Joan thought, Sons Sons?

"But Johnnie is more an engineering stunt than science," said Alyce Sigurdardottir. She had returned with plastic cups of cola for herself and Joan. "Isn't that true?"

Maughan smiled, easily enough. Joan realized belatedly that despite his appearance he must actually be one of JPL's more PR-literate employees; otherwise he wouldn't be here. "I can't deny that," he said. "But that's our way. At NASA, the engineering and the science have always had to proceed hand in hand." He turned back to Joan. "I'm honored you asked me here, though I'm still not sure why. My grasp of biology is kind of flaky. I'm basically a computer scientist. And Johnnie is just another space probe, a hunk of silicon and aluminum."

Joan said, "This conference isn't just about biology. I wanted the best and brightest minds in many fields to come here and get in touch with each other. We've got to learn to think in a new way."

Alyce shook her head. "And for all my skepticism about this specific project, I think you underestimate yourself, Dr. Maughan. Think about it. You come into the world naked. You take what the Earth gives you- metal, oil- and you mold it, make it smart, and hurl it across space to another world. another world. NASA's image has always been dismally poor. But what you actually do is so- romantic." NASA's image has always been dismally poor. But what you actually do is so- romantic."

Maughan hid behind a weak joke. "Gee, ma'am, I'll have to invite you along to my next career review."

The lounge was continuing to fill up with passengers. Joan said, "Does anybody know what's happening?"

"It's the protesters," Ian Maughan said. "They are lobbing rocks into the airport compound. The police are pushing them back, but it's a mess. They let us land, but it's not safe for our baggage to be retrieved right now, or for us to leave the airport."

"Terrific," Joan said. "So we're going to be under siege all through the conference."

Alyce asked, "Who's involved?"

"Mostly the Fourth World." An umbrella group, based on a splinter Christian sect, that claimed to represent the interests of the global underclass: the so-called Fourth World, Fourth World, people with less visibility even than the nations and groupings that made up the Third World- the poorest and most excluded, beneath the radar of the rich northern and western nations. "They think Pickersgill himself is in Australia." people with less visibility even than the nations and groupings that made up the Third World- the poorest and most excluded, beneath the radar of the rich northern and western nations. "They think Pickersgill himself is in Australia."

Joan felt a flickering of unease. British-born Gregory Pickersgill was the charismatic leader of the central cult; the worst kind of trouble- sometimes lethal- followed him around. Deliberately she put the worry aside. "Let's leave it to the police. We have a conference to run."

"And a planet to save," said Ian Maughan, smiling.

"Damn right."

In one corner of the terminal, there was a commotion as a large white box was wheeled in. It was like an immense refrigerator. Light flared, and cameras were thrust into Alison Scott's face.

"One piece of luggage that evidently couldn't wait," murmured Alyce.

"I think it's live cargo," Maughan said. "I heard them talking about it."

Now little Bex Scott came running up to Joan. Joan noticed Ian Maughan goggling at her blue hair and red eyes; maybe folk were a little backward in Pasadena. "Oh, Dr. Useb." Bex took Joan's hand. "I want you to see what my mother has brought. You, too, Dr. Sigurdardottir. Please come. Uh, you were kind to me on the plane. I really was frightened by all the smoke and the lurching."

"You weren't in any real danger."

"I know. But I was frightened even so. You saw that and you were kind. Come on, I'd love you to see."

So Joan, with Alyce and Maughan in tow, let herself be led across the lounge.

Alison Scott was talking to the camera. She was a tall, imposing woman. "...My field is in the evolution of development. Evo-devo, in tabloid-speak. The goal is to understand how to regrow a lost finger, say. You do that by studying ancestral genes. Put together a bird and a crocodile, and you can glimpse the genome of their common ancestor, a predinosaur reptile from around two hundred and fifty million years ago. Even before the end of the twentieth century one group of experimenters was able to 'turn on' the growth of teeth in a hen's beak. The ancient circuits are still there, subverted to other purposes; all you have to do is look for the right molecular switch..."

