Evolution

by Stephen Baxter

  After a year, one of the new replicator types would become two. Which after another year had made two more copies, a total of four. And in another year there were eight. And so on.

  The growth was exponential. The outcome was predictable.

  Within a century the factory-robots were everywhere on Mars, from pole to equator, from the peak of Mons Olympus to the depths of the Hellas crater. Some of them came into conflict over resources: There were slow, logical, mechanical wars. Others began to dig, to exploit the deeper materials of Mars. If you mined, there was still plenty of resources to go around — for a while, anyhow.

  The mines got deeper and deeper. In places the crust collapsed. But still they kept digging. Mars was a cold, hard world, rocky for much of its interior. That helped the mining. But as they dug deeper and encountered new conditions, the replicators had to learn quickly, adapt. They were capable of that, of course.

  Still, the penetration of the mantle presented certain technical challenges. The dismantling of the core was tricky too.

  Mars weighed one hundred billion billion times as much as any one of the tractor-replicators. But that number was small in the face of the doubling-every-generation rule. Because of the continuing conflicts, the pace of growth was a little slower than optimal. Even so, in just a few hundred generations, Mars had gone, all but a trace of its substance converted to the glistening bulks of replicators.

  With the whole planet transformed to copies of themselves — using solar sails, fusion drives, even crude antimatter engines — the swarm of replicators had moved out through the solar system, seeking raw material.

  The next day, roaming into the country around the town, Snowy saw birds, squirrels, mice, rabbits, rats. Once he thought he saw a goat; it fled at his approach.

  Not much else. There didn’t even seem to be many birds around. The place was silent, as if all the living things had been collected up and removed.

  Some of the rats were huge, though. And then there were the rat-wolves he thought he had glimpsed. Whatever they were, they fled at his approach.

  Rodents had always been in competition with primates, Sidewise said. Even at the peak of their technical civilization, people had had to be content with keeping rodents out of sight, and out of the food. Now, with people out of the picture, the rats were evidently flourishing.

  It was easy to hunt, though. Snowy set a few snares, in a spirit of experimentation. The snares worked. The hares and voles seemed peculiarly tame. Another bad sign if you thought about it, because it meant they hadn’t seen humans for a while.

  At the end of the second day, Ahmed had them sit in the ruins of the church, in a rough circle on corroded stone blocks.

  Snowy was aware of subtle changes in the group. Moon was looking down, avoiding everybody’s eyes. Bonner, Ahmed, and Sidewise were watching each other, and Snowy, with calculation.

  Ahmed held up an empty ration packet. “We can’t stay here. We have to plan.”

  Bonner shook his head. “The most important thing is finding other people.”

  “We’re going to have to face it,” Sidewise said. “There are no other people — nobody who can help us, anyhow. We haven’t seen anybody. We’ve seen no sign that anybody has been in this area recently.”

  “No contrails,” Ahmed said, pointing to the sky. “Nothing on the radio, on any frequency. No satellites. Something went wrong—”

  Moon laughed hollowly. “You can say that again.”

  “We can’t know how events unfolded. Before the end it must have become — chaotic. We were never recalled. Eventually, I suppose, we were forgotten. Until we were revived by chance.”

  Snowy forced himself to ask the question. “How long, Side?”

  Sidewise rubbed his nose. “Hard to say. If we had an astronomy almanac I guess we could figure it out from the changed positions of the stars. Failing that, your best guess is based on the maturity of the oak forest.”

  Bonner snapped, “You’re so full of shit, you scrawny bastard. How fucking long? Fifty years, sixty—”

  “Not less than a thousand years,” Sidewise said, his voice tight. “Maybe more. Probably more, actually.”

  In silence, they let that sink in. And Snowy closed his eyes, imagining he was plunging off the deck of an aircraft carrier into the dark.

  A thousand years. And yet it meant no more than the fifty-year gulf that he thought had separated him from his wife. Less, maybe, because it was just unimaginable.

  “Some future this is,” Bonner said edgily. “No jet cars. No starships, no cities on the Moon. Just shit.”

