But, almost to his own surprise, he gave up his displaying and stood back, panting.

In his heart he knew he had lost them, that he had pushed them too hard, that his troop was fissioning. Those who chose to follow him would find their way, with him, to a new destiny- a destiny he himself couldn't yet imagine. Those who stayed behind would just have to take their chances.

He loped quickly away, out of the heart of the forest and toward the daylight, without looking back- although he was unable to resist a final valedictory liquid fart in the direction of the rebels.

In the end about half the males and rather more of the females stayed behind. It was a drastic diminishing of Capo's domain. And as he walked toward the bright light of the plain he could hear the whoops and howling of the males. The battles over the new hierarchy had already begun.

At the forest's fringe, on the edge of emptiness, Capo paused.

Just as yesterday, gomphotheres grazed on damaged, half-drowned trees. To the north the grassy plain stretched to its misty horizon, littered with glimmering lakes and marshes, herbivore herds passing like shadows. To the south, beyond a kilometer or so, the ground gleamed white as bone. The salt pan would be a difficult place to cross. But Capo could see how the land rose, up toward a green plateau, where- it seemed to his poor eyes, adapted for the short focuses of the forest- a thick blanket of trees lay draped over the rock.

South, then, across the dry land, to the new forest on the plateau. Without glancing back to see if the others were following, he set off on knuckles and feet, pushing through grass that waved around him, shoulder-high.

The land rose, quickly becoming drier.

There were some trees here, but they were just thin-trunked pines clinging to arid ground, with none of the comforting density and moistness of the forest clump. So there was little shelter to be had from the high sun. Capo was soon panting hard, baking inside his thick fur, his knuckles and feet rubbed raw. He could not sweat, and his knuckle-walking gait, effective for clambering around the complex, crowded environment of the forest, was inefficient here.

And Capo, a creature of the forest, was intimidated by this great sweep of openness. He hooted softly and longed to cower, to hold his arms over his head, to hurl himself into the nearest tree.

There were animals to be seen, scattered over the dry plain: There were deer, some species of dog, and a family of grubbing animals like spiky-furred pigs. The larger animals were very few. But as Capo blundered on, many smaller creatures scampered away underfoot: lizards, rodents, even primitive rabbits.

The twenty or so of the troop who had followed him toiled painfully up the slope after him. They moved slowly, for they stopped frequently to feed, drink, groom, play, argue. This migration was more like a slow walk made by easily distracted children. But it was not in Capo's instincts to hurry them. They were what they were.

Capo crested a shallow, eroded hill. From here he looked back across the wet, glistening landscape with its islands of forest and crowding herbivores. But when he looked ahead, to the south, he could see the great dryness they approached. It was a broad, high, dry valley, scattered with thin trees and bits of vegetation. It was kept arid by an accident of geology which had left it cupped in a great subterranean bowl of rock, barren of springs, shadowed from rainfall.

It was an intimidating sight; the valley was exposed, utterly open. And yet he must cross it.

And from here, now that there was no forest to soak up the noise, he could make out that great, mysterious roaring from the west. The remote noise sounded like the groaning cry of some huge, pained, angry beast, or like the thunderous hoofs of some great herbivorous herd. But when he looked to the west he could see no dust clouds, no black wash of animal bodies. There was nothing but the roaring, continuing just as it had all his life.

He began to clamber down the rocky slope, still heading south.

The ground became bare. Still trees clung to life here, their roots wormed into faults in the rock. But these pines were sparse, their leaves spiky, jealous of their water. He stopped under one of these trees. Its branches and leaves offered him virtually no shade. He could find no fruit, and the leaves he plucked were sharp and dry in his mouth. He made a grab for a small mouselike creature with long, levered hind legs; his mouth watered at the thought of biting into its soft wet body, its small bones crunching in his mouth. But here on this rocky ground he was clumsy and noisy, and the mouse thing evaded him easily.

Now the ground changed again, becoming a broad slope of broken stone that spread out before him, a road leading to the depths of the dry valley. The going got even harder as Capo slid and slipped on the loose rubble. Hot, thirsty, hungry, scared, he hooted his protest and threw bits of the rubble around, tramping and kicking it. But the land was not to be intimidated even by Capo's mighty displays.

