"Not such large quantities," said Po.
"No?" said Sel.
"It's like steel-making back on Earth. Even though the purpose was smelting iron to make steel, and they mined coal only to fire their smelters and foundries, they didn't carry the coal to the iron, they carried the iron to the coal--because it took far more coal than iron to make steel."
"You must have gotten very good marks in geography."
"My parents and I were born here, but I'm human. Earth is still my home."
"So you're saying that whatever they took out of these tunnels, it wasn't in such large quantities that it was worth building a city here."
"They put their cities where the food was, or the fuel. Whatever they got here, they took little enough of it that it was more economical to carry it to their cities, instead of building a city here to process it."
"You may grow up to amount to something, Po."
"I'm already grown up, sir," said Po. "And I already amount to something. Just not enough to get any girl to marry me."
"And knowing the principles of Earth's economic history will attract a mate?"
"As surely as that bunny-toad's antlers, sir."
"Horns," said Sel.
"So we're going in?"
Sel mounted one of the little oil lamps into the flared top of his walking stick.
"And here I thought that opening at the top of your stick was decoration," said Po.
"It was decorative," said Sel. "It was also the way the tree grew out of the ground."
Sel rolled up his blankets and put half the remaining food into his pack, along with their testing equipment.
"Are you planning to spend the night down there?"
"What if we find something wonderful, and then have to climb back out of the tunnels before we get a chance to explore?"
Dutifully, Po packed up. "I don't think we'll need the tent in there."
"I doubt there'll be much rain," Sel agreed.
"Then again, caves can be drippy."
"We'll pick a dry spot."
"What can live in there? It's not a natural cave. I don't think we'll find fish."
"There are birds and other creatures that like the dark. Or that find it safer and warmer indoors. And maybe a species of some chordate or insect or worm or fungus we haven't seen yet."
At the entrance, Po sighed. "If only the tunnels were higher."
"It's not my fault you grew so tall." Sel lit the lamp, fueled by the oils of a fruit Sel had found in the wild. He called it "olive" after the oily fruit on Earth, though in no other attribute were they alike. Certainly not flavor or nutrition.
The colonists grew it in orchards now, and pressed and filtered it in three harvests a year. Except for the oil the fruit was good for nothing except fertilizer. It was good to have clean-burning fuel for light, instead of wiring every building with electricity, especially in the outlying settlements. It was one of Sel's favorite discoveries--particularly since there was no sign the formics had ever discovered its usefulness. Of course, the formics were at home in the dark. Sel could imagine them scuttling along in these tunnels, content with smell and hearing to guide them.
Humans had evolved from creatures that took refuge in trees, not caves, thought Sel, and though humans had used caves many times in the past, they were always suspicious of them. Deep dark places were at once attractive and terrifying. There was no chance the formics would have allowed any large predators to remain at large on this planet, particularly in caves, since the formics themselves were tunnel makers and cave dwellers.
If only the formic home world had not been obliterated in the war. What we could have learned, tracing an alien evolution that led to intelligence!
Then again, if Ender Wiggin had not blown the whole thing up, we would have lost the war. Then we wouldn't have even this world to study. Evolution here did not lead to intelligence--or if it did, the formics already wiped it out, along with any traces the original sentient natives might have left behind.
Sel bent over and squat-walked into the tunnel. But it was hard to keep going that way--his back was too old. He couldn't even lean on his stick, because it was too tall for the space, and he had to drag it along, keeping it as close to vertical as possible so the oil didn't spill out of the canister at the top.
After a while he simply could not continue in that position. Sel sat down and so did Po.
"This is not working," said Sel.
"My back hurts," said Po.
"A little dynamite would be useful."
"As if you'd ever use it," said Po.
"I didn't say it would be morally defensible," said Sel. "Just convenient." Sel handed his stick, with the lamp atop it, to Po. "You're young. You'll recover from this. I've got to try a new position."
