Before long the pithecines had overtaken her on both sides, and began to move closer.

She stumbled suddenly into a twilight-dark clearing — where a new monster reared up before her, bellowing. She squealed and fell flat in the dirt.

For a heartbeat the monster stood over Far. Beyond it squat forms sat; broad faces turned toward her, incurious, huge jaws chewing.

The monster was another hominid: another pithecine, in fact, a robust form. This big male, with an immense swollen belly, was taller and much bulkier than the gracile types who had captured her. His posture, even when he stood erect, was much more apelike; he had a sloping back, long arms, and bent legs. His head was extravagantly sculpted, with high cheeks, an immense, rocklike jaw filled with worn, stubby teeth, and a great bony crest that ran down the length of his skull.

Exhausted, in pain, her shoulder bleeding heavily, Far curled up on the ground, expecting those immense fists to come slamming down on her. But the blows never came.

The blocky creatures on the ground behind the big male huddled a little closer together. They were all females, with heavy breasts over those giant bellies, and as they stared at Fur, they pulled their tubby infants toward them. But still they sat and ate, Far saw. One female picked up a hard nut — so hard Far would have had to use a rock to crack its shell — placed it between her teeth and, pushing up on her jaw with her hand, cracked it easily. Then she began to crunch it down, shell and all.

But now the skinny pithecines came hurtling into the clearing. When they saw Big Belly they clattered to a halt, stumbling over one another like clowns. Instantly they began to display, stalking to and fro with their fur erect; they slapped the ground and hurled twigs and bits of dried shit at their new opponent.

Big Belly growled back. The truth was this gorilla-man was a vegetarian, forced by the low quality of his diet to spend most of his day sitting still while his vast gut strove to process his food. But this immense brute with his stumps of teeth, powerfully muscled frame, and cowering harem seemed a much more intimidating proposition than the skinny pithecines. He dropped to a knuckle-walk posture with a slam that seemed to make the ground shake, his huge gut wobbling. He stalked back and forth before his little domain, his own fur bristling, roaring back at the impertinent graciles.

The pithecines backed away, hooting their frustration.

Far scrambled out of the way and blundered on, still deeper into the seemingly unending forest. This time, she wasn’t pursued.

She couldn’t see the sun, not directly; there was only a scattering of green-tinged dappled light to mark her way. She had no sense of how long she plunged on through the forest, how far she had come. The deep cut in her shoulder had crusted over, but still she lost blood. Her head ached from the slamming it had taken from the pithecine’s rock, and her chest and back were just masses of bruises. And shock and bewilderment at losing her mother, and the small band of people who had made up her world, began to overwhelm her.

Exhaustion crept up.

At last she tripped over a root. She fell at the foot of a tree fern into soft, frond-littered loam.

She tried to push herself up, but her arms seemed to have no strength. She got to her hands and knees, but the color leached out of the world, its deep swallowing green turning gray. Then the ground seemed to tilt, the loamy ground swiveling up to slap into her face, hard.

The earth was cool under her cheek. She closed her eyes. The aches of her bruises and cuts seemed to fade, rattling into the distance like the storm’s thunder. A clamor filled her head, monotonous and loud, but somehow comforting. She let herself sink into the noise.

After Capo had come the great divergence from the chimps. The new kinds of apes that followed were hominids — that is, closer to humans than chimps or gorillas.

In the grand drama of the evolution of the hominids, learning to walk upright had been the easy part. Millions of years of apelike tree-climbing had seen to that. Now, as Capo’s descendants adapted to their new life on the interface between forest and savannah, to become more bipedal actually meant less body reorganization than needed to revert to all fours.

Their feet, no longer required to grip branches at odd angles, became simplified into compact pads that lost much of their flexibility, and their big toes no longer worked as thumbs — but their new arched feet served as shock absorbers that enabled them to walk long distances without injury. Knee joints and thigh bones were redesigned to absorb the new upright load. The uprights’ spines became longer and curved to push their centers of gravity forward so it lay over their feet, and on the center line of their vertical bodies. New, specialized hip joints arose, a design that enabled them to lift one leg off the ground without losing their balance, as chimps would, so that they could walk without swaying. Their hands no longer had to combine manipulation with support and so became more flexible: their knuckles slimmed; their thumbs were freed up for more complex and delicate grasping. They became less strong, weight for weight, now that they didn’t need to haul themselves through the trees all the time.

Bipedalism helped the new savannah apes by allowing them to walk or run long distances between scattered sources of food and shelter, and by enabling them to reach fruit and berries at higher levels. As time went on they became more upright and taller, succumbing to the same pressures that had shaped giraffes. Bipedalism was such a major advantage, in fact, that it had already evolved independently in other ape lineages — although all of those creatures would succumb to extinction long before true humans appeared.

The graciles, the skinny pithecines who had hunted Far, were like upright chimps. They were more upright than Capo or any ape. But their heads were like those of apes, with protruding muzzles, small brain pans, and flattened nostrils. Their posture, even when standing upright, was bent, the head thrust forward, and their arms were long, their grasping hands reaching almost to their knees. When they walked, they had to use more steps than Far would have done to cover the same ground, and they could not move so fast. But over the short distances they usually covered they were efficient and effective movers.

They had stuck to the forest fringe. But they had learned to exploit the resources of the savannah: especially the carcasses of the great herbivores laid low by predators. When the opportunity presented itself, they would rush out of the cover of their forest to a carcass, clutching their simple flake tools, and slice through tendons and ligaments. Stolen limbs could quickly be brought back to the safety of the forest for butchery and consumption, and hammer-stones could be used to crack the remnant bones for marrow.

All of this forced a selection for smartness. Hominids lacked the teeth of hyenas or the beaks of the carrion birds; if they were to scavenge effectively they needed better tools than Capo’s rudimentary kit. Meanwhile their bodies had gotten better at processing meat. Many pithecine types had teeth capable of shredding uncooked flesh, and a more efficient digestive system able to tolerate such rich fodder.

Still they were marginal scavengers, at the bottom of the hierarchy of meat eaters; they had to wait their turn until the lions and hyenas and vultures had taken what they wanted from the larger kills. And scavenging, and even their rudimentary hunting, wasn’t the only pressure on the savannah apes.

The savannah was predator hell. The leopards and bears of the forests had been bad enough. Out on the savannah there were huge flesh-shearing hyenas, and saber-tooths, and dogs the size of wolves. Small, slow, and defenseless, the hominids, walking blinking out of their forests, were an easy target for such creatures. Soon some of the predators, like the dinofelis, even learned to specialize in taking hominids.