3

THE INHABITANTS

ANY SEGMENT OF LAND—THE MOON, FOR EXAMPLE—CAN BE interesting of itself, but its greater significance must always lie in the life it sustains.

Toward dusk on a spring evening one hundred and thirty-six million years ago a small furry animal less than four inches long peered cautiously from low reeds which grew along the edge of a tropical lagoon that covered much of what was to be Colorado. It was looking across the surface of the water as if waiting for some creature to emerge from the depths, but nothing stirred.

From among the fern trees to the left there was movement, and for one brief instant the little animal looked in that direction. Shoving its way beneath the drooping branches and making considerable noise as it awkwardly approached the lagoon for a drink of water, came a medium-sized dinosaur, walking on two legs and twisting its short neck from side to side, as if on the watch for larger animals that might attack.

It was about three feet tall at the shoulders and not more than six feet in length. Obviously a land animal, it edged up to the water carefully, constantly jerking its short neck in probing motions. In paying so much attention to the possible dangers on land, it overlooked the real danger that waited in the water, for as it reached the lagoon and began lowering the forepart of its body so that it could drink, a fallen log which had lain inconspicuously half in the water, half out sprang into action.

It was a crocodile, well armored in heavy skin and possessed of powerful jaws lined with piercing teeth. It made a lunge at the drinking dinosaur, but it had moved too soon. Its well-calculated grab at the reptile’s right foreleg missed by a fraction, for the dinosaur managed to withdraw so speedily that the great snapping jaw closed not on the bony leg, as intended, but only upon the soft flesh covering it.

There was a ripping sound as the crocodile tore off a strip of flesh, and a sharp guttural click as the wounded dinosaur responded to the pain. Then peace returned. The dinosaur could be heard for some moments retreating. The disappointed crocodile swallowed the meager meal it had caught, then returned to its loglike camouflage, and the furry little animal returned to its earlier preoccupation of staring at the surface of the lagoon.

Its attention was poorly directed, for as it watched, it became aware, with a sense of terrible panic, of wings in the darkening sky, and at the very last moment of safety it threw itself behind the trunk of a ginkgo tree, flattened itself out, and held its breath as a large flying reptile swooped down, its gaping, sharp-toothed mouth open, and just missed its target.

Still flat against the moist earth, the little animal watched in terror as the huge reptile banked low over the lagoon and returned in what under other circumstances might have been a beautiful flight. This time it came straight at the crouching animal, but then, abruptly, had to swerve away because of the ginkgo roots. Dipping one wing, it turned gracefully in the air, then swooped down on another small creature hiding near the crocodile, unprotected by any tree.

Deftly the flying reptile snapped its beak and caught its prey, which uttered high shrieks as it was carried aloft. For some moments the little animal hiding in the ginkgo watched the flight of its enemy as the reptile dipped and swerved through the sky like a falling feather, finally vanishing with its catch.

The little watcher could breathe again. It was unlike the great reptiles, for they were cold-blooded and it was warm. They raised their babies from hatching eggs, while its came from the mother’s womb. It was a pantothere, one of the earliest mammals and progenitor of later types like the opossum, and it had scant protection in the swamp. Watching cautiously lest the flying hunter return, it ventured forth to renew its inspection of the lagoon, and after a pause, spotted what it had been looking for.

About ninety feet out into the water a small knob had appeared on the surface. It was only slightly larger than the watching animal itself, about six inches in diameter. It seemed to be floating on the surface, unattached to anything, but actually it was the unusual nose of an animal that had its nostrils on top of its head. The beast was resting on the bottom of the lagoon and breathing in this inventive manner.

Now, as the watching animal expected, the floating knob began slowly to emerge from the waters. It was attached to a head, not extraordinarily large but belonging obviously to an animal markedly bigger than either the first dinosaur or the crocodile. It was not a handsome head, nor graceful either, but what happened next displayed each of those attributes.

For the head continued to rise from the lagoon, higher and higher and higher in one long beautiful arch, until it stood twenty-five feet above the water, suspended at the end of a long and most graceful neck. It was like a ball extended endlessly upward on a frail length of wire, and when it was fully aloft, with no body visible to support it, the head turned this way and that in delicate motion, as if surveying the total world that lay below.

The small head and enormous neck remained in this position for some minutes, sweeping in lovely arcs of exploration. Apparently the small eyes which stood on either side of the projecting nose at the top of the skull were reassured by what they saw, for now a new kind of motion ensued.

From the surface of the lake an enormous construction began slowly to appear, an inch at a time, muddy waters falling from it as it rose. Slowly, slowly the thing in the lagoon came into view, until it disclosed a monstrous prism of dark flesh to which the prehensile neck was attached.

The body of the great reptile looked as if it were about twelve feet tall, but how far into the water it extended could not be discerned; it surely went very deep. Now, as the furry animal on shore watched, the massive body began to move, slowly and rhythmically. Where the neck joined the great dark bulk of the body, little waves broke and slid along the flanks of the beast. Water dripped from the upper part of the body as it moved ponderously through the swamp.

The reptile appeared to be swimming, its neck probing in sweeping arcs, but actually it was walking on the bottom, its huge legs hidden by water. And then, as it drew closer to shore and entered shallower water, there occurred a moment of marked grace and beauty. From the water trailing behind the animal, an enormous tail emerged. Longer than the neck and disposed in more delicate lines, it extended forty-four feet, swaying slightly on the surface of the lagoon. From head to tip of tail, the reptile measured eighty-seven feet.

Up to now it had looked like a long snake, floundering through the lagoon, but the truth was about to be revealed, for as the reptile advanced, the massive legs which had been supporting it became visible. They were enormous, four pillars of great solidity attached to the torso by joints of such crude construction that although the creature was amphibious, she could not easily support herself on dry land, where water did not buoy her up.

With slow, lumbering strides the reptile moved toward a clear river that emptied into the swamp, and now its total form was visible. Its head reared thirty-five feet; its shoulders were thirteen feet high; its tail dragged aft some fifty feet; it weighed nearly thirty tons.

It was diplodocus, not the largest of the dinosaurs and certainly not the most fearsome. This particular specimen was a female, seventy years old and in the prime of life. She lived exclusively on vegetation, which she now sought among the swamp waters. Moving her small head purposefully from one kind of plant to the next, she cropped off such food as she could find. This was not an easy task, for she had an extremely small mouth studded with minute peglike front teeth and no back ones for chewing. It seems incomprehensible that with such trivial teeth she could crop enough food to nourish her enormous body, but she did. It was this problem of chewing that had brought her toward the shore, this and one other strange impetus that she could not yet identify. She attended first to the chewing.

After finishing with such plants as were at hand, she moved into the channel. The mammal, still crouching among the roots of the ginkgo tree, watched with satisfaction as she moved past. It had been afraid that she might plant one of her massive feet on its nest, as another dinosaur had done, obliterating both the nest and its young. Indeed, diplodocus left underwater footprints so wide and so deep that fish used them as nests. One massive footprint might be many times as wide as the mammal was long.

And so diplodocus moved away from the lagoon and the apprehensive watcher. As she went she was one of the most totally lovely creatures so far seen on earth, a perfect poem of motion. Placing each foot carefully and without haste, and assuring herself that at least two were planted solidly on the bottom at all times, she moved like some animated mountain, keeping the main bulk of her body always at the same level, while her graceful neck swayed gently and her extremely long tail remained floating on the surface.

The various motions of her great body were always harmonious; even the plodding of the four gigantic feet had a captivating rhythm. But when the undulating grace of the long neck and the longer tail was added, this large reptile epitomized the beauty of the animal kingdom as it then existed.

She was looking for a stone. For some time she had instinctively known that she lacked a major stone, and this distressed her. She had become agitated about the missing stone and now proposed settling the matter. Keeping her head low, she scanned the bottom of the stream but found no suitable stones.

This forced her to move upstream, the delicate motion of her body conforming to the shifting bottom as it rose slightly before her. Now she came upon a wide selection of stones, but prudence warned her that they were too jagged for her purpose, and she ignored them. Once she stopped, turned a stone over with her blunt nose and scorned it. Too many cutting edges.

Her futile search made her irritable and she failed to notice the approach of a rather large land-based dinosaur that walked on two legs. He did not come close to approaching her in size, but he was quicker of motion, and had a large head, gaping mouth and a ferocious complement of jagged teeth. He was a meat-eater, always on the watch for the giant water-based dinosaurs who ventured too close to land. He was not large enough to tackle a huge animal like diplodocus if she was in her own element, but he had found that usually when the large reptiles came into the stream, there was something wrong with them, and twice he had been able to hack one down.

He approached diplodocus from the side, stepping gingerly on his two powerful hind feet, keeping his two small front feet ready like hands to grasp her should she prove to be in weakened condition. He was careful to keep clear of her tail, for this was her only weapon.

She remained unaware of her would-be attacker, and continued to probe the river bottom for the right stone. The carnivorous dinosaur interpreted her lowered head as a sign of weakness. He lunged at the spot where her vulnerable neck joined the torso, only to find that she was in no way incapacitated, for when she saw him coming she twisted adroitly, and presented the attacker with the broad and heavy side of her body. This repulsed him, and he stumbled back. As he did so, diplodocus stepped forward, and slowly swung her tail in a mighty arc, hitting him with such force that he was thrown off his feet and sent crashing into the brush.

One of his small front feet was broken by the blow and he uttered a series of awk-awks, deep in his throat, as he shuffled off. Diplodocus gave him no more attention and resumed her search for the right stone.

Finally she found what she wanted. It weighed about three pounds, was flattish on the ends and both smooth and rounded. She nudged it twice with her snout, satisfied herself that it was suited to her purposes, then lifted it in her mouth, raised her head to its full majestic height, swallowed the stone and allowed it to slide easily down her long neck into her gullet and from there into her grinding gizzard, where it joined six smaller stones that rubbed together gently and incessantly as she moved. This was how she chewed her food, the seven stones serving as substitutes for the molars she lacked.

With awkward yet attractive motions she adjusted herself to the new stone, and could feel it find its place among the others. She felt better all over and hunched her shoulders, then twisted her hips and flexed her long tail.

Night was closing in. The attack by the smaller dinosaur reminded her that she ought to be heading back toward the safety of the lagoon, back where fourteen other reptiles formed a protective herd, but she was kept in the river by a vague longing which she had experienced several times before, but which she could not remember clearly. She had, like all members of the diplodocus family, an extremely small brain, barely large enough to send signals to the various remote parts of her body. For example, to activate her tail became a major tactical problem, for any signal originating in her distant head required some time to reach the effective muscles of the tail. It was the same with the ponderous legs; they could not be called into instant action.

Her brain was too small and too undifferentiated to permit reasoning or memory; habit ingrained warned her of danger, and only the instinctive use of her tail protected her from the kind of assault she had just experienced. As for explaining in specific terms the gnawing agitation she now felt, and which had been the major reason for her leaving the safety of the herd, her small brain could give her no help.

She therefore walked with splashing grace toward a spot some distance upstream. How beautiful she was as she moved through the growing darkness! All parts of her great body seemed to relate to one central impulse, gently twisting neck, stalwart central structure, slow-moving mighty legs, and delicate tail extending almost endlessly behind and balancing the whole. It would require far more than a hundred million years of experiment before her equal would be seen again.

She was moving toward a white chalk cliff which she had known before. It stood some distance in from the lagoon, sixty feet higher than the river at its feet. Here, back eddies had formed a swamp, and as she approached this protected area, diplodocus became aware of a sense of security. She hunched her shoulders again and adjusted her hips. Moving her long tail in graceful arcs, she tested the edge of the swamp with one massive forefoot. Liking what she felt, she moved slowly forward, sinking deeper and deeper into the dark waters until she was totally submerged, except for the knobby tip of her head which she left exposed so that she could breathe.

She did not fall asleep, as she should have done. The gnawing insatiety kept her awake, even though she could feel the new stone working on the foliage she had consumed that day and even though the buzzing of the day insects had ceased, indicating that night was at hand. She wanted to sleep but could not, so after some hours the tiny brain sent signals along the extended nerve systems and she pulled herself through the swamp with noisy sucking sounds. Soon she was back in the main channel, still hunting vaguely for something she could neither define nor locate. And so she spent the long tropical night.

Diplodocus was able to function as capably as she did for three reasons. When she was in the swamp at the foot of the cliff, an area that would have meant death for most animals, she was able to extricate herself because her massive feet had a curious property; although they made a footprint many inches across as they flattened out in mud, they could, when it came time to withdraw them from the clinging muck, compress to the width of the foreleg, so that for diplodocus to pull her huge leg and foot from mud was as simple as pulling a reed from the muck at the edge of the swamp; there was nothing for the mud to cling to, and the leg pulled free with a swooshing sound.

Diplodocus, “double beams,” was so named because sixteen of her tail vertebrae—twelve through twenty-seven behind the hips—were made with paired flanges to protect the great artery that ran along the underside of the tail. But the vertebrae had another channel topside, and it ran from the base of the head to the strongest segment of the tail. In this channel lay a powerful and very thick sinew which was anchored securely at shoulder and hip and which could be activated from either position. Thus the long neck and the sweeping tail were the progenitors of the crane, which in later time would lift extremely heavy objects by the clever device of running a cable over a pulley and counterbalancing the whole. The pulley used by diplodocus was the channel made by the paired flanges of the vertebrae; her cable was the powerful sinew of neck and tail; her counterbalance was the bulk of her torso, and all functioned with an almost divine simplicity. Had she had powerful teeth, her neck was so excellently balanced that she could have lifted into the air the dinosaur that attacked her in the way the claw of a well-designed crane can lift an object many times its own apparent weight. Without this advanced system of cable and pulley, diplodocus could have activated neither her neck nor her tail, and she could not have survived. With it, she was a sophisticated machine, as well adapted to her mode of life as any animal which might succeed her in generations to come.

The third advantage she had was remarkable, and raises questions as to how it could have developed. The powerful bones of her legs, which were under water most of the time, were of the most heavy construction, thus providing her with necessary ballast, but those that were higher in her body were of successively lighter bulk, not only in sheer weight but also in actual bone composition, and this delicate construction buoyed up her body, permitting it almost to float.

That was not all. Many fenestrations, open spaces like windows, perforated the vertebrae of her neck and tail, thus reducing their weight. These intricate bones, with their channels top and bottom, were so exquisitely engineered that they can be compared only to the arches and windows of a Gothic cathedral. Bone was used only where it was required to handle stress. No shred was left behind to add its weight if it could be dispensed with, yet every arch required for stability was in place. The joints were articulated so perfectly that the long neck could twist in any direction, yet the flanges within which the sinews rode were so strong that they would not be damaged if a great burden was placed on neck or head.