Meanwhile the chasma watched the ragged group of anthropoids as they struggled down the uneven, treacherous slope.

She had never seen creatures like this before. With a predator's cold interest, she made unconscious calculations of their speed, strength, and meat yield, and began categorizing the individuals- here was one who seemed wounded and limped a little; here was an infant, clasped tightly to its mother's chest; here was a juvenile straying, foolishly, from the tight group.

This chasmaporthetes was actually a kind of hyena. But, long legged, slim, she looked more like a cheetah. She did not have all of the true cats' suppleness and speed, not quite; her kind had more adapting to do in the fleet conditions of this emerging world of grass. But her range was huge in this barren valley. She was the top predator here, and she was well equipped for her grisly work.

To her, the apes were new meat on the savannah. She waited, her eyes glowing like captive stars.

At last, exhausted, Capo gave up. He slumped to the ground. One by one, what was left of his troop joined him. By the time they had all arrived, the sun had started to set, filling the sky with fire and casting long, stark shadows along the floor of this gravel-littered bowl.

A kind of dull indecision raged within Capo. They shouldn't stay here, out in the open; his body longed to climb a tree trunk, to pull together branches to make a cozy, warm, safe nest. But there were no trees here, no security to be had. On the other hand they couldn't cross the valley floor in the dark. And they were all hungry, thirsty, exhausted.

He didn't know what to do. So he did nothing.

The troop began to disperse, following their own instincts. Finger picked up a cobble-shaped, palm-sized rock, perhaps hoping to use it in some future nut-cracking project. But a scorpion scuttled out from beneath the rock, and Finger fled, hooting.

Frond was sitting alone with his back to the rest of the group, assiduously working at something. Capo, suspicious, loped up as quietly as he could on this loose, scattered gravel.

Frond had found a termite mound. He was sitting before it, clumsily poking sticks into it. When he saw Capo he cowered, screeching. Capo delivered brisk, perfunctory blows to his head and shoulders, as Frond would have expected. He should have hooted to the rest on discovering this bounty.

Capo ripped open a shrub. All of its branches were spindly and bent, and when he stripped a branch by passing it through his mouth, the hard, spiky leaves hurt his lips. But it would have to do. He sat alongside Frond. He pushed his stick into a crevice in the mound, and worked it until it had slid in deep. It was not ideal; the stick was too short and bent to be truly effective, but it would have to do. He jiggled it around, waiting patiently. Then he withdrew the stick, centimeter by centimeter. To the stick clung soldier termites, sent to defend the colony from this invader. Capo took great care not to dislodge this cargo. Then he swept the stick through his mouth, enjoying a mouthful of sweet, moist flesh.

When they saw what was going on the rest of the troop crowded around, the older ones making their own fishing sticks. Very quickly a rough pecking order established itself, lubricated by kicks, punches, hoots, and sly grooming. The more senior male and females alike got closest to the mound while the young, who didn't understand what was happening anyhow, were excluded. Capo didn't care. He just concentrated on holding his own position close to the mound while working assiduously at the termites.

The termites were antique creatures whose complex society was the result of their own long evolutionary story. This mound was ancient, built of the mud that had pooled here when infrequent rainstorms caused temporary floods. Its rock-hard carapace protected the termites from the attentions of most animals, but not these apes.

Capo's use of tools- the termite-fishing sticks, the hammer-stones, the leaves he would chew to a sponge to extract water from hollows, even the fine toothpicklike sticks he sometimes used to perform crude dentistry- seemed sophisticated. He knew what he wanted to achieve; he knew what kind of tool he needed to achieve it. He would memorize the location of his favorite tools, like his hammer-stones, and made subtle decisions about using them- for instance trading off the distance he had to carry a hammer against its weight. And it wasn't a case of just picking up a handy rock, found by chance; he modified some of his tools, like this termite-fishing stick.

