Among the six followers accompanying the chestnut on his foray was a young dun-colored mare, and in recent weeks she had been keeping close to him and he to her. They obviously felt an association, a responsibility each to the other, and normally they would by now have bred, but they were inhibited by a peculiar awareness that soon they would be on the move. None of the older animals had signified in any way that the herd was about to depart this congenial land by the twin pillars, but in some strange way the horses knew that they were destined to move—and to the north.
What was about to happen would constitute one of the major mysteries of the animal world. The horse, that splendid creature which had developed here at the twin pillars, would desert his ancestral home and emigrate to Asia, where he would prosper, and the plains at the pillars would be occupied by other animals. By the year 6000 B.C. he would become extinct in the Western Hemisphere.
The horses were about to move north and they knew they could not accommodate a lot of colts, so the chestnut and the mare held back. But one cold morning, when they had been chasing idly over the plains as if daring the dire wolves to attack them, they found themselves alone at the mouth of a canyon where the sun shone brightly; he mounted her and in due course she produced a handsome colt.
It was then that the herd started its slow movement to the northwest. Three times the chestnut tried unsuccessfully to halt them so that the colt could rest and have a fighting chance of keeping up. But some deep instinctive drive within the herd kept luring them away from their homeland, and soon it lay far behind them. The dun-colored mare did her best to keep the colt beside her, and he ran with ungainly legs to stay close. She was pleased to see that he grew stronger each day and that his legs functioned better as they moved onto higher ground.
But in the fifth week, as they approached a cold part of their journey, food became scarce and doubt was cast on the wisdom of this trek. The herd had to scatter to find forage, and one evening as the chestnut and the mare and their colt nosed among the scrub for signs of grass, a group of dire wolves struck at them. The mare instinctively presented herself to the gray wolves in an effort to protect her colt, but the fierce beasts were not distracted by this trick, and cut behind her to make savage lunges at her offspring. This enraged the chestnut, who sprang at the wolves with flashing hooves, but to no avail. Mercilessly, the wolves attacked the colt, whose piteous cries were cut off almost instantly.
The mare was distraught and tried to attack the wolves, but six of them detached themselves and formed a pack to destroy her. She defended herself valiantly for some moments while her mate battled with the other wolves near the body of the colt. Then one bold wolf caught her by a hamstring and brought her down. In a moment the others were upon her, tearing her to pieces.
The whole group of wolves now turned their attention to the chestnut, but he broke loose from them and started at a mad gallop back toward where the main herd of horses had been. The wolves followed him for a few miles, then gave up the chase and returned to their feast.
Unlike reptiles, mammals have some capacity for memory, and as the trek to the northwest continued, the chestnut felt sorrow at the loss of his mate and the colt. But he did not grieve long because he was soon preoccupied with the problems of the journey.
It was a strange hegira on which these horses were engaged. It would take them across thousands of miles and onto land that had been under water only a few centuries earlier. For this was the age of ice. Vast glaciers crept from the North Pole to areas that are now Pennsylvania and Wisconsin and Wyoming, erasing whatever vegetation had developed there and carving the landscape into new designs.
At no point on Earth were the changes more dramatic than at the Bering Sea, that body of ice-cold water which separates Asia from America. The great glaciers used up so much ocean water that the level of this sea dropped three hundred feet. This eliminated the Bering Sea altogether, and in its place appeared a massive land bridge more than a thousand miles wide. It was an isthmus, really, joining two continents, and now any animal that wished, or man, too, when he came along, could walk with security from Asia to America—or the other way.
The bridge, it must be understood, was not constructed along that slim chain of islands which now reaches from America to Asia. Not at all. The drop of ocean was so spectacular that it was the main body of Asia that was joined substantially to America; the bridge was wider than the entire compass of Alaska.
It was toward the direction of this great bridge, barely existent when the true horse emerged, that the chestnut now headed. In time, as older horses died off, he became the acknowledged leader of the herd, the one who trotted at the head on leisurely marches to new meadows, the one who marshaled the herd together when danger threatened. He grew canny in the arts of leadership, homing in on the good pastures, seeking out the protected resting places.
As the horses marched to the new bridge in the northwest, to their right in unending procession lay the snouts of the glaciers, now a mile away but, later on, a hundred miles distant, but always pressing southward and commandeering meadowlands where horses had previously grazed. Perhaps it was this inexorable pressure of ice from the north, eating up all the good land, that had started the horses on their migration; certainly it was a reminder that food was getting scarce throughout their known world.
One year, as the herd moved ever closer to the beginning of the bridge, the horses were competing for food with a large herd of camels that were also deserting the land where they had originated. The chestnut, now a mature horse, led his charges well to the north, right into the face of the glacier. It was the warm period of the year and the nose of the glacier was dripping, sc that the horses had much good water and there was, as he had expected, good green grass.
