She surfaced reluctantly into the daylight.

She had had another bad dream. Her head felt muzzy, her limbs stiff. Through the crude roof of her treetop nest she saw the rustling green of the higher canopy, and slivers of bright blue tropical sky. Like the pallet under her body, the roof was just a pulled-together mass of twigs and leaves and slim branches, hastily constructed in the last hour before darkness, soon to be abandoned.

She lay on her back, her right arm pillowed under her head, her legs tucked up against her belly. Her naked body was covered with fine golden hair. At fifteen years of age she was in the prime of her life. Stretch marks on her belly and her small dugs showed that she had already given birth. Her eyes, crusted with sleep, were large, black, watchful: the mark of a slow readaptation to nocturnal living. Behind them a shallow brow led to a small, neat brainpan, its modest outline obscured by a thatch of curly dark hair.

A part of her never slept soundly, no matter how well she constructed her nests. Her dreams were always troubled by the huge spaces beneath her, into which she might fall. Since the treetops were the only safe place for her people to live, this didn’t make sense, but there it was. It was going to take more time yet for people to get used to their return to the trees.

It didn’t help, of course, that her only child so far had been taken by those spaces beneath her, his grip loosened from her fur by rain, his little body tumbling into the green depths.

She had never discussed this with anyone. In fact nobody discussed anything anymore. The days of endless talking were long gone, the larynxes and cognitive capacities of a loquacious folk put aside, irrelevant to life in the trees.

She didn’t even have a name. But perhaps something in her retained a deep memory of vanished, different days. Call her Remembrance.

She heard a rustling in the layers of vegetation beneath her, a trickle of discarded fruit husks falling through the leaves, the first tentative hooting pants of the males.

She rolled on to her belly and pressed her face into her bed of twigs. She could just make out the colony itself, a dark, pendulous mass in the deeper layers of the canopy, like a wooden submarine somehow lodged high in the green. All around the colony slim figures were moving, working, bickering. The business of the day was starting. And it didn’t pay to be a late arrival.

Remembrance stood upright and broke open her nest, like a bird bursting from its egg. With her small head raised to her full meter-tall height above the branch, she peered around at her world.

Everywhere the forest lapped in great green layers of life. The highest canopy was a roof far above her own elevation. To north, west, and east, beyond the trees, Remembrance could make out a blue, sparkling glimmer. The light off the ocean had always intrigued her. And though she could not make out the southern shore, she had a correct intuition that the ocean continued even there, making a great belt around the land: she knew that she lived on a vast island. But the ocean was another irrelevance, too far away for her to be troubled with.

This particularly dense pocket of forest had sprouted from a gorge cut deep into the bedrock. Sheltered by walls of hard rock, fed by streams that ran along the base of the gorge, this was a crowded, vibrant place, full of life — though here and there were bare patches cleared by borametz trees and their servants, a new kind of life.

But the gorge itself wasn’t natural. Long ago blasted out of ancient bedrock, it was the result of human road building. Erosion had taken its toll: When the drainage ditches and culverts were no longer maintained, the cutting slopes had collapsed. But nevertheless a patient geologist could have detected a fine dark layer in the sandstone that had slowly gathered at the bottom of the gorge. The dark layer was metamorphosing bitumen, a stratum still sprinkled here and there with fragments of the vehicles that had once come this way.

Even now the passing of humans left its mark.

A shadow flickered over the leaves that rustled around her, fast-moving, silent, cast by the low sun. Hastily she ducked down, seeking the safety of the green’s cover. It had been a bird, of course. The predators of the upper canopy had already started their day, and it did not do to be too visible.

With a last glance at the remains of her nest — littered by bits of shit and discarded hair, stained by her urine, soon to be forgotten — she began to clamber down.

As the tropical day brightened, the people had already spread out through the trees, lithe and graceful, beginning the day’s relentless search for fruit, bark-burrowing insects, and leaf-cupped water.

Remembrance, still listless, hung back, watching.

There were males and females alike, some of the women laden with clinging infants. The males also did a great deal of displaying, hooting, aggressive leaping to and fro. Here was something that had not changed down the long years: the structure of primate society was still the same, a flashy male-hierarchy superstructure imposed on top of a network of patient female clans.

In these middle layers of the canopy the taller trees thrust upward past the crowns of their smaller brethren. In this intermediate place, neither low nor high, the people were relatively safe from threats from above and below. And it was here, surrounded by the tall, slim stripes of the great trees’ trunks, that they had built their colony.

It was a ball some ten meters across. Its thick wall was made of twigs and dead leaves, crudely crammed together. The leaves had been softened by chewing before being pressed into gaps in the structure. The whole thing was neatly lodged in the crooks of the robust branches of the tree, in which it had been constructed over generations. And it was lived in: A thin stream of shit and piss slid down the tree’s great trunk, sewage trickling out of the openings that pocked the colony’s base.

This ball of spittle and twigs was the most advanced construction any posthumans were now capable of. But it was the result of instinct, not mind, as empty of conscious planning as a bower bird’s nest or a termite mound.

Remembrance could see small faces peering out timidly through gaps in the colony’s crude wall. She remembered her time with her own child inside those dank, ill-smelling walls. The colony’s basic purpose was to shelter the most vulnerable from the forest’s predators: at night the prepubescent young, the old and sickly would cram within its walls. But only the smallest infants and their mothers were allowed to stay in its shelter during the day while the rest risked the open spaces to forage.

And, as stray canopy-filtered rays of sunlight caught the colony, the walls sparkled. Embedded in the packed-together twigs and leaves were bright stones gathered from the forest floor. There were even bits of glass. Across millions of years glass was unstable, becoming opaque as tiny crystals formed within it — but nevertheless these fragments had retained their shapes, bits of windshields or taillights or bottles, now retrieved and gathered to adorn the walls of this shapeless building.

It looked like decoration, but it was not. The glass and bright stones were meant for defense. Even now predators on these postpeople could be deterred by the remnants of buildings, by glittering stones and shining glass, haunted by deep-buried instincts developed in the time of the most dangerous killers who had ever walked the Earth. So Remembrance’s folk aped the structures of their ancestors, not even capable of imagining what they were imitating.

Once, of course, the trees had been the domain of primates, where they had been able to roam with little fear of predation. Monkeys and chimpanzees had not needed fortresses of leaf and twig. Times had changed.