Roamer watched, dizzy, bemused. It was like watching an animated skeleton.

Left's last eerie calls faded to silence. His fingers remained outstretched, frozen forever in his final gesture. His shrunken stomach growled, and a final noxious belch passed through his lifeless lips.

Roamer looked dully at the others. They were heaps of bone and damaged flesh, not much better off than Left, barely recognizable as anthros at all. They made no effort to groom, to make any kind of contact. It was as if the sun had baked away everything that made them anthros, had stripped them of the gains made painfully in thirty million years of evolution.

Roamer turned away and limped painfully back to her patch of soiled leaves, seeking cover.

She lay passively, shifting only to relieve the pain of suppurating sores. Her mind seemed empty, free of curiosity. She existed in a dull reptilian blankness. She would cram her mouth full of bark and dry leaves, but the dead stuff only scratched her broken flesh.

And she kept thinking about Left's corpse.

She got up slowly and crossed to Left's body. His chest had split open, a postmortem wound opened up by the drying of his skin. The stench, oddly, wasn't too bad. On this brine desert, the processes of decay that would, in the forests, have quickly absorbed Left's body were largely absent, and the slow mummification that had begun while he was still alive had continued.

Cautiously she pushed her hand into the wound. She touched ribs, already dried. She tugged at the flesh over his chest. It peeled back easily, exposing his rib cage.

There was barely any muscle tissue left on the body. There was no fat either, only traces of a translucent, sticky substance. Within Left's body cavity she could see his organs, his heart, liver, kidneys. They had been shrunken; they were like hard, blackened fruit.

Fruit, yes.

Roamer pushed her hand into the chest cavity. The rib cage split open with a crack, exposing the meaty fruit within. She closed her hand around his blackened heart. It came away easily, with a soft ripping noise.

She sat with the heart, and, as if it were no more exotic than a peculiar variety of mango, bit into it. The meat was lean, fibrous, and it resisted teeth that wobbled loose in her jaw. But soon she was tearing into the organ, and was rewarded with a little fluid, blood from its core that had not yet dried.

Instead of easing her hunger pangs, the meat only served to inflame Roamer's atavistic drive to eat. Saliva flowed in her mouth again, and digestive juices pumped painfully through her stomach. She vomited out her first mouthfuls, losing them to the sea, but she persisted until the hard, fibrous meat stayed down.

Left's eyes, milky white and opaque, still stared sightlessly at the sun that had killed him; and his left hand was curled in its final gesture.

Patch had stirred now. She came loping cautiously toward Roamer. Her skin was a tight sack to which only a few clumps of her once-beautiful black fur still clung. Curious, she rummaged through Left's open chest. She came away with the liver, which she rapidly devoured.

Meanwhile Crest had not moved. Showing no signs of interest in the fate of his brother, he lay on his side, limbs splayed. He might have been dead, but Roamer made out a subtle movement, a slow rise and fall of his chest, slow as the ocean's swell, the last of his strength invested in keeping him breathing.

Instinct worked in Roamer now. Patch had been made pregnant by Whiteblood- but perhaps her body had destroyed the fetus by now, absorbing it like its own muscle and fat to keep itself functioning. Two females, alone, had nothing but their own deaths to look forward to. So Crest, the last male, must be preserved.

Roamer returned to the body and plucked out a kidney, another hard knot of blackened, shriveled meat. She carried it to Crest and pushed the meat into his shriveled mouth. At last he stirred. With a gesture as feeble as an infant's he reached up and took the lump of meat, and began to gnaw it slowly.

The food, such as it was, only made them more hungry, for it lacked the fat they needed to enable them to digest it properly. Still, all three of the survivors returned to the body over and over again, emptying the body cavity, gnawing flesh from limbs, ribs, pelvis, back. When they were done, only scattered bones remained- bones and a skull, from which eyeballs still stared at the sun.

After that the three anthros returned to their solitary corners. If they had been human, now that the taboo of devouring the flesh of their own kind had been broken, a kind of cruel mathematics would have begun to work in their minds. Another death, after all, would have provided the survivors with more food- and reduced the number who would share it.

It was, perhaps, a mercy that none of the anthros were able to plan that far ahead.

IV.

The raft jolted under her. It was a sharper motion than the broad, slow swell of the sea. But she was beyond curiosity, and she lay passively in the raft's rough cradling, knotted branches poking into her thin flesh.

