I stepped close to the water and squatted down. I rustled at the undergrowth, moving it aside. The leaves and fronds were heavy and damp; if this was VR the detail impressed me.
At last I saw something move. I disturbed plenty of insects: centipedes, cockroaches, beetles. Snails and worms crawled through the mud by the water’s edge, and a dragonfly fluttered into the air on filmy wings. Again I was struck by what was not here: no bees or wasps, no ants, not a single termite mound.
I made out a ripple in the water, a ridged back breaking the surface. It looked like a crocodile — but the head I glimpsed, the tail, didn’t look quite right.
Then something scuttled out from between my legs. I jumped back with a start. It was a little creature no larger than my hand, running on splayed legs. With four legs and a tail, it looked something like a lizard. But the shape of its head and body were subtly off, like a sketch made from memory. It scuttled back into the undergrowth.
And as I stared after the lizard thing, I heard a bellow, a deep, mournful sound. My heart pounding, I turned around.
Animals moved across the landscape, perhaps half a kilometer from me, a dozen of them in a scattered herd. They had massive barrel-shaped bodies, but their weak-looking limbs sprawled out to either side of them, and they moved slowly, clumsily. Their heads were big shovel-shapes with broad mouths. They were the size of cows, although there were a couple of smaller individuals, infants. But on those splayed legs they had a reptilelike gait; they looked like fat, land-going crocodiles.
The cow-crocs gathered around the tree ferns and dragged at their leaves with their big plated mouths. They didn’t seem to have any teeth. My anxiety subsided. Herbivores, then; I should have no trouble with them unless I got in the way of a stampede.
But then I made out a low, lithe shape slinking through the shade of a tree. It was smaller than the cow-crocs, maybe the size of a dog, with a bulky body and stubby tail. It had sideways-askew legs, another variant on the theme of crocodile. But there was nothing sluggish or ungainly about the way this creature moved, nothing stupid about the sharp eyes I could see gleaming in that blunt head.
I stood stock-still. It was foolish to be afraid. This must be a VR, and VRs were full of safeguards; I should have nothing to fear. But this VR was of a density and richness like none I’d experienced before — and it wasn’t under my control.
“Do you know what you’re looking at?”
I was startled. The voice was small, metallic, and it came from near my feet.
A toy robot, fifteen centimeters tall, stood on a patch of bare rock. Its shell was painted gaudy colors, red and blue and yellow, but the paintwork was chipped and scuffed, heavily played with. It had eyes like glass beads that lit up when it talked, and a tiny grill from which its insect-sized voice emanated. It was pointing a ray gun at me, but I didn’t feel too concerned, as the ray gun and the arm that held it were just shaped tin shells. It didn’t even have legs, just molded shapes concealing wheels. It rolled toward me now, and a friction mechanism crackled and sparked.
“I know you,” I said. “You’re uncle George’s companion. His home help.”
“Not quite.”
“What are you doing here?… Oh. You’re Gea, aren’t you?”
“You can think of me as Gea if you like.” She spoke with that ridiculous cod-American toy-robot accent.
“And you chose to manifest yourself as uncle George’s robot?”
“I used a form you are familiar with. What did you expect?” She ran back and forth a little, sparking. “Actually this form does the job. Although it’s sometimes tricky getting around.”
“I bet it is.” I glanced up the valley toward the shambling herd of cow-crocs. “Am I in the past? What are those creatures, dinosaurs?”
“Not dinosaurs. Dinosaurs haven’t evolved, yet.”
That yet chilled me. “They behave like mammals but they walk like reptiles.”
“They are neither. They are a class from which true mammals will one day evolve. The paleontologists call them mammal-like reptiles. The big herbivores are called pareiasaurs. Those you see on the far side of the river” — a huddle of smaller, more nervous-looking creatures — “are a kind of dicynodont. The predator is a type of gorgonospian.”
I glanced at my feet. “And the little lizards?”
“They aren’t lizards. Lizards haven’t evolved yet, either. Some of them are reptiles called procolophonids. Others have no name. Only species which have left a distinguishable trace in the fossil record have names assigned by human paleontologists.”
“So how can you reconstruct them?”
“Extrapolation, from traces in modern genomes, ecological-balance calculations, other sources. I am confident in the veracity of what you see.”
“Oh, are you? Where am I, Gea?”
“You are some two hundred and fifty million years into the past. This is an era known to the geologists as the Permian. If you want more precision—”
Two hundred and fifty million years.“That’s precise enough.”
“Much that is familiar has yet to evolve. The whole hundred-million-year history of the dinosaurs, their rise and fall, follows after this time. There are no grasses yet, no flowering plants, no wasps or bees or termites or ants. There are no birds. And yet there is much that is familiar, deeper qualities.”
“Yes.” I thought it over. “All the animals have four legs, one head, one tail.”
“The tetrapodal body plan is a relic of the first lungfish to crawl out of some muddy river onto the land, a choice once made never unmade; presumably all animal life from Earth will always follow this plan. And there are deeper, persistent patterns in the nature of life: the dance of predator and prey, for instance.”
At the base of this ancient food chain were plants, insects, and invertebrates. Little lizardlike creatures, like my procolophonids, ate the plants and insects, and in turn various carnivores munched on their bones. At the very top of the food chain were the gorgonospians, like the saber-tooth critter I had seen; gorgonospians ate pretty much everything, including each other.
“This is the first complex ecosystem on land,” the robot said. “But it is based on a web of food and energy flows nearly as complex as today’s. For such an ancient scene, it is remarkably rich.” Her tiny voice sounded even more ridiculous when she used words like ecosystem.
“So why are you showing me all this?”
“Because it is about to be wiped out.” The robot rolled backward. Her glass-bead eyes flashed. And the world changed.
I staggered. It felt as if the land surface beneath my feet melted and flowed.
And suddenly it was hot, a sweltering heat much more severe than the tropical humidity I had suffered earlier. It was dry, airless, and I found myself gasping; I tugged at my shirt, ripping buttons to open the neck.
The land had changed utterly.
The basic topography remained, the river and its valley, the eroded hills further away. But the river was low, a trickle in a plain of dried and cracked mud. And the green-brown blanket of life had shrunk back everywhere. The stands of ginkgolike trees were bare trunks, lifeless. Only scattered bushes and low ferns, and smaller undergrowth plants, weedlike, seemed to be surviving. I saw none of the big cow-sized herbivores, or the doglike carnivores that had hunted them. Suddenly this was an empty stage.
But still there was life here. An animal poked its nose out of a burrow, cautiously, like a badger emerging from its set. This was a low-slung reptilian, about the size of a cat, with the characteristic croclike splayed legs and wedge-shaped head of the time. Snuffling, the animal managed to expose a stand of mushrooms, pale and sickly, and it dug its face into their white flesh. There wasn’t much flesh beneath its warty skin, and I could see the bones of its spine and rib cage.