Evolution

by Stephen Baxter

  He found a heap of tools. A thick pile of spill showed that this was a place where stone tools were habitually made. He rummaged idly through the tools. Some were only half-finished. But there was a bewildering variety — he saw axes, cleavers, picks, hammer-stones, knives, scrapers, borers — and other designs he didn’t even recognize.

  Now he saw what looked like an ordinary ax, a stone head fixed to a handle of wood. But the head was bound by a bit of liana so tightly wound he couldn’t unpick it. He had seen lianas strangle other plants. It was as if someone had put this ax head and its handle into the grip of a living liana, and then waited until the plant had grasped the artifacts, binding them more tightly together than any fingers could manage.

  Here was a bit of netting like the one he had seen Harpoon wearing on the beach. It was a bag with tools of stone and bone inside it. He picked the bag up experimentally and lifted it to his shoulder, as he had seen Harpoon do. Pebble’s kind did not make bags. They carried only what they could hold in their hands or sling over their shoulders. He teased at the stringy netting. He thought it might be creepers or lianas. But the fibers had been twisted tightly into a strong rope that was finer than any liana.

  He dropped the bag, baffled.

  It was like his hut, and yet it was not. For one thing it was strange to have everything separated. At home, you ate where you liked, made your tools where you liked. The space was not divided up. Here there seemed to be one place to eat, one to sleep, one to make the fire, one to work on tools. That was disturbing. And -

  “Ko, ko, ko!”

  A man had come in through the entrance. Silhouetted against the daylight he was tall, skinny like Harpoon, and had the same bulging dome of a head. There was fear in his weak face, but he raised a spear.

  Adrenaline flooded Pebble’s system. He got to his feet quickly, assessing his opponent.

  The man, dressed in tied-on skins, was whip thin, with stringy muscles. He would be no match for Pebble’s brute strength. And that weapon was just a spear of carved and hardened wood, light for throwing: It wasn’t a thrusting spear, which was what was needed for fighting in this tight space. Pebble would be able to snap that scrawny neck easily.

  But the man, frightened, looked determined. “Ko, ko, ko!” he yelled again. And he took one step forward. Pebble growled, bracing himself to meet the thrust.

  “Ya ya.” Here was Harpoon. She grabbed the man’s arm. He tried to pull away. They began to argue. It was a conversation just as might have occurred in Pebble’s hut: a string of words — none of which he could understand — with no structure or syntax, and only repetition, volume, and gesturing for emphasis. It took a long time, as all such arguments did. But at last the man backed down. He glared at Pebble, spat on the floor of the hut, and stalked out.

  Cautiously Harpoon clambered into the hut. Watching Pebble, she sat on the trampled ground. Her eyes were bright in the gloom.

  Slowly, Pebble sat before her.

  At length Harpoon pushed her slim hand under a bark blanket and pulled out a handful of baobab fruit. She held it out to Pebble. Hesitantly he took it. For long heartbeats they sat in silence, representatives of two human subspecies, with not a word, not a gesture in common.

  But at least they weren’t trying to kill each other.

  After that day Pebble felt increasingly uncomfortable in his home, with his people.

  The stringy folk seemed to accept him. The tall man who had found him in the hut, Ko-Ko — for Pebble would always think of his cries of “Ko, ko!” “Get away!” — never quite trusted him, that was clear. But Harpoon seemed to take to him. They worked tools together, she showing off the subtle skills of her delicate fingers, he his immense strength. They peered across the sea at the rich island that still tantalized Pebble.

  And they tried to work out each other’s vocabulary. It wasn’t easy. There were many words, such as directional terms like “west,” which Pebble’s ancestors had never needed.

  He even went hunting with her.

  These newcomers were by preference scavengers or ambush hunters. With their lithe but feeble frames they used guile rather than brute strength to make their kills, and their weapons of choice were hurled, not thrust. But they grew to welcome Pebble’s mighty contributions during the closing stages of a kill, when the prey had to be finished off at close quarters.