She was in pain constantly now. Her bones felt as if they were working their way out through her skin, which was like one giant ulcer. She could barely close her dried eyelids. Her memory was a disorganized hall of images: the feel of her sister's strong, grooming fingers, the warm, safe scent of her mother's milk, the brazen cries of the males who believed they owned them all. But then her soft dreams would be shattered by the irruption of great slavering jaws from the floor of the world... Now came another jolt, a rustle of the dry timber around her. She heard the noise of waves breaking, quite different from the languorous lapping of the deep ocean.

Birds clattered overhead.

She peered up. They were the first birds she had seen since she had been washed from the land. They were brilliant white, and they wheeled high above her.

Something moved on her chest. It felt like fingers, tentatively scratching: perhaps someone was trying to groom her. With an immense effort she lifted her head. It lolled, her skin tight like a mask, her tongue a block of wood in her mouth. She had difficulty focusing her bleeding eyes.

Something was crawling over her: a flat orange shape with many segmented legs and big raised claws. She yelped, a thin, dry sound, and brushed her arm over her chest. The crab scuttled away, indignant.

With nostrils baked black as tar, she could smell something new. Water. Water. And not the stinking brine of the sea, but fresh water. And not the stinking brine of the sea, but fresh water.

She lifted an arm and grabbed at the foliage. Every scrap of her raw flesh, as scabs and blisters pulled and broke, was a source of lancing pain. With an immense heave she managed to get herself upright, her feet under her, her legs folded. Her head lolled, too heavy for her neck. It took her more energy yet to raise it, to squint through her broken eyes.

Green.

She saw green, a great horizontal slab of it, running from horizon to horizon. It was the first green she had seen since the last of the mango's leaves had curled and browned. After so many days of blue and gray, of nothing but sky and sea, the green seemed vibrantly bright, so bright it almost hurt her eyes, beautiful beyond imagining, and just looking at it seemed to strengthen her.

She levered herself forward, half crawling. The mango's dead foliage pricked and cut her, but there was no blood to flow, nothing but dozens of tiny sources of pain.

She reached the edge of the raft. No ocean, no water. She saw a shallow beach of coarse, young sand, stretching up a short rise to the foot of a sparse forest. Birds, bright blue and orange, flittered through the tops of the trees, piping brightly.

Her first impression could have been summarized as I am home. I am home. But she was wrong. But she was wrong.

She pulled herself over the branches and half fell onto the sand. It was hot, very hot, and it burned her exposed skin. She mewled, pulled herself up, and limped forward, as if she had grown very old, up the beach toward the forest.

At the forest edge was an undergrowth of low ferns and blessed shade. Taller trees towered above her. On their branches were clusters of a red fruit she didn't recognize. Her mouth was too dry to salivate, but her tongue clicked against her teeth.

She glanced back the way she had come. The mango tree and its raft of vegetation was just a scrap of driftwood, broken, rotten, seaweed clinging to it, now washed up on this shore. She could see the unmoving form of an anthro- Patch or Crest- lying inert on the broken, salt-crusted foliage. And beyond the raft the sea rolled, huge, eternal, blue gray, reaching as far as she could see to a horizon of chilling geometric perfection.

Now there was a crashing tread, a great snapping of foliage. Roamer shrank back.

A giant form emerged from the forest, like a tank rolling through the undergrowth. Huge, squat, under a great bony dome of a shell, it looked like a giant tortoise- or perhaps an armored elephant- a great plated body supported by four stumpy legs. Behind it a tail swung carelessly, tipped by a spiky club. And as its small reinforced head pushed out into the light, armored eyelids blinked. This tremendous ankylosaur-like creature was a glyptodont. Roamer had never seen anything like it in Africa.

But then, this wasn't Africa.

The giant armored monster lumbered away. Cautiously Roamer followed the glyptodont deeper into the forest. She came to a clearing, surrounded by a wall of tall, imposing trees. The floor was carpeted by aloes. Experimentally Roamer nibbled at a leaf. It was succulent, but bitter.

She moved further forward, and found the glimmer of still water. It turned out to be a shallow, reed-choked freshwater pond. At its shore browsed a pair of huge animals. They grazed on the plants at the pond's edge with snouts like spatulas. They looked like hippos, but were actually immense rodents.