  Ahmed said, “We have to assume we are not going to find anybody else. That we’re alone. We have to plan on that basis.”

  Sidewise snorted. “Civilization has collapsed, everybody is dead, and we’re stuck a thousand years in the future. How are we supposed to plan for that?”

  “That river is probably clean,” Snowy said. “All the factories must have shut down centuries ago.”

  Ahmed nodded gratefully at him. “Good. At last, something we can actually build on. We can fish, we can hunt; we can start that tomorrow. Sidewise, why don’t you use that brain of yours for something useful and think about the fishing? Figure out how we can improvise lines, nets, whatever the hell. Snowy, you do the same for the hunting. Further down the line, we’re going to have to find somewhere to live. Maybe we can find a farm. Start thinking about clearing the ground, planting wheat.” He glanced at the sky. “What do you think the season is? Early summer? We’re too late for a harvest this year. But next spring—”

  Sidewise snapped, “Where do you think you’re going to find wheat? Do you know what happens if you leave corn or wheat unharvested? The ears fall to the ground and rot. Cultivated wheat needed us to survive. And if you leave cows unmilked for a few days, they just die of udder bursts.”

  “Take it easy,” Snowy said.

  “All I’m telling you is that if you want to farm, you’ll have to start from scratch. The whole damn thing, agriculture and husbandry, all over again from wild stock, plants and animals.”

  Ahmed nodded stiffly. “We, Side. Not you. We. We all share the problems here. All right. So that’s what we’ll do. And in the meantime we gather, we hunt. We live off the land. It’s been done before.”

  Moon fingered her clothing. “This stuff won’t last forever. We’ll have to find out how to make cloth. And our weapons will be pretty useless once the ammo is gone.”

  Bonner said, “Maybe we can make more ammo.”

  Sidewise just laughed. “Think about stone axes, pal.”

  Bonner growled, “I don’t know how to make a fucking stone ax.”

  “Neither do I, come to think of it,” Sidewise said thoughtfully. “And you know what? I bet there aren’t even any books to tell us how. All that wisdom, painfully acquired since we were buck naked Homo erectus running around in Africa. All gone.”

  “Then we’ll just have to start that again too,” Ahmed said firmly.

  Bonner eyed him. “Why?”

  Ahmed looked up at the sky. “We owe it to our children.”

  Sidewise said simply, “Four Adams and one Eve.”

  There was a long, intense silence. Moon was like a statue, her eyes hard. Snowy noticed how close her hand was to her PPK.

  Ahmed got to his feet. “Don’t think about the future. Think about filling your belly.” He clapped his hands. “Let’s move it.”

  They dispersed. The crescent moon was already rising, a bonelike sliver in the blue sky.

  “So,” Sidewise said to Snowy as they moved off, “how are you finding life in the future?”

  “Like doing time, mate,” Snowy said bitterly. “Like doing fucking time.”

  III

  Maybe five kilometers from the base camp, Snowy was trying to build a fire.

  He was in what must once have been a field. There were still traces of a dry stone wall that marked out a broad rectangle. But after a thousand years it was pretty much
like any patch of land hereabouts, choked by perennial herbs and grasses, shrubs and deciduous seedlings.

  He had made a fire board about the length of his forearm, with a dish cut into its flat side. He had a spindle, a stick with a pointed end; a socket, a bit of rock that fit neatly into his hand; and a bow, more sapling with a bit of plastic shoelace tied tight across it. A bit of bark under the notch served as a tray to catch the embers he would make. Nearby he had made a little nest of dry bark, leaves, and dead grass, ready to feed the flames. He knelt on his right knee, and put the ball of his left foot on the fire board. He looped the bow string and slid the spindle through it. He lubricated the notch with a bit of earwax, and put the rounded end of the spindle into the dish of his fire board, and held the pointed end in the hand socket. Then, pressing lightly on the socket, he drew the bow back and forth, rotating the spindle with increasing pressure and speed, waiting for smoke and embers.