And yet he was not like a human craftsman. His modifications were slight: his tools, abandoned after use, would have been hard to distinguish from the products of the inanimate world. The actions he used to make the tools were part of his normal repertoire, like biting, leaf stripping, stone throwing. Nobody had invented wholly new new actions, like a potter's clay throwing or a wood carver's whittling. He used each tool for one use, and one use only; it never occurred to him that a termite fishing-stick might also be used as a toothpick. He did not improve his tools, once he had found a design that worked. And if- by some chance- he had in the course of his life happened upon a new kind of tool, however successful a design it was, its use would have spread only very slowly through his community, perhaps taking generations to reach every member. Coaching, the notion that the contents of someone else's mind might be shaped by rehearsal and demonstration, had yet to be discovered. actions, like a potter's clay throwing or a wood carver's whittling. He used each tool for one use, and one use only; it never occurred to him that a termite fishing-stick might also be used as a toothpick. He did not improve his tools, once he had found a design that worked. And if- by some chance- he had in the course of his life happened upon a new kind of tool, however successful a design it was, its use would have spread only very slowly through his community, perhaps taking generations to reach every member. Coaching, the notion that the contents of someone else's mind might be shaped by rehearsal and demonstration, had yet to be discovered.

So Capo's tool kit was staggeringly limited, and very conservative. Capo's ancestors, five million years gone, creatures of a different species, had used tools of only fractionally less sophistication. Capo wasn't even aware he was was using tools. using tools.

And yet here was Capo, working assiduously, knowing what he wanted, selecting materials to achieve his goal, making and shaping the world around him, the cleverest so far of all of Purga's long line of descendants. It was as if a slow fire were smoldering in his eyes, his mind, his hands, a fire that would soon burn much more brightly.

As the sun slid beyond the horizon at the valley's end the apes huddled closer. Deeply unhappy, they pushed, jostled, and slapped, hooting and screeching at each other. This wasn't their place. They had no weapons to defend themselves, no fire to keep the animals at bay. They didn't even have the instinct to keep silent at sunset, the hour of predators. All they had was the protection of each other, of their numbers- the hope that another would be taken, not me. me.

Capo made sure he was right at the center of the band, surrounded by the burly bodies of the other adults.

The young male called Elephant didn't have as powerful an instinct for self-preservation. And his mother, lost somewhere in the middle of the huddle, was too concerned with her newest child, a female; right now Elephant was a low priority. He was unlucky to be just the wrong age: too old to be defended by the adults, too young to fight for a place at the center, away from the danger.

He soon found himself pushed out to the fringe of the group. Still, he tried to settle down. He found a place close to Finger, a cousin. This ground was hard and bony, unlike the soft roosts he was used to, but by squirming he managed to make himself a bowl-shaped hollow. He pressed his belly against Finger's back.

He was too young even to understand the danger he was in. He slept uneasily.

Later, in the dark, he was woken by a soft pricking at his shoulder. It was almost gentle, like a grooming. He squirmed a little, burrowing closer to Finger's back. But then he felt breath on his cheek, heard a purring growl like a rock rolling down a hillside, smelled a breath that stank of meat. Instantly awake, his heart hammering, he screeched and convulsed.

His shoulder was ripped, painfully. He found himself dragged backward, like a branch torn off a tree. He caught a final glimpse of the troop- they were awake, panicking, hooting, scrambling over each other to get away. Then a starlit sky whirled around him, and he was slammed into the ground hard enough to knock the breath out of him.

A form moved over him, sleek, silhouetted against the blue-black sky. He felt a hard-muscled chest press against his, almost lovingly. There was fur with a scent of burning, breath like blood, and two yellow eyes that shone over him.

Then the bites came, to his legs, over one of his kidneys. They were sharp, almost clinical stabs, and he convulsed with the fiery pain. He screeched and rolled, tried to run. But his legs collapsed, his hamstrings cut. Now came those prickings at his neck again. He was lifted up by the scruff, lifted right off the ground, and he could feel sharp teeth working inside inside his skin. At first he struggled, scrabbling at the gravel with his hands, but his efforts only brought more pain as the flesh at his neck was torn further. his skin. At first he struggled, scrabbling at the gravel with his hands, but his efforts only brought more pain as the flesh at his neck was torn further.