But as they grazed, idling the summer away before they returned to the shoreline, where they would be once more in competition with the camels, he happened to peer into a small canyon that had formed in the ice, and with four companions he penetrated it, finding to his pleasure that it contained much sweet grass. They were grazing with no apprehension when suddenly he looked up to see before him a gigantic mammoth. It was as tall as three horses, and its mighty tusks were like none he had seen at the pillars. These tusks did not stretch forward, but turned parallel to the face in immense sweeping circles that met before the eyes.
The chestnut stood for a moment surveying the huge beast. He was not afraid, for mammoths did not attack horses, and even if for some unfathomable reason this one did, the chestnut could easily escape. And then slowly, as if the idea were incomprehensible, the stallion began to realize that under no circumstances could this particular mammoth charge, for it was dead. Its frozen rear quarters were caught in the icy grip of the glacier; its front half, from which the glacier had melted, seemed alive. It was a beast in suspension. It was there, with all its features locked in ice, but at the same time it was not there.
Perplexed, the chestnut whinnied and his companions ambled up. They looked at the imprisoned beast, expecting it to charge, and only belatedly did each discover for himself that for some reason he could not explain, this mammoth was immobilized. One of the younger horses probed with his muzzle, but the silent mammal gave no response. The young horse became angry and nudged the huge beast, again with no results. The horse started to whinny; then they realized that the great beast was dead. Like all horses, they were appalled by death and silently withdrew.
But the chestnut wanted to investigate this mystery, and in succeeding days he returned timorously to the small canyon, intrigued by a situation that he could not understand. The puzzle completely eluded him, so he returned to the grassy area and led his herd backward toward the main road to Asia.
It must not be imagined that the horses migrated to Asia in any steady progression. The distance from the twin pillars to Siberia was only thirty-five hundred miles, and since a horse could cover twenty-five miles a day, the trip might conceivably have been completed in less than a year, but it di
d not work that way. The horses never chose their direction; they merely sought easier pasturage, and sometimes a herd would linger in one favorable spot for eight or nine years. They were pulled slowly westward by mysterious forces, and no horse that started from the twin pillars ever got close to Asia.
But drift was implacable, and the chestnut spent his years from three to sixteen on this overpowering journey, always tending toward the northwest, for the time of the horse in America was ended.
They spent four years on the approaches to Alaska, and now the chestnut had to extend himself to keep pace with the younger horses. Often he fell behind, but he knew no fear, confident that an extra burst of effort would enable him to join the herd. He watched as younger horses took the lead, giving the signals for marching and halting. The grass seemed thinner this year, and more difficult to find.
One day, late in the afternoon, he was foraging in sparse lands when he became aware that the main herd—indeed the whole herd—had moved on well beyond him. He raised his head with some difficulty, for his breathing had grown tighter, to see that a pack of dire wolves had interposed itself between him and the herd. He looked about quickly for an alternate route, but those available would lead him farther from the other horses; he knew he could outrun the wolves, but he did not wish to increase the distance between himself and the herd.
He therefore made a daring, zigzag dash right through the wolves and toward the other horses. He kicked his heels and with surprising speed negotiated a good two thirds of the distance through the snarling wolves. Twice he heard jaws snapping at his fetlocks, but he managed to kick free.
Then, with terrible suddenness, his breath came short and a great pain clutched at his chest. He fought against it, kept pumping his legs. He felt his body stopping almost in midnight, stopping while the wolves closed in to grab his legs. He felt a sharp pain radiating from his hindquarters where two wolves had fastened onto him, but this external wolf-pain was of lesser consequence than the interior horse-pain that clutched at him. If only his breathing could be maintained, he could throw off the wolves. He had done so before. But now the greater pain assailed him and he sank slowly to earth as the pack fell upon him.
The last thing he saw was the uncomprehending herd, following younger leaders, as it maintained its glacial course toward Asia.
Why did this stallion that had prospered in Colorado desert his comfortable homeland for Siberia? We do not know. Why did the finest animal America developed become discontented with the land of his origin? There is no answer.
We know that when the horse negotiated the land bridge, which he did with apparent ease and in considerable numbers, he found on the other end an opportunity for varied development that is one of the bright aspects of animal history. He wandered into France and became the mighty Percheron, and into Arabia, where he developed into a lovely poem of a horse, and into Africa, where he became the brilliant zebra, and into Scotland, where he bred selectively to form the massive Clydesdale. He would also journey into Spain, where his very name would become the designation for gentleman, a caballero, a man of the horse. There he would flourish mightily and serve the armies that would conquer much of the known world, and in 1519 he would leave Spain in small, adventurous ships of conquest and land in Mexico, where he would thrive and develop special characteristics fitting him for life on upland plains. In 1543 he would accompany Coronado on his quest for the golden city of Quivira, and from later groups of horses brought by other Spaniards some would be stolen by Indians and a few would escape to become feral, once domesticated but now reverted to wildness. And from these varied sources would breed the animals that would return late in history, in the year 1768, to Colorado, the land from which they had sprung, making it for a few brief years the kingdom of the horse, the memorable epitome of all that was best in the relationship of horse and man.