  Snowy knew he looked older. He wore his hair long now, tied back in a ponytail by a bit of wire. His beard was growing too, though he hacked it back with a knife every couple of days. His skin was like tough leather, wrinkled around the eyes, the mouth. Well, I am older, he thought. A thousand years older. I should look the part.

  It was hard to believe that it was only a bit more than a month since they had come out of the Pit.

  They didn’t need to do this kind of thing yet, this fire building from scratch. They still had plenty of boxes of waterproof matches, and a supply of trioxane packs — a light chemical heat source much used by the military. But Snowy was looking ahead to the day when they wouldn’t be able to rely on what had come out of the Pit. In some ways he was “cheating,” of course. He had used his thousand-year-old finely manufactured Swiss Army knife to make the bow and the fire board; later he would have to try out stone knives. But one step at a time.

  This ancient field was close to an arm of the vast oak forest which, as far as they had scouted, dominated the landscape of this posthuman England. It was on a slight rise. To the west, further down the hill, a lake had gathered. Snowy could see traces of stone walls disappearing under the placid water. But the lake was choked with reeds and lilies and weeds, and on its surface he could see the sickly gray-green sheen of an algal bloom. Eutrophication, said Sidewise: Even now, artificial nutrients — notably phosphorus — were leaching out of the land into the lake and overstimulating the miniature ecology. It seemed incredible to Snowy that the shit long-dead farmers had pumped into their land could still be poisoning the environment around him, but it seemed to be true.

  It was a strangely empty landscape. Silence surrounded him. There wasn’t even birdsong.

  Some creatures had probably bounced back quickly once human hunting, pest control, and land use had ceased — hares, rabbits, grouse. Larger mammals reproduced so slowly that recovery must have taken longer. But there seemed to be various species of deer, and Snowy had glimpsed pigs in the forests. They’d seen no large predators. Even foxes seemed rare. There were no birds of prey either — apart from a few aggressive-looking starlings. Sidewise said that as their food chains had collapsed, the specialized top predators would have died out. In Africa there were probably no lions or cheetahs either, he said, even if they had escaped being eaten by the last starving human refugees.

  Maybe, Snowy thought. He wondered about the rats, though.

  Balance would return in the long run, of course. Variation, adaptation, and natural selection would see to that; the old roles would be filled one way or another. But it might not be anything like the community that had gone before. And, said Sidewise, since the average mammalian species lasted only a few million years, it would correspondingly be millions of years — ten, twenty maybe, twenty million years — before there would again be assembled a world of the richness it had enjoyed. So even if humans recovered and lasted, say, five million years, they wouldn’t see anything like the world Snowy had known as a kid.

  Snowy was not a tree hugger, definitely. But there was something deeply disturbing about these thoughts. How strange it was to have lived to see it come about.

  Still no smoke, still the damn embers hadn’t caught. He continued to work the bow.

  The main problem with fire making was that it gave him too much time to think. He missed his friends, the camaraderie of navy life. He missed his work, even the routine bits — maybe the routine most of all, since it had given his life a definition it lacked now.

  He missed the noise, he found, though that was harder to pin down: TV and the web and music, movies and ads, the logos and jingles and news. The one thing about the new world that would drive him crazy in the end, he suspected, was the silence, the huge, inhuman, vegetable silence. It gave him the shivers to imagine how it must have been in the last days, when all the machines had died, the winking logos and neon tubes and screens flickering and dying, one by one.

  And he missed Clara. Of course he did. He had never known his kid, never even seen him, or her.

  At the beginning he had been plagued by spasms of guilt: guilt that he was still alive where so many had gone into the dark, guilt that there was nothing he could do for Clara, guilt that he was eating and breathing and pissing and taking shits and covertly studying Moon’s butt while everybody he had ever known was dead. But that, mercifully, was fading. He had always been blessed, as Sidewise had once told him, by a lack of imagination.

  Or maybe it was more than that.

  In the clear light of this new time it seemed like it was his old life, in the crowded, murky England of the twenty-first century, which was the dream. As if he were dissolving into the green.