It was this marvel of engineering, this infinitely sophisticated machine which had only recently developed and which would flourish for another seventy million years, that floated along the shore of the lagoon that night, and when the little mammal came out of its nest at dawn, it saw her twisting her neck out toward the lagoon, then inland toward the chalk cliff.

Finally she turned and swam back toward the swamp at the foot of the cliff. When she reached there she sniffed the air in all directions, and one smell seemed familiar, for she turned purposefully toward fern trees at the far end of the swamp, and from them appeared the male diplodocus for which she had been searching. They approached each other slowly, poling themselves along the bottom of the swamp, and when they met they rubbed necks together.

She came close to him, and the little mammal watched as the two giant creatures coupled in the water, their massive bodies intertwined in unbelievable complexity. When he rutted he simply climbed on the back of his mate, locking his forepaws about her, and concluded his mating in seven seconds. The two reptiles remained locked together most of the forenoon.

When they were finished they separated and each by his own route swam away to join the herd. It consisted of fifteen members of the diplodocus family, three large males, seven females and five young animals. They moved together, keeping to the deep water most of the time but never loath to come into the river for food. In the water they poled themselves along with their feet barely touching bottom, their long tails trailing behind, and all kept in balance by that subtle arrangement of bone whereby the heaviest hung close to the bottom, allowing the lighter to float on top.

The family did not engage in play such as later animals of a different breed would; they were reptiles and as such were sluggish. Since they had cold blood with an extremely slow metabolism, they needed neither exercise nor an abundance of food; a little motion sufficed them for a day, a little food for a week. They often lay immobile for hours at a time, and their tiny brains spurred them to action only when they faced specific problems.

After a long time she felt another urge, positively irresistible, and she moved along the shore to a sandy stretch of beach not far from the chalk cliff. There she swept her tail back and forth, clearing a space, in the middle of which she burrowed both her snout and her awkward forelegs. When a declivity was formed, she settled herself into it and over a period of nine days deposited thirty-seven large eggs, each with a protective leathery shell.

When her mission ashore was accomplished, she spent considerable time brushing sand over the nest with her tail and placing with her mouth bits of wood and fallen leaves over the spot so as to hide it from animals that might disturb the eggs. Then she lumbered back to the lagoon, soon forgetting even where she had laid the eggs. Her work was done. If the eggs produced young reptiles, fine. If not, she would not even be aware of their absence.

It was this moment that the furry animal had been watching for. As soon as diplodocus submerged herself in the lagoon, he darted forth, inspected the nest, and found one egg that had not been properly buried. It was larger than he, but he knew that it contained food enough for a long time. Experience had taught him that his feast would be tastier if he waited some days for the contents to harden, so this time he merely inspected his future banquet, and kicked a little dirt over it so that no one else might spot it.

After the thirty-seven eggs had baked four days in the hot sand, he returned with three mates, and they began attacking the egg, gnawing with incisors at its hard shell. They had no success, but in their work they did uncover the egg even more.

At this point a dinosaur much smaller than any which had appeared previously, but at the same time much larger than the mammals, spotted the egg, knocked off one end and ate the contents. The pantotheres were not sorry to see this, for they knew that much meat would still be left in the remnants, so when the small dinosaur left the area, they scurried in to find that the broken eggshells did yield a feast.

In time the other eggs, incubated solely by action of the sun, hatched, and thirty-six baby reptiles sniffed the air, knew by instinct where the lagoon lay, and in single file, they started for the safety of the water.

Their column had progressed only a few yards when the flying reptile that had tried to snatch the mammal spotted them and with expert glide swooped down, catching one in its beak, taking it to its hungry young. Three more trips the reptile made, catching an infant diplodocus each time.

Now the small dinosaur that had eaten the egg also saw the column, and he hurried in to feed on six of the young. As he did so, the others scattered, but with an instinct that kept them moving always closer to the lagoon. The original thirty-seven were now down to twenty-six, and these were attacked continuously by the rapacious flier and the carnivorous dinosaur. Twelve of the reptiles finally reached the water, but as they escaped into it a large fish with bony head and jagged rows of teeth ate seven of them. On the way, another fish saw them swimming overhead and ate one, so that from the original thirty-seven eggs, there were now only four possible survivors. These, with sure instinct, swam on to join the family of fifteen grown diplodocuses, which had no way of knowing the young reptiles were coming.

As the little ones grew, diplodocus herself had no way of knowing that they were her children. They were merely reptile members that had joined the family, and she shared with other members of the herd the burden of teaching them the tricks of life.

When the young were partly grown, their thin snakelike bodies increasing immensely, diplodocus decided that it was time to show them the river. Accompanied by one of the adult males, she set out with the four youngsters.

They had been in the river only a short time when the male snorted sharply, made a crackling sound in his throat, and started moving as fast as he could back to the lagoon. Diplodocus looked up in time to see the most terrifying sight the tropical jungle provided. Bearing down upon the group was a monstrous two-legged creature towering eighteen feet high, with huge head, short neck and rows of gleaming teeth.

It was allosaurus, king of the carnivores, with jaws that could bite the neck of diplodocus in half. When the great beast entered the water to attack her, she lashed at him with her tail and knocked him slightly off course. Even so, the monstrous six-inch claws on his prehensile front feet raked her right flank, laying it open.

He stumbled, righted himself and prepared a second attack, but again she swung her heavy tail at him, knocking him to one side. For a moment it looked as if he might fall, but then he recovered, left the river and rushed off in a new direction. This put him directly behind the male diplodocus, and even though the latter was retreating as fast as possible toward the lagoon, the momentum of allosaurus was such that he was able to reach forward and grab him where the neck joined the torso. With one terrifying snap of the jaws, allosaurus bit through the neck, vertebrae and all, and brought his victim staggering to his knees. The long tail flashed, but to no avail. The body twisted in a violent effort to free itself of the daggerlike teeth, but without success.

With great pressure, allosaurus pushed the giant reptile to the ground, then, without relinquishing its bloody hold, began twisting and tearing at the flesh until the mighty teeth joined and a large chunk of meat was torn loose. Only then did allosaurus back away from the body. Thrusting its chin in the air, it adjusted the chunk of meat in its mouth and dislocated its jaw in such a way that the huge morsel could slide down into the gullet, from whence it would move to the stomach, to be digested later. Twice more it tore at the body, dislodging great hunks of meat which it eased down its throat. It then stood beside the fallen body for a long time as if pondering what to do. Crocodiles approached for their share, but allosaurus drove them off. Carrion reptiles flew in, attracted by the pungent smell of blood, but they too were repulsed.

As allosaurus stood there defying lagoon and jungle alike, he represented an amazing development, as intricately devised as diplodocus. His jaws were enormous, their rear ends lashed down by muscles six inches thick and so powerful that when they contracted in opposing directions they exerted a force that could bite through trees. The edges of the teeth were beautifully serrated, so they could cut or saw or tear; sophisticated machines a hundred and forty million years later would mimic their principle.

The teeth were unique in another respect. In the jaw of allosaurus, imbedded in bone beneath the tooth sockets, lay seven sets of replacements for each tooth. If, in biting through the neck bones of an adversary, allosaurus lost a tooth, this was of little concern. Soon a replacement would emerge, and behind it six others would remain in line waiting to be called upon, and if they were used up, others would take place in line, deep within the jawbone.

Now allosaurus lashed his short tail and emitted growls of protest. He had killed this vast amount of food but could not consume it. Other predators appeared, including the two smaller dinosaurs that had visited the beach before. All remained at a safe distance from allosaurus.

He took one more massive bite from the dead body but could not swallow it. He spit it out, glared at his audience, then tried again. Covered with sand, the flesh rested in his gaping mouth for several minutes, then slid down the extended neck. With a combative awk-awk from deep within his throat, allosaurus lunged ineffectively at the watchers, then ambled insolently off to higher ground.

As soon as he was gone, the scavengers moved in—reptiles from the sky, crocodiles from the lagoon, two kinds of dinosaurs from land and the unnoticed mammals from the roots of the ginkgo tree. By nightfall the dead diplodocus, all thirty-three tons of him, had disappeared and only his massive skeleton lay on the beach.

Wounded diplodocus and the four young dinosaurs that had witnessed this massacre now swam back to the lagoon. In the days that followed, she began to experience the last inchoate urge she would ever know. Sharp pains radiated slowly from the place where allosaurus had ripped her. She found no pleasure in association with the other members of the herd. She was drawn by some inexplicable force back to the swamp at the chalk cliff, not for purposes of recreating the family of which she was a part but for some pressing reason she had never felt before.

For nine days she delayed heading for the swamp, satisfying herself with half-sleep in the lagoon, poling herself idly half-submerged from one warm spot to another, but the pain did not diminish. Vaguely she wanted to float motionless in the sun, but she knew that if she did this, the sun would destroy her. She was a reptile and had no means of controlling body heat; to lie exposed in the sun long enough would boil her to death in her own internal liquids.

Finally, on the tenth day she entered the river for the last time, stepping quietly like some gracious queen. She stopped occasionally to browse on some tree, lifting her head in a glorious arc on which the late sun shone. Her tail extended behind, and when she switched it for some idle purpose it gleamed like a scimitar set with jewels.

How beautiful she was as she took that painful journey, how gracefully coordinated her movements as she swam toward the chalk cliff. She moved as if she owned the earth and conferred grace upon it. She was the great final sum of millions of years of development. Slowly, swaying from side to side with majestic delicacy, she made her way to the swamp that lay at the foot of the cliff.

There she hesitated, twisting her great neck for the last time as if to survey her kingdom. Thirty feet above the earth her small head towered in one last thrust. Then slowly it lowered; slowly the graceful arc capsized. The tail dragged in the mud and the massive knees began to buckle. With a final surge of determination, she moved herself ponderously and without grace into a deep eddy.

Its murky waters crept up her legs, which would never again be pulled forth like reeds; this was the ultimate capture. The torn side went under; the tail submerged for the last time, and finally even the lovely arc of her neck disappeared. The knobby protuberance holding her nose stayed aloft for a few minutes, as if she desired one last lungful of the heavy tropical air, then it too disappeared. She had gone to rest, her mighty frame imprisoned in the muck that would embrace her tightly for a hundred and thirty-six million years.

It was ironic that the only witness to the death of diplodocus was the little pantothere that watched from the safety of a cycad tree, for of all creatures who had appeared on the beach, he was the only one that was not a reptile. The dinosaurs were destined to disappear from earth, while this little animal would survive, its descendants and collaterals populating the entire world, first with prehistoric mammals themselves destined to extinction—titanotheres, mastodons, eohippus—and subsequently with animals man would know, such as the mammoth, the lion, the elephant, the bison and the horse.

Of course, certain smaller reptiles such as the crocodile, the turtle and the snake would survive, but why did they and the little mammal live when the great reptiles vanished? This remains one of the world’s supreme mysteries. About sixty-five million years ago, as the New Rockies were emerging, the dinosaurs and all their immediate relations died out. The erasure was total, and scholars have not yet agreed upon a satisfactory explanation. All we know for sure is that these towering beasts disappeared. Triceratops with its ruffed collar, tyrannosaurus of the fearful teeth, ankylosaurus the plated ambulating tank, trachodon the gentle duck-billed monster—all had vanished.

Ingenious theories have been advanced, some of them captivating in their imaginativeness, but they remain only guesses. Yet because the mystery is so complete, and so relevant to man, all proposals merit examination. They fall into three major groups.

The first relates to the physical world, and each argument has some merit. Since the death of the dinosaurs coincided with the birth of the New Rockies, there may have been a causal relationship, with the vast lowland swamps disappearing. Or temperatures may have risen to a degree that killed off the great beasts. Or plant life may have altered so rapidly that the dinosaurs starved. Or the disappearance of the extensive inland sea changed water relationships and dried up lagoons. Or mountain building somehow involved loss of oxygen. Or a combination of changes in plant food doomed the reptiles. Or a single catastrophic sun flare burned the dinosaurs to death, while the mammals, with their built-in heat-adjusting apparatus, survived.

The second theory is more difficult to assess, because it deals with psychological factors, which, even though they may be close to the truth, are so esoteric that they cannot be quantitatively evaluated. Classes of animals, like men, empires and ideas, have a predestined length of life, after which they become senescent and die out. Or the dinosaurs had overspecialized and could not adapt to changes in environment. Or they became too large and fell of their own weight. Or they reproduced too slowly. Or their eggs became infertile. Or carnivores ate the vegetarian dinosaurs faster than they could reproduce and then starved for lack of food. Or for some unknown reason they lost their vital drive and became indifferent to all problems of survival.

The third combines all the reasons that relate to warfare between a declining reptilian world and a rising mammalian one. Mammals ate the eggs of the dinosaurs at such a rate that the reptiles could not keep producing enough to ensure survival. Or mammals of increasing size killed off the smaller reptiles and ate them. Or mammals preempted feeding grounds. Or mammals, because of their warm blood and smaller size, could adjust more easily to the changes introduced by the mountain building or other environmental shifts. Or a world-wide plague erupted to which the reptiles were subject while the mammals were not.

For each of these theories there are obvious refutations, and scholars have expounded them. But if we reject these proposals, where does that leave us in our attempt to find out why this notable breed of animal vanished? We must know, lest the day come when we repeat their mistakes and doom ourselves to extinction.

The best that can be said is that an intricate interrelationship of changes occurred, involving various aspects of life, and that the great reptiles failed to accommodate to them. All we know for sure is that in rocks from all parts of the world there is a lower layer dating back seventy million years in which one finds copious selections of dinosaur bones. Above it there is an ominous layer many feet thick in which few bones of any kind are found. And above that comes a new layer often crowded with the bones of mammal predecessors of the elephant, the camel, the bison and the horse. The dead reach of relatively barren rock, representing the death of the dinosaurs, has not yet been explained.

Long after they disappeared, and after man had risen to the point where he could search out the fossilized skeletons of the dinosaurs, it would become fashionable to make fun of the great reptiles which had vanished through some folly of their own. The lumbering beasts would be held up to ridicule as failures, as inventions that hadn’t worked, as proof that a small brain in a big body makes survival impossible.

Facts prove just the opposite. The giant reptiles dominated the earth for one hundred and thirty-five million years; man has survived only two million and most of that time in mean condition. Dinosaurs were some sixty-seven times as persistent as man has so far been. They remain one of the most successful animal inventions nature has provided. They adjusted to their world in marvelous ways and developed all the mechanisms required for the kind of life they led. They are honored as one of the world’s longest-lived species, and they dominated their vast period of time just as man dominates his relatively brief one.

