she came to the walls of the quarry, up which she scrambled in a flash.
She looked back into the great pit, its floor studded with the lowering, silent forms of the borametz trees. And here came Cactus, running after her with a defiant grin.
II
The land was bare. There were a few stubby trees, and shrubs with bark like rock and leaves like needles, and cacti, small and hard as pebbles and equipped with long toxin-laden spines. Protecting their water, these plants were little balls of aggression, and Ultimate and Cactus knew better than to tackle such risky fare until it was essential to do so.
You had to watch where you put your feet and hands.
There were pits in the desert’s crimson floor. They were bright red, a little like flowers, barely visible against the red soil, but with knots of darkness at their centers. Foolish lizards and amphibians, and even the occasional mammal, would tumble unwarily into these waiting traps — and they would not emerge, for these pits were mouths.
These deadly maws belonged to creatures that lived in narrow burrows under the ground. Hairless, eyeless, their legs reduced to scrabbling finlike stubs with sand-digging claws, they were rodents, among the last remnants of the great lineages that had once ruled the planet.
This time of openness and lack of cover did not favor large predators, and the survivors had been forced to find new strategies. The frantic activity and sociability of their ancestors long abandoned, these burrowing rat-mouths spent their lives in holes in the ground, waiting for something to fall into their mouths. Shielded from the excesses of the climate, moving from their burrows only when driven to mate, the rat-mouths had slow metabolisms and very small brains. They made few demands of life, and in their way were content.
But for creatures as smart as Ultimate and Cactus, the rat-mouths weren’t hard to avoid. Side by side, the companions moved on.
The companions came to a little gully. It was nearly choked: the rainstorm had filled it with pebbles and stones. But there was still a trickle of silty runoff water. Ultimate and Cactus crouched down, Ultimate shielding her baby, and they pushed their faces into the water, sucking at it gratefully.
Ultimate found green here, in the damp. It was a kind of leaf, prostrate, dark, slightly crimped. Its form was very ancient, too primitive even to have the wherewithal to grow up toward the light. It was actually a descendant of a liverwort, all but unchanged by the passage of time, a barely modified copy of one of the first plants ever to colonize land — a land that had not looked so different from this harsh place. The times had come around, and the liverwort found room to live. Curious, Ultimate plucked the leaf from the rock it clung to, chewed it — it was waxy, sticky — and kissed her baby, letting bits of the leaf trickle into her mouth. The baby chomped with a sucking noise, her little eyes rolling.
Close to one of those pebblelike cactuses, Ultimate spotted a beetle, silvery-backed, toiling to push a dried-up pellet of dung along a miniature crevasse. Ultimate briefly considered making a grab for the beetle.
But as the beetle passed the shade of the cactus, a tiny crimson form shot out of the darkness. It was a lizard, smaller than Ultimate’s little finger, and its head was a lot smaller than the beetle itself. But nevertheless the lizard clamped its jaws on the toiling beetle’s rear end. Ultimate could hear the minuscule crunch: The beetle waved its legs and antennae, but it could not get away. The lizard, its burst of energy expended, spread great sail-like fans from its neck and legs. The cooling fans made the lizard look twice its resting size, though its red color gave it good camouflage against the Pangaean dust. Saved from overheating, it began the slow, luxurious process of sucking out the beetle’s salty vitals from within its carapace.
But it wasn’t to be given that luxury. From nowhere a small bird came running on to the scene. Black-feathered, its wings vestigial stubs hidden beneath its skin, it was flightless. Without hesitation, and with lethal precision, the bird lunged at the lizard with a yellow beak full of tiny teeth. The lizard released the beetle and tried to squirm away under the cactus, its sail-fans folding. But the bird had hold of one fin and it pulled the lizard back into the light, shaking its tiny body.
The mutilated beetle crawled away — only to be scooped up by Cactus’s little paw and delivered to her mouth.
There were plenty of birds around; that great, ancient lineage was much too adaptable not to have found a place even in this harsh, much-changed world. But few birds flew nowadays. Why fly when there was nothing to flee, nowhere to go that wasn’t exactly the same as
Meanwhile, disturbed by the bird’s attack, more lizards erupted from under the cactus. There were many of them, all of them smaller than the sail-fan caught by the bird, smaller than Ultimate’s own fingernail. They were so tiny, Ultimate saw, they had to clamber over pebbles and irregularities in the dirt as if they were hills and valleys. They scurried in all directions, disturbed from their daily slumber, and made for cover in the rocks and pebbles.
Ultimate watched, fascinated.
As new Pangaea’s great drying had continued, the larger species had fallen away. In the barren emptiness of the supercontinent there was nowhere for a creature the size of Ultimate to hide, still less a gazelle or a lion. On the largest scales the ancient game of predator and prey had broken down.
But on smaller scales, a new ecology proliferated. Under Ultimate’s feet there were holes in the rocks, crevasses in the sand, holes in borametz tree trunks, tangles in root systems. Even in the flattest landscape there was topography where you could hide from predators, or wait to ambush prey, or simply hole up and avoid the rest of the world — if you were small enough.
But if the world of the smallest scales was still rich in opportunity, it was a world largely excluded from the hot-blooded kind.
All hot-bloods had to maintain their high body temperatures. But there was a limit to how much insulating hair and fat you could grow before you became an immobilized little puff-ball, how fast a pulse you could sustain. The last of the shriveling mole folk, their tiny hearts rattling heroically, had been as small as a centimeter. But a centimeter-scale was still huge. There was plenty of room below this, plenty of ways to live.
