy plains of the land on which the species had evolved.

Cortez returned the horse North America, but the horse family has been no stranger to this soil. For over 60 million years horses evolved on this continent, dying out mysteriously over 10,000 years ago. Yet when reintroduced by the Spanish, the horses were not considered to be a native species. This could be compared to a man of advanced years who was born and lived in the same small American town all his life. One day he was forced to visit, say England, for a weekend, only to return and find that he was no longer considered a native.

Of course the situation is more complicated than a simple change of residency. Horses were probably domesticated about 6,000 years ago. Since that time, the genes of the original wild stock have been selectively manipulated by man, breeding for body type, speed, disposition, and coloration. The Spanish horses brought by Cortez were far removed from original Equus, and original Equus was even farther removed from the multi-toed, fox-sized early equids that inhabited North America 60 million years ago.

The earliest recognized member of the horse family was first found in England, by a bricklayer who spent large amounts of time digging clay for his bricks. Sometimes he would dig too far, and hit the sandy layer beneath. One day in 1838, he was tossing aside a shovel-full, when his eye was caught by a tiny tooth in the sand. It looked to be ancient, so he brought it home.

The following year a naturalist found part of a skull with teeth intact, that proved to be from the same species. Initially, he speculated that it must belong to some sort of rabbit or hyrax. He gave it the name Hyracotherium, meaning hyrax-like beast. He couldn't have known that this animal was the forerunner of the modern horse.

Hyracotherium didn't look even remotely equine. He was about the size of a fox, with a skull that looked halfway between a rabbit's and a sheep's. He had an arched, flexible backbone, and short legs that could rotate outwards like a cat's. His monkey-like teeth tell us that he lived on soft foliage such as leaves and tender buds. His feet were padded like a dog's , but instead of claws he had tough, hoof-like nails on his toes, which numbered three in the front and four in the back.

It was only after other, more recent fossil horses were found that scientists were able to trace the fossil record backwards, to conclude that Hyracotherium wasn't a hyrax at all. In North America, similar fossils from the same period found in were already associated with equine lineage, and were known by the more appropriate name of eohippus, or dawn horse. Eventually it was recognized that Hyracotherium and eohippus were essentially one and the same. The earlier name of Hyracotherium held, although eohippus remains in common usage.

With a small, primitive brain, eohippus was not very intelligent. But intelligence is relative to the task at hand, and he was as smart as he needed to be to be an eohippus. The genus was enormously successful. Sometimes, as we look at fossilized bones in a museum, we have trouble remembering that they were once inside a dynamic, active animal. Do not imagine that eohippus was somehow less suited to life on earth than modern animals, just because the species is currently extinct. Eohippus flourished for a good twenty million years, feeding, fighting, and escaping predators like any other animal. Compare this to the fact that Homo, our genus, has existed only a million or so years, and we were primitive creatures without clothes or tools for most of it.

Hyracotherium first arose in the Eocene epoch, 60 million years ago, from a primitive animal known as the condylarth, which was ancestral to all ungulates, or hoofed mammals. These early horses split into species of many different sizes, with a tendency towards greater stature towards the end of the Eocene.

The Eocene gave way to the Oligocene epoch, and with the new era came dramatic environmental changes. The woodlands were shrinking, replaced by expanding prairies. A promising new ecological niche was open for those species that adapted to utilize it.

Most of the species that led up to Equus showed a gradual trend towards characteristics that would increase their success in the grasslands. Eohippus had the soft teeth of a leaf-eater, but the dentition of subsequent species evolved ridges for grinding, and were formed of increasingly harder material. Grass contains silica, the same material from which sand is formed. Progressive horses had durable teeth capable of masticating abrasive grassy dinners that would have sandpapered the teeth of an eohippus down to the gums in short order. They developed higher crowns, allowing the teeth to emerge continuously from the gums as they wore away. The face grew longer and the jaw deeper to accommodate these teeth.

To better see predators over the open prairie, horses evolved longer legs and larger body size to make them taller than the grass. A long neck was necessary to reach grass from this height. Equine eyes evolved the ability to see almost a full circle around, and the capacity to focus simultaneously on the grass under his nose and predators that appear on the horizon. To run from these predators, some of the leg bones fused, and most of the lateral movement of the legs was eliminated. The resulting back-and-forth motion gave the evolving horse greater speed. The side toes became unimportant, and receded until the horses traveled on only the nail of the middle toe, which became the hoof.

