Evolution Read online

  But something moved beyond the troodon’s bulky body, something even more massive, a gliding mountain, utterly silent.

  The troodon was unbelievably careless. Giant didn’t care why. And he didn’t care about the warm scrap she held in her hands.

  His attack was fast, silent, and utterly savage, a single bite to her neck. Wounding Tooth had time for a moment of shock, of unbelievable pain — and then, as whiteness enfolded her, a peculiar relief.

  Her hands opened. A ball of fur tumbled through the air.

  Before Wounding Tooth’s body fell Giant had renewed his attack. Briskly he slit open the belly cavity and began pulling out entrails. He expelled their contents by shaking them from side to side; bloody, half-digested food showered the area.

  Soon his two brothers came racing across the clearing. Giganotosaurs hunted together, but their society was fragile at the best of times. Giant knew he couldn’t defend his kill, but he was determined not to lose it all. Even as he chewed on the liver of Wounding Tooth, he turned to kick and bite.

  Purga found herself on the ground. Above her, mountains battled with ferocious savagery. A rain of blood and saliva fell all around her. She had no idea what had happened. She had been ready for death. Now here she was in the dirt, free again.

  And the light in the sky grew stranger yet.

  The comet nucleus could have passed through the volume of space occupied by Earth in just ten minutes.

  In the great boiling it had endured the comet had lost a great deal of mass, but not a catastrophic amount. If it had been able to complete its skim around the sun, it would have soared back out to the cometary cloud, quickly cooling, the lovely coma and tail dispersing into the dark, to resume its aeonic dreaming.

  If.

  For days, weeks, the great comet had worked its way across the sky — but slowly, its hour-by-hour motion imperceptible to any creature who glanced up at it, uncomprehending. But now the bright-glowing head was sliding: sliding down the sky like a setting sun, sinking toward the southern horizon.

  All across the daylit side of the planet, silence fell. Around the drying lakes the crowding duckbills looked up. Raptors ceased their stalking and pursuit, just for a moment, their clever brains struggling to interpret this unprecedented spectacle. Birds and pterosaurs flew from their nests and roosting places, already startled by a threat they could not understand, seeking the comfort of the air.

  Even the warring giganotosaurs paused in their brutal feeding.

  Purga bolted for the darkness of her burrow. The disembodied head of the troodon fell behind her, lodging in the burrow’s entrance, following Purga with a grotesque, empty stare as the light continued to shift.

  CHAPTER 2

  The Hunters of Pangaea

  Pangaea. Circa 145 million years before present.

  Eighty million years before Purga was born, an ornitholestes stalked through the dense Jurassic forest, hunting diplodocus.

  This ornith was an active, carnivorous dinosaur. She was about the height of an adult human, but her lithe body was less than half the weight. She had powerful hind legs, a long, balancing tail, and sharp conical teeth. She was coated in brown, downy feathers, a useful camouflage in the forest fringes where her kind had evolved as hunters of carrion and eggs. She was like a large, sparsely feathered bird.

  But her forehead might almost have been human, with a high skullcap that sat incongruously over a sharp, almost crocodilian face. Around her waist was a belt and a coiled whip. In her long, grasping hands she carried a tool, a kind of spear.

  And she had a name. It would have translated as something like Listener — for, although she was yet young, it had already become clear that her hearing was exceptional.

  Listener was a dinosaur: a big-brained dinosaur who made tools and who had a name.

  For all their destructiveness, the great herds of duckbills and armored dinosaurs of Purga’s day were but a memory of the giants of the past. In the Jurassic era had walked the greatest land animals that had ever lived. And they had been stalked by hunters with poison-tipped spears.

  Listener and her mate slid silently through the green shade of the forest fringe, moving with an unspoken coordination that made them look like two halves of a single creature. For generations, reaching back to the red-tinged mindlessness of their ancestors, this species of carnivore had hunted in mating pairs, and so they did now.