Sel tried to crawl but instantly gave up on that--it hurt his knees too much to rest them directly on the rocky floor. He finally settled for sitting, leaning his arms forward, putting weight on them, and then scrabbling his legs and hips after him. It was slow going.
Po also tried crawling and soon gave up on it. But because he was holding the stick with the light, he was forced to return to walking bent over, knees in a squat.
"I'm going to end up a cripple," said Po.
"At least I won't have to hear your mother and father complain about what I did to you, since I don't expect to get out of here alive."
And then, suddenly, the light went dim. For a moment Sel thought it had gone out, but no--Po had stood up and lifted the stick to a vertical position, so that the tunnel where Sel was creeping along was now in shadow.
It didn't matter. Sel could see the chamber ahead. It was a natural cavern, with stalactites and stalagmites forming columns that supported the ceiling.
But they weren't the straight-up-and-down columns that normally formed when lime-laden water dripped straight down, leaving sediment behind. These columns twisted crazily. Writhed, really.
"Not natural deposits," said Po.
"No. These were made. But the twisting doesn't seem designed, either."
"Fractal randomness?" asked Po.
"I don't think so," said Sel. "Random, yes, but genuinely so, not fractal. Not mathematical."
"Like dog turds," said Po.
Sel stood looking at the columns. They did indeed have the kind of curling pattern that a long dog turd got as it was laid down from above. Solid yet flexible. Extrusions from above, only still connected to the ceiling.
Sel looked up, then took the stick from Po and raised it.
The chamber seemed to go on forever, supported by the writhing stone pillars. Arches like an ancient temple, but half melted.
"It's composite rock," said Po.
Sel looked down at the boy and saw him with a self-lighting microscope, examining the rock of a column.
"Seems like the same mineral composition as the floor," said Po. "But grainy. As if it had been ground up and then glued back together."
"But not glued," said Sel. "Bonded? Cement?"
"I think it's been glued," said Po. "I think it's organic."
Po took the stick back and held the flame of the lamp under an elbow of one of the twistiest columns. The substance did not catch fire, but it did begin to sweat and drip.
"Stop," said Sel. "Let's not bring the thing down on us!"
Now that they could walk upright, they moved forward into the cavern. It was Po who thought of marking their path by cutting off bits of his blanket and dropping them. He looked back from time to time to make sure they were following a straight line. Sel looked back, too, and saw how impossible it would be to find the entrance they had come through, if the path were not marked.
"So tell me how this was made," said Sel. "No toolmarks on the ceiling or floor. These columns, made from ground-up stone with added glue. A kind of paste, yet strong enough to support the roof of a chamber this size. Yet no grinding equipment left behind, no buckets to carry the glue."
"Giant rock-eating worms," said Po.
/> "That's what I was thinking, too," said Sel.
Po laughed. "I was joking."
"I wasn't," said Sel.
"How could worms eat rock?"
"Very sharp teeth that regrow quickly. Grinding their way through. The fine gravel bonds with some kind of gluey mucus and they extrude these columns, then bind them to the ceiling."
"But how could such a creature evolve?" said Po. "There's no nutrition in the rock. And it would take enormous energy to do all this. Not to mention whatever their teeth were made of."
"Maybe they didn't evolve," said Sel. "Look--what's that?"
There was something shiny ahead. Reflecting the lamplight.
As they got closer, they saw reflections from spots on the columns, too. Even the ceiling.
But nothing else was as bright as the thing lying on the floor.
"A glue bucket?" asked Po.
"No," said Sel. "It's a giant bug. Beetle. Ant. Something like--look at this, Po."
They were close enough now to see that it was six-legged, though the middle pair of limbs seemed more designed for clinging than walking or grasping. The front ones were for grasping and tearing. The hind ones, for digging and running.
"What do you think? Bipedal?" asked Sel.