  Meanwhile, the two kinds of people started a new kind of relationship. They did not fight, nor did they ignore each other, the only two ways people had had to relate to each other before.

  Instead, they traded. In exchange for the fruits of the sea and some of their artifacts, such as their massive thrusting spears, Pebble’s folk began to receive bone tools, meat from the interior, marrow, skins, and exotic items like honey.

  Despite the obvious benefits of the new relationship, many of Pebble’s folk felt uneasy. Hands and Seal had inquisitively explored the possibility of the new tools. Dust, aging quickly, seemed sunk in apathy. But Cry was unremittingly hostile to the new people — and to Harpoon in particular. This wasn’t the way things were done.

  These were, after all, an immensely conservative people, people who moved house only when forced to by an Ice Age. But they traded anyhow, for the advantages were undeniable.

  Harpoon had been able to hold back Ko-Ko from killing Pebble because, to these people, a stranger wasn’t necessarily a threat. You had to be able to think that way if you were going to trade.

  For hominids, that was a brand-new way of thinking. But then Harpoon’s kind was only five thousand years old.

  There had been a band of people, not unlike Pebble’s, who had lived on a beach, not unlike this one, on the eastern shore of southern Africa. The beach was crowded by thick, buff-colored sedimentary rocks. The vegetation was unique to that part of the world, an antique flora recalling Roamer’s days, dominated by bushes and trees covered by big, thistly flowers. It was a rich place to live. The sea was productive, offering mussels, barnacles, fish, seabirds. In places the forest came right down to the shore, echoing with the calls of monkeys and birds, and in the grassy glades there was game in abundance: black rhinos, springboks, wild pig, elephant, as well as long-horned buffalo and giant horses.

  Here Harpoon’s ancestors had had a home base close to the sea. Like Pebble’s folk, they had lived there for generations beyond counting, their bones lying thick in the earth. From here they would work across the landscape, never traveling more than a few kilometers from home.

  But then, with terrible suddenness, the climate collapsed. The ocean rose, and flooded their ancestral home. Just like Pebble’s group they had been forced to flee. And like Pebble’s folk, lost in a crowded land, they had had nowhere to go.

  Every step they took away from the lands they had known left them more baffled and confused. Many of them died. Many infants, in the arms of starving refugee mothers, failed to live much past birth.

  At last, desperate, starving, they were forced along a riverbank. They reached the river’s mouth, where mangroves grew thick. Here they could stay, because it was a place nobody else wanted. Much of the floor was covered with an oily brown water, through which slid crocodiles. Damp, fetid, unhealthy, it was a kingdom of lizards, snakes, and insects, many of which, even the marching ants, seemed to conspire to drive out the people.

  There was food to be had: water lily roots, shoots, and stems. Even mangrove fruits were palatable to the starving. But there was scarcely any meat. And there was no stone anywhere with which to make tools. It was as if they were trying to live on a great soaked-through mat of vegetation.

  Stranded out of their environment, the people might have died out within a generation, if they hadn’t adapted.

  It had started innocently. A woman, Harpoon’s remote grandmother, had wandered as far as she could up the river valley and on to drier land. Here, on the floodplains and in the seasonal swamps, the well-watered, silty soil supported many annuals, herbs, legumes, vines, lilies, and arrowroots. After years in t
he swamp she had grown adept at using crude wooden tools and her bare hands to harvest food from soggy, unpromising terrain. She had already filled her belly, and was gathering clumps of roots to take home to her children.

  Then she came upon the stranger. The man, from another group further upriver, was using a knife of basalt to skin a rabbit. The two of them stared at each other, one with meat, the other with roots. They might have fled, or tried to kill each other. They did not.

  They traded: meat for roots. And they went their separate ways.

  A few days later the same women returned to the same spot. Again the man returned. Scowling, suspicious, their tongues mutually incomprehensible, they traded again, this time shellfish and barnacles from the river’s mouth for a couple of basalt knives.

