It wasn’t just the plesiadapids that were becoming rare in North America. It was no coincidence that Noth’s kind had been pushed up into this marginal polar forest. In the future Noth’s line would migrate further, passing over the roof of the world to Europe and thence to Asia and Africa, adapting and reshaping as they went. But in North America the rodent victory would, within another few million years, be complete. A new ecology would arise, populated by gophers, squirrels, pack rats, marmots, field mice, and chipmunks. There would be
When the rodent was done feeding, Noth crept cautiously out of his hiding place. With his agile hands he sought out the scraps of kernel the ailu had dropped, and crammed them into his mouth without shame.
For a few hours a day the southern sky still grew bright. But the sun made its cycles beneath the horizon now. Almost all of the lakes were frozen over, and the trees were laden with frost, some of it gleaming in thick lacy shards where mist had frozen out on spiderwebs. The notharctus’ movements through the trees and over the silent forest floor were sluggish and dull. But it didn’t matter; the forest could offer them little more food this autumn.
There came a last clear day, when layers of red-tinged cloud stacked up against a violet southern sky, and the purple-green aurora rolled like a vast curtain over the stars.
The notharctus hurried to the ground and began to dig in places where the soil had been kept unfrozen by layers of leaves or under the roots of trees. Tonight would be the hardest frost of the winter so far, and they all knew it was time to get under cover. So the primates dug, building burrows in which Purga would have felt comfortable. It was as if the brief interval in the trees had been nothing but a dream of freedom.
In the deepest dark, Noth pushed his way through tunnels quickly worn smooth by the passage of primate bodies and over a floor littered with loose fur. At last his powerful nose guided him to Right.
Gently Noth sniffed his sister. She was already dormant, curled tightly up with her tail wrapped around her, close to the belly of Big. She had grown during their months with Biggest’s troop, but Right would always be small, always retain traces of the runt who had been bullied by her now-dead twin. Still her winter fur seemed sleek, healthy, and free of knots and dirt, and her tail was fat with the store that should sustain her through the winter.
Noth felt a kind of satisfaction. Given their dreadful start to the summer, they had both beaten the survival odds better than expected. With no pups of his own, this was still the only kin Noth had — his entire genetic future depended on Right — but for now there was nothing more he could do for her.
In darkness, immersed in the scents and subtle noises of his kind, Noth snuggled as close as he could to his sister. He shut his eyes, and was soon asleep.
Briefly he dreamed, of fragments of summer light, of long shadows, of his mother’s fall from the trees. And then, as his body shut down, his mind dissolved.
IV
The sun’s rays, almost horizontal, shone like searchlights into the forest. Above the slowly melting ponds a chill mist hovered, shining in elaborate pink-gray swirls, pointlessly beautiful. From the gaunt tree trunks immense black shadows stretched north. But the first leaves were budding on the bare branches, tiny green plates hanging almost vertically to catch the sun’s light. The leaves were already at work: The days of spring and summer were so short that these hardy vegetable servants had to gather every droplet of light they could.
It was just a glimpse, a dawn that would last no more than a few minutes. But it was the first time for several months that the disk of the sun had shown.
The forest was quiet. The great herbivorous migrants were still hundreds of kilometers to the south; it was weeks yet before they would come back, seeking their summer feeding grounds, and even the birds had yet to arrive. But Noth was already awake, already out, working.
Fresh from his burrow he was gaunt, his tail flaccid and drained of fat. His fur, ragged and stained yellow by urine, hung around him in a cloud, lit up by the sun, making him look twice his true size. There was still little fodder to be had in the trees, so he had to scurry over the littered, frosty ground. After the winter’s chill, it was as if nobody had ever lived here, and everywhere he moved he marked rocks and tree trunks with his musk.
All around him, in grim competition, the males of the troop were foraging. They were all adults: Even those born less than a year ago were approaching their full size, while relative veterans like the Emperor himself, approaching his third birthday, moved more stiffly than last year. After their winter of starving sleep, all of them looked sick, and the lingering cold bit hard through their loose fur and into their fat-deprived bodies.
There were risks in moving around so early. In the burrows, the females still slept, consuming the last of their winter stores. The predators were already active — and as food was still scarce, early-bird primates made a tempting target. If one of the males did find an unexpected cache of food he was quickly surrounded by snapping, jealous rivals, making the empty forest echo to their hoots and yips.
But Noth had no choice but to risk the cold. The days of breeding were approaching, a time of ferocious competition for the males. Noth’s body knew that the sooner it laid down a store of strength and energy for the battles to come, the better chance he would have of finding a mate. He had to accept the risks.
Navigating with a blurred recollection of the landscape map he had built up last season, Noth made his way to the largest of the nearby lakes.
The lake was still mostly frozen, covered by a lid of gray ice littered with loose, hard-grained snow. A pair of ducklike birds, early immigrants, padded over the ice, pecking hopefully at its surface. Beneath the gray Noth could see the chill blue of older ice, a lens of deep-frozen material that had failed to melt through last summer, and would likewise fail to melt this year.
Close to the water’s edge he passed a gray-white bundle. It was a mesonychid. Like the Arctic fox of later times, it endured the winter above ground. But in a sudden cold spell during the winter this meso had become lost in a blizzard, and, succumbing to exposure, had died, here at the shore of the lake. Its body had quickly frozen, and for now appeared perfectly preserved. But as it thawed the bacteria and insects had begun feasting: Noth could detect the sweet stench of decay. Saliva spurted into his mouth. The half-frozen meat would be good, and maggots were a salty treat. But his thirst outweighed his hunger.