"Six or four, and bipedal at need." Po nudged it with his foot. No response. The thing was definitely dead. He bent over and flexed and rotated the hind limbs. Then the front ones. "Climb, crawl, walk, run, all equally well, I think."
"Not a likely evolutionary path," said Sel. "Anatomy tends to commit one way or the other."
"Like you said. Not evolved, bred."
"For what?"
"For mining," said Po. He rolled the thing over onto its belly. It was very heavy; it took several tries. But now they could see much better what it was that caught the light. The thing's back was a solid sheet of gold. As smooth as a beetle's carapace, but so thick with gold that the thing must weigh ten kilos at least.
Twenty-five, maybe thirty centimeters long, thick and stubby. And its entire exoskeleton thinly gilt, with the back heavily armored in gold.
"Do you think these things were mining for gold?" asked Po.
"Not with that mouth," said Sel. "Not with those hands."
"But the gold got inside it somehow. To be deposited in the shell."
"I think you're right," said Sel. "But this is the adult. The harvest. I think the formics carried these things out of the mine and took them off to be purified. Burn off the organics and leave the pure metal behind."
"So they ingested the gold as larvae..."
"Went into a cocoon..."
"And when they emerged, their bodies were encased in gold."
"And there they are," said Sel, holding up the light again. Only now he went closer to the columns, where they could now see that the glints of reflection were from the bodies of half-formed creatures, their backs embedded in the pillars, their foreheads and bellies shiny with a layer of thin gold.
"The columns are the cocoons," said Po.
"Organic mining," said Sel. "The formics bred these things specifically to extract gold."
"But what for? It's not like the formics used money. Gold is just a soft metal to them."
"A useful one. What's to say they didn't have bugs just like these, only bred to extract iron, platinum, aluminum, copper, whatever they wanted?"
"So they didn't need tools to mine."
"No, Po--these are the tools. And the refineries." Sel knelt down. "Let's see if we can get any kind of DNA sample from these."
"Dead all this time?"
"There's no way these are native to this planet. The formics brought them here. So they're native to the formic home world. Or bred from something native there."
"Not necessarily," said Po, "or other colonies would have found them long before now."
"It took us forty years, didn't it?"
"What if this is a hybrid?" asked Po. "So it exists only on this world?"
By now, Sel was sampling DNA and finding it far easier than he thought. "Po, there's no way this has been dead for forty years."
Then it twitched reflexively under his hand.
"Or twenty minutes," said Sel. "It still has reflexes. It isn't dead."
"Then it's dying," said Po. "It has no strength."
"Starving to death, I bet," said Sel. "Maybe it just finished its metamorphosis and was trying to get to the tunnel entrance and stopped here to die."
Po took the samples from him and stowed them in Sel's pack.
"So these gold bugs are still alive, forty years after the formics stopped bringing them food? How long is the metamorphosis?"
"Not forty years," said Sel. He stood up, then bent over again to look at the gold bug. "I think these cocooned-up bugs embedded in the columns are young. Fresh." He stood up and started striding deeper into the cavern.
There were more gold bugs now, many of them lying on the ground--but unlike the first one they found, many of these were destroyed, hollowed out. Nothing but the thick golden shells of their backs, with legs discarded as if they had been...
"Spat out," said Sel. "These were eaten."
"By what?"
"Larvae," said Sel. "Cannibalizing the adults because otherwise there's nothing to eat here. Each generation getting smaller--look how large this one is? Each one smaller because they only eat the bodies of the adults."
"And they're working their way back toward the door," said Po. "To get outside where the nutrients are."
"When the formics stopped coming..."
"Their shells are too heavy to make much progress," said Po. "So they get as far as they can, then the larvae feed on the corpse of the adult, then they crawl toward the light of the entrance as far as they can, cocoon up, and the next generation emerges, smaller than the last one."
Now they were among much larger shells. "These things are supposed to be more than a meter in length," said Sel. "The closer to the entrance, the smaller."