  There was a rustle in the waist-high foliage, a dozen paces away. He turned that way, still and silent. A single grass stem, laden with seeds, nodded gracefully. He had set a snare over there. Was there something in the foliage — a curve of shoulder, a bright, staring eye?

  He put down the bow and spindle. He stood, stretched, and casually walked toward the place he had seen the rustle. He slid his bow from his back, scooped an arrow from his rabbit-skin quiver, notched it carefully.

  There was no movement in the foliage — not until he was almost on it — and then there was a sudden blur, a lunge away from his approach. He glimpsed pale skin flecked with brown, long limbs. A fox? But it was big, bigger than anything he’d seen here so far.

  Without hesitating further he ran up to the thing, lodged his boot in the small of its back, and raised his arrow toward its head. The creature squirmed onto its back. It yowled like a cat, put its hands over its face.

  He lowered the bow. Hands. It had hands, like a human, or an ape.

  His heart thumping, he dropped the bow. He knelt over the creature, trapping its torso, and got hold of its wrists. It was spindly, lithe, but very strong; it took all of his power to force those hands away from the face. Still the creature spat and hissed at him.

  But its face — no, her face — was no chimp’s, no ape’s. It was unmistakably human.

  For long seconds Snowy sat there, astounded, astride the girl.

  She was naked, and though her pale skin showed through, she was covered by a loose fur of straggling orange-brown hairs. The hair on her head was darker, a tangle of filthy curls that looked as if they had never been cut. She was not tall, but she had breasts, sagging little sacks with hard nipples protruding from the hair, and beneath the triangle of darker fur at her crotch there was a smear of what might be menstrual blood. And she had stretch marks.

  Not only that, she stank like a monkey cage.

  But that face was no ape’s. Her nose was small but protruding. Her mouth was small, her chin V-shaped with a distinct notch. Over blue eyes, her brow was smooth. Was it a little lower than his?

  She looked human, despite her hairy belly. But her eyes were — cloudy. Frightened. Bewildered.

  His throat tight, he spoke to her. “Do you speak English?”

  She screeched and thrashed.

  And suddenly Snowy had an erection like an
iron rod. Holy shit, he thought. Quickly he rolled off the girl, reaching for his bow and his knife.

  The girl couldn’t get up. Her right foot was trapped by his snare. She scrabbled over the moist ground until she was hunched over her foot. She rocked back and forth, crooning, obviously scared out of whatever wits she had.

  Snowy’s spasm of lust faded. Now she looked like a chimp in her gestures, in her mindless misery, even though her body had felt like a woman’s under his. (Clara, forgive me, it’s been a long time…) The scrapings of shit on her legs, the puddles of droppings where she had been lying, put him off even more.

  He rummaged in a pocket of his flight suit, and pulled out the remains of a ration pack. It still contained a handful of nuts, a bit of beef jerky, some dried banana. He pulled out the banana and held it out, a handful of curling flakes, toward the girl.

  She shied back, pulling as far as she could on the wire.

  He tried miming, putting a flake or two into his own mouth and exaggeratedly devouring it with every expression of enjoyment. “Yum, yum. Delicious.”

  But still she wouldn’t take the food from his hand. Then again, neither would a deer or a rabbit, he thought. So he put the flakes on the ground between them and backed away.

  She grabbed a couple of the flakes and crammed them into her mouth. She chewed and chewed at the bits of banana, as if extracting every bit of flavor from them, before finally swallowing them. She must never have tasted anything so sweet, he thought.

  Or maybe it was just that she was starving. He had set the trap a couple of days before; she might have been here for forty-eight hours already. All the shit and piss, the way the fur on her legs was matted and stained, indicated that too.

  As she ate he got a good look at the foot that had been caught in the snare. It was a simple loop snare, meant for the heads of rabbits and hares. In her efforts to get free she had pulled the snare tighter — it had worked just as it had been designed — and it had cut so deeply into her leg that it had made a grisly, bloody mess of her flesh, and he thought he could see the white of bone in the wound.