Jack just stared at him. Rudy’s face was pale. Ben didn’t look well either. Jack sifted through more of the pieces and found fragments of the dark-red leg segments and a bit of an antenna.
“Okay, so—” Ben rubbed his eyes—“these millipedes feed on the slime. And now there’s something else down here that’s feeding on the millipedes.”
“Yeah,” Rudy grunted. “It’s called a food chain. We just haven’t come across the predator yet.”
“You think it was those things that were making the clicking sounds?” Jack said.
Rudy shrugged. “I’m as much in the dark as you guys.”
Ben’s lips tightened. “Well, whatever it was, it managed to tear this giant millipede apart.”
“That’s one possibility.” Jack tried to offer another, less-alarming hypothesis. “Of course, we don’t know if this millipede was even alive when it got eaten. It could be that whatever did this is just a scavenger. You know, feeding off carrion.”
“C’mon, Jack,” Rudy said. “Scavengers don’t tear a carcass apart like this. I mean, it looks like this guy put up a bit of a fight.”
Jack surveyed the tunnel. Rudy was right; the segments and legs were cracked and separated, strewn about the passage.
Rudy went on. “This looks more like a predatory kill. Maybe multiple predators, operating with a pack mentality. Or like a feeding frenzy.”
“A feeding frenzy,” Ben repeated and shook his head. “That’s great.” He shifted the leather sheath around his waist and started crawling forward again. “Let’s just find a way out before we run into one of them.”
They crawled through the tight, damp passage, sometimes having to squeeze through sections barely eighteen inches wide. Jack was covered in mud and started feeling a chill in his arms and feet. But mostly he struggled to keep his mind off the thought of an unknown predator lurking somewhere in the tunnels.
Ben stopped and dimmed his light. Jack could see a dark shape moving between the rocks up ahead. His heart raced.
Ben whispered over his shoulder, “It’s more millipedes. Two of them.”
Jack and Rudy crept closer. Two of the creatures milled lazily in the passage, munching on a small patch of the slime. One appeared to be an adult, roughly four feet long, with a juvenile maybe half its size.
The two animals scurried off in the glare of Ben’s flashlight, disappearing into a small side tunnel. Ben led on, and soon they emerged into a larger open area. Jack sighed in relief. His back and legs ached from crawling through the narrow passage, and he was glad now to stand straight again.
They inspected their new surroundings and found themselves at the bottom of a deep shaft. A steady trickle of water cascaded down from somewhere above them.
Rudy was filming up the length of the shaft with the night-vision setting. “This place is huge. I can’t even see the top.”
The other side of the shaft opened to a narrow passage that seemed to twist and turn on an angle downward like a very narrow canyon.
Ben shone his light into the mouth of the tunnel. “Looks like we go this way.”
They proceeded along the passage slowly. The water trickling from above snaked along the ground in tiny rivers as if leading them on, deeper into the mountain. They’d traveled for less than five minutes when Ben stopped again.
“I see light up ahead.”
“A way out?” Rudy said.
Ben looked closer and shook his head. “Don’t think so. I don’t feel any wind.”
They moved forward, and soon Jack could see the light as well. It grew brighter with each twist in the passage until finally the tunnel opened.
Ben stood still and Rudy drew up beside him. “Wow.”
Jack stood, openmouthed, staring at the sight in front of him.
“Whoa” was all he could think of to say.
Chapter 08
They stood at the mouth of an enormous cavern, easily the largest chamber they had encountered so far. Jack tried to estimate the dimensions and guessed it to be nearly three hundred feet across. Like a huge, domed amphitheater rising to a height of a hundred feet or more. Frothy springs peppered the floor and bizarre rock formations rose up across the chamber. Fat, gnarled stalagmites twisted upward from the ground; long, slender stalactites reached down from above. A few met in the middle to form statuesque pillars around the edges of the great hall.
And the glowing slime was everywhere. It grew in dense, foaming patches around the pools. Winding tendrils spread out through the cavern, creeping up the columns and walls toward the ceiling.
Jack could see several of the millipedes munching lazily on the slime like cattle out in a meadow. And there were other creatures as well. Fat, round beetles the size of overturned coffee cups marched across the cavern in a little tea-set caravan.
The light was mesmerizing. Almost dizzying.
Jack found his voice first. “It’s like Las Vegas.”
Rudy switched on his camera and began filming. “This is incredible.”
Jack was grimy and sore, but he and Rudy spent the next several minutes traversing the chamber end to end, getting shots of rock formations, the pools, the slime, and the millipedes. And they found more of the big, plodding beetles they’d seen earlier. Rudy said he thought they looked like dung beetles. In fact, he discovered three different species and took copious shots of them all. It was odd that none of the creatures appeared to be disturbed by their presence but rather seemed content to simply graze on the slime.
They gathered around one of the larger hot springs, observing the foam being generated by the slime.
“So what’s with all the foam?” Jack said.
“Well…” Rudy bent down to inspect the pool. “I think it’s hydrogen peroxide.”
Jack frowned. “How do you know that?”
“I’ve been working on a theory,” Rudy said. “Chemiluminescent reactions require hydrogen peroxide in order to work, right?”
“Chemi-what?”
“Chemiluminescent.” Rudy stood and pointed to the slime. “A chemical reaction that generates light. Glowsticks, fireflies, or our slime here. They all need hydrogen peroxide in order to glow.”
“Okay…”
“And hydrogen peroxide is produced naturally in most organisms as a by-product of their metabolic activity.”
“Of course it is.”
“So this slime, whatever it is, must be generating copious amounts of hydrogen peroxide to cause it to glow like it does. It’s called oxidative phosphorylation.”
“It’s kind of funny.” Jack shook his head. “I know you’re speaking English; I just have no idea what you’re saying.”
Rudy sighed. “If this slime is producing hydrogen peroxide and there are other microorganisms in the water that produce catalase, it would cause a chemical reaction.”
“Catalase?” Jack snorted. “Y’know, I slept through biology.”
“It’s the enzyme used to break down hydrogen peroxide into oxygen and water. So basically this could all be part of a symbiotic ecosystem that acts like a natural oxygen generator.”
Jack was starting to understand. “Oxygen… So that’s how the millipedes get so big?”
“It’s just a theory,” Rudy said. “But we got in here through that underwater tunnel. So if these caverns are sealed off from the outside and this slime is somehow giving off oxygen, it could easily raise the levels in here considerably.”
“Makes sense, I guess.” Jack nodded. “But my question is, why haven’t they found this slime in other caves before? Why only this one?”
Rudy shrugged at that. “Maybe it’s all the hot springs and geologic activity or something indigenous to this region; I don’t know. But this cave has an ecosystem that’s developed totally isolated from the rest of the planet. We have no idea how many other caves like this there are throughout the world. We’re just now discovering new species on the ocean floor and places we’ve never explored. Think about it—we know more about the surface of Mars than we do about some places on Earth.”