Eohippus evolved to Mesohippus, then onto Miohippus, following these trends. By the time the Miocene came around, early horses were so successful that they had speciated into many diverse types. The main evolutionary line bifurcated into two major branches plus a less successful offshoot of "pygmy horses".

One of these important forks was that of the Anchitheres, a lineage of three-toed forest horses who saw no reason to evolve to grazers, instead browsing like deer. They thrived for tens of millions of years, until they finally died out, leaving no modern survivors.

The other branch was the one from which Equus arose, the line that took to the grasslands and evolved as efficient grazers. These horses also enjoyed enormous success, and as the Miocene progressed, a genus known as Merychippus took hold, about fifteen million years ago.

Merychippus was very horsy in appearance, and stood forty inches at the shoulder, or 10 hands, if you measure him by equine standards. This is about the height of a small shetland pony. He had a very equine brain and greater intelligence than his ancestors, and so his behavior was probably similar to that of modern members of the horse family.

Merychippus traveled primarily on his middle toe, the two toes on either side still fully formed but becoming increasingly unimportant. Springy ligaments in the lower legs served to keep his weight on the hoof of the center toe, giving Merychippus speed and agility as he grazed on the open savanna.

During the reign of Merychippus, the horse family speciated with more variation than equids had ever known before, or since. There were browsers and grazers of every description, and most were highly successful, moreso than artiodactyls, the even-toed hooded mammals that dominate today.

Scientists have long puzzled over the presence of fossae, or hollows, in the facial bones of horses of this period. As soft tissue does not usually fossilize, and modern horses do not have these fossae, it is a matter of speculation just what purpose these served. They must have been important, as nearly every species had some form of fossae. But they couldn't have been necessary for survival, or modern horses would have them.

The mysterious fossae varied between species, and between individuals of a species. Did the hollows house a gland? A sensory organ? Attachments for a structure that made an individual sexually appealing to others of the species? Muscles to move an especially long and flexible nose? (Picture Secretariat with a trunk!) The gland theory is currently popular, but for now we can only guess why they evolved and what purpose they served.

Three-toed horses eventually died out, and it isn't clear why they did. During their reign, they enjoyed tremendous success. Perhaps some day the fossil record will revel reasons for the extinction of the three-toed species, and the proliferation of their one-toed descendants.

Evidence for these evolutionary stages can be observed, not only in fossil bone collections, but in the anatomy of any horse today. The splint bones in the legs of modern equids are vestiges of their three-toed days. If you feel behind the fetlock of a horse, you will feel a small, horny growth, the remainder of what used to function as the dog-like pads on the feet of ancient relatives. Even the DNA of modern horses remembers the code for being a three-toed horse. On occasion, a foal will be born with two small, atavistic toes on either side of the fetlock.

Pliohippus was one of the descendants of Merychippus that closely resembled Equus. With this genus, the side toes had been reduced to a single, well-formed hoof, and Pliohippus approached Equus in size. However the facial fossae shoed no reduction in size, and the curved cheek teeth indicate that while the feet were more Equus-like, the species was probably not ancestral to Equus, representing a lateral move on the evolutionary tree.

Recently discovered Dinohippus, who lived twelve million years ago in the Pliocene, is now thought by many paleontologists to be the horse that gave rise to Equus. Dinohippus showed more Equus-like features, such as decreasing facial fossae and straighter teeth, as well as evolving to a single hoof.

Towards the end of the Pliocene, Equus appeared. Those first horses of four million years ago were of the same genus of all members of the horse family that survive today. The first true horses were about the size of a large pony, about 13.3 to 14 hands in height, about 800 pounds, heavy boned, and built similarly to today's Prezwalski horse.