Fifty-three million years ago, while the New Rockies were still developing and long after diplodocus had vanished, in the plains area, where the twin pillars formed, an animal began to develop which in later times would give man his greatest assistance, pleasure and mobility. The progenitor of this invaluable beast was a curious little creature, a four-legged mammal, for the age of reptiles was past, and he stood only seven or eight inches high at the shoulder. He weighed little, had a body covering of part-fur, part-hair and seemed destined to develop into nothing more than a small inconsequential beast.

He had, however, three characteristics which would determine his future potential. The bones in his four short legs were complete and separate and capable of elongation. On each foot he had five small toes, that mysteriously perfect number which had characterized most of the ancient animals, including the great dinosaurs. And he had forty-four teeth, arranged in an unprecedented manner: in front, some peglike teeth as weak as those of diplodocus; then a conspicuous open space; then at the back of the jaw, numerous grinding molars.

This little animal made no impression on his age, for he was surrounded by other much larger mammals destined for careers as rhinoceroses, camels and sloths. He lived carefully in the shady parts of such woods as had developed and fed himself by browsing on leaves and soft marsh plants, for his teeth were not strong and would quickly have worn down had they been required to eat rough food like the grass which was even then beginning to develop.

If one had observed all the mammals of this period and tried to evaluate the chances of each to amount to something, one would not have placed this quiet little creature high on the list of significant progenitors; indeed, it seemed then like an indecisive beast which might develop in a number of different ways, none of them memorable, and it would have occasioned no surprise if the little fellow had survived a few million years and then quietly vanished. Its chances were not good.

The curious thing about this little forerunner of greatness is that although we are sure that he existed and are intellectually convinced that he had to have certain characteristics, no man has ever seen a shred of physical evidence that he really did exist. No fossil bone of this little creature has so far been found; we have tons of bones of diplodocus and her fellow reptiles, all of whom vanished, but of this small prototype of one of the great animal families, we have no memorials whatever. Indeed, he has not yet even been named, although we are quite familiar with his attributes; perhaps when his bones are ultimately found—and they will be—a proper name would be “paleohippus,” the hippus of the Paleocene epoch. When word of his discovery is flashed around the world, scholars and laymen in all countries will be delighted, for they will have come into contact with the father of a most distinguished race, one which all men have loved and from which most have profited.

Perhaps thirteen million years after “paleohippus” flourished, and when the land that would contain the twin pillars had begun to form, the second in line and first-known in this animal family appeared and became so numerous that in the land about the future pillars hundreds of skeletons would ultimately be laid down in rock, so that scientists would know this small creature as familiarly as they know their own puppies.

He was eohippus, an attractive small animal about twelve inches high at the shoulder. He looked more like a friendly dog than anything else, with small alert ears, a swishing tail to keep insects away, a furry kind of coat and a longish face, which was needed to accommodate the forty-four teeth, which persisted. The teeth were still weak, so that the little creature had to content himself with leaves and other soft foods.

But the thing that marked eohippus and made one suspect that this family of animals might be headed in some important direction was the feet. On the short front feet, not yet adapted for swift movement, the five original toes had been reduced to four; one had only recently disappeared, the bones which had once sustained it vanishing into the leg. And on the rear foot there were now three toes, the two others having withered away during the course of evolution. But the surviving toes had tiny hoofs instead of claws.

One could still not predict what this inconspicuous animal was going to become, and the fact that he would stand second in the sixty-million-year process of creating a noble animal seemed unlikely. Eohippus seemed more suited for a family pet than for an animal of distinction and utility.

And then, about thirty million years ago, when the land that was to form the twin pillars was being laid down, mesohippus developed, twenty-four inches high at the shoulders and with all the basic characteristics of his ancestors, except that he had only three toes on each of his feet. He was a sleek animal, about the size of our collie or red fox. The forty-four teeth kept his face long and lean and his legs were beginning to lengthen, but his feet still contained pads and small hoofs.

Then, about eighteen million years ago, a dramatic development took place which solved the mystery. Merychippus appeared, a most handsome three-toed animal forty inches high, with bristly mane, extended face and protective bars behind the eye sockets.

He had one additional development which would enable the horse family to survive in a changing world: his teeth acquired the remarkable capacity to grow out from the socket as they wore down at the crown. This permitted the proto-horse to quit browsing on such leaves as he found and to move instead to grazing on the new grasses that were developing on the prairies. For grass is a dangerous and difficult food; it contains silica and other roughnesses that wear down teeth, which must do much grinding in order to prepare the grass for digestion. Had not merychippus developed these self-renewing grinders, the horse as we know it could have neither developed nor survived. But with this almost magical equipment, he was prepared.

These profound evolutions occurred on the plains that surrounded the site of the twin pillars. There on flat lands that knew varied climates, from tropical to sub-arctic, depending upon where the equator was located at the time, this singular breed of animal went through the manifold changes that were necessary before it stood forth as an accomplished horse.

One of the biggest changes in the antecedents of the horse appeared about six million years ago, when pliohippus, the latest in the breed, evolved with only one toe on each foot and with the pads on which his ancestors had run eliminated. It now had a single hoof. This animal was a medium-sized beautiful horse in almost every sense of the word, and would have been recognized as such, even from a considerable distance. There would be minor refinements, mostly in the teeth and in the shape of the skull, but the horse of historic times was now foreshadowed.

He arrived as equus about two million years ago, as splendid an animal as the ages were to produce. Starting from the mysterious and unseen “paleohippus,” this breed had unconsciously and with great persistence adapted itself to all the changes that the earth presented, adhering always to those mutations which showed the best chance of future development. “Paleohippus,” of the many capacities, eohippus of the subtle form, merychippus with the horselike appearance, pliohippus with the single hoof—these attributes persisted; there were dozens of other variations equally interesting which died out because they did not contribute to the final form. There were would-be horses of every description, some with the most ingenious novelties, but they did not survive, for they failed to adjust to the earth as it was developing; they vanished because they were not needed. But the horse, with its notable collection of virtues and adjustments, did survive.

About one million years ago, when the twin pillars were well formed, a male horse with chestnut coloring and flowing tail lived in the area as part of a herd of about ninety. He was three years old and gifted with especially strong legs that enabled him to run more swiftly than most of his fellows. He was a gamin creature and had left his mother sooner than any of the other males of his generation. He was the first to explore new arrivals on the prairie and had developed the bad habit of leading any horses that would follow on excursions into canyons or along extended draws.

One bright summer morning this chestnut was leading a group of six adventurous companions on a short foray from the main herd. He took them across the plains that reached out from the twin pillars and northward into a series of foothills that contained passageways down which they galloped in file, their tails flowing free behind them as they ran. It was an exhilarating chase, and at the end of the main defile they turned eastward toward a plain that opened out invitingly, but as they galloped they saw blocking their way two mammoths of extraordinary size. The great smooth-skinned creatures towered over the horses, for they were gigantic, fourteen feet tall at the shoulders, with monstrous white tusks that curved downward from the head. The tips of the tusks reached sixteen feet, and if they caught an adversary, they could toss him far into the air. The two mammoths were imposing creatures, and had they been ill-disposed toward the horses, could have created havoc, but they were placid by nature, intending no harm.

The chestnut halted his troop, led them at a sober pace around the mammoths, coming very close to the great tusks, then broke into a gallop which would take him onto the eastern plains, where a small herd of camels grazed, bending awkwardly forward. The horses ignored them, for ahead stood a group of antelope as if waiting for a challenge. The seven horses passed at full speed, whereupon the fleet antelope, each with a crown of four large antlers, sprang into action, darting after them.

For a few moments the two groups of animals were locked in an exciting race, the horses a little in the lead, but with a burst of speed the antelopes leaped ahead and before long the horses saw only dust. It had been a joyous race, to no purpose other than the challenge of testing speed.

Beside the grazing area on which the antelope had been feeding there rested a family of armadillos, large ratlike creatures encased in collapsible armor. The horses were vaguely aware of them but remained unconcerned, for the armadillo was a slow, peaceful creature that caused no harm. But now the round little animals stopped searching for slugs and suddenly rolled themselves into a defensive position. Some enemy, unseen to the horses, was approaching from the south and in a moment it appeared, a pack of nine dire wolves, the scourge of the plains, with long fangs and swift legs. They loped easily over the hill that marked the horizon, peering this way and that, sniffing at the air. The wolf serving as scout detected the armadillos and signaled his mates. The predators hurried up, inspected the armor-plated round balls, nudged them with their noses and turned away. No food there.

With some apprehension, the horses watched the nine enemies cross the grassland, hoping that they would pass well to the east, but this was not to be. The lead wolf, a splendid beast with sleek gray coat, spotted the horses and broke into a powerful run, followed instantly by his eight hunting companions. The chestnut snorted and in the flash of a moment realized that he must not lead his six horses back into the canyons from which they had just emerged, for the two mammoths might block the way, allowing the dire wolves to overtake any straggler and cut him down.

So with an adroit leap sideways he broke onto the plains in the direction the antelope had taken and led his troop well away from their home terrain. They galloped with purpose, for although the dire wolves were not yet close at hand, they had anticipated the direction the horses might take and had vectored to the east to cut them off. The chestnut, seeing this maneuver, led his horses to the north, which opened a considerable space between them and the wolves.

As they ran to their own safety, they passed a herd of camels that were slower-moving. The big awkward beasts saw the apprehension of the horses and took fright, although what the cause of the danger was they did not yet know. There was a clutter on the prairie and much dust, and when it had somewhat settled, the horses were well on their way to safety but the camels were left in the direct path of the nine wolves. The lumbering camels ran as fast as they could, scattering to divert attack, but this merely served to identify the slowest-moving and upon this unfortunate the wolves concentrated.

Cutting at him from all sides with fearful teeth, the wolves began to wear him down. He slowed. His head drooped. He had no defense against the dire wolves and within a few moments one had leaped at his exposed throat. Another fastened onto his right flank and a third slashed at his belly. Uttering a futile cry of anguish, the camel collapsed, his ungainly feet buckling under the weight of the wolves. In a flash, all nine were upon him, so that before the horses left the area, the camel had been slain.

At a slow walk they headed south for the hills that separated them from the land of the twin pillars. On the way they passed a giant sloth who stood sniffing at the summer air, dimly aware that wolves were on the prowl. The huge beast, twice the size of the largest horse, knew from the appearance of the horses that they had encountered wolves, and retreated awkwardly to a protected area. An individual sloth, with his powerful foreclaws and hulking weight, was a match for one wolf, but if caught by a pack, he could be torn down, so battle was avoided.

Now the chestnut led his horses into the low hills, down a gully and out onto the home plains. In the distance the twin pillars—white at the bottom where they stood on the prairie, reddish toward the top, and white again where the protecting caps rested—were reassuring, a signal of home, and when all seven of the troop were through the pass, they cantered easily back to the main herd. Their absence had been noted and various older horses came up to nuzzle them. The herd had a nice sense of community, as if all were members of the same family, and each was gratified when others who had been absent returned safely.

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 twin pillars, would desert his ancestral home and emigrate to Asia, where he would prosper, and the congenial plains at the pillars would be occupied by other animals. Then, about four hundred thousand years later, the horse would return from Asia to reclaim the pastures along the river, but 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, and 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 the wisdom of this trek, doubtful. Then 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 intuitively presented herself to the wolves in an effort to protect her colt, but the fierce gray beasts were not deluded by this trick, and cut behind her and made savage lunges at it. This enraged the chestnut, who sprang at the wolves with flashing hoofs, but to no avail. Mercilessly, the wolves cut down the colt. His piteous cries sounded for a moment, then died in harrowing gurgle as his own blood drowned him.

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 at 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.

Mammals, unlike reptiles, had 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 the recollection did not last long, and he was soon preoccupied with the problems of the journey.

It was a strange hegira on which the horses of Centennial 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. From the north pole to Pennsylvania and Wisconsin and Wyoming vast glaciers crept, 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 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 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 progression lay the snouts of the glaciers, now a mile away, 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 good land, that had started the horses on their emigration; 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, so 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 most 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 mammoth gave no response. The young horse became angry and nudged the huge beast, again with no results. The horse started to whinny; then they all realized that this great beast was dead. Like all horses, they were appalled by death and silently withdrew.

The chestnut alone wanted to investigate this mystery, and in succeeding days he returned timorously to the small canyon, still puzzled, still captivated by a situation that could not be understood. In the end he knew nothing, so he kicked his heels at the silent mammoth, returned to the grassy area, and led his herd back toward the main road to Asia.

It must not be imagined that the horses emigrated to Asia in any steady progression. The distance from the twin pillars to Siberia was only 3500 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 did not work that way. The horses never chose their direction; they merely sought easier pasturage and sometimes a herd would languish 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 in 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 regain 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 forelocks, 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 midflight, stopping while the wolves closed in to grab his legs. He felt a sharp pain radiating from his hind quarters 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 breath 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 so in Colorado desert his amiable 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 a 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 cities 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.

It would be dramatic if we could claim that as the horse left America he met on the bridge to Asia a shaggy, lumbering beast that was leaving Asia to take up his new home in America, but that probably did not happen. The main body of horses deserted America about one million years ago, whereas the ponderous newcomers did not cross the bridge which the horses had used—for it closed shortly after they passed—but a later bridge which opened at the same place and for the same reasons about eight hundred thousand years later.

The beast which came eastward out of Asia had developed late in biologic time, less than two million years ago, but it developed in startling ways. It was a huge and shaggy creature, standing very high at the shoulder and with enormous horns that curved outward, then forward from a bulky forehead that seemed made of rock. When the animal put its head down and walked resolutely into a tree, the tree usually toppled. This ponderous head, held low because of a specialized thick neck, was covered with long, matted hair which itself took up much of the shock when the beast used its head as a battering ram. Males also grew a long, stiff beard, so that their appearance at times seemed satanic. The other major characteristic was that the weight of the animal was concentrated in the massive forequarters, topped by a sizable hump, while the hindquarters seemed unusually slender for so large a beast. The animal, as it had developed in Asia, was so powerful that it had, as an adult, no enemies. Wolves tried constantly to pick off newborn calves or superannuated stragglers, but they avoided mature animals in a group.

This was the ancestral bison, and the relatively few who made the hazardous trip from Asia flourished in their new habitat, and one small herd made its way to the land about the twin pillars, where they found themselves a good home with plenty of grass and security. They multiplied and lived contented lives to the age of thirty, but their size was so gigantic and their heavy horns so burdensome that after only forty thousand years of existence in America, during which time they left their bones and great horns in numerous deposits, so that we know precisely how they looked, the breed exhausted itself.

The original bison was one of the most impressive creatures ever to occupy the land at twin pillars. He was equal in majesty to the mammoth, but like him, was unable to adjust to changing conditions, so like the mammoth, he perished.