  That was how it began. The people of the swamp, unable to find everything they needed to stay alive in the scrap of land they had inherited, exchanged the produce of the sea, the swamp, and the floodplain for meat, skin, stone, and fruit from the interior.

  After a couple of generations they migrated out, and began a new kind of life. They became true nomads, following the great natural highways, the coasts and the inland water courses. And everywhere they went they traded. As they moved, so they fissured and spread, and tentative trading networks grew. Soon it was possible to find bits of shaped rock hundreds of kilometers from where they had been formed and seashells deep in the interior of the continent.

  Living like this was a challenge, though. Trading meant building up a new kind of map of the world. Other people were no longer just passive features of the landscape, like rocks and trees. Now a track had to be kept of who lived where, what they could offer, how friendly they were — and how honest. There was a ferocious pressure on the swamp people to get smarter, fast.

  The design of their heads changed drastically. Their skulls enlarged to make room for bigger brains. And changing diets and lifestyles had a dramatic effect on their faces. No longer used to chew tough, uncooked food or to treat leather, their teeth became more feebly rooted. As chewing muscles withered, the upper tooth row shrank back. The lower jaw was left jutting, and the face tilted back, so that these hominids lost the last trace of their ancient apelike muzzles. The declining muzzle and ballooning foreheads provided new anchoring surfaces for the muscles of the face, and the old projecting browridges disappeared.

  Meanwhile, as they got smarter, they didn’t need to be as strong. Their bodies shed much of the robustness of their immediate ancestors, and reverted to something like the graceful litheness of Far’s people.

  Pebble’s first impression, that Harpoon had seemed childlike, was not accidental. With the proportions of their faces and their thinned bones these new people, compared to ancestral stock, were in some ways like children arrested in their growth. Once again, under ferocious selection pressure, the genes had reached for variations that could be implemented quickly: Adjusting the comparative growth rates of skeletal features was comparatively easy.

  All of these changes had been essentially complete within a few millennia. After this process Harpoon, anatomically, was all but identical to a human of Joan Useb’s time, even in her skull and the gross features of her brain. And it had been trading, a new way of dealing with other people, that had made them what they were.

  But even Harpoon was not yet human.

  There was a little more invention, a little more organization in her life. Her kind built hearths, for instance. But her tool kit was scarcely more advanced than that of Pebble and his ancestors. Her language was the same unstructured babbling. Much of the way she lived her life, like her sexuality, had been inherited with little change from the kinds of people who had gone before. There were still rigid barriers in her mind, a lack of connections in the neural wiring of her brain. A true human of Joan Useb’s age, stranded in this age of her ancestors, would quickly have been driven crazy by the sameness, the routine, and ritual, the lack of art and language — the boring, drab poverty of life.

  And, human form or not, these folk had not been dramatically successful. Though they had spread across Africa from their origins in that southeastern swamp, their lifestyle remained marginal. It was difficult to trade if there was nobody like you to trade with. Even now the new nomads’ survival was chancy, and most extant groups, around the continent, would not survive.

  The children of Harpoon were destined to pass through this bottleneck, but their genes would always bear the imprint of that narrow passage. In the future, the swarming billions who would spring from this unpromising seed would be virtually identical, genetically; every human would be a cousin.

  Pebble’s relationship with Harpoon came to a head during a hunt.

  One day, Pebble found himself in a blind, upwind of a herd of giant horse who cropped the long grass peacefully. The blind was just a lean-to frame of saplings, loosely woven together and covered with palm fronds and grass. Here Pebble huddled, his thrusting-spear at his side, peering out at the big, lame animal that was their target. And Harpoon was at his side. He was tense, adrenaline pumping, and the heat of the day and the sweat scent of the horse filled his head.

  Suddenly he felt her fingers on his face.

  He turned. Her skin seemed to glow in the green gloom. She traced the vertical ocher stripes he still wore. And then her fine fingers moved to his arm, the long-healed cuts he had inflicted there. Her every touch was startling, as if her fingers were made of ice or fire.