Po stopped, pointed at the lamp. "They're heading toward the light?"
"Maybe we'll be able to see one."
"Rock-devouring larvae that grind up solid rock and poop out bonded stone columns."
"I didn't say I wanted to see it up close."
"But you do."
"Well. Yes."
Now they were both looking around them, squinting to try to see movement somewhere in the cavern.
"What if there's something it likes much better than light?" asked Po.
"Soft-bodied food?" asked Sel. "Don't think I haven't thought of it. The formics brought them food. Now maybe we have, too."
At that moment, Po suddenly rose straight up into the air.
Sel held up the stick. Directly above him, a huge sluglike larva clung to the ceiling. Its mouth end was tightly fastened on Po's back.
"Unstrap and drop down here!" called Sel.
"All our samples!"
"We can always get more samples! I don't want to have to extract bits of you from one of these pillars!"
Po got the straps open and dropped to the floor.
The pack disappeared into the larva's maw. They could hear hard metal squeaking and scraping as the larva's teeth tried to grind up the metal instruments. They didn't wait to watch. They started toward the entrance. Once they passed the first gold bug's body, they looked for the bits of blanket to mark the path.
"Take my pack," said Sel, shrugging it off as he walked. "It's got the radio and the DNA samples in it--get out the entrance and radio for help."
"I'm not leaving you," said Po. But he was obeying.
"You're the only one who can get out the entrance faster than that thing can crawl."
"We haven't seen how fast it can go."
"Yes we have," said Sel. He walked backward for a moment, holding up the lamp.
The larva was about thirty meters behind them and coming on faster than they had been walking.
"Is it following the light or our body heat?" asked Po as they turned again a
nd began to jog.
"Or the carbon dioxide of our breath? Or the vibrations of our footfalls? Or our heartbeats?" Sel held out the stick toward him. "Take it and run."
"What are you going to do?" said Po, not taking the stick.
"If it's following the light, you can stay ahead of it by running."
"And if it's not?"
"Then you can get out and call for help."
"While it has you for lunch."
"I'm tough and gristly."
"The thing eats stone."
"Take the light," said Sel, "and get out of here."
Po hesitated a moment longer, then took it. Sel was relieved that the boy would keep his promise of obedience.
Either that, or Po was convinced the larva would follow the light.
It was the right guess--as Sel slowed down and watched the larva approach, he could see that it was not heading directly toward him, but rather listed off to the side, heading for Po. And as Po ran, the larva began speeding up.
It went right past Sel. It was more than a half-meter thick. It moved like a snake, with a back-and-forth movement, writhing along the floor, shaping itself exactly like the columns, only horizontally and, of course, moving.
It was going to reach Po while he was scrambling through the tunnel.
"Leave the light!" shouted Sel. "Leave it!"
In a few moments, Sel could see the light leaning against the wall of the cavern, beside where the low tunnel began, leading toward the outside world. Po must already be inside the tunnel.
The larva was ignoring the light and heading into the tunnel behind Po. The larva didn't have to crawl or walk bent over--it would catch Po easily.
"No. No, stop!" But then he thought: What if Po hears me? "Keep going, Po! Run!"
And then, wordlessly, Sel shouted inside his mind: Stop and come back here! Come back to the cavern! Come back to your children!
Sel knew it was insane, but it was all he could think of to do. The formics communicated mind to mind. This was also a large insectoid life form from the formics' home world. Maybe he could speak to it the way the hive queens spoke to the individual worker and soldier formics.
Speak? That was asinine. They had no language. They wouldn't speak.
Sel stopped and formed in his mind a clear picture of the gold bug lying on the cavern floor. Only the legs were writhing. And as he pictured it, Sel tried to feel hungry, or at least remember how it felt to be hungry. Or to find hunger within himself--after all, he hadn't eaten for a few hours.
Then he pictured the larva coming to the gold bug. Circling it.