Near the lake’s shallow, muddy shore the ice was thin and cracked, and Noth could smell dank open water. The water was greenish, already full of life, and littered by grayish chunks of old ice cover. Noth dipped his muzzle into the water and drank, straining out the worst of the mucous slime between his teeth.
He could see that the open water bulged with clusters of small clear gray spheres: the spawn of the lake’s amphibian inhabitants, laid down as early as possible. And closer by, in the shallows at his feet, Noth made out tiny wriggling black forms: the first tadpoles. He ran his hands through the water, letting the slime cling to his palms, and crammed the slippery harvest into his mouth.
With a flexing strain his bowels moved, and watery shit pooled beneath him.
But now the surface of the water broke, the ice cracking with sharp reports. Something huge was coming out of the lake. Noth scurried back to the cover of the nearest trees, eyes wide.
Like Noth, the crocodile had woken early, disturbed from its slumber by the brightness of the day. As it rose from the lake, bits of ice tumbled from its back. With a single graceful motion it clamped its jaws on the frozen meso: frost crackled, bones crunched. Then the croc slid backward into the water, dragging the carcass effortlessly, making barely a sound.
The crocodile was hungry.
Before the comet the largest animals in each of the world’s ecologies had been reptilian: the plesiosaurs and ichthyosaurs in the oceans, the dinosaurs on land, and the crocodilians in fresh water. The disaster had wiped away these great families, and in their empty realms they would soon be replaced by functionally equivalent mammals — all save the crocodiles.
The freshwater environment had always been a difficult place to live. While the supply of plant material on land and in the sea was pretty reliable in space and time, freshwater environments were very variable. Erosion, abrasion, silting, flood, drought, and extremes of water quality were all hazards.
But the crocodiles — and other enduring freshwater species like turtles — were resilient. Some learned to walk overland in search of water. Others could take to the sea. Or they would just bury themselves eight or ten meters deep in the mud, and wait for the next cloudburst. And as for food, even during the worst of the killings on land and in the sea, they would subsist off the nutrients that continued to leach off the corpse-littered land, a 'brown' food chain that persisted long after the green, growing things and the creatures that browsed them had died.
In this way the crocodiles had survived across a hundred and fifty million years, through extraterrestrial impacts, glaciation pulses, sea level changes, tectonic upheavals, and competition from successive dynasties of animals.
After all this time they were still capable of evolutionary novelty. Briefly, after the comet impact, the top predators around the water courses had been crocodile cousins with long legs and hooflike claws. They had been a nightmare, running predatory crocodiles capable of chasing down animals as large as small horses. Crocodiles had even adapted to survive here at the pole, where the sun didn’t shine for months on end; they would simply wait out the winter months in deep hibernation.
Unlike the dinosaurs, unlike the plesiosaurs, the crocodiles would not be forced out of their freshwater niches by upstart mammals: not now, not ever.
Noth had lost the meso carcass, but some scraps of flesh and crushed maggots were smeared over the ground where it had lain. Hungrily he licked at the frozen ground.
At last the days of breeding arrived.
The females of the troop gathered in the branches of one tall conifer. They were feeding on ripe young fruit, cramming their bodies with the resources they would need to survive the drain of motherhood to come. The females were loosely marshaled by the more senior among them, including Big and Biggest. Right was among them. She had survived her first winter. She was filling out quickly, and when her scrappy winter fur had blown away she had emerged as a small but elegantly built adult, ready to mate.
The Emperor himself was among his female subjects. He moved from one to the other, heroically humping. Already he had been accepted by Biggest twice, and had deflowered an unprotesting Right. Now he was taking Big. She was bent over, clinging to a low branch, her head tucked between her knees, her tail uplifted. The Emperor was behind her, arms wrapped around her waist, hips thrusting with a rapidity born of exhaustion and urgency.
This was the day toward which the Emperor had worked all year, and now was the time for him to spend all of his authority and energy by covering as many of the females as possible.
But the Emperor was already tiring. And this female troop was only one of several in the wider territory he commanded.
In this ferociously seasonal place, baby rearing had to be squeezed into a drastically short period, so that offspring were produced when food was abundant and their new mothers could eat enough to produce plenty of milk. Any female who mated outside the breeding season was unlikely to see her offspring survive to adulthood. And any male who missed the chance to mate with a fertile female would have to endure a whole year of hardship, danger, and privation before getting another chance.
For the notharctus, the breeding season was just
Today, the start of the females’ simultaneous estrus, the air was full of an invisible pheromone cloud, and there were males everywhere, helplessly drawn, erections poking out of their fur. Every male had prepared since the return of the sun, feeding to build up his strength, practicing spectacular tree swings and engaging in mock battles: They had been like athletes preparing for a contest. It was impossible for the Emperor to keep them all away, and there was intense competition. Today the hierarchy of males was stressed to the point of collapse.
The stress on the females would come later, during pregnancy and nursing, when the fast-growing fetus or newborn pup demanded the mother find a stream of high-energy food — and she must eat well at a time when almost every other adult female was nursing too. It was the heavy cost of reproduction that had led to the general dominance of females over males, and it was the reason why the females always got the best of the food.
It was the same all over the forest. Every notharctus troop was hitting its brief mating season simultaneously, the timing dictated by the invisible chemical scents that permeated the air for kilometers around. For today and tomorrow, the forest was filled with primate lust: a tremendous clamor of battling males, pheromone-laden females, and frantically thrusting hips.
Noth, pursuing another young male he thought of as Rival, hurled himself through a loose stand of conifers. He swung one-armed on spindly branches. On each dip the earth tipped up like a vast bowl, dead leaves and new green ferns and the dull forms of snuffling ground feeders fleeing under him.