That might have been the end of the bison in America, as it was the end of the mammoth and the mastodon and smilodon, the saber-toothed cat, and the huge ground sloth, except that at about the time the original bison vanished, a much smaller and better-adapted version developed in Asia and made its own long trek across a new bridge into America. This seems to have occurred some time just prior to 6000 B.C., and since in the span of geologic time that was merely yesterday, of this fine new beast we have much historic evidence. Bison, as we know them, were established in America and one herd of considerable size located in the area of the twin pillars.

It was late winter when a seven-year-old male of this herd shook the ice off his beard, hunched his awkward shoulders forward as if preparing for some unusual action, and tossed his head belligerently, throwing his rufous mane first over his eyes and then away to one side. He then braced himself as if the anticipated battle were at hand, but when no opponent appeared, he quit his performance and went about the job of pawing at the snow to uncover grass that lay succulent and sweet below.

He stood out among the herd not only for his splendid bulk but also for his coloring, which was noticeably lighter than that of his fellows. He comported himself not with dignity, for he was not an old bull, but with a certain violent willingness; he was what might be called a voluntary animal, eager for whatever change or accident might befall.

For reasons which he could not clearly understand but which were associated somehow with the approach of spring, he started on this wintry day to study carefully the other bulls, and when occasion permitted, to test his strength against theirs. The two- and three-year-olds he dismissed. If they became testy, which they sometimes did, a sharp blow from the flat of his horn disciplined them. The four- and five-year-olds? He had to be watchful with them. Some were putting on substantial weight and were learning to use their horns well. He had allowed one of them to butt heads with him, and he could feel the younger bull’s amazing power, not yet sufficient to issue a serious challenge but strong enough to upset any adversary that was not attentive.

There were also the superannuated bulls, pitiful cases, bulls that had once commanded the herd. They had lost their power either to fight or to command and dragged along as stragglers with the herd, animals of no consequence. They grazed about the edges and occasionally, when fighting loomed, they might charge in with ancient valor, but if a six-year-old interposed himself, they made a few futile gestures and retreated. In earlier years they had suffered broken bones and shattered horn tips and some of them limped and others could see from only one eye. Some of them had even been attacked by wolves, if the wolves caught them alone, and it was not uncommon to see some old bull with flesh wounds along his flanks, filled with flies and itching pain.

The old bulls could be ignored. They were tolerated, and on some long march they would fall behind and fail to climb a hill and the wolves would close in and they would be seen no more.

It was the bulls nine and ten years old that caused perplexity, and these Rufous studied meticulously. He was not at all confident that he could handle them. There was one with a slanting left horn; he had dominated the herd three years ago, and even last year had been a bull to conjure with, for he had massive shoulders which could dislodge an opponent and send him sprawling. There was the brown bull with the heavy hair over his eyes; he had been a champion of several springs and had only a few days ago given Rufous a sharp buffeting. Particularly there was the large black bull that had dominated last spring; he seemed quite unassailable and aware that the others held him in awe. Twice in recent weeks Rufous had bumped against him, as if by accident, and the black bull had known what was happening and had casually swung his head around and knocked Rufous backward; this black bull had tremendous power and the skill to use it.

As spring approached and the snows melted, disclosing a short, rich grass refreshed by moisture, the herd began to mill about as if it wished to move to other ground, and one morning as Rufous was grazing in the soft land between the twin pillars, with the warm sun of spring on his back, one of the cows started nudging her way among the other cows and butting the older bulls. This was the cow that made important decisions for the herd, for although the commanding bull disciplined the herd and stood ready to fight any member at any time, he did not direct them as to where they should move or when. It was as if the lead bull were the general in battle, the lead cow the prime minister in running the nation.

She now decided that it was time for her herd to move northward, and after butting others of her followers, she set out at a determined pace, leaving the twin pillars behind. She headed for a pass through the low chalk hills to the north, then led her charges up a draw to the tableland beyond. There she kept the herd for several days, after which she led them slowly and with no apparent purpose to the river that defined this plateau to the north. Testing the water at several places, she decided which crossing was safest and plunged in.

The water was icy cold from melting snow, but she kicked her legs vigorously, swimming comfortably with the current and climbing out at last to shake her matted hair, sending showers of spray into the sunlight. From the north bank she watched with a leader’s care as older cows nudged yearlings into the river, then swam beside them, keeping the younger animals upstream, so that if the current did overcome them, they would bounce against their mothers and thus gain security for the next effort.

When the main body of the herd was safely across, the old bulls grudgingly and sometimes with growls of protest entered the river, swimming with powerful kicks as the water threw their beards into their faces. When they climbed onto the north bank they shook themselves with such fury that they produced small rainstorms.

Rufous was one of the last to cross, and he did so carefully, as if studying this particular crossing against the day when he might have to use it in some emergency. He did not like the footing on the south bank, but once the lead cow was satisfied that the cows and calves were safely across, she ignored whatever bulls were left behind and set out purposefully for the grazing lands to which she was leading her herd.

When she reached this spot, less than a hundred miles from the twin pillars, she stopped, smelled the ground to assure herself that it was good, then turned the leadership of the herd back to the bulls, assuming once more the passive role of merely another cow. But if any decision of moment were required, she would again step forth and assert herself, and when she grew too old to assume this task the responsibility would pass to some other strongly opinionated cow, for the leadership of a large group was too important to be left to males.

It was now spring and the calving season was at hand. The sun would rise, as on a normal day, but some cow would experience a profound urge to be by herself, and she would move with determination toward some unknown objective, and if any other cow, or even a bull, tried to interpose, she would knock the offender aside and pursue her course. She would seek some secluded area, even if it were only behind the brow of a low hill, and there she would lie on the ground and prepare for the birth of her calf.

This year a small black cow left the herd as soon as the new grounds were reached, for her time was at hand. As she passed two old bulls they nuzzled her as if to ask what she was about, but she repelled them brusquely and sought a spot not far from the river where trees gave her some protection. There she gave birth to a most handsome black bull calf, and as soon as he appeared she began licking him, and butting him with her head and goading him to stand alone. She spent two hours at this task, then began mooing softly as if to attract the attention of the others, but when they ambled over to inspect her new calf, nudging it with their snouts, she made short and ineffectual charges at them, as if to prove that the calf was hers.

Among the bison that came to inspect the new calf was Rufous, and his nosy intrusion was an error he would regret. The newborn calf liked the smell of Rufous and for a few moments rubbed its small head against his leg. Some intuition told the calf that there would be no milk in that quarter, and he returned to his mother. But the damage had been done.

Now came the days which would be most crucial in the life of this little bison. Within a brief period it had to imprint on its mind the image of its mother, her smell, her feel, the taste of her milk, her look, the sound of her call. Because if it failed to make this indelible and vital connection, it might become unattached when the herd moved and be lost in the strangling dust. If this happened, it would survive only a few hours, for the wolves and vultures, seeing its plight, would close in.

Therefore the mother cow was careful to allow it to nuzzle her, to taste her milk, to smell her urine and to hear her cry. She attended the calf constantly, and when it moved among the other calves that were being born at this time she tried to train him to respond to her cry.

But the calf had proved its inquisitiveness by making friends with Rufous shortly after its birth, and it continued this behavior, moving from one adult to another and failing to establish an indelible impression of its own mother. She tried frantically to correct this defect, but her baby bull would wander.

One of its strongest memories was of the smell of Rufous, and as the days progressed it tried to associate more with the bull and less with its mother, trying even to get milk from Rufous. This irritated the bull, who knocked the confused infant away. The little fellow rolled over in the dust, got up bewildered and ran after another adult bull.

At this point, a fairly large herd of strange bison from the north moved onto the feeding ground, and there was a general milling about of animals, so that the baby bull became lost at the edge of the swirling crush. The two herds were excited enough by their chance meeting, but now they detected strange movement to the west, and this triggered precipitate action on the flank, which quickly communicated itself to the mass. A stampede began, and those calves which had been strongly imprinted by their mothers performed miraculously: no matter how swiftly their mothers ran nor how deftly they dodged, the calves kept up with them stride for stride, their little noses often pressed against their mothers’ flanks.

But the handsome black infant had not been adequately trained and had no intuition of where its mother was, nor could it detect her cry in the confusion. It fell behind, far behind, then gave a little cry of joy, for it smelled a reassuring odor. It was not its mother; it was Rufous, lagging behind because he had been grazing on the sweet grass down by the river.

The bull had no intention of caring for a confused baby and rushed past, but the infant, catching a stronger whiff of the familiar smell, joined the gallop and clung to the older bull’s flank. This annoyed Rufous, who tried to kick at the pestering calf as they ran, but nothing would divert the baby bull. With a sense of total security, as great as if Rufous had been its mother, it clung to the galloping bull.

But now the wolves which always hung about the edges of a herd, hoping for a bit of luck, spotted the little calf. They had a good chance of picking it off, since the older bull was endeavoring to kick it to one side, so they closed in on the running pair, trying to insert themselves between the baby bull and the mature one.

They failed. Once Rufous recognized their strategy, he became a changed animal. It was his responsibility to protect calves, no matter how bothersome, no matter how distant the retreating herd. Accordingly, he scanned the terrain as he ran and spotted a small embankment which might afford protection.

Twisting his head abruptly to the right, he headed for the rocky bank. As if the young calf had been attached to him by vines, it turned at the same moment, and the two galloped to the refuge. There Rufous turned to confront his enemies, keeping the calf beside him and well protected by his large reddish flank.

The wolves closed in, eleven of them, but they were powerless against his horns and massive head, nor could they slip behind him to attack his tendons because he kept his rear tight against the rocks. If he had not been hampered by this irritating calf, he could have beaten back the wolves and returned to the herd, but with that encumbrance he could do no more than protect himself.

He did manage one other defense. He bellowed, several times, a low guttural cry that seemed to roll vainly across the vast prairies. But he was heard. The bison, having outrun their fright, had stopped and were pointlessly milling around when the master fighter of the herd to which Rufous belonged, the large black bull, heard the cry of distress and doubled back to investigate. With him came the bull with the slanting left horn, and the closer they approached to the intermittent bellow, the faster they ran.

They came up to the encircling wolves in a rush, their hind feet digging in like brakes and throwing clouds of dust. In the first moment they perceived what was happening, saw Rufous trapped against the rocky bank with the calf beside him. With lowered heads and flashing hoofs they crashed into the wolves and sent them scattering. The black bull caught one on his horn, tossed him in the air, then stamped on him mercilessly when he fell to earth. The wolf was crushed and the others withdrew.

The three victorious bulls formed a miniature herd, with the calf in the center, and slowly they walked back toward the real herd, which had now stabilized. The calf, exhilarated by the adventure and the consoling smell of his savior Rufous, trotted happily inside the protective triangle.

When the calf regained the herd and the excitement caused by the wolves died down, it felt hungry—and there was the good smell of Rufous. It ran to the bull and tried to nurse, but Rufous had had enough. Lowering his horn, he caught the little fellow under the belly and tossed him well into the air. It uttered pitiful cries and crashed to earth. It rose bewildered, still smelled Rufous and still wanted to join him, but as he approached, Rufous lowered his head and gave the calf another toss in the air.

This time its cries reached the distraught mother; she recognized them and rushed to reclaim the infant she thought she had lost. She licked its coat and nursed it and did her best to bring it to her, but it still remembered the familiar smell of Rufous as they confronted the wolves.

Now the rutting season was at hand. Rufous and the other bulls began a strange but long-inherited chain of behavior. One morning, for no apparent reason, Rufous began suddenly charging at cottonwood trees along the riverbank, tearing into them with wild force as if they were living enemies, then stopping and cleaning his horns against their trunks. The next day as he was walking idly toward the herd he felt an uncontrollable compulsion to throw himself on the ground, twisting and turning in the dust a dozen times until he was laden with sand. Then he rose, urinated heavily in the wallow and threw himself into it again, smearing the muddy urine over his head and body as if to announce to the world, “When you smell that smell, remember. It belongs to Rufous.”

At this period of the rutting season he did not yet care to confront the other bulls; indeed, he stayed well away from them, as if he were unsure of his capacity to challenge them on equal terms, but he continued to fight the cottonwoods and to wallow excessively. He also stood by himself and threw out guttural threats, ignoring those that were being voiced by other bulls in the vicinity.

And then one morning, on a day no different from others that had preceded it, a quiet brown cow that had been inconspicuous felt an overpowering surge of vitality, and her entire personality changed within the passing of an instant. She became more rhythmic in her motions, gentler in her manner. She left the cows with whom she had been associating and kicked aside her last year’s calf when it endeavored to stay close to her, as she had so painfully taught it to do only a year ago.

She sought out the bulls on the edge of the herd and moved from one to the other until she came to its leader. He licked her coat and rubbed his head against hers. Often he rested his shaggy head in the hollow of her back as if it were an accustomed pillow. Wherever she moved, he stayed with her, waiting for the proper time for mating, two huge beasts caught in the throes of passion.

Now the drama of the rutting season began. A four-year-old bull that had not yet mated with any cow left the lesser bulls with whom he had for some time been sparring and marched boldly up to the courtship couple. Ignoring the cow, he took a stubborn stance so that his dark beard was close to that of the black bull. The latter, long prepared for such a challenge but unable to anticipate which bull would issue it, stared for a moment at the intruder.

Then, with shuddering force, the two animals leaped at each other, their shaggy foreheads meeting in a crack that could be heard across the plains. To the surprise of the older bull, this first shattering blow seemed to have no effect upon the young challenger, who pawed the earth, lowered his head and drove with incredible force at the older one’s forehead. The black bull was tempted to sidestep and allow the young bull to slide harmlessly off his flank, but he sensed that this opening fight would be crucial, and he intended settling it unmistakably. So he braced himself, lowered his head and took the charge full on his forehead.

For an instant the horns of the two powerful beasts locked, and it looked as if the kinetic force of the younger must drive the older back, but the black bull had reserves of power. His back legs stiffened. His backbone absorbed the shock. And now he began applying pressure of his own. Slowly the younger bull had to retreat. He could not fix his legs.

With a sudden twist, the older bull turned his challenger aside, and as the younger bull’s belly was exposed, the old warrior lunged at it. He could hear ribs cracking beneath skin and then the cry of pain. The younger bull withdrew, shook himself to assess the damage, felt his ribs grating, and with no further desire for fight, retreated.

The older bull, victor once more, returned to the cow that he had rightfully won. By this process, wasteful and cruel, cows were assured that they would mate only with the strongest bulls and that the species would be preserved.

But this time it was not to be so easy, for no sooner had the victorious bull turned his back on the herd and resumed his attentions to the cow than he heard a belligerent snort. When he turned, he saw the bull Rufous headed toward him in a slow purposeful march. This was a more serious challenge.