Fossil horses laid out in chronological order in a museum exhibit give the impression that Equus was the "goal" of evolution, that success meant gaining features that progressed the evolutionary trend towards Equus, and leaving behind those that did not. We must keep in mind that there is no goal to evolution. Evolutionary trends are simply adaptations to changes in the environment. There were many side branches of the equine family tree that were just as successful as today's horse, even more so, if time present on earth is considered the deciding factor. The fact that Equus happens to be the only horse that exists today does not imply that other lines were less efficient. If time on earth is considered the criterion for success as a species, Equus is still quite young.

All of this evolution took place primarily on the North American continent. As the Pliocene drew to a close, the horses took advantage of a land bridge that then linked North America to the old world, across what is now the Bering Strait. Some settled in Asian desert regions and evolved to asses and onagers. The equids that reached Africa mostly evolved into zebras, or the small, hardy, proto-Arabian horses. Equus caballus is the species that migrated through Asia and Europe to submit to domestication.

Other species of Equus migrated to South America and became common there. Until the Pliocene, South America was detached from North America, preventing species from moving between the continents. During the Pliocene, this changed, resulting in the evolution of several equine species unique to South America.

The horse family had experienced astonishing success in he past, but these early days of Equus were perhaps the most successful of any. Before one million years ago, Equus was well-established on every continent except for Australia and Antarctica. Except for bison and mammoths, horses were the most abundant large animal. Some scientists think they even outnumbered the bison. They migrated freely back and forth between North America and the old world. Highly adaptable, they were capable of living anywhere from the oven-like deserts, to periglacial tundra, to swamps, to mountain ranges, to open savanna. Horses were present in great numbers, almost everywhere.

Then suddenly, starting about 14,000 years ago, they vanished from North and South America, over the course of a few thousand years, (a mere eye-blink in the context of geological time). Where horses numbered in the tens of millions, suddenly there were none, for the first time in sixty million years.

Horses were not the only species to disappear during this period. Other large species such as the woolly mammoth, dire wolves, saber tooth cats, and North America's indigenous camels and elephants became extinct in this same short time frame. In America, almost three quarters of all large species died out, about 33 genera.

Why did they vanish? It wasn't the glaciers. Glaciers were present during times that horses enjoyed great prosperity, and were beginning to recede when the extinction occurred. Horses did well living on the steppes near the glaciers, and also thrived in distant climates unaffected by glaciation.

If some factor had decreased the amount of forage available, the antelope and bison would have suffered, too. Yet their numbers were on the increase as the horse disappeared. And the extinction was confined to the Americas. The old world horses continued to thrive as they always had.

The most widely accepted theory is that man played at least some role in their extinction. Mankind first came across the Bering Strait land bridge shortly before the horses began to disappear. Coincidence? Most scholars think not.

Humans are a quirky bunch, and individual cultural beliefs can be quite unique. These humans are presumed to be as intelligent and imaginative as people today, and one can only guess how they perceived horses, mammoths, and the rest twelve thousand years ago. We don't know much about the culture of these paleo-Indians. Maybe the horse and the mammoth were preferred as a source of meat, as cattle are to North Americans today. Maybe they defied horses, the way Hindus worship cattle, but believing that horseflesh must be consumed to bring blessing to the tribe. Perhaps they spun legends and myths about horses, and believed consuming the meat of the horse would make warriors as strong and fleet as a stallion. Or maybe they felt that horses were a pest that should be killed and eaten on sight..

Could people destroy millions of horses within a few thousand years? Certainly! Look at what we did to the passenger pigeon.

Prior to the 1800's passenger pigeons were so abundant in North America that the migrating flocks would literally darken the sky as they flew overhead. They were possibly the most numerous birds on earth. In the year 1810, ornithologist Alexander Wilson sat down one day beside a stream in Kentucky, to count the pigeons in the flock flying overhead. He guessed that they traveled at a speed of 60 miles per hour, at least three birds per cubic yard of air, on a front more than a mile wide. After an hour, the passing flock was wider and deeper than at the outset. The flock continued to flow across the sky until after sunset. His calculations: over two billion pigeons in a flock 240 miles long! Audubon, in 1913, observed a flock of more than a billion.

Early settlers found them easy to kill and useful for meat, feathers, and fat. As the railroads reached to the west in the 1850's, it became easier to transport the birds to the cities without spoilage, and pigeon hunters found a lucrative living in the infinite flocks, shipping them out by the millions. Killing methods were sloppy and indiscriminate. Often, during a hunt, just as many birds were mangled and left to die or fed to hogs. Nesting sites were plundered, adults not given the chance to reproduce.