The pond was on the fringe of a broader plain. And there, dimly visible now, much stranger mysteries awaited Roamer. There were creatures that might have been horses, camel, deer, and smaller animals, like hoofed pigs. Alongside them moved a small family of dinomyids: bulky, bearlike grazers. They were giant rodents, the extravagant relations of dormice and rats. There were predators here too, creatures who ran in packs like dogs- but they were marsupials, only distantly related to placental counterparts elsewhere, shaped by convergent evolution, similarly adapted for a similar role.

From a green shadow near Roamer, a head turned, startling her. The head was upside down. Two black eyes peered at her dimly. Above the head was a huge brown-furred body, dangling from limbs that clutched a branch above. This was a sloth, a kind of megatherium.

Cautiously, Roamer crept forward, at last, to the pool. The water was muddy, greenish, warm. But when she plunged her face into it, it was the most delicious thing she had ever tasted. She sucked down great mouthfuls. Soon her shrunken belly was full, and agonizing pains shot through her, as if she were being torn apart from inside. She fell forward, crying out, and threw up almost all she had drunk. But she pushed her face back into the water and drank again.

This brackish pond was actually a sinkhole. Fifty meters deep, it had been caused by groundwater dissolving the underlying limestone. There were many such sinkholes in the area, aligned along great, deep-buried faults in the rocks.

Seen from the air, the sinkholes would have formed a huge semicircle some hundred and fifty kilometers across. The arc of sinkholes marked a boundary fault of the ancient, long-buried Chicxulub crater, the rest of which stretched under the Gulf of Mexico's shallow waters and sediments. This was the Yucatan Peninsula.

Expelled by an African river, riding westward currents, Roamer's raft had crossed the Atlantic.

Nowhere on Earth was truly isolated.

Everywhere was connected by the ocean currents, some of which covered as much as a hundred kilometers a day. The great currents were like conveyor belts that bore flotsam around the world. In later times, inhabitants of Easter Island would burn logs of American redwood, washed ashore after a journey of five thousand kilometers. People living on coral atolls in the deep Pacific would make tools from stones embedded in the roots of stranded trees.

With the flotsam traveled animals. Some insects rode the surface of the water itself. Other creatures swam: Westward currents could carry leatherback turtles across the Pacific from their feeding ranges near Ascension Island to breeding grounds in the Caribbean.

And some animals rode across the oceans on impromptu rafts- oceanic odysseys undertaken not by choice or design, but by the vicissitudes of chance, just as had befallen Roamer.

The Atlantic, which had been widening since the shattering of Pangaea, was still much narrower than in human times: no more than five hundred kilometers wide at its narrowest point. It was not an impossible distance, a traverse that could be survived even by fragile forest creatures like Roamer, with luck. Such crossings were improbable. But they were possible, possible, given the outflows of mighty rivers, the narrow oceans, perhaps the help of hurricane winds. given the outflows of mighty rivers, the narrow oceans, perhaps the help of hurricane winds.

On the longest of timescales, over millions of years, the workings of chance defied human intuition. Humans were equipped with a subjective consciousness of risk and improbability suitable for creatures with a lifespan of less than a century or so. Events that came much less frequently than that- such as asteroid impacts- were placed, in human minds, in the category not of rare, rare, but of but of never. never. But the impacts happened even so, and to a creature with a lifespan of, say, ten million years, would not have seemed so improbable at all. But the impacts happened even so, and to a creature with a lifespan of, say, ten million years, would not have seemed so improbable at all.

Given enough time even such unlikely events as ocean crossings from Africa to South America would inevitably occur, over and again, and would shape the destiny of life.

Thus it was now. In the trees that towered above Roamer there was not a single primate- not one, not in all the continent, for her remote cousins, other children of Purga, had succumbed to extinction here millions of years ago, beaten by the rodents' competitive pressure.

So, in this place where a world had ended, where differently evolved creatures foraged through different forests, a new life was starting, a new line of Purga's great family. From just three survivors- given enough time, and the slow plastic working of their genetic material- would radiate a whole spectrum of new species.

By any standards the New World monkeys would be successful. But on this crowded jungle continent, the fate of Roamer's grandchildren would be quite different from those of her sister's in Africa. There, the primates, molded cataclysmically by the shifting climate, would rapidly develop new forms. There, Purga's line would continue- through the apes- its slow shaping toward humanity. Even the later monkeys who Roamer so resembled would diversify away from the forest, finding ways to live in savannah, mountain plateaus, and even deserts.