Joan raised her eyebrows. "Good grief. You'd think it was her event."

"The woman's work is show business," Alyce said with cold disapproval. "Nothing more, nothing less."

With a flourish, Alison Scott tapped the box beside her. One wall turned transparent. There was a gasp from the pressing crowd- and, beyond that, a subdued hooting. Scott said, "Please bear in mind that what you see is a generic reconstruction, no more. Details such as skin color and behavior have essentially had to be invented."

"My God," said Alyce.

The creature in the box looked like a chimp, to a first approximation. No more than a meter tall, she was female; her breasts and genitalia were prominent. But she could walk upright. Joan could tell that immediately from the peculiar sideways-on geometry of her hips. However, right now she wasn't walking anywhere. She was cowering in a corner, her long legs jammed up against her chest.

Bex said, "I told you, Dr. Useb. You don't have to go scraping for bones in the dust. Now you can meet meet your ancestors." your ancestors."

Despite herself, Joan was fascinated. Yes, she thought: to meet my ancestors, to meet my ancestors, all those hairy grandmothers, that is what my life's work has really been all about. Alison Scott evidently understands the impulse. But can this poor chimera ever be real? And if not, what were they all those hairy grandmothers, that is what my life's work has really been all about. Alison Scott evidently understands the impulse. But can this poor chimera ever be real? And if not, what were they really really like? like?

Bex impulsively grasped Alyce's hand. "And, you see?" Her crimson eyes were shining. "I did say you didn't have to be upset about the loss of the bonobos."

Alyce sighed. "But, child, if we have no room for the chimps, where will we find room for her her?"

The mock australopithecine, terrified, bared her teeth in a panic grin.

CHAPTER 9.

The Walkers Central Kenya, East Africa. Circa 1.5 million years before present.

I.

She loved to run, more than anything else in her life. It was what her body was made for.

When she sprinted, she covered a hundred meters in six or seven seconds. At a more steady pace, she could finish a mile in three minutes. She could run. run. As she ran, her breath scorched in her lungs, and the muscles of her long legs and pumping arms seemed to glow. She loved to feel the sting of the dust where it clung to her bare, sweat-slick skin, and to smell the scorched, electric scent of the land's hot dryness. As she ran, her breath scorched in her lungs, and the muscles of her long legs and pumping arms seemed to glow. She loved to feel the sting of the dust where it clung to her bare, sweat-slick skin, and to smell the scorched, electric scent of the land's hot dryness.

It was late in the dry season. The day's most powerful heat lay heavy on the savannah, and the overhead sun skewered the scene with bright symmetry. Between the pillowlike volcanic hills the grass was sparse and yellow, everywhere browsed and trampled by the vast herds of herbivores. Their pathways, across which she ran, were like roads linking pastures and water courses. In this era the great grass eaters shaped the landscape; none of the many kinds of people in the world had yet usurped that role.

In the noon heat the grass eaters clustered in the shade, or simply lay in the dust. She glimpsed great static herds of elephant types, many species of them, like gray clouds in the distance. Clumsy, high-stepping ostriches pecked listlessly at the ground. Sleek predators slept lazily with their cubs. Even the scavengers, the wheeling birds and the scuttling feeders, were resting from their grisly chores. Nothing stirred but the dust that she kicked up, nothing moved but her own fleeting shadow, shrunk to a patch of darkness beneath her.

Fully immersed in her body, her world, she ran without calculation or analysis, ran with a fluency and freedom no primate kind had known before.

She was not thinking as a human would. She was conscious of nothing but her breath, the pleasurable ache in her muscles, her belly, the land that seemed to fly beneath her feet. But, running naked, she looked human.