When Rufous stood horn to horn with the older bull, the latter could smell the strong urine in which his challenger had rubbed himself that morning. It was the smell of a mature bull, one ready to assume his place among the leaders of the herd. So the black bull stood very still, made no movement of any kind, and stared into the eyes of his challenger. The two powerful beasts stood that way for more than a minute, then slowly Rufous broke the gaze, lowered his head, and without raising dust, backed away. This was not a good day for extending his challenge. There would be others more propitious.

The black bull did not raise his voice in triumph nor did he make any move to follow Rufous to demonstrate once and for all his supremacy. He seemed quite content to have resolved this particular challenge in this way. He, too, sensed that a more likely day would come, a day he could not escape, and that then the issue would be resolved.

As the rutting season progressed, only three bulls served the cows: the black leader, the bull with the slanted horn and the brown bull with heavy hair over his eyes. Each was challenged repeatedly by younger bulls; each sustained his prerogatives, and it seemed as if the summer would end with those three in ascendancy.

And then, as the mating season drew to a close, Rufous experienced antagonisms he had not felt before. No amount of charging cottonwood trees satisfied him, and wallowing gave him no release. So one bright morning he sought out an old wallow which he had known favorably before. It was a prairie-dog town, where the little squirrel-like animals had piled up much sand. Plodding his way to it, he thrust himself into the soft earth, ignoring the protests of the little animals as they watched their homes destroyed. He wallowed for a long time, till his hair was well filled with dust. Then he rose, urinated copiously and threw himself into it with a fierceness he had not shown before. Now when he got up, his body was well mudded and the matted hair about his head exuded a powerful scent.

With stolid determination he marched back to the herd, seeking whichever older bull was courting that day. It was the ugly brown bull. He was with a fine cow well along in heat, and had it not been for the arrival of Rufous, the two might soon have been mating.

This time Rufous did not waste his time staring into the eyes of his enemy. As soon as he arrived at the scene he lowered his head and charged at the brown bull, but his tactic was not successful because the little bull calf that had adopted him as its mother had caught the scent of the urine-covered body as it passed through the herd and now galloped up to suckle. This interrupted Rufous’ charge and allowed the brown bull to slash at him as his attack was aborted. A serious gash appeared on Rufous’ shoulder and blood began to spurt out.

This enraged him, and he vented his wrath on his would-be son. With a violent toss of his head he caught the persistent calf and threw it high into the air and some distance away. Without pausing to see where it fell or how, he rushed at the brown bull in such a way as to catch that defender with his head not fully prepared. There was an ugly shock, and the brown bull fell back.

Instantly Rufous leaped at him, boring in with his powerful horns until he struck the right hip of the brown bull. With a ripping sound he swept his horn along the hip, damaging his enemy severely.

This encouraged him, and he swarmed all over the brown bull, jabbing and thrusting and applying constant pressure. It was as if the brown bull were being attacked from all sides, and in time the pressures began to tell. He fell back farther, tried to mount one last counterattack, and failed. Knowing that defeat was inevitable, he backed off and left the area.

Lowing triumphantly, Rufous took over the waiting cow and licked her coat. He was about to lead her into the cottonwoods when the little calf, recovered from its flight, returned to the strong smell of its supposed mother. Sidling up to Rufous, it again tried to nurse, but this time the victorious bull gently nosed him away. He had other matters on his mind.

For the rest of the year Rufous occasionally caught sight of the old brown bull moving along the outer edges of the herd, an embittered elder whose place had been permanently usurped. Never again would the old fellow mount a cow, for if he were to try, the younger bulls would challenge him, remembering that Rufous had humiliated him.

He was free to stay with the herd as long as he wished, and to feed with it and to play with the calves that other bulls sired, but he could have no part in the leadership and certainly no part in the breeding. Some old bulls elected to remain with the herd; many chose to wander off, a part of nothing, afraid of nothing, impregnable to attack, until the closing days when blinded sight and worn-down teeth and blunted horns made them vulnerable. Then wolves moved in. The slashing attacks were sustained, sometimes for three days, with a dozen wolves trying to cut down one stubborn old bull until he could fight no more and the fangs destroyed him.

It was now autumn, and the leader cow sensed that her charges ought to be congregating with the larger herd, so she led them northward, and as they moved ponderously, they merged with larger herds, and then with larger still. Bison seemed to be moving in from all directions until the prairie was black. They stretched to the horizon and blotted out the land, but still more came. They moved in accordance with no plan, but only in response to the ebb and flow which their ancestors had observed.

That spring, during the calving season, the herd to which Rufous belonged had contained only thirty-nine members. In summer, when it joined with another small herd, it numbered about a hundred. After the rutting season it grew to several thousand. And now, on the northern prairie, it contained nearly a million.

In such a congregation the little black bull with the faulty imprinting would have been destroyed had it not clung close to Rufous. It had no chance of locating its mother, for it could not remember her smell, but the strong odor of its adopted father was easy to identify, and the little fellow clung to him.

No matter how sorely Rufous abused his unwanted companion, the latter stayed close. Deprived of its mother’s milk, the little bull learned to depend upon grazing seven months before other calves his age, and whereas they clung to their mothers for protection, it developed a wildly independent nature. By the time snow fell it was willing to bang heads with any animal encountered. Having already survived one attack from wolves, it was not even afraid of them. As its hump matured, so its pugnacity grew; it was a tough little bull.

With Rufous it moved freely within the vast herd, sometimes under the leadership of their own cow, sometimes far from her on the edge of the mob. One day when the herd had begun to fragment into the usual smaller units for winter grazing, some hundred thousand bison moved south across the river, and it was fortunate that Rufous and the calf were not in the middle that day. The herd was feeding well west of the twin pillars, heading for the chalk cliff, now forty feet high, and if the bison had approached it normally, they would have separated into two segments, one going west to escape the cliff, the other east.

But on this day a pack of wolves set up a commotion on the eastern flank. This stampeded the bison in that area and they dashed forward. Others, seeing them on the move, joined the flight automatically, and before long a general panic set in until eighty or ninety thousand bison were in motion.

They swept forward irresistibly, overriding anything that came within their path. If a bison stumbled and fell, he was crushed to death by hammering hoofs, and any calf separated even momentarily from its mother was either killed or forever lost.

The center of the stampeding herd drove directly for the chalk cliff, and as the lead animals approached and saw the precipitous drop ahead, they tried to stop, but this they were powerless to do, for the animals surging behind kept coming and forced the first rank over the cliff. Most of them perished in the fall, but those that didn’t were soon crushed by succeeding waves of bison as they too plunged over the edge.

The bison on the flanks, of course, easily made their way around the cliff and suffered no fatalities except those few that fell beneath the pounding hoofs. But at the center more than twelve hundred perished and wolves did not have to bother trailing the herd for stragglers.

Rufous and the bull calf were on the left flank that day, and when panic struck they galloped easily to safety on the plains below the cliff. The little bull enjoyed the wild excitement of the chase so much that thereafter he roamed with Rufous, and when their herd reassembled under the leadership of their determined cow, the two moved eastward to the twin pillars, where the self-orphaned bull grew into a stalwart animal.

He had a raffish disposition, and at the age of nineteen months, when he was well formed, with sturdy horns growing out of his jet-black head, he was already seeking adventure. One day he limped back to the herd, badly cut up: his rear left leg was shredded above the ankle; his face was gashed; and his right flank was scored by sharp teeth. When Rufous and the other bulls gathered about him to smell whatever mementos there were of the disaster, they could tell that the blood on his right horn was not his. Sniffing more closely, they detected the smell of wolf, and next morning three of them, wandering east of the twin pillars, came upon a scene of carnage, with three wolves lying dead beside some low bushes which had been broken and trampled.

It had been a notable triumph, but thereafter the young bull would be lame in his left rear leg. He did not limp badly, but when he dug in for a charge against his fellow bulls he favored that leg, and when the charge came, there was a noticeable drag to the left. This did not deter him from fighting with everyone in the herd. Once he even challenged the lead cow when she was leading them north, but she gave him two swift jabs with her horn, indicating that she intended to accept no nonsense from brash young bulls.

He liked best the autumn, when the massive herd coalesced north of the two rivers. In western America two distinct kinds of bison had always existed, wood bison that kept to the hills, and plains bison. The latter were divided into two herds, the northern and the southern, and the land around the twin pillars marked the dividing line. This was because the southern herd usually stayed below the South Platte, while the northern herd stayed above the North Platte. The neutral land between the two rivers was sometimes occupied by a million or two bison from either herd, but they rarely stayed long.

In these years the northern herd, had it ever assembled at one spot, which it did not, would have numbered about thirty-five million animals; the southern herd, twenty-five million. Even such partial concentrations as gathered along the North Platte could number into the two or three millions, and for them to cross the river might require three days. They darkened the prairies; when they moved, the sky was gray with rising dust; they were magnificent and in the whole region at this time they had no enemy except the lurking wolf. They were masters of creation, a force of such magnitude that it could never be diminished, a stable community whose laws were so sound and whose behavior was so reasonable that it could reproduce itself perpetually.

It was this herd, more vast than the eye of a bison could contemplate, that the tough young bull loved, for when he was a part of it he seemed to grow larger. If the herd broke into a gallop, for some unexplained reason, he longed to be at the very heart of it, going where it led, thundering his hoofs, pulled this way or that by the timeless instinct of the herd. Sometimes, at such moments of wild movement, he bellowed for sheer joy.

He found pleasure in milling around the center, fighting whatever young bulls cared to engage him. The fact that he limped deluded other bulls into thinking that here was an easy enemy, and in the first years he was often challenged, always to the dismay of those who did the challenging. For he was not only strong and canny; he could also be downright mean, with sly tricks that other bulls had not learned. It was usual, when two bulls found contact in their first violent charge, for them to remain locked, their great foreheads touching, their back legs pumping in a contest of brute strength. But with a weak leg this jet-black bull knew that he must always lose that battle, so when his stupid and stolid adversary dug in for a traditional contest, he feinted forward, made enough contact to fix his opponent in position, then slid to the side, raking his foe with his sharp right horn.

He startled many bulls in this way, but he himself was also badly scarred in the brawling. Two ribs had already been broken and the tip of his left horn had been knocked off. He bore many scars in addition to the wolf bites, yet he loved the smell of combat when the vast herd assembled.

But when the excitement bred by the giant herd died down, in some mysterious manner the smaller herd of the twin pillars reestablished itself: the lead cow for that year reasserted her dominance and even fractious bulls like the jet-black one fell in line and willingly took up the trek south to their own familiar territory. Then he marched with Rufous, and the two, the younger now as hefty as the older, formed as handsome a pair as even the great master herd could have provided.

Bison had short memories, if any, and the younger bull no longer looked upon the older as his stay in life; indeed, that ridiculous passage in the young one’s maturing had been forgotten. To him Rufous was merely the commanding bull of the herd, the one who had not yet been defeated during the rutting season. And here was where the trouble started, for when the jet-black bull was six years old he determined to possess cows of his own; to do otherwise would be ridiculous. And this placed him athwart the prerogatives of Rufous.

That spring the half-lame bull started to train for the extra-rigorous battles he knew lay ahead. He tested his horns against cottonwood trees and bellowed for hours at a time down by the river. He wallowed a good deal and sought fights with younger bulls. With great intensity he watched the three or four older bulls that commanded the cows, and especially he kept his eye on Rufous. It seemed to him that the old tyrant was losing his power.

During the calving season the young bull continued shadow-fighting with trees and galloping suddenly along the edge of the feeding ground, then stopping with dust-raising sharpness, thrusting his horns this way and that. He now ceased any playing around with younger bulls, for he knew that more serious matters were at hand.

When the rutting season began, he became a violent creature, slashing at any animal that came his way. And then, one day when Rufous had singled out a cow for himself, he watched with meticulous care for the right moment to assault him, but while he was making preparatory steps, another young bull stepped forward and boldly challenged the old champion. There was the initial confrontation, the stare, the refusal to back down, the digging in of the hind feet, the colossal charge and the shattering jolt as foreheads crashed.

It was a major fight, a real test of the older bull’s power, and he met it with distinction, holding his ground and slowly driving the young challenger back. But when he had humbled the younger bull and given the triumphant bellow of the victor, he found that he was not exactly victorious, for while the two had been fighting, the half-lame bull had skirted off with the cow and was now breeding her in the lush area between the two pillars.

For the rest of that year Rufous and the young bull were enemies. They did not engage in actual battle, for the younger bull sensed that Rufous was so enraged that victory was impossible. In his canny way he bided his time, and when the great herd assembled that autumn he stayed clear of Rufous.

When the time again came for cows to come into heat, the young bull was at the height of his powers, a handsome creature with heavily matted hair and long beard. His forequarters were immense and more than compensated for the inadequate left rear leg. Insolently he muscled his way through the younger bulls, always keeping his eye on Rufous.

It happened with startling suddenness. On the first day of the rutting season he challenged Rufous over the first cow. The two great animals stood glaring at each other for almost a minute and Rufous squared for the initial shock, but when it came he was unprepared for its ferocity. For the first time he backed a little to find a better footing. The second clash was as violent as the first, and again he adjusted his rear feet, but before they found a footing, the younger bull made a feint, followed by a devastating thrust to the other side, and Rufous felt his flank being laid open by a scimitar horn.

For the first time in these fights Rufous was actually hurt, with violent pain coursing through his body. With unprecedented fury he turned upon his assailant and drove at him with such terrible force that he cracked two of the other bull’s ribs.

Ordinarily this would have been sufficient to drive a challenger from the field, but the jet-black bull was no ordinary bison. He was an animal trained in adversity and one that would not surrender until death itself intruded. Twisting his side so as to accommodate the pain of the broken ribs, he drove directly at Rufous, staggering him with blows to the chest and flank. Here was no stylized dueling; here was a fired-up young bull trying his best to kill.

Relentlessly he gored and smashed at Rufous, never allowing the older bull a chance to pull himself together. With a mixture of astonishment and panic Rufous sensed that he was not going to defeat this explosive young adversary. Vaguely he acknowledged that a better animal than he had come onto the scene, and with an apprehension of tragedy and lonely years ahead, he began to back away. First one foot moved, grudgingly, then another. He was in retreat.

With a snort of triumph the younger bull charged at him for the last time, knocking him sideways and into confusion. Lowering both his tail and his head, Rufous started running from the battle, disorganized and defeated, while the black bull took possession of the cow he had so clearly won.

The other bison did not react to Rufous as he retreated from the battleground; they displayed neither regret nor satisfaction as he moved disconsolately through their ranks. He had been defeated, and that was that. He was through forever as the commander of the herd and must now make what peace he could with himself.

This proved difficult. For the rest of that summer he stayed apart, taking his position about a quarter of a mile from the edge of the herd. Throughout the autumn he was a lost soul and not even the excitement of the massing of the herds inspirited him. Once or twice he caught a glimpse of the handsome new champion, but the two did not travel together this time, and on the return trip even the lead cow ignored him.