He gave up. Hanging passively from the chasma's mouth, his head and damaged legs clattering against the uneven ground, his thoughts dissolved. He could no longer hear the hooting cries of his troop. He was alone now, alone with the pain and the iron stink of his own blood, and the steady, patient padding of the chasma's footsteps.

Perhaps he was unconscious for a while.

He was dropped on the ground. He did not land hard, but all his wounds flared with pain. Mewling, he pushed at the ground. It was littered with rubble like the place he had come from, but was covered in fur, and the stink of chasmas.

And now small shapes bounded around him, black on black, fast moving, a little clumsy. He felt the brush of whiskers on his fur, tiny nips at his ankles and wrists. They were chasma pups. He hooted his defiance, and swung a fist blindly. He connected with a hot little bundle that was knocked off its feet, yowling.

There was a short, barking roar: the mother chasma. In sudden panic, he tried to crawl.

The pups yapped excitedly as they completed their short chase. And now the biting started in earnest, digging into his back, buttocks, belly. He rolled onto his back, lifting his legs to his chest and flapping at the air. But the pups were fast, furious, and dogged; soon one of them had dug her teeth into his cheek, applying all her small weight to ripping open his face.

Again the mother roared, scattering the pups. Again Elephant tried to flee. Again the pups caught him and inflicted a dozen more tiny, debilitating wounds.

If not for her pups, the chasma would have killed Elephant quickly. She was giving them the chance to chase down a prey animal and knock it over. When they were older, they would be able to finish off prey themselves, ripping it apart; later still she would release some of her prey almost unharmed and allow the pups to finish the hunt. It was a kind of learning by opportunity. This was no more human-style teaching than what occurred among the apes: it was an innate behavior evolved in this clever carnivorous species to enable the young to acquire the skills they would need when hunting alone.

And as the lesson went on Elephant was still conscious, a spark of terror and longing buried in a broken shred of blood, flesh, and gristle. The boldest of the pups even fed on the tongue that dangled from his broken jaw.

But the pups were too young to finish off Elephant alone.

At last the mother took over. As her great jaw closed around his skull- as he felt a prickle of biting teeth around his scalp, like a crown of thorns- the last thing Elephant heard was that remote purring growl.

When the morning came, everyone knew that Elephant had been taken.

Capo peered with fascination at the scuffed, hair-strewn gravel patch where Elephant had briefly struggled, at the line of bloody paw marks, already dried to brown, that led away into the distance. He felt a vague regret at the loss of Elephant. It seemed baffling that he would never again see that clumsy youth with his stiff, awkward attempts at grooming, his clumsy fumbling as he tried to figure out how to get the flesh out of an oil palm nut.

But before the day was done, only Elephant's mother would remember him. And when she was dead in her turn, there would be nothing to say he had ever existed, and he would be gone into the final blank darkness that had swallowed up all of his ancestors, every one.

Elephant had paid the price of the troop's survival. Capo felt a cold relief. Without hesitation, without even performing the follow-me display, Capo moved down the slope and out onto the salt flats.

III.

The next day they had to cross the salt. Under a washed-out blue-white sky the pan spread almost to Capo's horizon, where hills, trees, and marshes crowded. It was as if this gray sheet were a flaw in the world.

The salt, lying over hard, grayish mud, was broadly flat, but the surface had texture, streaked here and there by swooping concentric lines that crowded to central knots. In one place an underground spring had caused the salt to billow up in great blocks that the apes had to clamber over.

But nothing grew, here on the salt. There weren't even any tracks. Nothing moved save the apes, no rabbits or rodents, not even an insect. The wind moaned across this hard mineral stage, nowhere broken by the rustle of bushes and trees, the hiss of grass.

But still Capo kept on, for there was nothing else to do.

It took hours to cross the salt pan. But at last, his feet and hands aching, Capo found himself reluctantly climbing a ridge. At the crest of the ridge there was a belt of forest- even if it was a dense, uncomfortable-looking kind of forest.

Capo hesitated, facing the forest. He was overheated; his legs and feet were bleeding from a dozen small lesions. Then he pushed forward awkwardly and entered the forest's green gloom.

