The two great cracks that had doomed ancient Pangaea — the east-west Tethys Sea, and the north-south Atlantic Ocean — closed and opened respectively. Africa was undergoing a slow collision with Europe. Meanwhile India was drifting north to crash into Asia, and the Himalayan Mountains were being thrust into the air. But immediately after the young mountains were born, the rain and the glaciers had begun their work, gouging and eroding, washing the mountains back to the sea: On this turbulent planet, rock flowed like water, and mountain ranges rose and fell like dreams. But as the continents closed, the Edenic flow of the Tethys was doomed, though fragments of the shrinking ocean would survive as the Black, Caspian, and Aral Seas, and in the west as the Mediterranean.
As the Tethys died there was a great drying, right across the belly of the world. Once there had been mangrove forests in the Sahara. Now a great belt of semiarid scrub spread around the old track of the Tethys, across North America, southern Eurasia, and northern Africa.
Meanwhile, the huge land bridge that had closed off the northern Atlantic, spanning from North America to northern Europe via Greenland and Britain, was being severed, and the Atlantic reached up to the Arctic Ocean. As the ancient east-west ocean passage was being closed, so a new channel from south to north was opening.
Thus ocean currents were reshaped.
The oceans were great reservoirs of energy, restless, unstable, mobile. And all the oceans were laced with currents, great invisible Niles that dwarfed any river on land. The currents were driven by the sun’s heat and the Earth’s rotation; the top few meters of the oceans stored as much energy as the whole of the atmosphere.
Now the huge equatorial currents that had once rolled around the Tethys belt were disrupted. But already the great flows that would dominate the widening Atlantic were in place: A precursor of the Gulf Stream flowed, a mighty river sixty kilometers across, running south to north with the force of three hundred Amazons.
But this change in circulation patterns would reconstruct the planet’s climate. For while equatorial currents promoted warming, north-south interpolar currents provoked a vast refrigeration.
To make matters worse, Antarctica had settled over the Earth’s southern pole. Now its great ice cap had begun to gather, for the first time in two hundred million years. Vast, cold circumpolar ocean currents gathered in the southern seas, feeding the great northward currents of the Atlantic.
It was a crucial change: the start of a mighty planetary cooling, a downturn of the graph, that would persist to human times and well beyond.
All over the planet, the old climate belts shrank toward the equator. Tropical vegetation types survived only in the equatorial latitudes. In the north, a new kind of ecology appeared, a temperate woodland of mixed conifers and deciduous trees. Vast swaths of it covered the northern lands, stretching across North America, Europe, and Asia from the tropic to the Arctic.
This climatic collapse triggered a new dying — what paleobiologists would later call the Great Cut. It was a drawn-out, multiple event. In the ocean the plankton population crashed repeatedly. Many species of gastropods and bivalves disappeared.
And on the land, after thirty million years of comfortable success, the mammals suffered their first mass extinction ever. Mammalian history was cut in half. The exotic assemblages of Noth’s times finally succumbed. But new, larger herbivores began to evolve, with heavy-duty ridged teeth able to cope with the new, coarser vegetation typical of seasonal woodland. By Roamer’s time the first proboscideans, properly equipped with trunks and tusks, were already walking the African plains. The trunk, unparalleled for muscular flexibility save for an octopus’s arm, was used for stuffing the animal’s mouth with the vast quantity of food it needed. These deinotheres had stubby trunks, and odd, downward-curving tusks that they used for stripping the bark from trees. But, unlike their moeritherium ancestors, they looked like elephants, and some already grew as tall as the African elephants of later times.
And this was a time of success for the horses. The descendants of the timid creatures of Noth’s forest world had diversified into many woodland browser types — some of them as large as gazelles, but with tougher teeth than their ancestors had had to take leaves rather than soft fruit — along with longer-legged plains animals slowly adapting to a diet of grass. Most of the horses now had three toes on both their front and back feet, but some plains-living runners were starting to lose their side toes, and were putting all their weight on their central toes. But as the forests shrank this diversity was already falling; soon many of the forest species would disappear. The rodents, too, were diversifying, with the appearance of the first gophers, beavers, dormice and hamsters, a great diversity of squirrels — and the first rats.
But the new conditions were not kind to the primates. Their natural habitat, the tropical forests, had shriveled back to the southern tropics. Many of the primate families had gone extinct. Fruit eaters like Roamer lingered only in the tropical woodlands of Africa and southern Asia, clinging to the year-long food supply these forests still provided. By the time Roamer was born there were no primates left north of the tropics, and — since the rise of the rodents — none in the Americas at alclass="underline" not a single species.
But that was soon to change.
The sea around Roamer was a sheet of gunmetal gray across which waves rippled, languid as mercury. Roamer was in an utterly baffling place: a sketchy, elemental two-dimensional environment, static yet full of mysterious churning motion, that could not have been more different from the forest.
She felt nervous climbing around on top of the vegetation. She expected some ferocious aerial predator to bite into her skull at any moment. And as she moved she could feel the uneasy raft shift under her, its loosely tangled components rustling with the slow breathing of the sea. It felt as if the whole thing might disintegrate at any moment.
There were just six anthros: three males, two females — including Roamer — and the infant who still clung sleepily to the fur of its mother. These were the only survivors of Whiteblood’s troop.
The anthros sat on a tangle of branches, eyeing one another. It was time to form provisional hierarchies.
For the two females the priorities were clear enough.
The other female, the mother, was a burly individual more than a decade old. This child was her fourth and — though she could not know it — now her only surviving offspring. Her most noticeable characteristic was a fur-free patch of scar tissue on one shoulder where she had once been burned in a forest fire. The infant, clinging to Patch’s chest, was tiny, small even for its age, just a scrap of fur. Patch, the mother, studied Roamer dismissively. Roamer was small, young, and a stranger, not even remote kin. And, as a nursing mother, Patch would always have priority. So she turned her broad back on Roamer and began to stroke her infant, Scrap.
Roamer knew what she had to do. She scuttled over the branches to Patch, and dug her fingers into fur that was still moist and began to comb out tangles and bits of debris. When she probed at Patch’s skin, she found knots of muscle, and places which made Patch wince to be touched.
As Roamer’s strong fingers worked, Patch relaxed slowly. Patch, like all of them, had been battered by her precipitate removal from the forest, and was stressed by her sudden dumping into this extraordinary emptiness and the loss of her family. It was as if she could, for a moment, under the magic of the other’s touch, forget where she was. Even the infant, Scrap, seemed soothed by the contact between the two females.
Roamer herself was calmed by the simple, repetitive actions of the grooming, and by the subtle social bond she was building up with Patch.