  The forest of this age was dominated by tall araucaria and ginkgoes. In the open spaces there was a ground cover of ground ferns, saplings, and pineapple-shrub cycadeoids. But there were no flowering plants. This was a rather drab, unfinished-looking world, a world of gray-green and brown, a world without color, through which the hunters stalked.

  Listener was first to hear the approach of the diplo herd. She felt it as a gentle thrumming in her bones. She immediately dropped to the ground, scraping away ferns and conifer needles, and pressed her head against the compacted soil.

  The noise was a deep rumble, like a remote earthquake. These were the deepest voices of the diplos — what Listener thought of as belly-voices, a low-frequency contact rumble that could carry for kilometers. The diplo herd must have abandoned the grove where it had spent the chill night, those long hours of truce when hunters and hunted alike slid into dreamless immobility. It was when the diplos moved that you had a chance to harass the herd, perhaps to pick off a vulnerable youngster or invalid.

  Listener’s mate was called Stego, for he was stubborn, as hard to deflect from his course as a mighty — but notoriously tiny-brained — stegosaur. He asked, They are moving?

  Yes, she replied. They are moving.

  Hunting carnivores were accustomed to working silently. So their language was a composite of soft clicks, hand signals, and a ducking body posture — no facial expressions, for the faces of these orniths were as rigid as any dinosaur’s.

  As they approached the herd, the noise of the great animals’ belly-voices became obvious. It made the very ground shake: The languid fronds of ferns vibrated, and dust danced up, as if in anticipation. And soon the orniths could hear the footfalls of the mighty animals, tremendous, remote impacts that sounded like boulders tumbling down a hillside.

  The orniths reached the very edge of the forest. And there, before them, was the herd.

  When diplodocus walked, it was as if the landscape were shifting, as if the hills had been uprooted and were moving liquidly over the land. A human observer might have found it difficult to comprehend what she saw. The scale was wrong: Surely these great sliding masses must be something geological, not animal.

  The largest of this forty-strong herd was an immense cow, a diplo matriarch who had been the center of this herd for over a century. She was fully thirty meters long, five meters tall at the hips, and she weighed twenty tons — but then even the youngsters of the herd, some as young as ten years old, were more massive than the largest African elephant. The matriarch walked with her immense neck and tail held almost horizontal, running parallel to the ground for tens of meters. The weight of her immense gut was supported by her mighty hips and broad, elephantine legs. Thick ropelike ligaments ran up her neck, over her back, and along her tail, all supported in canals along the top of her backbone. The weight of her neck and tail tensed the ligaments over her neck, thereby balancing the weight of her torso. Thus she was constructed like a biological suspension bridge.

  The matriarch’s head looked almost absurdly small, as if it belonged to another animal entirely. Nevertheless this was the conduit through which all her food had to pass. She fed constantly; her powerful jaws were capable of taking bites out of tree trunks, huge muscles flowing as the low-quality food was briskly processed. She even cropped in her sleep. In a world as lush as this late Jurassic, finding food wasn’t a problem.

  Such a large animal could move only with a chthonic slowness. But the matriarch had nothing to fear. She was protected by her immense size, and by a row of toothlike spines and crude armor plates on her back. She
did not need to be smart, agile, to have fast reactions; her small brain was mostly devoted to the biomechanics of her immense body, to balance, posture, and movement. For all her bulk the matriarch was oddly graceful. She was a twenty-ton ballerina.

  As the herd progressed the herbivores snorted and growled, lowing irritably where one mighty body impeded another. Under this was the grinding, mechanical noise of the diplos’ stomachs. Rocks rumbled and ground continually within those mighty gizzards to help with the shredding of material, making a diplo’s gut a highly efficient processor of variable, low-quality fodder that was barely chewed by the small head and muscleless cheeks. It sounded like heavy machinery at work.