The ground was hidden by a tangle of roots, branches, moss, and leaves. Wild celery grew in clumps everywhere. Although it was around noon, the air here was cold, made damp by a faint mist like a morning fog. The tree trunks were clammy, and thick lichen and moss left uncomfortable green streaks on his palms. The dampness seemed to dig through his fur. But after the aridity of the salt pan he relished the close, comforting tangle of green around him, and he devoured the leaves, fruit, and fungi he was able to pluck from the ground around him. And he felt safe from predators. Surely there was nothing that could strike at the hungry, weary band in this green density.

But now he saw hulking brown-black shapes just ahead, dimly visible through the tangled green. He froze.

A huge arm reached out to a branch wider than Capo's thigh. Muscles worked in a great mound of shoulder, and the branch was snapped in two as easily as Capo might snap off a twig to clean his teeth. Giant fingers plucked leaves from the nearby branches and pushed them steadily into immense jaws. The whole head worked as the big animal chewed, heavy muscles working the skull and jaw together.

The nearest creature was an ape, as Capo was, a male- and yet unlike Capo. The big male watched the odd, scrawny little apes without curiosity. He looked powerful, threatening. But he didn't move. The male, and a small clan of females and infants, did nothing but sit around and feed on leaves and the wild celery that carpeted the forest floor.

This was a gorilla: a remote cousin of Capo's. His kind had split off from the broader lineages of apes a million years ago. The split had come in a period when another forest had fragmented, isolating the populations it supported. As their habitat shrank to the mountaintops, these apes had turned to a diet of leaves, endlessly abundant even here, and became huge enough to resist the cold- yet they remained oddly graceful, able to move silently through this dense forest.

Though populations of gorillas would later adapt back to lowland conditions, learning to climb trees and subsist off fruit, in a sense their evolutionary story was already over. They had become specialized in their environments, learning to eat food that was so well-defended- covered in hooks, spikes, and stings- that no other creatures competed for it. They could eat nettles, for example, with an elaborate maneuver that involved stripping leaves from a stem, folding in the stinging leaf edges, and popping the whole packet into their mouths.

Sitting in their montane islands, lazily eating their leaves, they would survive almost unchanged until human times, when the final extinction would overtake them all.

When he was sure the gorillas were no threat, Capo crept away, leading the others onward through the forest.

At last Capo emerged from the far side of the forested ridge.

They had at last clambered out of the arid lowland basin. When he looked south across the plateau he had reached, he faced a rocky, rubble-strewn valley that scoured its way down to lower ground. But there, beyond the valley, he could see the land he had hoped to find: higher than the plain he had left behind, but well watered, glistening with lakes, coated green by grass, and studded with pockets of forest. The shadowy forms of a great herd of herbivores- proboscideans, perhaps- drifted with stately grandeur across the lush plain.

With a hoot of triumph Capo capered, vaulted over rocks, drummed on the stony ground, and shit explosively, spraying the dry boulders with his stink.

His followers responded to Capo's display only listlessly. They were hungry and dreadfully thirsty. Capo was exhausted himself. But he displayed anyway, obeying a sound instinct that every triumph, however small, should be celebrated.

But now he had climbed so high that the remote, persistent growling from the west had grown louder. Dimly curious, Capo turned and looked that way.

From this elevated place he could see a long way. He made out a remote turbulence, a white billowing. It seemed to hover above the ground like a boiling cloud. He was actually seeing a kind of mirage, a very remote vision carried to him by refraction in the warming air. But the billowing steam clouds were real, though their suspension above the ground was not.

What he was glimpsing was the Strait of Gibraltar, where even now the mightiest waterfall in Earth's history- with the power and volume of a thousand Niagaras- was thundering over shattered cliffs and into an empty ocean basin. Once the plain from which Capo had climbed had been covered by water two kilometers deep, for it was the floor of the Mediterranean.