Passenger pigeons required large flocks for breeding and migration, but by 1880, the numbers were dwindling. The species was unable to recover. They didn't breed well in captivity, and in 1914, the last passenger pigeon, a female named Martha, died in the Cincinnati Zoological Garden.

Passenger pigeons numbered in the hundreds of millions, yet were wiped out in only fifty years. It is certainly plausible that people could exterminate millions of horses over a few thousand years. We do know prehistoric man killed horses by stampeding them over cliffs, using as many animals as they required and abandoning the rest.

Over the past 2,000 years, over a hundred mammals have become extinct, most because of the encroachment of mankind. Over the last few centuries, humans have destroyed many other species, such as the heath hen, and the dodo. We have taken the prolific, successful Prezwalski and Tarpan horses and killed them off in the wild state. We have also killed off the Persian onager, the "wild ass " mentioned in the Bible. We have exterminated the zebra-like quagga. Many other species are threatened directly or indirectly by our presence on this planet. It shouldn't surprise us if early civilizations wiped out our American horses.

And what of the mammoths and saber-tooth cats? Maybe the ancient human hunters were like those of today - prizing the trophy of great tusks, horns or fangs.

It could have been a species-specific disease that wiped out the horses in North America. Again, there is no proof for such a theory, but the idea is plausible. Imagine a deadly equine disease spread by say, respiratory secretions. Two horses meeting each other blow into each other's nostrils. Horses are highly sociable animals, and rarely live alone. The young horses are driven off to join other bands. What would happen if they brought a highly contagious, deadly disease with them?

For now, we can only speculate. Whatever caused the extinctions -- and like most occurrences, probably more than one factor was contributory -- Old World populations of horses continued to thrive. It is fortunate that horses had taken hold in Europe, Africa, and Asia, or they would have been lost to us forever.

As it was, the Equus caballas line divided into several different subspecies. While mankind lived primitive in caves, Equus Caballas Przewalski ranged across the plains of central Asia. Prezwalski's horse persisted in the wild until the 1960's, a uniquely -- constructed, stocky animal with an upright mane, large head, colored in various shades of buckskin. There are no records of the Prezwalski horse ever having been trained to ride or drive. Zebras and quaggas, while not easily trained, have been on occasion saddle broken. Equus caballas Przewalski will submit to captivity and breed in zoos, but will not bend to the whims of a trainer. The Przewalski also has a different chromosomal count, having thirty-three pairs, which is one pair more than the domestic horse. Bred to the latter, they produce robust, fertile hybrids with a chromosomal count of sixty-five.

Often called the only "true" wild horse, the Przewalski is no longer wild at all. The story is a discouraging one.

The subspecies Equus caballas przewalski was adapted to life on the Siberian steppes. These horses of ten thousand years ago were thought to be migratory animals, seasonally relocating in a mighty throng of thousands of individuals, in the same fashion as reindeer. Eventually, mankind displaced the Przewalski horses from their preferred environment to more remote corners. These horses, suited for living on the tundra, were forced to their most recent habitat -- the furnace-like conditions of the Mongolian desert! What a tribute to equine versatility! They were actually able to survive in this forbidding climate, but the guns of hunters were a challenge against which they were defenseless.

The horse was officially named after the Russian explorer, N.M. Przewalski, who in 1879 received a skin and skull of the previously unrecognized equid as a gift. Around the turn of the century, Freidrich von Falz-Fein wanted a herd of about fifty for his zoological park at Askania Nova in the Ukraine. His agents sent almost two thousand hunters into the desert to capture live foals. The Przewalski horses were an intractable bunch, and the easiest way to capture live foals was to kill the parents. Of the many shipped, most died en route.

Natural history museums requested Przewalski horses shot and stuffed for educational dioramas. Zoos worldwide were interested in acquiring Mongolian wild horses, and more adults were exterminated to capture foals, most of which died in transit. The survivors arrived in poor condition, looking much like ill-bred, filthy, ornery domestic horses. The zoos were not impressed.

