"This is a Formic ship," he said. "The proteins in the rat-crab are the complete set of Formic-world proteins, with no extras.
"But here's the odd thing. The DNA is almost identical to the Formics' own genome as gathered and recorded from the many corpses after the war. There are key differences, but they're localized. It's as if the Formics went for a kind of perverse neoteny -- these rat-crabs seem to be a deliberate throwback to an earlier stage in Formic evolution, with these savage claws spliced on, and a hard carapace, which is only vestigial in the adult Formics."
Carlotta and Sergeant understood the implications at once. "So the Hive Queens can modify their own offspring," said Sergeant. "They decided that some of their babies would be those little monsters."
"I doubt they thought of them as their children anymore, if they ever did," said Carlotta. "When you have babies by the thousand, I bet the Hive Queens had no qualms about regarding a few of them as animals."
"There must be some limiting factor to their population," said Sergeant. "Or so the Hive Queen that created them intended. It might not have been the Hive Queen of this colony. They might have been developed long before this voyage and then reproduced naturally. The Formics might not even have remembered that these rat-crabs began as their kin."
"Do you think they're edible?" asked Carlotta. "Not to us, but ..."
"They're meaty," said Ender. "You're right, this might be dinner on the hoof."
"What kills them?" asked Sergeant.
"Anything. Their carapace doesn't protect them from anything stronger than the teeth of smaller animals. They could crush each other, and they could be mashed by a fist-sized rock. So you tell us what weapons we should use to keep them at bay."
Sergeant nodded. "No bullets, not on a ship. I wondered if we could slow them down with a sedative spray."
"I'd have to have a living specimen to see what worked on them," said Ender. "But there are sedatives that have been used on specimens of Formic-world fauna from several of the colony worlds. I could whip up a cocktail of seds that have no effect on humans."
"I just don't want to go in killing them wholesale," said Sergeant. "Now that we know they're Formic-derived, it's not impossible that they're actually the ones piloting the ship."
"Brain's too small," said Ender.
"But they might have queens," said Sergeant. "Or some kind of collective mind that's smarter than any individual. I just don't think we should go in killing. I keep thinking of the old vids of the Formics during the Scouring of China, that vile fog that reduced living creatures to pools and piles of protoplasmic goo."
"So let's have several sedatives ready that can be delivered as a fog," said Bean. "And a good solid backup plan. An acid spray, for instance. Even if they're sentient or semisentient, if they come at us to kill us, we hit them first and leave them dead."
"Carlotta?" he said. "What do we know about their ship?"
"It's definitely older tech. And it's Formic technology -- no writing, but some major color coding. Lots of little motors, which is why they need to have all these maintenance hatches. Of course they had to eliminate a lot of doorage in later ships when they got up to relativistic speeds. This design wouldn't do at all.
"I think they build the ship in space by attaching everything to an asteroid they sculpted into the shape we're seeing. Probably most of the metal in the ship's frame and hull came from the iron and nickel and such in the rest of the asteroid. But it's not the impermeable alloy they used in the ships that invaded Earth back in the 2100s."
"They didn't need it yet," said Sergeant. "At only ten percent lightspeed."
This ark showed that Formics sent out their colony ships with no defenses against attack, only a primitive collision shielding at the front. The Formics had turned out to be devastatingly formidable in war, but war was almost certainly not their intention when they came to Earth.
"Nice to know," said Bean. "Fortunately, the argument never mattered anyway. What else?"
"The huge pillars are structural -- the whole strength of the ship is vertical rising out of the rock, like a skyscraper. But they're also hollow. Rocket engines, and they carry fuel. Not radioactive, lots of carbon traces. It must be a very efficient fuel because even if the rock contains huge fuel reservoirs, it's not as if they can ever take this thing down to a planetary surface to process whatever carbon-based fuel source they use."
"They don't need much fuel," said Bean. "It's a generation ship, so they don't have to accelerate much. Very slow burn until they reach cruising speed, and then nothing until deceleration."
"No way to guess how much fuel they have left. This planet might be their last hope, or just a casual visit to see if it might do. The machinery I looked at was aging but it works fine."
"Aging like a thousand years?" asked Bean.
"No. More like a hundred years. I think everything's been replaced again and again during the voyage. Plenty of indications that there's been a lot of servicing over the years. But none recently."
"Good work, all of you," said Bean. "I know there's a lot more in your reports, and I've scanned your data as you collected it. I think we have all the useful information we're going to get from the outside, and from that lump of rab that Sergeant brought back."
"Rab," said Sergeant, giggling a little. "Rat-crab."
"Half a rabbit," said Carlotta.
"'Rab' it is," said Ender. "Until they tell us what they call themselves."