She was tall- more than a hundred and fifty centimeters. Her kind were taller than any earlier people. She was lithe, lanky, and didn't weigh more than forty-five kilograms; her limbs were lean, her muscles hard, her belly and back flat. She was just nine years old. But she was at the cusp of adulthood, her hips broadening and her breasts small, firm, already rounded. And she was not done with growing yet. Though she would keep her slim body proportions, she could expect to grow to around two meters. Her sweat-flecked skin was bare, save for a curly black thatch on her head, and dark scraps at her crotch and armpits. In fact, she had as many body hairs as any other ape, but they were pale and tiny. Her face was round, small, and she had a fleshy, rounded nose, protruding like a human's, not lying flat like an ape's.

Perhaps her chest was a little high, a little conical; perhaps in the proportion of her long limbs she might have looked unusual. But her body was within the boundaries of human variation; she might have looked like a denizen of a desert country, like the Dinka of the Sudan, or the Turkana, or the Masai, who would one day walk the land she now crossed.

She looked human. Her head was different, though. Above her eyes ran a broad ridge of bone, which led back to a long, back-sloping forehead. From there, the bone ran with almost no rise to the back of her skull. The shape of her head was masked by her thick mass of hair, but it would have been impossible to mistake its flatness, the smallness of her cranium.

She had the body of a human, the skull of an ape. But her eyes were clear, sharp, curious. Nine years old, suffused with the joy of her body in this brief moment of life and light and freedom, she was as happy as it was possible for her to be. To human eyes, she would have been beautiful.

Her people were hominids- closer to humans than chimps or gorillas- and were related to the species one day tentatively labeled Homo ergaster Homo ergaster and and Homo erectus. Homo erectus. But all across the Old World there were many, many variants, many subspecies based on the same overall body plan. They were a successful and diverse kind, and there would never be enough bones and bits of skull to tell their whole story. But all across the Old World there were many, many variants, many subspecies based on the same overall body plan. They were a successful and diverse kind, and there would never be enough bones and bits of skull to tell their whole story.

Something darted out at her feet. She pulled up, startled, panting. It was a cane rat, a rodent; disturbed from its slow foraging it scuttled away, indignant.

And she heard a cry. "Far! Far!"

She looked back. Her people, a remote blur, had gathered on the rocky outcrop where they intended to stay for the night. One of them- her mother or grandmother- had clambered to the rock's highest point, and was calling to her through cupped hands. "Far!" It was a cry no ape could have made, not even Capo. This was a word.

The sun had begun to slide away from the zenith, and already the shadow at her feet had lengthened. Soon the animals would begin to stir; she would no longer be safe, no longer be shielded by the noon world's somnolence.

Alone, far from her people, she felt a delicious frisson of fear. Every day, every chance she got, she ran too far; and every day she had to be called back. She did not have a name. No hominid had yet given herself a name. But if she had, it would have been Far. Far.

She turned back toward the rock and began to run again, at her steady, ground-devouring pace.

There were twenty-four people in the band.

Most of the adults were dispersed over the landscape near the eroded sandstone bluff. They moved like slim shadows across the dusty ground, seeking out nuts and small game, silent, intent, expert. Mothers had taken their youngest children along, clamped to their backs or scuttling at their feet.

Far's mother was working through a small stand of acacia trees that had been comprehensively destroyed by the passage of a herd of deinotheres. These ancient elephant types had used their downward-pointing tusks and stubby trunks to leave the trees broken and splintered, the ground churned up, and the roots hauled out. People weren't the only foragers here: warthogs and bushpigs grunted and squealed as they pushed their ugly faces into the churned-up earth. The destruction was recent. Far could see giant beetles at work burying fresh deinothere dung, and aardvarks and honey badgers rooting in the ground, seeking the beetles' larvae.

Such a place made for good foraging. A good strategy for finding food in an unfamiliar land was to seek out the leftovers of other animals, especially destructive types like elephants and pigs. In the smashed-up stand of trees, Far's mother would find food that would have otherwise been hidden or inaccessible. Among the broken trunks there were even ready-made levers, struts, and digging sticks to prize out roots from the ground, broken branches to shake to get at fruit, and slivers of palm to dig out pith.

