It was a ruthless attrition, a relentless pressure. But the hominids responded. They learned to understand the predators’ behavior, and how to seek effective refuge. They learned to cooperate better with one another, for there was safety in numbers, and they used tools to drive off their assailants. Even the development of language was driven, in part, by these pressures, as the specialized alarm cries that dated back to the forests of the notharctus slowly morphed into more flexible words.

The savannah shaped the hominids. But they were not hunters; they were the hunted.

The pithecines had their limitations. They needed the shelter of the forest as their base, for they were not built to withstand long periods out in the open. And they were tied to rivers, lakes, and marshes, for their bodies had little fatty tissue and so were not resilient to long periods without water.

But as time went on, and Africa’s climate and habitat range fluctuated, the forest-fringe environment the pithecines favored spread: In a landscape of forest clumps, there was plenty of edge. The pithecine form had proved effective and enduring, and there had been a great churning of speciation events, a radiation of ape people.

The robust gorilla folk had abandoned the adventure of the forest fringe and had taken to the deeper green. Here they had begun to exploit a source of food for which there was little competition: leaves, bark, and unripe fruit unfit for any other hominid type to digest, and nuts and seeds too hard for other animals to crack. To adapt to this lifestyle they had, like potbellies and gigantopithecines, developed huge energy-expensive guts to process their low-quality food and heavily engineered skulls capable of driving those huge jaws with their slablike teeth.

Their social lives had changed too. In the dense forest, where there was always a supply of leaves and bark, stable groups of females came together to live off a single patch of forest. Males became solitary, each trying to maintain his hold over the females in his territory. So the males became larger than the females, and there was a premium on brute physical strength, so that each male could fight off those who would usurp him.

The gorilla-man’s kind were among the least intelligent of the hominids of his day. That big gut was very energy expensive; to balance its budget his body, in the course of its adaptation, had had to make sacrifices elsewhere. Smarts weren’t essential among the harems in the dim, stable gloom of the deep forest, and so the gorilla folk’s big primate brains, very costly in blood and energy, had dissolved.

But because the gorilla-man could be sure of sexual access to his females, his testicles were small. By comparison the skinny pithecine chimp-men had to mate as often as possible with as many females as they could, and needed the large, pendulous balls they displayed so readily, to produce oceans of sperm.

Within these basic pithecine types, the gracile chimp folk and the robust gorilla types, there were many variants. Some enhanced their bipedalism. Some all but abandoned it. Some skinnies were smarter than others; some gorilla folk were dumber than the rest. There were skinnies who used tools even less advanced than Capo’s, and gorilla types who used tools more sophisticated than the gracile pithecines’ stone flakes. There were large and small, skulkers and runners, pygmies and giants, slim omnivores and pillar-toothed herbivores. There were creatures with protruding faces like a chimp’s and others with delicate, flat features almost like a human’s. And there was much crossbreeding among the types, a proliferation of subspecies and hybrids, ornamenting the carnival of hominid possibilities.

Baffled paleontologists of the future, trying to piece this diversity together from fragmentary fossils and stone tools, would devise elaborate family trees and nomenclatures, calling their imagined species Kenyanthropus platypus; or Orrorin tugenenis; or Australopithecus garhi, africanus, afarensis, bahrelghazali, anamensis; or Ardipithecus ramidus; or Paranthropus robustus, boisei, aethiopicus; or Homo habilis. But few of the names fit the reality. And besides, the boundaries between these categories of creature were very blurred. Out in the real world, of course, such labels did not matter; there were only individuals, struggling to survive and raise their offspring, as they always had.

Most of the diverse assemblage here would be lost in time, their poor bones swallowed up forever by the forest’s voracious green. No human would ever know how it was to live in a world like this, crowded with so many different types of people. It was a bubbling evolutionary ferment, as many variants were spun off a fundamentally successful new body plan.

But none of this myriad of species had a future, for all these ape folk had clung to the forest. Their fingers and toes remained long and curved to help grab hold of tree trunks, and their legs were a peculiar compromise between the needs of knuckle-walking tree climber and those of biped. At night they would even make treetop nests like their forest-dwelling ancestors before them. And their brains never developed much beyond the size of Capo’s, and those of their cousins, the ancestral chimps, because their low-quality diet could sustain nothing bigger.

For four million years the pithecines had been a wide, diverse, very successful flourishing of the hominid family. Once, in fact, the only hominids in the world had been ape-men. But their time of significant change was already over. They had been seduced by the shelter and protection of the forest, and this had robbed them of much possibility. The future lay with another group of hominids — descendants of pithecine stock themselves — but who, unlike any pithecine, had made the decisive break away from the forest.

The future lay with Far.

Reluctantly she opened her eyes. She saw a patch of dirty ground, tilted up under her face. When she raised her head she could see brightness filtering through the dense tree trunks.

She pushed at the ground, and got her body off the floor. Leaves and dirt stuck to her breasts and injured shoulder. She used a tree trunk to pull herself upright, and stood still until the pounding of her heart subsided. Then she began to stagger as best she could through the forest toward the light.

She stumbled out into the day. She raised her hand, shielding her eyes against a low, reddening sun. The land was scorched, the grass blackened, the ground cracked and dried. But beyond a low rise she saw the glint of water: a stream that rolled from eroded hills a little further away.

She didn’t know this place. She had come right through the patch of forest, from east to west.

She stepped forward gingerly. The scorched ground was still hot — here and there tree stumps and bushes still smoked — and the crisped grass blades hurt her feet. Soon her lower legs, already filthy from her time in the forest, were coated with a deep black soot.

But she made it to the water. The stream was clear and fast moving. It ran over a bed of rounded volcanic cobbles, and bits of blackened vegetation skimmed over its surface. She plunged in her face and drank deeply. The dirt and dried blood washed off her skin, and the lingering stink of smoke in her nose and throat began to dissipate.

And then she heard a call. A voice. A word. But it wasn’t a word she knew.

She scrambled out of the water and threw herself flat behind an eroded boulder. In her world, strangers were bad news. Like their pithecine cousins her nomadic people were fiercely xenophobic.

A man knelt on the ground, his hands nimbly exploring the scorched soil for any pickings the fire had left behind. He was young, his skin smooth, his hair thick.