Here it would be different. On a more equable continent, it would always be too tempting to stay in the vast rain forests.

Roamer's grandchildren would never leave the trees. They would never grow much smarter than they were now. And they would play no part in the future destiny of mankind- save as pets, or prey, or objects of scientific curiosity.

But all that lay in the unimaginable future.

Roamer already felt remarkably revived by her brief time in the green and the water she had drunk. She looked around. In the undergrowth she saw a splash of red, and she stumbled that way. She found a fruit, unfamiliar, but fat and soft-skinned. She bit into it. As she munched on the flesh, juice burst out and dribbled over her fur. It was the cleanest, sweetest thing she had ever tasted.

CHAPTER 7.

The Last Burrow Ellsworth Land, Antarctica. Circa 10 million years before present.

I.

The burrowers worked through the tough, scrubby grass that clung to the dunes. There were many, many of them. They were so crowded they looked like a ground-covering carpet of squirming brown-gray fur.

Dig spotted a dense patch of ferns on a little headland overlooking the ocean. The foraging crowd seemed a little less dense there, so she headed that way. In the shelter of the fern patch, she picked apart fronds with her agile, five-fingered hands, and she nibbled on brown spores.

At three years old Dig was already one of the oldest of the burrowers. She was just a few centimeters long. She was fat and round and coated with thick layers of brown fur, the better to retain her body's heat. She looked something like a lemming. But she was no lemming. She was a primate.

From here she could see the ocean. The sun hung low in the northern sky, over the endless, impassable water. As polar autumn drew on, the sun spent more than half of each day beneath the horizon. And already, far from the land, great sheets of pack ice had gathered. Closer to shore Dig could see slushier gray ice forming in great sheets that rippled over the water's muscular swell. Her body knew what these things meant. The light-filled days of summer were a blurred memory; soon she would have to endure the winter months of continual darkness.

On one pack ice plate she saw a bloody stain, smeared over the gleaming surface, and an unidentifiable mound of inert flesh. Birds wheeled overhead, cawing, waiting their turn at the bloody pickings. And a shadow slid through the water, long, powerful. A huge snout pushed out of the chill water to take a share of the kill.

The seagoing carnivore was an amphibian, a descendant of a form called koolasuchus. Four meters long, it looked like a monstrous predatory frog. The frog was a relic of much more ancient times, when amphibians had dominated the world. In tropical climes, its ancestors had been outcompeted by the crocodiles, whom they closely resembled in size and form; the great amphibians had already been in decline when dinosaurs first appeared on the Earth, but they had clung on in the cooler waters of the poles.

Even from this distance, tucked under her ferns, Dig shuddered.

Suddenly a squat, feathered form came bursting from the tundra plain. The scrambling burrowers scattered in panic, and Dig cowered. The new arrival ran upright on long, powerful legs, and its hands, barely visible against thick white feathers, were grasping and equipped with cruel claws. This creature ran out into the water and splashed its way out to the ice floe. There it began to compete with the amphibian for scraps of the carcass, just as in later times Arctic foxes would try to steal the kills of polar bears.

This battling white-feathered predator looked like a flightless bird. It wasn't. It was a descendant of the velociraptors of the Cretaceous era.

On Antarctica, fifty-five million years after the comet impact, there were dinosaurs.

Dig made her way inland, away from the bloody scene at the shore. She moved cautiously, sticking to cover. Here and there she saw white feathers, discarded by the raptor in its haste to reach the kill on the ice.

As she clambered over the last dune, she could see the shape of the landscape.

It was a broad plain of green and brown, littered here and there by the blue of water. The grass was still thick, though it had begun to die back, and where it had not yet been cropped to the ground, it was turning golden brown. Most of the flowers had gone, for there were no insects to attract; but here and there bright, pretty blooms like saxifrage still lingered. Around the glimmering freshwater ponds, animals crowded, seeking drink. But the ponds were already gray with surface ice.

It was a classic tundra scene, part of a belt of such landscape that still encircled the continent.

And, over this tundra, dinosaurs walked.

