sense her mate approaching the pup, step by step, mouth wide, as if stalking a centipede.
Third was angry, confused, frightened, and very, very hungry. But what he was doing made a certain sense. After all, there was nothing to eat here. If the flesh of the pup kept the adults alive a little longer, long enough for them to produce another litter, the genetic program would be fulfilled. The calculations were relentlessly logical.
Perhaps in other times Purga would have submitted to Third’s aggression, even helped him finish off the pup. But Purga’s life had already been long for her kind, and she had suffered a series of extraordinary events: the destruction of her first home, her dogged pursuit by Wounding Tooth — and now the nightmare of the comet impact and her stranding in this world of cold and silence.
The imperatives resolved themselves. She bit Third savagely on the thigh, and scrambled past him to stand alongside her daughter.
Last was just as confused as the others. But she figured out that her mother was defending her from some kind of attack by her father. And so she stood with Purga and bared her teeth at Third. For a full half-minute the burrow was filled with hissing and the sound of tiny paws scraping the ground aggressively; three sets of whiskers filled the space between the primates, each of them waiting for the other to strike.
In the end it was Third who backed off. He gave up quite suddenly, abandoning his aggressive posture and curling up alone in a corner of the burrow. Purga stood with her daughter until the anger and aggression had drained out of her system.
It was this final incident that changed the balance of the forces in Purga’s mind.
They couldn’t stay here, for they would starve, or freeze, if they didn’t kill each other first. They had to go out, regardless of what mysterious dangers lurked in the newly silent world above. Enough was enough. When her body clock next woke her, Purga pushed away the dirt that clogged the entrance to the burrow.
And emerged into the dark.
After two days, the fire in the sky had died. But now, from pole to pole, dust and ash covered the wounded Earth, a black shroud laced with wispy, yellow-white clouds of sulfuric acid. The Earth had been transformed from a starlike shining to a dismal, gloomy darkness, darker than the core of the comet which had wrought such devastation. Dust and ash: The dust was comet fragments, and sea-bottom dirt, and even volcanic debris spewed out after the immense seismic shocks that had rippled through the planet. And the ash was burned life, trees and mammals and divergent species of dinosaurs from America and China and Australia and Antarctica, burned to cinders by the global firestorms and then burned again in the pulse of superheat, now mingled together in the choked stratosphere. Meanwhile, sulfur, baked out of seabed rock in the first moments of the impact, had lingered in the air, forming sulfuric acid crystals. The high, bright acid clouds reflected away sunlight and drove the cold deeper still.
Followed by Third and Last, Purga crept cautiously away from her burrow’s mouth, whiskers twitching nervously. It was late afternoon, here in the chill heart of North America. If the sky had been clear, the sun would still have been well above the horizon. There was only the gloomiest of twilights, barely sufficient even for Purga’s huge, sensitive eyes.
She stumbled forward over bare, scorched rock. Everything was wrong. There was no scent of green growing things, nor the pungent, spicy stink of the dinosaurs, not even of their dung. Instead, she smelled only ash. The whole of the great thick green-brown layer of Cretaceous life had been burned off: even the dead leaves, even the dung, all destroyed. All that was left were minerals, lifeless dirt, and rock. It was as if Purga had been transported to the surface of the Moon.
And it was
She came to the ruins of what had been a small stand of tree ferns. She scraped at the ground with her claws, but the ground was strangely hard — and it was cold, deep cold, so cold it hurt the pads of her hands. But when she licked her hand, a slow trickle of water gathered in her mouth.
Just a few days earlier this had been a place of tropical forest and swamplands. No frost had formed here in millions of years. But now there was frost. Purga scrabbled at the ground, cramming the strange, chill stuff into her mouth. Slowly she got mouthfuls of water — and plenty of ash and dirt along with it.
She tried to dig deeper. She knew that even after the most ferocious fire there was food to be had: hardened nuts, deep-buried insects, worms. But the nuts and spores were trapped under a lid of frozen ground, too tough for Purga’s small paws.
She moved on, feeling her way through the dark with her whiskers.
She came to a shallow puddle. In fact it was the footprint of a vanished ankylosaur. Her snout hit a hard surface: brutally cold and hard as rock. The cold that stabbed through her fur was intense. She backed up hastily.
Like frost, she had never encountered solid ice before either.
More cautiously she poked at the ice with her snout and hands. She scraped and scratched — she could smell the water that was somehow hidden here, and it maddened her to be able to get no closer to it. Frustrated, she began to circle the little puddle, pushing and probing. At last she came to a place where the ankylosaur’s foot, pushing into what had been soft warm mud, had dug a somewhat deeper pit. The ice here was thin, and when she pushed at it, the surface cracked and lifted up. She jumped back, startled. The fragment of ice, upended, slid slowly into the black water. Cautiously she slid forward once more. And this time, when she tentatively dipped her snout, she found liquid water: chill, already frosting over with fresh ice, but liquid nonetheless. She sucked in great mouthfuls, ignoring the bitterness of the ash and dust that laced it.
Attracted by the sound of her drinking, Third and Last came hurrying to her side. They quickly extended the hole she had broken, jostling to slurp up the gritty water.
For the first time since the comet had struck, things had gotten better for Purga: not by much, but better.
But now something touched her shoulder: something light, cold. She yelped and turned. It was a wisp of white, already melting.