Far's mother was a serene, elegant woman, tall even for her kind; she might have been called Calm. She walked with her two children, the sleeping baby cradled over one shoulder, and a son. The boy was half Far's age but already nearly as tall as she was, a skinny youth Far thought of as the Brat: irritating, clever, and much too successful at competing for their mother's attention and generosity.

Calm's own mother, Far's grandmother, was at her side. In her midforties now, the grandmother was too stiff to be of much help digging for food. But she assisted her daughter by keeping an eye on the youngest child. No human would have been surprised to see old people in this group; it would have looked very natural. But no previous types of primates had grown old; few had survived much past their fertile years. Why should their bodies continue to keep them alive when they could not contribute further to the gene pool? But now it was different; among Far's kind, old people had a role.

Panting, dusty, Far climbed the rock. It was just an outcrop a hundred meters across bearing nothing but strands of tough grass and a few insects and lizards. But for the people it was a temporary home base, an island of comparative sanctuary in this open savannah, this sea of danger. On the outcrop itself a couple of men were repairing wooden spears. They worked absently, eyes roving, as if their hands were working by themselves. Some of the older children played, rehearsing for the adulthood to come. They wrestled, chased, mock-stalked each other. Two six-year-olds were engaged in clumsy foreplay, fingering each other's nipples and bellies.

Far was neither an adult nor a child, and in this small band there was nobody close to her age. So she kept away from the rest and walked to the summit of the eroded sandstone lump. She found a bit of antelope jaw, deposited here by some scavenger, now scraped clean by hungry mouths and the patient work of insects. She cracked the bone into fragments on the rock, and used a sharp edge to scrape the sweat and dirt from her legs and belly.

From this vantage, the landscape was laid out, presenting a complex panorama. This was an immense valley. Huge geological anguish showed in a panorama of domes, lava flows, tiltings, and craters. To the east- and, beyond the horizon, in the west- the land had been uplifted, forming a plateau some three thousand meters high at its maximum, laden with fertile volcanic soil. The great plateau came to an end in a precipitate wall that plunged down into the valley.

This was the Rift Valley: a fracture between two separating tectonic plates. It ran for three thousand kilometers from the Red Sea and Ethiopia in the north down through Kenya, Uganda, Tanzania, and Malawi, terminating in Mozambique to the south. For twenty million years geological activity along the length of this great wound had created volcanoes, built highlands, and collapsed lowlands into valleys that channeled the waters into some of the continent's largest lakes. The land itself had been remolded, laid down as layer upon layer of volcanic ash, interspersed with broad beds of shale and mudstone. On the volcanic hills grew humid forests, and a complex mosaic of vegetation, from woodland to savannah to scrub, filled the floor. It was a crowded, jumbled, varied place.

And it was full of animals.

As the sun continued to roll down the sky, so the creatures of the savannah became more active: the hippos wallowing in the marshes, the herds of stately elephant types washing serenely across the grasslands. There were many species of elephant, in fact, subtly differing in the shape of their backs, skulls, trunks. They trumpeted shrilly to each other, sailing like dusky ships through the sea of dust they kicked up. As well as these large herbivores there were many other species directly dependent on the grass: hares, porcupines, and cane rats, rooting pigs. Predators upon the grass eaters- and themselves prey for still more dangerous animals- included jackals, hyenas, and mongooses.

The animals of the savannah would have looked startlingly familiar to human eyes, for they had already become finely adapted to savannah conditions. But the richness and variety of the life here would have astounded an observer used to the Africa of human times. This was the richest region on Earth in terms of the number of mammalian species, their diversity and abundance, and this was one of its most prolific periods. In this crowded, complicated place, plains creatures like antelopes and elephants lived close to forest dwellers like pigs and bats. The Rift provided a rich, sprawling landscape that presented opportunities for adaptation for many species of animals, like elephants, pigs, antelopes- and people. This, indeed, was the crucible from which Far's kind had emerged.