  He ran his fingers down her arm. His fist enclosed her forearm easily, as if it were a bird’s leg. He felt he could snap the bone with a gesture. Suddenly it was just as it had been on the first day he had met her, on the beach. His mouth dried, his throat tightened.

  He didn’t understand his lust: the lust that had never gone away. He thought of the clever tools she made, her long, easy stride across the ground, the food she had brought his people — and that harpoon, the exquisite harpoon point, unimaginable before he had seen it that first day. There was something in her his body wanted; the longing was unbearable.

  He rolled on his back. In the rustling shade of the blind, she straddled him and smiled.

  IV

  Each lump of flint was a miniature cemetery. In some long-vanished sea the corpses of crustaceans had settled into sediment, and minute glassy needles that had once formed the skeletons of sponges became the nuggets of flint embedded inside the gathering chalk seams.

  Pebble had always loved the feel of flint. He turned the smooth-faced, brittle rock over in his hands, sensing its structure. Flint knappers got to know all of the stone’s subtle properties. The more a flint was exposed to the elements the more likely it was to contain fractures, caused by frost or a battering by river or ocean currents. But this flint lacked the patina of exposure. It was fresh and clean. It had only recently been dug out of its chalk matrix, after a cliff had collapsed. You couldn’t get such flint in this area, anywhere within the people’s old range. Pebble had missed good flint, in the long years on this beach, before Harpoon had walked into his life.

  These days he was never more content than when working stone — or, rather, he was never less discontented.

  Seven years had elapsed since his first encounter with Harpoon. At twenty-six, his body was already declining, battered and scarred by the cumulative challenges of a life that continued to be very hard, despite his people’s collaboration with the newcomers.

  He had embraced Harpoon, and he had embraced the newness and changes she had brought — but those changes themselves had become bewildering. Pebble’s mind was immensely conservative. And as he grew older he increasingly relished these moments alone with the stone, when he could retreat into the recesses of his roomy mind.

  But this moment of peace didn’t last.

  “Hai, hai, hai! Hai, hai, hai!”

  Here came his son and daughter, squat Sunset and spindly Smooth, running along the beach side by side, jabbering in the patois that had resulted as a merger of Pebble’s tongue and Harpoon’s.
“Come, come, come here with us!” The children, naked, their skin crusted with salt and sweat, wanted him to come work on the logs that Ko-Ko and others were pushing into the sea.

  He pretended not to hear them until they were almost on top of him. Then he grabbed them both with a roar, and all three of them rolled in the sand, wrestling. At last Pebble relented. He put aside his flint, got to his feet, and lumbered after the kids along the beach.

  The morning was bright, the sun hot, and the air filled with the scent of salt and ozone. As the children flew ahead of his own lumbering gait, Smooth quickly outstripping her brother, Pebble felt briefly joyful at their youthful energy. This place would never be home to him, but it had its pleasures.

  Ko-Ko, Hands, and Seal were making a kind of raft. Harpoon was here, her hands resting on a belly that was already showing a bump. She grinned fiercely as Pebble came up.

  The men had cut down two stout palms from the inland forests, stripped them of their branches, and lashed them together with lianas and plaited vine. Now Hands and Seal were hauling this crude construction across the sand and down to the water. There was much straining and jabbering: “Push, push, push!” “Back back, no, back, back…” “Hai, hai!”

  Pebble joined Hands and Seal at their task. Even with three of them it was hard work, and Pebble was soon sweating like the rest, his legs coated with stinging hot sand. Ko-Ko tried to help, but for sheer brute strength the robust folk had no match. And they were helped, and hindered, by the two children, and by Harpoon’s wolf companion who ran around their legs, barking.

  The wolf, raised from a captured cub, was all but feral. This was just the start of a relationship longer than any other between people and animals, a relationship that would ultimately shape both species.

  Pebble had never forgotten his determination to reach the island. At last, as he sat brooding on his beach, he had watched skinny youngsters playing on bits of driftwood in the water — and a connection had closed in his mind.