But all these niches were taken by insects and reptiles and amphibians. Small and skinny, the cold-bloods hid from the heat of the sun and the chill of the night, under rocks and in the shade of trees and cacti. In a handful of dirt it was possible now to find tiny, perfectly formed descendants of frogs and salamanders, snakes — and even the endlessly enduring crocodiles. There were even tiny lungfish, silvery little creatures hastily adapted for the land as the inland waters had dried. This largest of continents was dominated by the smallest of animals.
Without the Tree’s support, such large hot-blooded mammals as Ultimate’s postpeople could never have survived so long. They were like throwbacks to easier times, out of place in this marginal environment. As the Earth warmed relentlessly, as the great desiccation continued, even the Tree-based communities shrank back and died, one by one. And yet they were here: And yet here was Ultimate, the latest link in a great chain that now passed back through a hundred million grandmothers, morphing and changing, loving and dying, back to Purga herself, and into the formlessness of the still deeper past beyond.
Ultimate and Cactus watched the tiny scramblings in the dirt. Then, hooting, the posthumans fell on the scrambling lizards. Most of them were too small to catch — you would close your hand around them only to see them squirming out the other side — and even when Ultimate managed to cram one into her mouth it was too small a morsel to be satisfying.
But they didn’t need to eat the lizards. They were playing. Even now you could have fun. But in the silence of New Pangaea their whoops and hooting cries echoed from the bare rocks, and as far as could be seen they were the only large creatures moving, anywhere.
The sunset came quickly.
The air was scrubbed clean of dust by the rains. As soon as the sun touched the horizon, darkness striped across the flattened land, small ridges, dunes, and pebbles casting shadows tens of meters long. The light in the sky faded from blue to purple, quickly sinking to black at the zenith. It was like a sunset on the airless Moon.
Ultimate and Cactus huddled together, the baby between their bodies. Every night of her life Ultimate had spent in the Tree’s enfolding vegetable embrace. Now the shadows were like raptor fingers reaching out for them.
But as the temperature fell, so Ultimate’s adaptations to the desert came into operation.
Her skin was actually hot to the touch. During the day her body stored heat, in layers of fat and tissue. In the cooler air of night, her body was able to radiate a lot of the heat back to the environment. If she had not been able to perform this trick of refrigeration she would have had to lose the heat by sweating — and that would have used up water she couldn’t afford to waste. And Cactus and Ultimate were breathing, deeply and slowly. That way a maximum amount of oxygen was extracted from each lungful of air, and a minimum amount of water was lost. Meanwhile Ultimate’s body was manufacturing water from the carbohydrates in the food she had eaten. She would finish the night with more water in her body’s stores than when she had started.
But still, for all this remarkable physiological engineering, the two of them could do little but sit and endure the night, breathing slowly, lapsing into a kind of dull half dream as their bodies’ functioning slowed to a crawl.
While above them a bewildering sky unfolded.
Ultimate had a grandstand perspective view of the Galaxy. The huge spiral arms were corridors of brightness that spanned the sky, studded with pinpricks of sapphire-blue young stars and ruby-red nebulae. At the center of the disk was the Galactic core, a bulge of yellow-orange stars like the yolk of a fried egg: the light had taken twenty-five thousand years to travel here to Earth from that crowded core.
In human times the sun had been embedded in the body of the huge flat disk, so that the Galaxy had been seen edge-on, its glory diminished by the obstructing dust clouds that littered the disk. But now the sun, following its slow orbit around the core, had sailed out of the Galaxy’s plane. Compared to the random scattering of a few thousand lamps that had marked man’s sky, this was like glimpsing the lights of a hidden city.
Ultimate cowered.
A bony hook rose in the sky. It was the Moon, of course, an old Moon, tonight a narrow crescent. The same patient face that had peered down on Earth since long before the birth of man was all but unchanged across half a billion years. And yet this thin crescent Moon shone more brightly over the new supercontinent than it had over the more equable lands in the past. For the Moon shone by reflected sunlight — and the sun had grown brighter.
Had she known where to look Ultimate might have made out a dim smudge in the sky away from the Galaxy’s disk, easily visible on the clearest nights. That remote smudge was the great galaxy known as Andromeda, twice the size of its neighbor. It was still a million light-years distant from Earth’s Galaxy — but in human times it had been twice as far away as that, and even then it had been visible to the naked eye.
Andromeda and the Galaxy were heading for a collision, still another half-billion years distant. The two great star systems would pass through each other like mingling clouds, with direct collisions between stars rare. But there would be a vast gush of star formation, an explosion of energy that would flood the disks of both galaxies with hard radiation. It would be a remarkable, lethal light show.
But by then there would be little left alive on Earth itself to be troubled by the catastrophe. For the brightening of the sun was life’s final emergency.
Morning came with its usual stark suddenness. Scuttling lizards and insects disappeared into the nooks and crannies where they would ride out the day, waiting for the richer opportunities of evening.
The baby mewled. Her fur stuck up in clumps, and the pucker where the belly-root should sit looked inflamed. She kept up her complaints, her bulbous little head turning to and fro, until Ultimate had chewed some more liverwort and dribbled it into her mouth. Cactus, too, was grumbling, picking dirt and bits of dried shit from her fur.
This morning it didn’t seem such a good idea to be out here in the middle of nowhere, so far from home. But as she held her baby Ultimate knew she had to stay away from the Tree — stay away, or lose her baby. She clung to that one irreducible fact.
Ultimate and Cactus began to work their random way across the landscape, heading roughly away from the quarry. Just as they had yesterday, they ate where they could — though they found