But they had not stayed here.

After Capo's time, liberated from the last ancestral ties to the forest, Far's people had become a wandering species. They had walked out of Africa: The first hominid footsteps had already been planted all along the southern coasts of the Asian landmass. Far's grandmothers, though, had unwittingly completed a great circuit to north, east, and south, over many generations returning here, to the place their kind had originated.

Sitting on her outcrop, Far surveyed the landscape with a professional, calculating eye. In their wanderings, the people mostly followed water courses. They had come to this place from the north, and she could see the streambed they had followed, a silver snake that slashed through the grass and scrub. Along the riverbank the land was silty, watered, and dense with nutrients, and a vigorous mix of trees, thicket, and grassland grew there, marked by pillars of termite mounds. To the east the ground rose, becoming dry and barren, and to the west the forest grew thicker, making an impassable belt. But if she looked south she could see possibilities for tomorrow, a great corridor of savannah with the mixture of grass, scrub, and forest patches that her people preferred.

Far was still young, still learning about the world and how best to use it. But she had a deep, systematic understanding of her environment. She was already capable of assessing an unfamiliar landscape like this and picking out sources of food, water, and danger, even spying out routes for onward migration.

It was a necessary skill. Committed to the open, Far's kind had been pushed by a harsh winnowing to develop a new kind of awareness of nature. They had been forced to understand the habits of game, the distribution of plants, the changes of seasons, the meanings of tracks- to solve the endless puzzles of the complex, unforgiving savannah. By comparison, her remote ancestor Capo, who had lived and died thousands of kilometers northwest of this place, had learned the features of his generous forest world by rote: Unable to read the land, to figure out new patterns, he had been endlessly baffled by the unfamiliar.

Now the adults and their infants were coming back to the rock, carrying food. They were naked, and they carried only what they could cram into their hands and cradle in their arms. Most of them came back with mouths still full and chewing. The people ate as fast as they could, helping themselves, feeding only close family members, not averse to stealing when they thought they could get away with it. And they ate silently save for belches, grunts of pleasure or disgust when a bit of rotten food turned up- and an occasional word. "Mine!" "Nut," "Break," "Hurt, hurt, hurt..."

They were simple nouns and verbs, possessives and challenges, one-word sentences with no structure, no grammar. But nevertheless it was a language, the words labels that referred to definite things- a system far advanced over the jabbering of Capo's time, and that of any other animal.

Here came Far's brother, the Brat. He was carrying the limp corpse of some small animal, maybe a hare. And her mother, Calm, had an armful of roots, fruit, and palm pith.

Far was suddenly hungry. She hurried forward, mewling, her hands held out and her mouth open.

Calm hissed at her, theatrically holding her armful of food away from her daughter. "Mine! Mine!" It was a rebuke, and it was backed up by glares from the grandmother. Far was getting too old now to be fed like an infant. She should have come to help her mother rather than waste her energy running purposelessly about the landscape. Why, here was her brother, the Brat, who had been hard at work and had even returned with his own scrap of meat. All of that was conveyed in a word.

Life was not as it had been in Capo's time. Nowadays the adults tried to coach the youngsters. The world had become too complex for children to be given the time to reinvent all the technology and techniques of survival from scratch; they had to be taught how to survive. And one of the roles of elders like Far's grandmother was to drive such wisdom home.

But Far held her hands out again, making piteous animal mewls. Just once more. Just for today. I'll help tomorrow. Just once more. Just for today. I'll help tomorrow.

"Graah!" Calm, as Far had known she would, dumped the food on the rock. She had gathered nuts, tsin beans, cowpeas, and asparagus bean tubers. She handed Far a fat tuber; Far bit into this quickly.

The Brat sat close to his mother. He was still too young to sit with the men, who were pawing through their own pile of food. The Brat had pulled apart his hare by main force, twisting off the limbs and head, and was using a chip of rock to lay open the chest. But as he performed this miniature butchery his gestures were tense, shivery.