Winter was a trying time. When snow covered the prairies and freezing winds with temperatures far below zero swept in from the west where the mountains stood, Rufous stayed alone, turning his matted head into the storm and doggedly waiting until the blizzard subsided. Then, alone, he faced the problem of finding enough to eat, so he lowered his massive head into the snow, down two or three feet, and with slow side-to-side rhythmic swings, knocked a path in the snow, deeper and deeper, until the frozen grass at the bottom lay revealed. Then he fed, pushing his head into new drifts when the grass in any one spot was gone.

Snow froze in his matted hair. Long icicles formed on his beard. The hair on his cheeks was worn away and his face became raw, but still he stayed by himself, a defeated old bull fighting the blizzard alone until his bones were weary and his face heavy with accumulated ice.

He stayed alive. One night wolves tracked him, and once they attempted an attack, but he was too strong for them, much too strong. Methodically and with old skill he slashed them to pieces when they came near. One wolf he caught on his horn, and before it could get away, he dashed it to the ground and stamped it to a pulp, relishing each repeated thrust of his still-powerful feet. After that the wolves left him alone. An outcast he was, by his own volition, but food for wolves he would not be for many years.

The snow was extremely heavy that year, and in the mountains it accumulated to a depth of forty feet. When spring came and days of hot sun, the melting was sudden and devastating. Huge bodies of water formed and had to find some way down to the plains, so rivulets became streams and streams became rivers, and the South Platte surged out in preposterous flood.

The lead cow, having anticipated this disaster by some intuition, kept the herd at the twin pillars, where the land was high, but since Rufous no longer felt himself a part of the herd, and roamed as he wished, he chose the land that lay beside the river, where the ice was thick and where the grass would be fresh within the next few weeks. He was therefore not prepared when his refuge was abruptly engulfed in water from the mountains, and he delayed leaving for higher ground. He expected that the water would go away; instead it increased.

Now the main body of the flood hit the South Platte, inundating new regions, and Rufous was trapped. Ice floes, broken loose by the flooding, began to pile up about him, and he realized that if he stayed in that area he was doomed, so he struck out for what he remembered as higher ground, but here, too, the water had invaded, with large chunks of ice backing up against the cottonwoods.

Abandoning that possible escape route, Rufous decided to trust his fortunes on the south side of the river, but this meant that he would have to cross the river itself, something he had often done in the past but could not possibly do now. This was a wrong decision, and before he launched into the water he looked about wildly, as if searching for the lead cow to give him directions. Receiving none, he valiantly plunged into the turbulent river, felt himself carried along by its fury, and struck out forcefully for the opposite bank, now miles distant because of the flooding.

He kept his legs pumping, and had this been a normal river he would have mastered it. Even so, he trusted that he was headed safely for the opposite shore and kept swimming. As he did, he lacked the power of mind to reflect that it was the little black bull—the one he had saved and reared—that had driven him from the herd. He knew only that he was outcast.

Down the middle of the swollen river came a congregation of broken logs, ice chunks, large rolling stones and bodies of dead animals. It was a kind of floating island, overwhelming in its force as it swept along. It overtook him, submerged him, ground him relentlessly in dark waters, and passed on.

When the bison straggled over the land bridge into America he encountered a huge misshapen creature that was in many ways the opposite of himself. The bison was large in front, slight in the rear, while the native animal was very large in the rear and slight in front. The bison was a land animal; the other lived mostly in water. The beast weighed some three hundred and fifty pounds as it slouched along, and its appearance was fearsome, for its conspicuous front teeth were formidable and as sharp as chisels. Fortunately, it was not carnivorous; it used its teeth only to cut down trees, for this giant animal was a beaver.

It had developed in North America but would spread in desultory fashion through much of Europe; its residence in the streams of Colorado would prove especially fortuitous, bringing great wealth to those Indians and Frenchmen who mastered the trick of getting its pelt.

The first beavers were too massive to prosper in the competition that developed among the animals of America; they required too much water for their lodges and too many forests for their food, but over the millennia a somewhat smaller collateral strain became dominant, with smaller teeth and softer pelts, and they developed into one of the most lovable and stubborn of animals. They thrived especially in the streams of Colorado.

One spring the mother and father beavers in a lodge on a small creek west of the twin pillars made it clear to their two-year-old daughter that she could no longer stay with them. She must fend for herself, find herself a mate and with him build her own lodge. She was not happy to leave the security in which she had spent her first two years; henceforth she would be without the protection of her hard-working parents and the noisy companionship of the five kits, a year younger than herself, with whom she had played along the banks of the stream and in its deep waters.

Her greatest problem would be to find a young male beaver, for there simply were none in that part of the creek. And so she must leave, or in the end her parents would have to kill her because she was mature enough to work for herself and her space inside the lodge was needed for future batches of babies.

So with apprehension but with instinctive hope, this young female left her family for the last time, turned away from the playful kits and swam down the tunnel leading to the exit. Gingerly, as she had been taught, she surfaced, poked her small brown nose toward shore and sniffed for signs of enemies. Finding none, she gave a strong flip of her webbed hind feet, curling her little paws beneath her chin, and started downstream. There was no use going upstream, for there the building of a dam was easier and all the good locations would be taken.

One flap of her hind feet was sufficient to send her cruising along the surface for a considerable distance, and as she went she kept moving her head from side to side, looking for three things: saplings in case she needed food, likely spots to build a dam and its accompanying lodge, and any male beavers that might be in the vicinity.

Her first quest was disappointing, for although she spotted quite a few cottonwoods, which a beaver could eat if need be, she found no aspen or birch or alders, which were her preferred foods. She already knew how to girdle a small tree, strip its bark and fell it so that she could feed on the upper limbs. She also knew how to build a dam and lay the groundwork for a lodge. In fact, she was a skilled housekeeper, and she would be a good mother, too, when the chance presented itself.

She had gone downstream about a mile when there on the shore, preening himself, she saw a handsome young male. She studied him for a moment without his seeing her, and she judged correctly that he had chosen this spot for his dam. She surveyed the site and knew intuitively that he would have been wiser to build it a little farther upstream, where there were strong banks to which it could be attached. She swam toward him, but she had taken only a few powerful strokes of her hind feet when, from a spot she had not noticed, a young female beaver splashed into the water, slapped her tail twice and came directly at the intruder, intending to do battle. It had taken her a long time to find a mate and she had no intention of allowing anything to disrupt what promised to be a happy family life.

The male on shore watched disinterestedly as his female approached the stranger, bared her powerful front teeth and prepared to attack. The stranger backed away and returned to the middle of the stream, and the victorious female slapped the water twice with her tail, then swam in triumph back to her unconcerned mate, who continued preening himself and applying oil to his silky coat.

The wandering beaver saw only one other male that day, a very old fellow who showed no interest in her. She ignored him as he passed, and she kept drifting with no set purpose.

As late afternoon came on and she faced her first night away from home, she became nervous and hungry. She climbed ashore and started gnawing desultorily at a cottonwood, but her attention was not focused on the food, and this was good, because as she perched there, her scaly tail stretched out behind her, she heard a movement behind a larger tree and looked up in time to spot a bear moving swiftly toward her.

Running in a broken line, as she had been taught, she evaded the first swipe of the slashing paw, but she knew that if she continued running toward the creek, the bear would intercept her. She therefore surprised him by running parallel to the creek for a short distance, and before he could adjust his lunge to this new direction, she had dived to safety.

She went deep into the water, and since she could stay submerged for eight or nine minutes, this gave her time to swim far from where the bear waited, because even from the bank a bear could launch a powerful swipe which might lift a beaver right onto the bank. When she surfaced, he was far behind her.

Night fell, the time when her family had customarily played together and gone on short excursions, and she was lonely. She missed the kits and their noisy frolic, and as night deepened she missed the joy of diving deep into the water and finding the tunnel that would carry her to the warm security of the lodge.

Where would she sleep? She surveyed both banks and selected a spot which offered some protection, and there she curled up as close to the water as she could. It was a miserable substitute for a proper lodge, and she knew it.

Three more nights she spent in this wretched condition. The season was passing and she was doing nothing about the building of a dam. This bothered her, as if some great purpose for which she had been bred was going unattended.

But the next day two wonderful things happened, the second having far more lasting consequences than the first. Early in the morning she ventured into a part of the creek she had not seen before, and as she moved she became aware of a strong and reassuring scent. If it were serious, and not an accident, it would be repeated at the proper intervals, so she swam slowly and in some agitation to the four compass directions, and as she had anticipated, the keen smell was repeated as it should have been. A male beaver, and young at that, had marked out a territory and she was apparently the first female to invade it.

Moving to the middle of the stream, she slapped her tail, and to her joy a fine-looking young beaver appeared on the bank of the creek and looked down into the water. The slapping could have meant that another male had arrived to contest his territory and he was prepared to fight, but when he saw that his visitor was the kind he had hoped to attract, he gave a little bark of pleasure and dived into the stream to welcome her.

With strong sweeps of his webbed feet he darted through the water and came up to her, nudging her nose with his. He was highly pleased with what he found and swam twice around her as if appraising her. Then he dived, inviting her to follow him, and she dived after him, deep into the bottom of the creek. He was showing her where he intended building his lodge, once he found a female to help.

They returned to the surface and he went ashore to fetch some edible bark, which he placed before her. When beavers mated, it was for life, and he was following an established pattern of courtship. The female was eager to indicate her interest, when she noticed that his gaze had left hers and that any fruitful communication had ended.

He was looking upstream, where one of the most beautiful young beavers he had ever seen was about to enter his territory. This female had a shimmering coat and glowing eyes, and she swam gracefully, one kick sending her to the corners of his areas, where she checked the markers he had left. Contented that she was in the presence of a serious suitor, she moved languidly to the center of the area and signaled with her tail.

The young male left his first visitor and with lightning strokes sped to this newcomer, who indicated that she was interested in the segment of the creek he had laid out for himself and was willing to move in permanently. In this brief space of time their destiny was determined.

What now to do with the first visitor? When the new female saw her she apprehended immediately what had happened, so she and the male came to where the young beaver waited and started to shove her out of the delimited area. But she had got there first and intended to stay, so she dived at the intruding female and started to assault her, but the male knew what he wanted. He had no desire to settle for second best, so he joined the newcomer, and together they forced the unwanted intruder downstream, and as she disappeared, chattering in rage, they slapped their tails at her and made joyous noises and prepared to build their dam.

The outcast drifted aimlessly and wondered whether she would ever find a mate. How could she build a home? How could she have kits of her own? Bitterly she sought the next miserable place to spend a night.

But as she explored the bank she became aware of a soft sound behind her and was certain it must be an otter, the most fearful of her enemies. She dived deep and headed for any cranny within the bank that might afford protection, and as she flattened herself against the mud she saw flashing through the waters not far distant the sleek, compacted form of an otter on the prowl.

She hoped that his first sweep would carry him downstream, but his sharp eye had detected something. It could have been a beaver hiding against the bank, so he turned in a graceful dipping circle and started back. She was trapped, and in her anxiety, fought for any avenue of escape. As she probed along the bottom of the bank she came upon an opening which led upward. It could well be some dead end from which there was no escape. But whatever it was, it could be no worse than what she now faced, for the otter was returning and she could not swim fast enough to escape him.

She ducked into the tunnel and with one powerful kick sent herself upward. She moved so swiftly that she catapulted through the surface and saw for the first time the secret cave that had formed in the limestone, with a chimney which admitted air and a security that few animals ever found. Soon her eyes became accustomed to the dim light that filtered in from above and she perceived what a marvelous spot this was, safe from otters and bears and prowling wolves. If she built her dam slightly below the cave and constructed her lodge in the body of the creek, attaching it by tunnel to this secret place, and if she then widened the chimney upward and masked its exit so that no stranger could detect it, she would have a perfect home. To complete her delight she found inside the cave and above the water level a comfortable ledge on which she could sleep that night.

Before dawn she was at work. Moving to all the prominent places on shore and to the ledges in the creek, she stopped at each and grabbed a handful of mud. With her other hand she reached to the opening of her body where two large sacs protruded and from these she extracted a viscous yellow liquid which would become famous throughout the west as castoreum, one of the most gratifying odors in the natural world.

Kneading the castoreum into the mud and mixing in a few grasses to make the cake adhere, she placed it carefully so that its odor would penetrate in all directions, and when she had set out nine of these—for this was a spot worth preserving and protecting—she stopped and tested the results of her labor. She swam upstream and down, and wherever she went she got the clear signal that this stretch of water belonged to a beaver who intended holding it.

She became, that summer, a capable beaver, lively in her pursuit of things she required. The limestone cavern became not only a place of refuge but also a satisfactory home. She built three secret escape hatches, one leading a good twenty feet inland from the bank of the creek, so that if a bear or wolf did take her by surprise, she could dive into it and make her way back to her home before the predator knew where she had gone.

The cycle of her life, however, was still incomplete. By herself she would not build a dam, nor a lodge either, for they were needed primarily for the rearing of young. She could survive in the limestone cave, but without the act of building a lodge with a mate, she was still an outcast.

This did not prevent her from attending herself as carefully as ever. Each day, when the sun was low, she perched on the bank overlooking her domain and preened. She did this by using the two peculiar toes on each of her hind legs; the nails on these toes were split so as to form small combs, and these she dragged through her pelt until even the slightest irregularity was removed. Then she took oil from her body and carefully applied it to each part of her coat, combing it in deeply until her fur glistened in shimmering loveliness. No one saw or applauded this grooming, but it was impossible for her to go to bed until she had completed it.

And then, in early autumn when she had given up hope of finding a mate, a shabby beaver seven years old who had lost his family in some catastrophe, wandered down the river and turned by chance into her creek. He was by no means a handsome creature; indeed, he was not even acceptable, for a long gash ran down the left side of his face and he had lost the two toes on his left hind leg that he needed for cleaning himself, so that his appearance was disreputable.

As he sashayed up the creek he detected the markers and realized immediately that a mistake had been made. The creek spot looked inviting but any flood from the river would wash it away. He looked about for the family which occupied it to warn them of the danger they faced, and after a while he saw the head of the owner breaking through the surface. She swam out to him cautiously and looked for his mate, while he looked for hers. There was a period of motionless silence. He was tired and winter was at hand.

They stared at each other for a long time, for a very long time, and each knew all there was to know. There would be no illusions, no chicanery.

It was he who broke the silence. By the way he looked and moved his tail he indicated that this spot was no place to build a dam.

