When he had reached a patch dense with fruit, he pulled off another branch and set it down over the thorns. Sitting on his impromptu saddle, he began to feed.

From here he could see that this forest clump had grown up around an oxbow lake, cast off by a river that wound its way back into the deeper country to the south, across this rich, vegetated Sahara. In the future this great Nile-like artery would be dislodged by tectonic shifting from its present course, and would curl around to the south, no longer crossing the Sahara. Eventually it would outflow into the Bight of Benin in western Africa, and humans would know it as the Niger: Even rivers were molded by time, as the land rose and fell, as the mountains grew and shrank away like dreams.

But for now this river was a great green corridor into the interior of the country. The troop could work that way, following the forest, penetrating deeper, moving away from the coast.

A piercing hoot echoed through the forest. It was a cry with only one meaning: Danger is here. Capo spat out a mouthful of fruit and scrambled down to the ground.

Before he got to the lake he knew what the problem was. He could smell them. And as he looked more carefully he could see the signs of their passing: bits of fruit skin, dumped even under this kapok, what looked like nests high in the taller trees.

Others.

They came swarming out of the trees and the undergrowth. There were many of them, bewilderingly many — fifty, sixty — more than Capo’s troop had ever numbered. Their males came toward the water’s edge. They were all displaying ferociously, fur bristling, drumming on roots and branches and hurling themselves through the low branches of the trees.

After all they had endured to get here, this patch of forest was not empty. Capo’s heart sank, heavy with a sense of failure.

But Capo’s troop was responding. Weak as they were, fur too damp to bristle effectively, nevertheless the males and even a couple of the older females were displaying as best they could. Capo threw himself forward to the front row of his troop and immediately began his own display, summoning up all his long experience to create as spectacular and intimidating a show as possible.

The two troops lined up; two walls of shrieking, posturing apes faced each other. They were the same species, and they looked indistinguishable, one from the other. But they could smell the differences between them: on the one hand the subtle, familiar savor of kin, and on the other the sharper stink of strangers. There was true xenophobic hatred in these displays, an authenticity in the threat they conveyed. Here was the other side of these clever animals’ social bonds: If you were locked into a group, then everybody else became your enemy, just because they weren’t you.

But Capo was scared. He quickly realized that these others were showing no signs of backing down. Indeed, their displays were becoming more ferocious, and those big lead males were steadily advancing on his troop.

Capo knew how it would go. It would not be an all-out war. The strongest would go first, the males and senior females; the infants would probably provide some sweet flesh for the bellies of these strangers. One by one. It would be a slow, bloody killing, but it would continue until it was complete. Such systematic slaughter was a horror new to the world, a horror only these apes, of all the Earth’s animals, were smart enough to conceive of and see through.

They couldn’t stay here, Capo knew. Maybe they could go on, resume the trek across the plain; maybe Capo could yet lead his troop somewhere empty, somewhere safe.

But in his deepest gut he intuitively knew the truth. In this world of shrinking forests, the surviving animals had already crammed themselves into all the remaining islands of the old vegetation. And that was why the others would fight so hard to exclude them. There were already too many of them for this dwindling patch — and they had nowhere else to go either.

There was nowhere safe to go, but no choice but to leave.

With much foot scuffing and branch waving, he began the subtle dance that indicated he wanted to lead his troop away from this place — back to the edge of the forest, back to the savannah. One or two of the females responded. Intimidated by these ferocious others, realizing how hopeless their situation was, Leaf and the others gathered up their infants and prepared to follow. Even Frond, one of the defiant young males, turned in confusion.

But Finger would not accept it.

He had been slamming a hammer-stone against an exposed root, adding its powerful noise to his display. Now, with a sudden, terrifying surge, he turned away from the others and launched a ferocious assault on Capo. He slammed into Capo’s back, knocking him flat, and he pounded his leader’s head with his fists. Then he rolled away and threw himself with equal vigor at the largest of the others’ males. Suddenly the noise, already high, became cacophonous, and the air filled with the stink of blood and panic shit.

Capo rolled on to his back and sat up, his neck aching. The other males subtly moved away, even as they hooted and yelled.

Finger was not faring well. He had managed to pin the big male to the ground. But now more of the others were throwing themselves into the melee. Soon they had hold of Finger. They hauled him away from his opponent, holding his limbs and head as if he were a hunted monkey; already blood streamed from bite-inflicted gashes in his skin. And then they threw him to the ground. But his cries soon became gurgles, drowned in blood, and Capo heard the grisly rip of flesh, the cracking of bone, the snapping of ligaments.

But Finger’s attack had had a profound effect. If anyone was going to attack these others, it should have been Capo. Capo knew he had already lost. He would be lucky to survive the day: If these others did not kill him, then his own former subordinates would.

Capo, though shamed and beaten, resumed his calling dance, trying to get his troop to come away. There was nothing else he could do.

They didn’t all respond, even now. Some of them, spitting fear and defiance, dispersed into the forest to seek their own destinies. He would never see them again.

The young female Howl glanced at her troop with wide, fearful eyes — and then made directly for the others. She would suffer a beating at the hands of the females, but maybe she would be attractive enough to the other males to be allowed to live, especially if she managed to become pregnant quickly through the hard matings she would have to endure.

Those who remained with Capo at last began moving, back toward the fringe of the forest — but only when Frond echoed Capo’s dance.

Capo understood, of course. They were following Frond, not him.

They came back to the fringe of the forest. They were not pursued, not for now. They picked at leaves and scraps of fruit, dismayed, uncertain.

Capo was depressed to be back where he had started. He could even see the corpse of that infant gomphothere, still lying on the ground. He clambered into a tree away from the others, and built an impromptu nest.

Now that Finger was dead, he wasn’t sure who would emerge as his main challenger. Frond, perhaps? It was possible Capo could continue to maintain a powerful position by forming an alliance with one male against the other. He might no longer be the boss of bosses, but like a kingmaker his backing would be crucial, and he would continue to enjoy many of the privileges that came with power, notably mating privileges. Maybe he could even work his way back to the top that way. His subtle mind thought further, considering shifting alliances, treacheries…

His thoughts dissolved. He felt overwhelmed by the journey he had made, the crashing disappointment that had waited at the end of it. Nothing seemed to matter anymore, not even the intricate political games that had won him so much in the past.