In the morning, they packed their knapsacks, evenly dividing among them one poptent and three sleeping blankets, a coil of rope, knives, an axe, crocodile jerky and hadrosaur pemmican for food, a medicine kit, homebrew sun block and insect repellant, a Leica 8X20, a cell phone with solar recharger, map and compass, a friction lighter for starting fires, hooks and fishing line, a coil of snare wire, the butt end of a roll of duct tape in case anybody’s shoes started falling apart, sunglasses, rain gear and a change of clothing apiece, toothbrushes, a towel, two pens and a notebook, a pot for boiling water, and three water bottles. They went over the list three times to make sure they hadn’t left anything out, and then unfolded the map to plan their route.
“Originally, Daljit and Jamal traveled down to the mouth of the Styx, and then up the Eden River Valley,” Gillian said. “With the herds coming down the valley right now, that’s not advisable. You’re going to have cut cross-country.” She drew a straight line from Smoke Hollow to Water Gap with her finger. “That’s about twenty-five miles.”
“Piece of cake,” Chuck said.
“We ought to be able to do that,” Tamara said judiciously.
Leyster agreed. “How hard can it be?”
“It’s all up-and-down terrain, low hills, a few ridges. There ought to be streams, but since it’s mostly forested, the surveillance map doesn’t show them. The phone has a built-in positional system, so anytime the satellite’s above the horizon, you can locate yourself on the map.”
“Nobody here’s had a lot of experience in forested environments,” Nils said. “We’ve spent so much time in the river valley, we’ve gotten used to its ways. But the gods of the hills are not the gods of the valley. Keep that in mind, okay, guys?”
“No fear,” Leyster said. “Let’s go.”
Leyster took a compass reading from the top of Barren Ridge, and they started west-southwest. Each carried a spear in one hand and another tied to the back of their packs, all of them (except for Tamara’s Folly) with points of sharpened tyrannosaur ivory. In addition, Leyster carried the axe in a holster on his left hip. He was careful to keep the compass away from it.
The forest closed around them, and the shouted farewells of their friends faded away.
They walked.
For the first few hours they didn’t talk much, concentrating instead on making a good start. But the longer the silence lasted, the more time Leyster had to think. And the more he thought, the more he came up with speculations he wanted to know if the others shared.
Finally he said, “If tyrannosaurs and anatotitans do communicate with each other—and I’m not saying they do—what would they have to say to each other?”
“ ‘Surrender, Dorothy,’ ” Chuck said in a deep, rex-ish sort of voice. “ ‘I’ll get you and your little dog, too.’ ”
Tamara tried to choke back her laughter, and snorted instead. Then she said, “You remember last year, after the titanosaurs had eaten their way through the valley and were gone, how the Lord of the Valley stalked around the perimeter? And then, a couple of days later, the herds came pouring in?”
“Yeah?”
“Suppose he was staking out his territory, the way hawks do. He makes his claim to the valley and everything in it. Then maybe he’s actually calling the herds in. Telling them that the territory’s ready.”
“Why would they come, though?” asked Leyster, who’d been thinking along the same lines himself. “What’s in it for them?”
“A nice lush valley with plenty to eat, and a promise that if any other tyrannosaurs try to move in on them, the Lord will kick their butts. We’ve seen him drive away several bachelor rexes over the past year.”
“You’ve got to admit,” Chuck said. “It makes for an attractive package. Good food, good company, an absolute minimum of predation. If I were a hadro, I’d go for it in an instant.”
They were walking through a stretch of old-growth forest. The tree trunks were far apart from each other, and the floor was a soft and silent carpet of pine needles. They could talk quietly here, and without fear.
“As long as we’re speculating,” Tamara said, laying emphasis on that last word, “there could be any number of interspecific communication loops. Say the herds got too large for the carrying capacity of the valley, the rexes could split off smaller fragments of the herds and drive them away. We’ve seen behavior that looks very much like that.”
“How would they know to do that?” Leyster asked quickly.
“Infrasound again,” Tamara said. “If there’s too much of it around, too many trikes and titans gossiping back and forth, the rexes get irritable.”
“Only one thing can cure this headache,” Chuck said. “Scaring the crap out of a few herbivores.”
“Don’t forget,” Tamara said, “the behavior doesn’t have to be intentionally mediated. Ants engage in complex social behavior, and their brains are negligible, even by dinosaur standards.”
“Okay, but what’s in it for the tyrannosaur?”
“Easy prey. The herds are too large to keep together in tight, compact groups. They have to spread out to forage. Old Rexie can step in and bag one at his convenience.”
They were coming to the end of the old-growth forest. Ahead in the distance, the unvarying gloom brightened slightly, the diffuse effect of small shafts of light reaching through the canopy to the ground.
Leyster nodded. “I remember Dr. Salley gave a talk once in which she said that tyrannosaurs were farmers. I wonder if this is what she was talking about.”
“I was there too!” Chuck said. “You remember she said that mountains danced to the music of sauropods? I bet she was right about that one too.”
“Okay, now you’ve lost me.”
“Me too.”
“Hear me out. You know that continental drift isn’t silent, right? Those huge tectonic plates moving a couple of inches a year put out long, slow sound waves—infrasound. Now, if two oneirosaurs can hear each other a hundred miles apart, why can’t they hear the sound of the mountains moving and the plates shifting? And if they do, then there’s a mechanism for their migration. They can use those sounds to guide themselves into the interior and back again every year.
“But that’s not all! It would explain why all the non-avian dinosaurs died out at the K-T. There have been studies modeling the effects of the Chicxulub impactor and it would have struck the Earth like a gong! The infrasonic reverberations would have echoed back and forth for years.”
“So?” Tamara asked.
“So, during a time of enormous environmental stress, the major dinosaurs would have been deaf. Unable to migrate. Unable to communicate with each other. They, and everything reliant upon them, would have been at an incredible disadvantage. Imagine if ants suddenly lost the ability to cooperate socially! That’s where the dinosaurs would be.”
There was a moment’s silence. Then Tamara said, “Chuck, you’ve outdone yourself.”
“It’s inspired lunacy,” Leyster agreed. Chuck looked crestfallen. “Right up there with continental drift, or the notion that birds might be descended from dinosaurs.” Chuck brightened. “But it’s also right up there with Eric Van Danniken and Lamarckian genetics. Until we’ve tested it out, it’s just a nifty hypothesis, no more.”
“So let’s test it!”
“From here? I don’t see how. It hasn’t even happened yet. What kind of experiment could you…?” He lapsed into silence, considering the problem. If they could somehow jam the natural infrasonic emissions of the Earth, and then transmit a false signal, it would be possible to see if the migrating dinosaurs then went astray. But that would require equipment well beyond anything Lai-tsz could donkey together out of instrument chips and bailing wire. If they knew what part of the brain processed the infrasonics and then isolated it surgically—but that was as much a fantasy as the first notion. If they…
Leyster walked mechanically forward, spinning off idea after idea, until finally he came to the conclusion that the notion was untestable with the resources at hand. It was a problem they’d never be able to tackle, unless they were someday, against all odds, rescued.