With a fierce toss of her head she let him know that this was where she would live. And she led him underwater to the entrance of her secret cave and showed him the escape hatches and how she planned to link it to the lodge and the dam, but still he was not satisfied, and when they surfaced, he started to swim to a much safer spot, and she followed, chattering and slamming her tail and halting in disgust as he left her premises.

In the morning he swam back and indicated hesitantly that she was welcome to accompany him if she would consent to build their dam at a proper site.

Again she abused him, protesting furiously and snapping at him, driving him from her water, and that afternoon he came back quietly with a length of aspen in his teeth. Diving to the bottom of the creek, he fastened it to the floor with mud, the first construction in their new home.

It was then September and they set to work with a passion. They labored all night, dragging trees and branches into the stream, weighting them with mud and gradually building the whole construction high enough to check the flow of water. Again and again as they worked he betrayed his doubt that the dam they were building would hold, but she worked with such fervor that he swallowed his precautions.

When the two beavers were satisfied that the dam would impound the water necessary for their establishment, she began tying branches and tree lengths into the bottom, weighting them with rocks and mud and other trees, and it was now that she realized that in the building of the dam she had done most of the work. He was great on starting things, and showed considerable enthusiasm during the first days, but when it came time for doing the hard, backbreaking work, he was usually absent.

She had to acknowledge that she had accepted a lazy mate, one who could not be cured, but instead of infuriating her, this merely spurred her to greater effort. She worked as few beavers, an industrious lot, had ever worked, lugging huge trunks of trees and slapping mud until her paws ached. She did both the planning and the execution, and when the pile from which their lodge would be constructed was nearly finished, and she was eleven pounds lighter than when she started, he indicated for the final time that when the floods came, this would all vanish. She made no response, for she knew that just as she had done most of the building this time, she would have to do it again if floods ever did come.

When the pile in the middle of the small lake behind the dam was completed, they dived to the bottom and began the gratifying task of cutting entrances into it, and providing sleeping levels above the waterline, and places for kits when they came, and digging connecting runways to the secret chamber, and at this planning he was a master, for he had built lodges before.

Only a few days remained before the freeze, and this period they spent in a burst of superenergy, stripping bark and storing it for their winter’s food. Where eating was concerned, he was willing to work, and in the end they had a better lodge than any other on the creek, and better provisioned too.

In the early days of winter, when they were frozen in, they mated, and in spring, after she gave birth to four lovely babies, the river produced a flood which washed away the dam and most of the lodge. He grunted as it was happening, but she rescued the babies and took them to higher ground, where a fox ate one.

As soon as the floods receded, she began to rebuild the dam, and when it was finished, she taught the babies how to help rebuild the lodge, which took less effort.

They then enjoyed four good years in their tight little kingdom, but on the fifth, sixth and seventh years there were floods, the last of such magnitude that the whole establishment was erased. This was enough for him, and he spent considerable time upstream looking for a better site, but when he found one, she refused to move. He found her marking the corners of her estate with castoreum and teaching her children how to start erecting a higher and better dam.

He halted at the edge of her territory and watched as this stubborn little creature proceeded with her engineering, making the same mistakes, dooming her dam to the same destruction.

He was now fifteen years old, an advanced age for a beaver, and she treated him with respect, not requiring him to haul logs or do much actual construction on the lodge. He snapped at the kits when they placed branches carelessly, indicating that if he were in charge he would not accept such sloppy workmanship. As he aged, his face grew uglier, with the scar predominating, and he moved with crotchets and limps, and one day while he was helping girdle some cottonwoods, he failed to detect a wolf approaching and would have been snatched had he not been bumped toward the safety tunnel by his mate.

That year there was no flood.

Then one day in early autumn when the food was safely in and the lodge never more secure, she happened to wander up the tunnel into the secret place which the family had so much enjoyed, and she found him lying there on the limestone ledge, his life gone. She nudged him gently, thinking that he might be asleep, then nuzzled him with affection to waken him for their evening swim through the lake they had built and rebuilt so many times, but he did not respond, and she stayed with him for a long time, not fully comprehending what death signified, unwilling to accept that it meant the end of their long and necessary companionship.

In the end the children took the body away, for it was no longer of any use, and automatically she went about the job of gathering food. Dimly she sensed that now there could be no more babies, no more kits playing in the limestone chamber and scampering down the runways.

She left the security of the lodge and went to each of the compass points and to the salient ridges in between, and at each she scooped up a handful of mud and mixed it with grass and kneaded in a copious supply of castoreum, and when the job was done she swam back to the middle of her lake and smelled the night air.

This was her home, and nothing would drive her from it, neither loneliness nor the attack of otters nor the preying of wolves nor the flooding of the river. For the home of any living thing is important, both for itself and for the larger society of which it is a part.

Diplodocus had evolved in Colorado but had died out. The horse had evolved here but had left. The bison had originated elsewhere and had moved in. The beaver had originated here but had emigrated. Was there no inhabitant that had originated here and had stayed? Indeed there was, perhaps the most terrifying creature now living on earth.

For the first four animals that occupied the land about the twin pillars there was self-evident justification. Diplodocus was a magnificent creature that harmed no one; the horse would make man mobile; the bison would make him warm and well fed; and the beaver would make him rich. Even the omnipresent wolf was needed, for he policed the area and kept the herds strong through killing off the old and the weak, while the chattering prairie dog could be justified for the humor it provided. But for the fifth inhabitant no acceptable justification had ever been proposed; the reason for his presence on earth was a mystery.

On a hot summer’s day a female eagle flying lazily in the sky watched as a herd of bison left the shadows of the twin pillars and headed north for rendezvous on the far side of the North Platte. The eagle watched with unconcern as the great beasts moved out in single file, for there was nothing of advantage to her in the movement of bison or even in their congregation in large numbers. All they produced was dust.

But as the bison moved north she noticed that at a certain spot each animal shied to the left, even the most aggressive bulls, and this was worth inspecting, so she hovered for some minutes to confirm her observation, then flew in lazy circles till the herd passed.

As soon as the last straggler had come to this spot, looked down and veered, she dropped like an arrow from aloft, keeping her eye on the spot and noticing with pleasure that her deduction had been right. Below her in the dust beside a rock was food.

Increasing her speed, she swooped to earth, almost touching the sand with her wings. At the last moment she extended her talons and grabbed at the object which had attracted her, an enormous rattlesnake some five feet long and very thick in the middle. It had a flat, triangular head and on the end of its tail a curious set of nine hornlike knobs.

The eagle miscalculated slightly, for its talons did not strike the snake squarely. Only one claw of the right foot caught the rattler, well toward the tail, and although the eagle tried to carry the snake aloft so as to drop it on rocks and perhaps kill it, she failed, for the snake, with a violent twisting effort, tore free, and with blood flowing from the wound, immediately coiled itself to repel the next attack.

Seeing that the rattler was in a position to strike, the eagle realized that she could not swoop down and take it by surprise, so she landed some distance away, her feet and wings throwing up a cloud of dust, and with wary, high-stepping movements, approached to give battle.

The snake watched her come and adjusted his position to match hers, but he was not prepared for the kind of attack she made. Uttering a wild cry, she ran directly at the snake, raised her wings, encouraging it to strike at the feathers, then brought the edge of her left wing sharply across the snake’s backbone. It was a staggering blow, delivered with all the force the eagle could muster, and it flattened the rattlesnake.

Instantly she leaped upon it, catching it squarely in the middle, so that her claws dug all the way through that part of the snake’s body. With a flap of her extended wings she soared into the air, but she did not rise to the highest heavens, for she was working on a plan of calculated cunning. Searching not for rocks but for a terrain quite different, she found what she wanted. She flew with her eyes into the wind to assure herself that it was not strong enough to blow the snake off target when she dropped him. Satisfied, she disengaged the serpent and watched as it plummeted into the middle of a cactus thicket, whose needle-sharp spines jutted upward.

With a thud the rattlesnake fell onto the cactus, impaling itself in a score of places. As it writhed, the jagged edges of the spines cut deep and held fast. There was no way the snake could tear itself loose, and death became inevitable.

Had the eagle realized that exposure to the sun and loss of blood must soon kill the snake, it could merely have waited, then hauled the dead carcass off to its young. But the bird was driven by deep inner compulsion and felt obligated to kill its enemy, so it flapped its great wings slowly and hovered above the cactus spines, lowering itself until its curved talons could catch the serpent again.

This time the eagle flew in wide circles, searching for an area of jagged rocks on which to drop the rattler. Locating what she wanted, she flapped her wings and rose to a great height and shook the snake free, watching with satisfaction as it crashed onto the rocks. The fall did great damage, and the snake should have been dead, but like all rattlers he had a terrible determination to survive, so as soon as he struck the rocks he marshaled his remaining strength and took the coiled position.

The eagle had made a sad miscalculation in dropping the snake onto the rocks, for she had counted upon the fall to kill him outright, but this it had not done, so now she was forced to leave the flat, sandy terrain where she had an advantage and go among the rocks, where the advantage was his. However, since the snake was obviously close to death, she judged that she could quickly finish him off.

But when she sought to deliver the culminating blow with the edge of her wing, he somehow thrust himself about her body and enclosed it in a constricting embrace, fighting desperately to bring his lethal head into contact with some vital part.

She was too clever to permit this. Keeping his head at a disadvantage, she strained and clawed and bit until he had to release his hold. For the moment he was defenseless, and she took this opportunity to pierce him for the third time, and now she carried him very high, kicking him free over the rocks again, and once more he crashed onto them.

He should have been dead, and he feigned that he was, lying stretched out and avoiding the coil. Sorely shattered by this last fall and bleeding from numerous wounds, he made no sound, for his rattles were broken.

The eagle was fooled. She inspected him from the air, then landed on the rocks and walked unsteadily over to carry him aloft for the last time, but as she neared, the snake coiled and struck with what force he had left and plunged his fangs into the unprotected spot where her thin neck joined her torso. The fangs held there for only a moment, but in that brief instant the muscles in his neck contracted, sending a jet of lethal poison deep into her bloodstream. Easily, so easily, the fangs withdrew and the snake fell back upon the rocks.

The startled eagle made no motion. She merely stared with unbelieving eye at the snake while he stared back at her with basilisk gaze. She felt a tremor across her chest and then a vast constriction. She took two halting steps, then fell dead.

The rattlesnake lay motionless for a long time, one wing of the eagle across his wounded body. The sun started to go down and he felt the coldness of the night approaching. Finally he bestirred himself, but he was too damaged to move far.

For a long period it seemed that he would die, there on the rock with the eagle, but just before sundown he mustered enough strength to drag himself into a crevice where there would be some protection from the night cold. He stayed there for three days, slowly regaining strength, and at the end of this time he started his painful trip home.

He lived, as did several hundred other rattlers, some much bigger than he, in the rocks at the twin pillars. They had lived there for two million years, a mass of snakes that found the area good hunting for rats and prairie dogs, with safe crevices in the rocks for hibernation in the winter. When men reached the area the twin pillars would become known as Rattlesnake Buttes, reassuring beacons in the desert when spotted from afar, dangerous death traps when approached too closely.

Rattlesnake Buttes! A thousand westward travelers would remark about them in their diaries: “Yesterday from a grate distance we seen the Rattlesnake Butes they was like everbody said tall like castels in Yurope and you could see them all day and wundered who will be bit by the snakes like them folks from Missuri?”

The myriad poisonous snakes that infested the buttes served no purpose that man could discern: they terrorized, they ate harmless prairie dogs, they killed whatever they struck, and after a long life they died. Why had they been made custodians of such a deadly poison? It was impossible to say.

The two fangs that folded back against the roof of the mouth when not needed dropped into operating position when the snake wanted to kill. They were not teeth as such, but hollow and very sharp hypodermic needles, so formed that pressure from the rattler’s throat would not only deposit the poison but inject it to astounding depths. The poison itself was a combination of highly volatile proteins which reacted with the blood of the victim, producing quick and painful death.

The snakes at Rattlesnake Buttes were apt to leave intruders alone unless the latter did something to frighten them. Bison roamed the area by the thousands, and always had, and as calves they learned to avoid the rattlers. Indeed, even the sound of a rattle, that dreaded clatter in the dust, was enough to make a line of bison move in another direction.

Occasionally some stupid one would put himself into a position from which there was no escape for the rattler, and then the snake would strike him. If the venom entered the bison anywhere near the head or face, it was invariably fatal, but if it struck a leg, there was a fighting chance that the poison would be absorbed before it reached the heart, but the bison would thereafter be lame in that leg, its nerves and muscles half destroyed by the venom.

In the days when horses roamed the area, many a fine steed went lame because it blundered upon a rattlesnake and had taken a shot of venom in its fetlock. But if either a bison or a horse saw a rattler about to strike, and saw it in time, it would take protective action and stamp the snake to death. Sharp hoofs were more dangerous to rattlers than eagles or hawks, so that if the bison tried to avoid the snakes, so, too, did the rattlers keep out of the way of bison—and especially deer, whose ultrasharp hoofs could cut a snake in half.

The rattler that had defeated the eagle in mortal combat took a long time to recover. For the next two years he was in poor shape, able to leave the buttes for only short trips and always gratified when winter came so that he could sleep for five or six months, but gradually he began to feel better, and the gaping wounds in his body retreated into scars. He started to move about, and when the weather was good he joined some of the other snakes in short expeditions in search of mice and small birds.

Then his full vigor returned and he resumed a normal life. For him this had always consisted of matching wits with prairie dogs, those chattering little squirrel-like animals that built intricate subterranean towns. There was such a town, rather extensive, not far from the buttes, and for a hundred thousand years the rattlesnakes had invaded it.

On a warm day, when the sun relaxed and vivified the muscles that had grown stiff in winter, he set out from the buttes and slithered across the desert toward dog-town. From a distance he could see the little mounds that indicated where the creatures lived, and he noticed with gratification that they were as numerous as ever.

As he approached the town, which contained several thousand dogs, he tried to move as inconspicuously as possible, but from a hillock a sharp-eyed lookout spotted the grass moving and gave a loud chirping sound, which lookouts elsewhere in the town repeated, so that within an instant the whole area was alerted. Where there had been thousands of little prairie dogs sunning themselves and chattering, there were now none and all was silent.

He had encountered this tactic before and was prepared for it. Crawling as close as practical to a concentrated nest of houses, he coiled the long length of his body and waited. The one thing he could count on was curiosity; no matter what threatened, the prairie dog sooner or later had to come out of his safe burrow to inspect. A hawk could be perched at the opening, his feet showing, but the little dogs had to come out to satisfy themselves that he was really there.

So the snake waited, and before too many minutes had passed, from one of the burrows a furry little head appeared. By chance its first glance was directly into the eyes of the snake, which startled it so, it gave one wild cry and disappeared down its hole, but before it had ceased trembling from fright, another dog from another hole came out to see if there really was a snake, and this one was not so fortunate as to look directly at the rattler. It turned first in the opposite direction and before it ever saw the snake, the fangs had sunk into its neck.