None of his family knew it, but he was already gravely ill, through hypervitaminosis. A few days before one of the men had given him a few scraps of hyena liver, brought down in a brief battle over the remains of an antelope. Like that of most carnivorous predators, the liver had been full of vitamin A, and that subtle poisoning would soon become visible in the boy's body.

In a month he would be dead. In twelve, forgotten, even by his mother.

But for now Calm cuffed him, reasonably gently, and grabbed some of his hare away from him, making him share with his sister.

Since Capo's time the world had continued to cool and dry.

North of the equator, a great belt of taiga stretched right around the world, through North America and Asia, a forest of nothing but evergreen trees. And in the far north tundra had formed for the first time in three hundred million years. For the animals, the living offered by the taiga was meager compared to the old mixed deciduous and coniferous temperate forests. Similarly, the great grasslands continued to expand- grass was less thirsty than trees- but grass made arid plains, able to support only a much-reduced assemblage of animal species compared to the vanishing forests. As the slow desiccation continued, there were extinctions again.

But if the quality was diminished, the quantity quantity of life was tremendous, astonishing. of life was tremendous, astonishing.

The need to ride out periods of seasonal food shortages, and the need for guts able to process coarse diets all year round, favored the development of large herbivores. Giant mammals, a new "megafauna" on a scale not seen since the death of the dinosaurs, spread across the planet. Ancestral mammoths had already spread across northern Eurasia and, crossing the land bridges periodically exposed by the falling ocean levels, walked into North America. For now, living in equable climes, they were hairless and ate foliage rather than grass. They looked like typical elephants, but they had the high crowns and curling tusks of their woolly descendants.

Meanwhile there were giant camels in North America, and in Asia and Africa wandered the huge, mooselike sivatheres. A type of large rhino called an elasmotherium roamed across northern Eurasia. For a rhino it had long legs and a horn that could grow to two meters in length: It looked like a muscular unicorn.

And along with these huge packages of meat came new, specialized predators. The cats, freshly evolved, had perfected the technology of killing. They had side teeth like shears that could slice through skin, rip it aside, and get inside a body, where their incisors could nibble at the flesh. The saber-tooths were the acme. The saber-tooths would grow to twice the size of the lions of human times, becoming vast muscular predators built like bears, with short stocky limbs. They were built for power, not speed, and were ambush hunters, with mouths that could open hugely wide to crush prey. But all cats made even the dogs look like generalists by comparison; cats were perhaps the ultimate land predators.

But then, some half million years before Far's birth, a new and dramatic worsening of the climate began. For the world's creatures, the rules changed again.

There was a call from the plain. "Look, look! Me, look, me!" People stood up, gathering to see.

A man was approaching. He was tall, more heavily muscled than the rest, with a powerful, abnormally prominent browridge. This man, Brow, was dominant right now, the boss man in the tight, competitive world of the males. And he had a dead animal draped across his shoulder, a young eland.

The eight other adult men in the band began dutifully to whoop and yell, and they ran down the rocky slope. They slapped Brow on the back, stroked the eland respectfully, and ran and capered, kicking up a spectacular cloud of dust that hung, glowing, in the light of the descending sun. Together they hauled the eland up the slope and hurled it to the ground. The older children ran to see the eland, and began competing for its meat. The Brat was amongst them, but he was weaker even than others younger than himself, and he was easily pushed aside. Far could see a snapped-off wooden spear buried in the animal's chest. That was how Brow had killed his prey, probably after an ambush, and perhaps he had left the spear in there to show how he had achieved this feat.

Brow, meanwhile, had sprouted an impressive erection. The women, including Calm, Far's mother, made subtle signs of availability- a crooked hand here, thighs smoothly parting there.

Far, neither woman nor child, hung back from the rest. She nibbled on a root and waited as events unfolded.