  Surrounding this immense parade were the great herbivores’ camp followers. Insects hovered around the diplos themselves and their immense piles of waste. Through their swarms dove a variety of small, insectivorous pterosaurs. Some of the pterosaurs rode on the diplos’ huge uncaring backs. There was even a pair of ungainly protobirds, flapping like chickens, running around the feet of the diplos, snapping enthusiastically at grubs, ticks, and beetles. And then there were the carnivorous dinosaurs, who hunted the hunters in turn. Listener spotted a gaggle of juvenile coelurosaurs, gamely stalking their prey among the tree-trunk legs of the herbivores, at every moment risking death from a carelessly placed footfall or tail twitch.

  It was a vast, mobile community, a city that marched endlessly through the world forest. And it was a community of which Listener was part — where she had spent all her life, which she would follow until she died.

  Now the diplo matriarch came to a grove of ginkgoes, quite tall, ripe with green growth. She raised her head on its cable neck for a closer inspection. Then she dipped her head into the leaves and began to browse, tearing at the leaves with her stubby teeth. The other adults joined her. The animals began simply to barge down the trees, snapping trunks and even ripping roots out of the ground. Soon the grove was flattened; it would take decades for the ginkgoes to recover from this brief visit. Thus the diplos shaped the landscape. They left behind a great scribble of openness, a corridor of green savannah in a world otherwise dominated by forest, for the herd so ravaged the vegetation of any area that it had to keep moving, like a rampaging army.

  These were not the mightiest herbivores — that honor went to the giant, tree-cropping brachiosaurs, who could grow as massive as seventy tons — but the brachiosaurs were solitary, or moved in small groups. The diplo herds, sometimes a hundred strong, had shaped the land as no animal had before or since.

  This loose herd had been together — traveling forever east, its members changing, its structure continual — for ten thousand years. But there was room for such titanic journeys.

  Jurassic Earth was dominated by a single immense continent: Pangaea, which meant “the land of all Earth.” It was a mighty land. South America and Africa had docked to form a part of the mighty rock platform, and a titanic river drained the heart of the supercontinent — a river of which the Amazon and Congo were both mere tributaries.

  As the continents had coalesced there had been a great pulse of death. The removal of barriers of mountain and ocean had forced species of plants and animals to mix. Now a uniformity of flora and fauna sprawled across all of Pangaea, from ocean to ocean, pole to pole — a uniformity sustained even though vast tectonic forces were already laboring to shatter the immense landmass. Only a handful of animal species had survived the great joining: insects, amphibians, reptiles — and protomammals, reptilian creatures with mammalian features, a lumpen, ugly, unfinished lot. But that handful of species would ultimately give rise to all the mammals — including humans — and to the great lineages of birds, crocodiles, and dinosaurs.

  As if in response to the vast landscape in which they found themselves, the diplos had grown huge. Certainly their immensity was suitable for these times of unpredictable, mixed vegetation. With her long neck a diplo could work methodically across a wide area without even needing to move, taking whatever ground cover was available, even the lower branches of trees.

  In the clever orniths, though, the diplos faced a new peril, a danger for which evolution had not prepared them. Nevertheless, after more than a century of life, the matriarch had absorbed a certain deep wisdom, and her eyes, deep red with age, betrayed an understanding of the nimble horrors that pursued her kind.

  Now the patient orniths had their best opportunity.

  The diplos still crowded around the wrecked ginkgo grove, their great bodies in a starburst formation. Their heads on their long necks dipped over the scattered foliage like cherry picker mechanical claws. Youngsters clustered close, but for now they were excluded by the giant adults.

  Excluded, forgotten, exposed.

  Stego ducked his head toward one of the diplo young. She was a little smaller than the rest — no larger than the largest African elephant, a genuine runt. She was having trouble forcing her way into the feeding pack, and she snapped and prowled at the edge of the formation with a massive birdlike twitchiness.

  There was no real loyalty among the diplos. The herd was a thing of convenience, not a family grouping. Diplos laid their eggs at the edge of the forest, and then abandoned them. The surviving hatchlings would use the cover of the forest until they had grown sufficiently massive to take to the open land and seek a herd.