Zoos never acquired large numbers of the animals, resulting in a small gene pool for captivity-bred horses. World war two further reduced the breeding population by destroying the entire herd at Askania Nova. Inbreeding predisposed them to disease and infertility. At one point, domestic horses accidentally mated with zoo Przewalskis. This was both a blessing and a curse. The purity was muddied by outside genes, compromising the original undiluted lineage. But the zoo animals sorely needed an infusion of new genes, because the hybrid offspring were stronger, hardier, and more fertile. The numbers increased in captivity. (The zoo-bred horses in America escaped this interbreeding, and remained pure of blood.) In 1973, only 206 Przewalskis existed worldwide (all in zoos), twenty years later, the number had grown to 1,000.

Even in the wasteland of the Gobi desert, Przewalski horses were seen as pests, consuming vegetation better utilized by domestic livestock, and running off with mares in heat. Often, they were shot on sight. In 1968, the last documented native Przewalski was observed in the wild.

Fortunately for the species, the animals acquired by zoos increased their numbers. In 1993, a Dutch conservation foundation brought a herd of them to Mongolia, and managed them for a year while they adjusted to the challenging climate. In June of 1994, nineteen horses were given their freedom in the land where they once ranged. In 1995, every one of the released mares gave birth to a healthy foal, an amazing success rate. Hopefully by the year 2000, the herd will be fully reestablished in the wild.

Which brings us back to the question, should these Przewalskis be considered wild or feral? Yes, they are the purebred descendants of wild horses captured from the wild and re-established into their natural environment. (Or was their natural environment the tundra of ten-thousand years ago?) Then again, they are the result of generations of breedings carefully planned by zoos, matings arranged to give the few remaining survivors of the species the greatest possible genetic variability. These are horses that can not be trained for riding or draft, yet man has been their provider for generations. Are they domesticated? Are the released horses wild or feral?

The Tarpan, Equus caballas ferus, roamed the vast forests of eastern Europe since prehistoric times. Their range was contracted by expanding civilization, until they were killed off entirely in the mid-1800's. Once humans began to farm eastern Europe and the Ukraine, native horses were considered pests. They competed with livestock for forage, and the wily stallions would kidnap mares from the farmers of the Polish steppes. Some Tarpans were domesticated, many more were hunted down and eaten. In 1851, they became extinct.

Eventually people realized with regret that extinct is forever, and attempted to recreate the Tarpan subspecies by breeding together animals thought to have a high percentage of Tarpan blood. Over time, they developed a steel-gray, primitive-looking animal that can be seen in zoos today. Physically, these animals look like ancient Tarpans did, but genetically they cant be considered to represent the original subspecies, as we don't even know the chromosomal count of the old Tarpan.

The Tarpan is thought by many researchers to be the ancestor of all domestic breeds. Again, there are many different opinions on this. Some experts do not agree that the Tarpan should be considered a subspecies, suggesting that it descended from the Przewalski. With no horses remaining from the old line, little can be proved.

Other types included the proto-draft horse, found in Scandinavia, great Britain and into Spain ten thousand years ago. Reconstructions of fossil remains suggest this horse was quite similar to today's Exmoor pony. The proto-Arabian and Barbs were light, durable horses adapted to the hot deserts of the Middle East and northern Africa. Proto-warmblood horses ranged over central Europe.

Domestication of the horse was possible six to eight thousand years ago, pre-dating the invention of the wheel. Perhaps a foal was gentled and kept as a pet. More likely, man, a long-time consumer of horse flesh, recognized the advantages of keeping them close at hand as a source of meat during lean winter months. Other uses became apparent. Mares produced milk. Horses could pull a travois. Microscopes reveal wear on the teeth of horse skulls dating from 4,000 BC, indicating that horses were then being ridden with a bit of some sort in the mouth.

It probably didn't take long for man to recognize advantageous differences between individual horses, and selectively breed captive horses for these traits. If a stallion had a particular eye-catching coloration, it would be obvious before long that mares bred to him would be likely to bear similarly marked offspring. The same thinking could be applied to select for characteristics such as speed, stamina, gentle disposition, size, and so on. This practice resulted, over generations, in the development of breeds.

