Sven shuts his eyes and draws a deep breath, evidently gathering his thoughts. I remain standing, glancing about every so often. I don't like just chatting out here in the open like this.
"Let me tell you what we know about them," says Sven. "You remember how they came here, right?"
"Yeah," I say, with a hint of sarcasm. As if I could ever, ever forget. "They came inside the meteor rocks, didn't they?"
"Not quite," says Sven. "They were the meteor rocks. We figure that's how they spread from planet to planet. You've seen how they're armoured on the outside, right? Well that armour's as hard as diamond. Solid. So a group of them lump themselves together and go hurtling through space. They smash into the surface of a planet, making a huge mess of everything, then untangle themselves and start to harvest the local wildlife."
"Harvest?" I say, wrinkling my nose. Knowing what it is the Creatures are harvesting makes the word sound horrible and sticky in my head.
"There are two types," Sven continues. "We call them Hunters and Feeders. Several Hunters for each Feeder. The Hunters are the ones who make the noise. It's their job to find food and bring it to the Feeder. It's a symbiotic relationship, like ants with their queen. See, the Hunters don't eat at all. The Feeder does that for them. Don't ask me how it works, because I don't know. Think of the Feeder as the brain and the body, and the Hunters as the arms. They do all the work to keep the body alive, because without the body they're nothing."
"Okay," I say. "Makes sense, I guess. How do you know all this?"
"I'll tell you in a bit. Let's just get it all out first. Now, the other thing we found is that they have tribes. The Hunters are loyal to the Feeder they came to ground with. They compete with the other Hunters for food if food is scarce. Like different gangs all trying to carve up territory for their leaders. They don't fight though. That's something we've never seen. But sometimes it'll be the case that a Feeder doesn't get fed, and if that happens it dies. Now bear with me here, because this is where things get interesting. When a Feeder dies, all its Hunters go AWOL. They lose it, like they can't think for themselves. I've watched it happen myself. They just wander off all dazed and helpless. That is, until they find themselves another Feeder to serve."
Sven stares at me with wide eyes. He looks like he's willing me to understand what he's saying. I nod. "I've been seeing empty craters," I say. "Out in the countryside mostly. That must be where they couldn't get enough food. So the Worm died and the Creatures..." Something clicks in my head. I flash back to the image of the giant thing squatting in its crater in the middle of town. "The Creatures...the Hunters, I mean, they must have all gone to join the nearest Feeder and ended up..." I trail off. "So what happens to the ones that don't die? The Feeders I mean. What happens when they just keep getting fed?"
Sven looks me dead in the eye, and says what I was afraid he was going to say. "They grow, David. They get big, and they get strong, and they get a bloody army of Hunters. It's Darwinism, of a sort. The strongest survive, and they're only going to get stronger."