A few kilometers to the southwest, Dig saw what looked like a dark cloud washing over the ground. It was a herd of muttas. Their breath created great clouds of steam that hung in the chill air. They were dinosaurs, huge herbivores. From a distance they looked like tuskless mammoths. But closer in it could be seen that they retained classic dinosaur features: Their hind legs were more powerful than their forelegs, they had powerful balancing tails, they behaved in an oddly skittish and nervous way, more like birds than any huge mammal- and sometimes they would rear up on their hind legs and bellow with the ferocity of a tyrannosaur.

The muttas were descended from muttaburrasaurs, beefy Jurassic herbivores that had once feasted on cycads, ferns, and conifers. As the cold had descended on Antarctica, the muttas had learned to subsist on coarse tundra produce. Their bodies had become squat and round, and they had developed a thick coat made up of multiple layers of dark-brown, scaly feathers. Gradually they became large, migrating tundra herbivores, a role later occupied elsewhere by animals like caribou and musk oxen- and mammoths. Their mournful hooting, made with inflatable skin sacs on their great horny snouts, echoed from the walls of ice to the south.

Once the muttas had migrated all over this continent, taking advantage of the short, rich summer. But as the ice had spread the muttas' numbers had been much diminished, and now, somewhat forlornly, the remaining herds wandered around the narrowing tundra fringe between ice and sea.

This mutta herd was being stalked by a solitary hunter.

Standing stock-still, the dwarf allosaur inspected the mutta herd. It looked like a golden, feathered statue. The allo was a dwarfed relic of a family of creatures long extinct elsewhere- a direct descendant, in fact, of the Jurassic lion who had killed Stego. But the herd was wary of the allo and stayed tightly bunched, their young at the center. This allo's movements were slow, as if it had been drugged. Its hunting had already been successful; with its store of fat laid in, its metabolism was already slowing as the air's chill gathered. Soon the allo would dig out its customary winter den in a snowbank, after the manner of polar bears.

Female allos laid their eggs toward the end of winter, and hatched them out inside their snowy dens, where they would be safe. For the mammals of Antarctica, spring was made more interesting by the possibility that from any snowbank there might suddenly erupt a clutch of ravenous allosaur chicks, snapping and squabbling in pursuit of their first meal.

Now there was a commotion among a throng of burrowers, not far from Dig, and the cold breeze off the ice cap brought her a sharp, meaty scent. Eggs. Eggs.

She ran as hard as she could through the ferns and the long grass, for once reckless of her own safety.

The nest contained dinosaur eggs: the eggs of a mutta. This was an unusual find so late in the season, and far away from the muttas' usual nesting sites. Perhaps these eggs had been laid by a sick or injured mother. There were burrowers already at work here, and in amongst the squabbling crowd there were a few bulkier steropodons: clumsy, black-haired, oddly primitive-looking, these creatures were descended from mammals that had inhabited the southern continent since Jurassic times.

Dig was able to force her way into the nest before it was utterly destroyed. Soon her face and hands were coated with sticky yolk. But the competition for the eggs quickly degenerated into a ferocious battle. There were many, many burrowers here on the tundra this autumn, many more than last year. And Dig was smart enough to be worried by the burrowers' overcrowding on a deep, gnawing level.

There was no simple cause for rises in numbers like this. The burrowers were locked into intricate ecological cycles involving the abundance of the vegetation and insects they browsed, and the carnivores who preyed on them in turn. At times of excess bodies it was the burrowers' instinct to get away, to strike out blindly over the green land in search of empty places to establish new burrows. Many of them fell to predation, but that was the way of things: Enough of them would survive.

At least, that was how it had happened in the past. But now, as the ice advanced and the tundra shriveled back, there was nowhere left to go that wasn't already colonized. And so there were always great crowds like this, and you always had to fight.

Of course, it was bad for the mutta who had laid these eggs. The muttas hatched their eggs on the ground, as their ancestors had always done, which made them vulnerable to opportunistic predators like the burrowers. Indeed, the key cause of the decline in the muttas' numbers was the increasing competition for the protein locked up in their huge eggs. Giant mammalian herbivores, like mammoths or caribou, would have fared better here, as their young would have been safer at such a crucial moment in their lives. But the muttas, stranded like the rest when Antarctica had sailed away from the other continents, had had no choice in the matter.

Suddenly a claw came sweeping out of the sky. With an instinct more than two hundred million years old, Dig flattened herself against the ground, while burrowers squeaked and scrambled over each other.