For the first time in history, horse phenotypes were determined more by the preferences of man than by environmental suitability and evolutionary advantages. Over the generations, domestic horses diverged from their wild cousins, and mankind continued to manipulate their genes for thousands of years.

And so, the horses brought by Cortez and the other Spaniards were merely returning to the land of their ancestors, after a relatively short absence. It is fortunate that the Spanish had preferred a stocky, hardy, agreeable mount. These horses had to endure brutal trans-Atlantic voyages over rough seas with no exercise and little food. Even the durable Spanish Jennets suffered high mortality during the crossing. A more delicate breed would not have survived at all.

The Spanish Jennets of 400 years ago do not exist today. The modern Andalusian breed has been modified over the years, and the breed characteristics have changed. There are some that claim that the Corolla, North Carolina feral horses are living examples of the Spanish Jennet, but genetic experts suggest that the blood has been somewhat diluted over time. Some believe the Cerbat mustangs, an isolated pocket of Spanish-looking horses found in the Cerbat mountains of Arizona, are genetically closest to the original Conquistador horses. Others insist that the modern Paso Finos and Peruvian Pasos most accurately represent the old Spanish animals.

Equine geneticist Dr. E. Gus Cothran comments "It is difficult at this point to say whether the Paso breeds are most like the Jennet. The results of my research are conflicting on this point right now. The Pasos tend to be more like the Old World Iberian horses than other New World descendants of Iberian horses."

Dr. Phil Sponenberg, of Virginia Polytechnic Institute and State University, points out that the old Spanish horse type was somewhat variable. This characteristic can be observed today in the strongly Spanish-based Lippazanner breed today. "Lippazaners have a history of largely or solely Spanish breeding for centuries, but in fact are very variable in type and conformation." explains Sponenberg. It is likely the Jennets of the fifteenth and sixteenth centuries displayed a similar variability. Breeders selected body types that best suited their needs and aesthetic preferences. Some types were refined continuously until they became a distinct new breed, like today's Andalusians. Some were crossed with other breeds to create new lines. Over time, the Jennet evolved into other types.

These hardy Spanish horses were instrumental to the success of the conquistadors, but with every settlement and expedition, more and more animals were lost to the wilds of the New World. Coronado, in a 1541 conquest, had a thousand extra horses and mules with him, until a hailstorm caused almost every one to escape. Desoto released some more in 1543. Within a century or two, wild North American Spanish mustangs numbered in the millions.

Many horses escaped or were stolen in the innumerable conflicts with Indians. Over generations these horses migrated through North and South America. Feral horses thrived in large numbers from Florida through the west. They spread up through Oregon and Idaho, and up into Canada. They enjoyed amazing biological success, so much that Charles Darwin, pondering the extinction of earlier horses, wrote in Origin of Species "I was filled with astonishment; for, seeing that the horse, since its introduction by the Spaniards into South America, has run wild over the whole country and has increased in numbers at an unparalleled rate, I asked myself what could so recently have exterminated the former horse under conditions of life apparently so favorable."

Could a few lost horses multiply so quickly to millions, considering a mare can only have one foal a year under the best of circumstances? In an article appearing in Horseman magazine written by Don Coldsmith, it is calculated how many offspring could result from a small number of escaped horses. Coldsmith maintains that if a mare's fertility is estimated somewhat conservatively, the progeny of a single pair of horses could produce almost 3 million offspring in six decades. Other researchers may put this figure lower, but the fact remains that these adaptable animals freed onto optimal habitat with few predators reproduced at an astounding rate.

The early North American mustangs were mostly the descendants of Spanish horses, but genes have been contributed from many other sources over the years. As civilization pressed westward, saddle horses, draft horses, and carriage horses escaped or were set free. Indians thieved horses from trappers, soldiers and farmers, only to have wild stallions steal mares from the loosely-tended Indian herds. Domestic horses escaped to run with the wild ones. Farmers who tried to wrest a living from the land often failed, and returned east, abandoning the livestock. The eastern breeds each contributed a subtle new flavor to the genes of the mustang. It is unlikely there are any mustangs remaining that are pure Spanish, but most carry a variable percentage of Spanish blood.