  The herds made strategic sense: Diplos helped protect each other by their presence together. And any herd needed new blood for its own replenishment. But if a predator took one of the young, so be it. In the endless Pangaean forests, there was always another who would take her place. It was as if the herd accepted such losses as a toll to be paid for its continuing passage through the ancient groves.

  Today it looked as if this runty female would pay that toll.

  Listener and Stego took their whips of diplo leather from around their waists. Whips raised, spears ready, they crept through the rough scrub of saplings and ferns that crowded the edge of the forest. Even if the diplos spotted them they would probably not react; the diplos’ evolutionary programming contained no alarm signals for the approach of two such diminutive predators.

  A silent conversation passed in subtle movements, nods, eye contacts.

  That one, said Stego.

  Yes. Weak. Young.

  I will run at the herd. I will use the whip. Try to spook them. Separate the runt.

  Agreed. I will make the first run…

  It should have been routine. But as the orniths approached, coelurosaurs scuttled away and pterosaurs flapped awkwardly into the air.

  Stego hissed. Listener turned.

  And looked into the eyes of another ornith.

  There were three of them, Listener saw. They were a little larger than Listener and Stego. They were handsome animals, each with a distinctive crest of spiny decorative scales running down the back of its head and neck; Listener felt her own spines rise up in response, her body obeying an unbidden, ancient instinct.

  But these orniths were naked. They had no belts of woven bark around their waists like Listener’s; they carried no whips, no spears; their long hands were empty. They did not belong to Listener’s hunting nation, but were her remote cousins — wild orniths — the small-brained stock from which her kind had arisen.

  She hissed, her mouth gaping wide, and strode into the open. Get away! Get out of here!

  The wild orniths stood their ground. They glared back at Listener, their own mouths gaping, heads bobbing.

  A tinge of apprehension touched Listener. Not so long ago three like these would have fled at her approach; the wild ones had long learned to fear the sting of weapons wielded by their smarter cousins. But hunger outweighed their fear. It had probably been a long time since these brutes had come across a diplo nest, their primary food source. Now these clever opportunists probably hoped to steal whatever Listener and Stego managed to win for themselves.

  The world forest was getting crowded.

  Listener, confronted by this unwelcome reminder of
her own brutish past, knew better than to show fear. She continued to stalk steadily toward the three wild orniths, head dipping, gesturing. If you think you are going to steal my kill you have another think coming. Get out of here, you animals. But the mindless ones replied with hisses and spits.

  The commotion was beginning to distract the diplodocus. That runty female had already ducked back into the mass of the herd, out of reach of the hunters. Now the big matriarch herself looked around, her head carried on her neck like a camera platform on a boom crane.

  It was the chance the allosaurs had been waiting for.

  The allos stood like statues in the forest’s green shade, standing upright on their immense hind legs, their slender forearms with their three-clawed hands held beneath. This was a pack of five females, not quite fully grown but nevertheless each of them was ten meters long and weighed more than two tons. Allosaurs were not interested in runtish juveniles. They had targeted a fat male diplo, like themselves just a little short of full maturity. As the herd milled, distracted by the commotion of the squabbling orniths, that fat male got himself separated from the protective bulk of the herd.

  The five allos attacked immediately, on the ground, in the air. With hind claws like grappling hooks they immediately inflicted deep, ugly wounds. They used their strongly constructed heads like clubs, battering the diplo, and teeth like serrated daggers gouged at the diplo’s flesh. Unlike tyrannosaurs they had big hands and long, strong arms they used to grab on to the diplo while dismembering him.

  Allosaurs were the heaviest land carnivores of all time. They were like upright, meat-eating, fast-running elephants. It was a scene of immense and ferocious carnage.

  Meanwhile the diplo herd was fighting back. The adults, bellowing in protest, swung their huge necks back and forth over the ground, hoping to sweep aside any predator foolish enough to come close. One of them even reared up on her hind legs, a vast, overpowering sight.