There were many burrows in this town, and sometimes the rattlesnakes, caught far from the buttes in bad weather or when the sun was dangerously hot—for a snake, like the great reptiles before him, would quickly perish if exposed too long to the direct rays of the sun—would crawl into the burrows, and even make them their home for extended periods, in which case the prairie dogs would simply leave by another exit.

Sand owls, which built their nests and raised their young underground, also liked to preempt the burrows rather than take the trouble to build their own, and it was not unusual to see within one town the prairie dogs inhabiting one set of burrows, the sand owls another, and the rattlesnakes a third, with each allowing the other to go pretty much his own way.

This rattlesnake had no intention of taking up residence in dog-town. It came only to feed, and when it had caught its prey and swallowed it, there were other areas to visit, down by the river, for example, where mice lived among the roots of the cottonwoods. A rattler would always prefer a mouse above any other food, but they were not easy to catch. There were also birds, especially the young, but catching them required unusual patience, and after his encounter with the eagle this rattler was not much attracted to birds.

As autumn approached, it was essential that each rattler fortify himself with a series of meals upon which he could draw in the months of hibernation, and the hunting became more intense. In those days he practically lived in the heart of dog-town, picking off whatever inquisitive little animals he could, but as the days shortened he felt an irresistible urge to seek protection at the buttes. It was no trivial thing to go to sleep for a series of months during which he would be vulnerable to any foe that came upon him; it was essential that he return to deep rocky crevices which had protected him in the past.

So he started the trek back to the buttes, and as he went he saw many other rattlesnakes on their way, too, and as they convened at familiar places they moved together and sometimes formed intertwined balls of writhing forms, a score of large rattlers twisted together. When men reached this area, as they soon would, they would sometimes in autumn stumble upon such a ball of writhing snakes—“they was as big as a watermillion”—and they would be horrified; memory of the sight would haunt them, and years later they would speak of it: “I was ridin’ a gray mustang, a very steady brute, and all at oncet he shies and like to throw me on my ass and thank God he didn’t because there by them red rocks at Rattlesnake Buttes was this ball of snakes all twisted up I like to died.”

Now as the snakes crawled down a path which they had often used before, the old rattler became aware of an unfamiliar creature blundering toward him from the opposite direction. Following his ancient custom, he coiled himself in the middle of the path and emitted a sharp rattle. The stranger, unfamiliar with this warning, ignored it, stumbling directly at the rattler, which made an even sharper sound.

At last the intruder took notice, almost too late.

The snake struck at the thing that stood close to its fangs, but this was to be a unique experience, for deftly the target leaped aside, and from aloft something descended, striking the rattler a heavy blow behind the head. Knocked out of its coil, the snake endeavored in bewilderment to adjust to this unprecedented assault. It formed a half-coil, preparing to strike anew at its assailant.

And then it looked up, and instead of seeing a buffalo or a sharp-hoofed deer, it saw a new creature, standing erect, bearing a heavy weapon not seen before, and the last sensation this rattler had was the sight of the weapon descending toward his head with tremendous force, and the strange cry of triumph from the standing figure, and sharp death.

Man had come to the plains. From the far northwest, from a distant origin, across strange bridges and down green corridors, the two-legged one had journeyed to the buttes, where before only the horse and the camel and the mammoth, the sloth and the beaver and the snake had lived. His first act was symbolic, the instinctive killing of the snake, and for as long as time endured, enmity between these two would continue.

At this watershed of history it might be prudent to look at the land as it then was, for we must remember our inheritance if we are to retain a vision of what it might once more be.

It was a cruel land, that year when man arrived. The New Rockies rose perhaps a millionth of an inch; certainly they did not stand still, for they never had and they never would. They were either rising in birth or falling in decay, and in time to come they might be higher than the Himalayas or lower than the Appalachians. In that year no man could have guessed what their destiny would be.

From the mountains great bodies of water and silt cascaded down onto the plains, as they had been doing for seventy million years. That year there was a flood which killed many bison and swept away all beaver lodges, but at the same time it deposited some of the silt and many of the minerals which would make the area unusually rich when time came for tillage.

The grass grew a little better than usual, making it one of the finest pasture areas in the world, and the bison increased in number, so that when the cows led the northern herd into the yearly convocation the count was at its maximum, around forty million, with thirty million in the southern herd. They darkened the earth in such great numbers, they could never be obliterated.

Beaver had a poor year. The floods killed many in their lodges, especially the kits and one-year-olds. The two-year-old beavers who were expelled from home that year had little trouble finding locations for their lodges, but a lot of trouble finding trees the right size for building their dams; the flood had uprooted too many and swept them downstream.

At Rattlesnake Buttes the animals lived in subtle and long-approved harmony. The little sand owls stole a burrow now and then from the prairie dogs, and occasionally they ate a young dog, but only one that was too weak to survive normally. They also kept the mice in check, but themselves provided food for hawks.

The main problem of the prairie dogs was not the loss of an occasional burrow to the owls, or even the constant depredations of the rattlesnakes, but the fact that in the summer the rutting bulls, frustrated as males often are by the problems of sex, insisted upon wallowing on top of the town where the earth was fine and dusty and then urinating on it; they did a lot of damage and it took time to rebuild a town after such treatment.

The pronged antelope and the wolverine and the sleek deer and gray wolves that watched everything lived together in delicate balance, each needing the other and each dependent upon the land and its abundant grass.

There was another factor which has not been mentioned but which would, in the years ahead, become increasingly important. This land was beautiful.

From the buttes at sunrise a man would be able to look east and see a hundred miles to unbroken horizons, stark meadow after meadow reaching beyond the human imagination. The colors were superb, but the uninitiated could look at them and not see them, for they were soft grays and delicate browns and azure purples.

The vast plains had a nobility that would never diminish, for they were a challenge, with their duststorms, their wild blizzards, their tornadoes and their endless promise, if men treated them with respect. They were a resource inexhaustible in their variety but demanding in their love. In the years ahead they would terrify easterners and Europeans afraid of loneliness, but they would be a haven for all who understood them, and they would be loved in contrary ways and with harsh curses. The great plains—illimitable in both challenge and fulfillment.

If a man looked northward from the buttes he could see the chalk cliffs of Nebraska, those extraordinary white rocks that had once lain at the bottom of some vanished sea. It was infuriating; he could be dying of thirst on the parched plains, yet know that the whole area had once been under water, and there the white cliffs were to prove it. If he poked among them he would find fossil fish and clams, and the only way such things could have been caught in the rocks was for everything to have been under water. Hell, in some places the rock was twenty thousand feet thick, and all of it made under water.

To the south were the cottonwoods, that thin line of useless trees, barely edible for beavers, who would eat any tree that grew. Yet when a traveler saw those trees, broken-branched and torn by storms, his heart skipped a beat, for they marked the South Platte, and wherever it ran, there was at least water, foul though it might be, and some chance that another human being could be in the vicinity, because he needed water too.

It was to the west, however, that the conspicuous grandeur lay, for there the mountains rose in such splendor that when men saw them they gasped. Row upon row the marvelous peaks marched north and south, so many and so varied that the eye could never tire of them. In winter they were white with snow and looked as if they had been pasted against the deep-blue sky. In spring they shone green in their lower reaches and granite-blue above the tree line. In all seasons they were glorious, reaching fourteen thousand feet into the air and visible for more than a hundred miles out in the prairie.

There was one peak visible from the buttes, the largest of all, which captured the affection of every man or woman who saw it from this area. It was a noble peak of itself and would have been outstanding even if it had no significant features, but up its eastern flank crawled a granite beaver. It was really the oddest thing, but when a man looked at this master-mountain, a thing of obvious majesty, all he remembered was that stone beaver trying to climb to the top. Travelers could see him from a long way off, and from the buttes he commanded attention. This peak should have been called Beaver Mountain, but unfortunately, men are sometimes not imaginative. Other peaks had poetic names like Never-Summer Range, Rabbit’s Ear, Medicine Bow, Sangre de Cristo, and one with a perpetual mark of snow in its crisscrossed ravines, the Mount of the Holy Cross. Even Pikes Peak had an alliterative ring, but the best mountain of them all, with a little beaver crawling up its flank, was given the drabbest name of all—Longs Peak.

The Rockies had a characteristic not shared by other ranges of the west, and this both endeared them to people who lived in their shadow and infuriated those who came upon them as strangers. The air surrounding them was so pure that from a distance it was impossible to calculate how far away they were. Of course, the air was just as pure around the ranges to the north, but they were not faced by flat plains across which people traveled, so the phenomenon did not apply to them. If an immigrant came from a flat land like Illinois, he would wake up one morning after crossing the Missouri to see the Rockies as clear as a row of corn on his farm back home, and he would exult and cry, “Tonight we sleep in the mountains!”

But he could travel westward all the next day, and the mountains would still appear to be where they had been at dawn, and the next night they would be no closer, nor the next either. Distance could not be calculated, and occasionally a man and his wife would become mesmerized by the noble mountains; never had they seen anything so grand and so perplexing. The good part was that close up, these splendid ranges were just as impressive as they had been from a distance. They dominated the plains and served as a backdrop to extraordinary beauty.

It was at sunset that the mountains came into their own, for on some days clouds would rest over them like a light blanket and reflect the dying sun. Then the mountains would be bathed in splendor: gold and red and soft radiant browns and deep blues would color the underside of the clouds and frame the mountains in a celestial light, so that even the most stolid Indiana immigrant would have to halt his oxen and look in amazement at a setting so grand that it seemed to have been ordained solely for the stupefaction of mankind.

The loveliest moment came, however, when the sun had set and its flamboyant coloring had faded. Then, for about twenty minutes, the softest colors of the spectrum played about the crests of the mountains, and the little stone beaver crawled toward the summit to sleep, and many a traveler bit his lower lip and looked away, thinking of a home he would not see again.

Centennial, when it was founded, would stand at the spot where a man could look eastward and catch the full power of the prairie, or westward to see the Rockies. The history of the town would be a record of the way it responded to the impossible task of conciliating the demands of the mountains with the requirements of the prairie. Many would destroy themselves in this conflict, but those who survived, assimilating the best of these two contrasting worlds, would attain a largeness of soul that other men who chose easier paths would not discover.

CAUTION TO US EDITORS. Even as I was working on this section a group of leading geologists announced that in their opinion the Pleistocene epoch, which covers the period of the glaciers, should be considered to start not at one million years before the present but two to three million. At the same time another specialist suggested that North America did not experience the five periods of glaciation which I was taught—with five interglacial periods, the last being the one we are in now—but rather a recurring series of shorter-lived glaciers interspersed with many interglacial periods. I tend to agree with each of these opinions, because they are consistent with ideas I have expressed before, that we will probably push all dates back in time. We are older than we used to think. However, in my notes I have respected the established chronology. If your own researches incline you toward the newer dates, use them.

Land bridge. I must also warn you concerning two facts about the land bridge. Its existence cannot be challenged, but it may not have been as vital as my notes make it out to be. A very good geologist told me the other day, “There is no need to posit this famous land bridge of yours. For much of the time when the exchange of animal life was under way the Asian plate and the North American were in contact and the two continents were undifferentiated. The so-called bridge must have then been two or three thousand miles wide, and glaciers had absolutely nothing to do with it.” Incidentally, do not think of the Eskimo as using the bridge. They got here very late, long after the last glaciation, when there could have been no bridge. No matter. They could get from Asia to Alaska simply by canoeing for fifty-six miles, which is what they did.

Amphibians? Although every text agrees that the sauropods, the family to which diplodocus belonged, were amphibians, the exact significance of this description is uncertain. Some experts like G. Edward Lewis argue that animals as enormous as brontosaurus and diplodocus could not have supported their weight on dry land, considering their crude joints; they must have lived in swamps and lagoons where water buoyed them up. Others point out that the legs, awkward though they were, did persist through millions upon millions of years, whereas unused appendages, like the human tail, atrophied and vanished. Of seventeen illustrations I was able to find of diplodocus, all showed her on land, but Lewis explains that this cannot be accepted as evidence; the artists merely wished to display her total conformation.

Origins of the horse. Some readers may, with scientific backing, object to a Colorado origin for the horse. They argue that the missing “paleohippus” of which I write could just as properly have originated in Europe, since there was a well-known European equivalent to the second-generation eohippus. In Europe the little creature was given the totally erroneous name hyracotherium, because his discoverers could not imagine him to be related in any way to the horse; they classified him as a forebear of the hyrax, a small shrewlike animal, the cony of the Old Testament. Such experts believe our horse originated in Europe from the hyracotherium. I think not. That eohippus died away into forms with no aptitude for survival. The horse as we know it developed where and as I said. The Arabian, the Percheron, the Clydesdale—all had their beginnings not far from Rattlesnake Buttes. Crazy idea, isn’t it?

Appaloosa. I would advise you not to get involved over the origins of this most beautiful of horses. A group of new scholars is pushing the line that the ancestors of our horse developed in America only as far as mesohippus, which then emigrated to Asia, where it developed into the horse proper, in the form of the Appaloosa, which thus becomes the great ancestor of subsequent breeds. This theory is most ardently voiced, as you might suspect, by Appaloosa owners, but is rejected by others. The Appaloosa is a distinguished animal, one of the great breeds of the world and possibly the most ancient. It has solid-color front quarters, mottled rear, skimpy tail and mane and curiously streaked hoofs. The Nez Percé Indians of western Idaho were responsible for cultivating the strain in North America, and from them a few passed into the hands of western ranchers, who in 1938 banded together to reestablish the breed. They’ve done a good job, and later on we’ll see the effect on a town like Centennial.

Origins of the beaver. You may get some flak regarding the beaver. Some experts have argued that he originated in Europe, or perhaps Egypt, and immigrated to North America rather late. But the greater scholars like Stout and Schultz, both of Nebraska, believe that he originated from American stock dating far back and that he emigrated over the land bridge to Asia to develop collaterally there.

Definitions. It’s difficult to find a precise definition of butte. A vast upland area is a plateau. When bounded on all four sides by cliffs, it’s a mesa. When the boundaries of the mesa erode to a point at which the height is greater than the width, it’s a butte. If it continues eroding, it becomes in succession a monument, a chimney, a spire, a needle, and finally, a memory.

Eagle-serpent. This enmity is celebrated in many folklores. The preeminent visual depiction appears, of course, in the Mexican flag, where a serpent held in the talons of an eagle perched on a cactus serves as the national insignia. Traditionally the eagle (manly virtue) kills the snake (guile and venality); the account I send you, in which the rattlesnake triumphs, is an invention of the western plains, where it occurs in various oral versions.