THE MASTODON
The world has known many ice ages, two of which lasted for millennia when much of Europe and North America lay crushed beneath monstrous thicknesses of ice. The winds howled across endless wastes and freezing night seemed perpetual. When the sun did appear, it was unproductive, shining down on deadly ice surfaces. All visible living things perished: grasses and trees, worms and insects, fish and animals. Desolation ruled.
But each protracted ice age was followed by intervals of equal length when the ice mysteriously retreated to release from its frozen prison an Earth bursting with energy and the capacity to restore life in all its manifestations. Grasses flourished to feed the animals that returned. Trees grew, some bearing fruits. Fields, nourished with minerals long unused, bore lavish crops, and birds sang. The future Wisconsins and Austrias exploded into life as the sun brought back warmth and well-being. The world had returned to abundant life.
The first two great ice ages began to evolve so very long ago—say, about seven hundred million years—that they need not concern us. But some two million years ago when the historical record was about to begin, a series of much briefer ice ages arrived, and their dates, extents and characteristics were so well defined that they have been given distinctive names: Nebraskan, Kansan, Illinoian, Wisconsin, and—in Europe—Gunz, Mindel, Riss, Wurm, with the last segment in each group subdivided into three parts, making six in all.
Strangely, although a permanent ice cap came in time to cover the South Pole, which was a continent, to a depth of two miles, none developed at the North, which was only a sea. The glaciers that covered North America stemmed from caps in Canada; those that submerged Europe, from the Scandinavian countries; and those that struck Russia, from sites near the Barents Sea. And because the movement of ice in North America was mainly to the south, Alaska would never lie under a massive ice sheet. It would become known as a cold and barren land covered with ice and snow, but it would never know in all its millennia as much ice as a more habitable state like Connecticut had once known.
The later ice ages created in Alaska a result more dramatic than what happened anywhere else in America, and for a reason that becomes obvious once it is pointed out. If an ice sheet more than a mile thick is going to cover much of North America, the water it imprisons will have to come from somewhere, and it cannot come mysteriously from outer space. It cannot arrive on the surface of the Earth; it can come only from water already here, which means that it must be stolen from the oceans. And that is what happened: dry winds whipping across the oceans lifted huge quantities of water that fell as cold rain over the high latitudes and as snow toward the poles. As it was compressed into ice it began to expand outward, covering hitherto barren sites, and causing more and more of the incoming moisture to fall as snow. This in turn fed the existing glaciers and created new ones.
In the recent period with which we are concerned, this theft of water continued for thousands of years, until the snowfields were immensely aggrandized and the oceans seriously depleted. In fact, when the deficiency was at its worst, only some twenty thousand years ago, the level of the world’s oceans—all of them—was more than three hundred feet lower than it is now. All the American states that faced the Atlantic Ocean had shorelines that extended miles farther eastward than they do now; much of the Gulf of Mexico was dry; Florida was not a peninsula, nor was Cape Cod a cape. Caribbean islands coalesced into a few huge islands, and the shoreline of Canada could not be seen at all, for it was smothered in ice.
This sharp droppage in the level of the oceans meant that land areas which had previously been separated were now joined by necks of land, which the subsiding waters revealed. Australia was attached to Antarctica by such a land bridge, Ceylon to India, Cyprus to western Asia, and England to Europe. But the most spectacular join was that of Alaska to Siberia, for it united two continents, allowing animals and people to pass from one to the other. It was also the only one that acquired its own name, scientists having christened it Beringia, the lost land of the Bering Sea.
About three hundred eighty-five thousand years ago, when the oceans and continents were in place as w
e know them today, the land bridge from Alaska to Siberia was open, and a huge, ponderous animal, looking much like an oversized elephant but with enormous protruding tusks, slowly made his way eastward, followed by four females and their young. He was by no means the first of his breed to cross the bridge, but he was among the more interesting, for his life experience symbolized the majestic adventure in which the animals of his period were engaged.
He was a mastodon, and we shall call him by that name, for he was a progenitor of those noble massive beasts who ranged Alaska. Obviously, a million years before, he had stemmed from the same source that produced the elephant, but in Africa, in Europe, and later in Central Asia, he had developed those characteristics that differentiated him from his cousin the elephant. His tusks were larger, his front shoulders lower, his legs more powerful, and his body was covered with hair that was more visible. But he behaved in much the same way, foraged for the same kinds of food, and lived to about the same age.
When he crossed the bridge—less than seventy miles from Asia to Alaska—Mastodon was forty years old and could expect to survive into his late seventies, supposing that he escaped the ferocious wild cats who relished mastodon meat. His four females were much younger than he, and as was common in the animal kingdom, they could anticipate a somewhat longer life.
As the mastodons entered Alaska they faced radically different types of terrain, varying somewhat from the land they had left behind in Asia. At the farthest north, facing the Arctic Ocean, lay a thin strip of Arctic desert, a bleak and terrifying land of shifting sands on which little that was edible grew. During the dozen winter weeks when no sun appeared, it was covered by thin snow that piled up into high drifts that were whipped by intense winds across the barren landscape and came to rest in low drifts behind some bridges or rocks.