Centennial (9 page)

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 sinewy 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 weigh 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 dagger-like 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.