Capo had been born in the basin that lay between the coast of Africa, to the south, and Spain, to the north. In fact, he was not very far from the place where a clever dinosaur called Listener, long ago, had stood at the shore of Pangaea and gazed out on the mighty Tethys Sea. Now he had climbed out of the basin to reach Africa proper. But if Listener had seen the birth of the Tethys, Capo was witnessing something like its death. As the ocean levels dropped, this last fragment of the Tethys had become dammed at Gibraltar. Landlocked, the great ocean had evaporated- until at last it emptied, leaving behind a great valley in places five kilometers deep, littered with salt pans.

But as the climate oscillated, the sea level rose again, and Atlantic waters broke through the Gibraltar barrier. Now, the ocean was refilling. But Capo had nothing to fear of giant waves cascading from the west, for even a thousand Niagaras could not refill an ocean overnight. The Gibraltar waters suffused the great basin more gradually, creating great rivers. The old seafloor turned slowly into sodden marshland, where the vegetation slowly died, before the waters rose so high they covered over the ground altogether.

But after each refilling the global ocean levels would drop again, and once again the Mediterranean would evaporate. This would happen as many as fifteen times fifteen times over the million years bracketing Capo's brief life. The Mediterranean would be left with a complex seabed geology, with layers of silt sandwiching salt pans laid down in the successive dryings. over the million years bracketing Capo's brief life. The Mediterranean would be left with a complex seabed geology, with layers of silt sandwiching salt pans laid down in the successive dryings.

But this trapped ocean's dryings were having a profound effect on the area Capo lived in- and on Capo's kind. Before the great dryings, the Sahara region had been densely forested and well watered, and home to many species of apes. But with the climatic pump of the dryings, and in the lengthening rain shadow cast by the more remote Himalayas, the Sahara was becoming increasingly arid. The old forests were breaking up. And with them the communities of apes were splintering, each fragmentary population embarking on its own journey to a new evolutionary destiny- or extinction.

But the great rumbling, the blurred vision of Gibraltar, was too remote to have any meaning for Capo. He turned away, and stumbled down onto the plain.

At last Capo moved off bare rock on to vegetation. He relished the green softness of the grass under his knuckles as he loped forward. As the others tumbled after him they rolled and sprawled, pulling up the long grass around them, relishing the delicious contrast with the hard lifeless rock.

But they weren't home yet. A stretch of a few hundred meters of open savannah, studded with thorn bushes, separated them from the nearest forest clump- and the plain was not unoccupied.

A group of hyenas worked at a fallen carcass. Bulky, round, it might have been an infant gomphothere, perhaps felled by a chasma. The hyenas snapped and growled at each other as they worked at the scavenged meat, their heads buried in the creature's stomach, their sleek bodies writhing industriously.

As Capo cowered in the grass, Frond and Finger came up alongside him. They hooted softly, and gave Capo's backside a perfunctory groom, picking out bits of dust and rock. The younger males were cursorily acknowledging his authority. But Capo could tell they were impatient. Weary, thirsty, hungry, thoroughly spooked by the trek across the openness, they, like the rest of the troop, longed to reach the shelter and provision of the trees. And that was corroding Capo's hold on them. The tension between the three males was powerful, toxic.

But it was a confrontation conducted in near silence, as the three of them kept their presence concealed from the hyenas.

While Capo still hesitated, it was Frond who made the move. He took one, two tentative shuffles forward. He received a hefty clout on the back of his head from Capo for his defiance. But Frond just bared his teeth, and moved out of reach.

The tall grass stems waved languorously at Frond's passing, as if he were swimming through a sea of vegetation. And now Frond got up on to his hind legs, poking his head, shoulders, and upper torso out of the grass so he could see better. He was a slim shadow, upright, like a sapling.

The hyenas were still intent on their baby elephant. Frond ducked back into the grass and continued on his way.

At last he reached the nearest stand of trees. Capo, with a mixture of resentment and relief, saw him climb up a tall palm tree, his legs and arms working in synchrony, like components of a smoothly oiled machine. When Frond had reached the top of the palm he hooted softly, calling the others. Then he began plucking nuts from the palm and throwing them down to the ground.

One by one, led by Finger and the senior female, Leaf, the apes scurried through the grass toward the forest pocket.