Now more flakes came drifting down out of the sky. They fell with a random, gentle movement. When a flake came close enough, she leapt up and took it in her mouth, like plucking a fly from the air. She got a mouthful of soft ice.
It was snowing.
Spooked at last beyond endurance, she turned and bolted for the security of the burrow.
The impact had hurled vaporized ocean water into the air. After weeks of suspension, it began to fall back.
There was a
But the rain itself brought further devastation. It was full of sulfuric acid from the ice clouds, and the impact had injected thin clouds of toxic metals into the atmosphere, metals that now rained out. Nickel alone reached twice the threshold of toxicity for plants. Runoff water washed substances like mercury, antimony, and arsenic out of the soils, concentrating them in lakes and rivers.
And so on. For years, every raindrop would be poisoned.
The great rain washed out the dust and ash. All over the world, a fine layer of blackened clay was laid down, a band of darkness that would forever show up as a punctuation in the sedimentary rocks of the future — a boundary clay, one day to be studied by Joan Useb and her mother, the last remnant of a biosphere.
After months of dark the sun showed, at last, through the planet-girdling layers of dust and ash. But it was only a pinprick, shedding barely any heat on the frozen land; there would be no more than a murky twilight for another year.
The returning sun illuminated a skeletal landscape.
Tropical plants, if not burned, had been killed by the sudden cold. Any surviving dinosaurs were succumbing to hunger and cold, their bones quickly stripped of flesh by the surviving predators. But here and there living things moved in the ash: insects like ants and cockroaches and beetles, snails, frogs, salamanders, turtles, lizards, snakes, crocodiles — creatures that had been able to hide in mud or in deep water — and many, many mammals. Their furry bodies and habits of burrowing into the shelter of the ground were protecting them from the worst of the cold. Their indiscriminate eating habits helped as well.
It was as if the world ran with rats.
And even now the survivors were breeding. Even now, despite the cold and the shortage of food, in the absence of their ancient predators, their numbers were increasing. Even now the blind scalpels of evolution took raw material adapted for a vanished world and cut and shaped it for the conditions of the new.
Alone, the female euoplocephalus stumbled through the endless cold, seeking the rough forage she needed.
She was of a species of ankylosaur. Her body was ten meters long and, before her slow starvation had begun, she had weighed as much as six tons. Her armor was bone: plates of it set in the skin of her back, neck, tail, flanks, and head. Even her eyelids were plates of bone. The plates were woven into a layer of tough ligaments, making the great carapace flexible, if heavy. Her long tail terminated in a fused mass of bone. Once she had used this club to lame a young male tyrannosaur, her greatest triumph — not that she was able to remember it; all that armor had left little room, and little need, for a large brain.
Though geologically sudden, the great death unfolding across the planet was not instant in the consciousness of those who endured it. For days, weeks, months, many of the doomed clung to life — even dinosaurs.
Relatively speaking, the euoplos had been well-equipped to survive the end of the world. Their massive bulk, great strength, and heavy armor — together with a fortunate placing beneath a thick layer of cloud close to the bank of a river — had enabled a few of her kind to endure the first few horrific hours. She had survived droughts before; she ought to withstand this unexpected calamity. All she had to do was keep moving and fend off the predators.
And so, wandering the freezing Earth, she sought food. And found hardly any.
One by one her companions had fallen away, until the euoplo was alone.
But, in a final irony, she had endured one last mating, from a male now dead; and she found herself heavy with eggs.
In this new world, a land of ice and blackness and a lid of gray-black sky, the euoplo had been unable to find the ancestral rookeries. So she had constructed a nest of her own as best she could, from the bare, cinder-strewn floor of what used to be a rich forest. She had laid her eggs, lowing, setting them carefully in a neat spiral on the ground. Euoplos were not attentive mothers; six- ton tanks were not well equipped to deliver tender loving care. But the euoplo had stayed close to her nest, defending it from the predators.
Perhaps, despite the cold, the eggs might have hatched. Perhaps some of the young could have survived the great chill; of all the dinosaurs, perhaps it was an ankylosaur who might have endured best in the new, harsher world to come.
But the stinging rain had leached away the nutrients the euoplo’s body needed to manufacture successful eggs. Some of them had been laid with shells so thick no infant could ever break out, others were so thin they were broken as soon as she produced them. And then the rain began to damage the eggs directly, the grimy downpour etching away their protective surfaces.
None of the eggs had hatched. The euoplo, mournful, baffled on a deep cellular level, had moved away. Immediately after she was gone, a furry cloud of mammalian predators had descended on the eggs, in their squabbling reducing the nest to a muddy battlefield.
The last of her kind, the euoplo wandered the land, driven on by a final imperative: to survive. But the poison and the rain worked on her too. Creatures like Purga sheltered from the worst of the rain in her burrow, or under rocks — or even, once, under the scooped-out shell of a dead turtle. The euoplo was too big: There was nowhere for her to hide, and she could not burrow into the ground. So her back was ferociously scalded, and great bony plates of armor were stripped of flesh, the connecting ligaments etched and burned.
Unthinking, she staggered toward the sea.
Three months after the impact, Purga and Last stumbled across ground frozen as hard as rock.
They saw few animals: Sometimes a cautious frog would watch them go by, or a bird would flee at their approach, chirping with eerie loudness, abandoning some frozen bit of offal on the
