Robert Sawyer - End of an Era

I saw in an instant that he was right. “It also explains the extensive vascularization in dinosaur bones,” I said. Dinosaur bone is remarkably porous, which is part of the reason it fossilizes so well through permineralization. “They wouldn’t need as much bone mass to support their weight in a lower gravity.”

“I thought that vascularization was because they might be warm-blooded,” said Klicks, sounding genuinely curious. He was, after all, a geologist, not a biologist. “Haversian canals for calcium interchange, and all that.”

“Oh, there’s probably a correlation there, too. But I’ve never bought the idea of warm-blooded brontosaurs, and even they have bones that look like Swiss cheese in cross section. I’m sure you’ve seen the studies that say they’d break their own legs if they tried to walk faster than three kilometers an hour. That figure assumed normal gravity, of course. And, say, speaking of odd bone structure—it never quite seemed possible to me that Archaeopteryx and the pterosaurs could really fly. Their skeletons are weak for normal gravity, but they should be more than adequate in this.”

“Hmmm,” said Klicks. “It does explain a lot, doesn’t it? We’ll have to have a good look at dinosaurian heat production while we’re here. I seem to remember that another argument in favor of warm-blooded dinosaurs was that their fossils have been found inside the Cretaceous Arctic Circle, where the nights would be months long.”

“That’s right,” I said. “The idea was that dinosaurs must be warm-blooded because they couldn’t have possibly migrated far enough to avoid the long nights.”

“Hell,” said Klicks, taking off his boot and shaking it upside down to get rid of a pebble that had found its way inside, “I could walk to here from the Arctic Circle in this gravity.”

“Yeah,” I said. “But I’d still like to know why the gravity is less. I guess the gravitational constant could have increased in value over time.”

“That would mean it’s not much of a constant, then, wouldn’t it?”

“Well, I don’t know a lot of physics,” I said, ignoring his smart-ass comment, “but didn’t Einstein more or less pull the value for G out of the air to get his equations to balance? We’ve only been measuring its value for a century, and measuring it precisely for only a few decades. A general tendency for it to increase over time might not have shown up yet.”

“I suppose, although I’d expect to find—” Suddenly he fell silent, his head swinging around. “What was that?” he said.

“What?”

“Shhsh!”

He pointed to the deciduous forest, the sun now well above the trees. There was a rustling as something man-sized pushed aside fronds. I caught a flash of emerald in my peripheral vision. My heart began pounding and my mouth went dry. Could it be a dinosaur?

We didn’t have much of an armament. Hell, we didn’t have much of a budget. Someone had suggested we bring modern automatic assault weapons to protect ourselves, but no corporate donor came through with any of those—bad PR to be associated with killing animals, after all. All we had were a couple of old elephant guns, each holding two bullets at a time.

Klicks had brought his elephant gun with him when he’d come out this morning. It was propped up against the crater wall, about a dozen meters away. He sauntered over to it, casually picked it up, and motioned for me to follow. It took about forty seconds for us to reach the dense wall of trees. Pushing foliage aside with his hands, Klicks made his way into the forest. I was right behind him.

We heard the rustling again. Breath held tight, I strained to listen, scanning the dense growth for any sign of an animal. Nothing. Branches and leaves stood still, as if they, too, were frozen in anticipation. Seconds ticked by, heartbeats added up. Whatever it was must be nearby, either to my left or in front of me.

Suddenly in a flurry of motion the thick vegetation parted and a green bipedal dinosaur leapt into view, the top of its head coming to no more than the height of my shoulder.

It was a slender theropod, using a stiff, whip-thin tail held parallel to the ground to balance a horizontally carried torso. At the end of its darting neck was a head about the size and shape of a borzoi dog’s, drawn out and pointed. Two huge eyes, like yellow glass billiard balls, stared forward, their fields of vision overlapping, providing the kind of depth perception a predator needed. The creature opened its mouth, revealing small, tightly packed teeth, serrated like steak knives along their rear edges. Long, thin arms dangled in front of its body, the three-fingered hands ending in sickle claws. The animal flexed them in anticipation and I saw that the third finger was opposable to the other two digits. Bobbing and weaving its head, it cut loose a sticky sound like a person trying to kick up phlegm.

I recognized this creature in an instant: Troodon , long hailed as the most intelligent dinosaur, a carnivore armed not only with slashing claws and razor dentition but also with a hunter’s keen senses and—perhaps—with cunning. Although the best troodon skeletons were known from a time 5 million or more years before the end of the age of dinosaurs, fossil troodon teeth were found in beds right up to the close of the Cretaceous. These specimens were on the large side for troodon, but the shape of the skull was unmistakable.

Klicks had already brought up his elephant gun, its wooden butt resting against his shoulder. I don’t think he intended to fire unless the animal attacked, but he was aiming along the gun’s shaft, finger on the trigger. Suddenly he pitched forward. The gun went off, missing the troodon, the thunderclap of its report startling a flock of golden birds and a smaller number of white-furred pterosaurs into flight. A second troodon had kicked Klicks in the small of his back, its slender claws shredding the khaki material of his long-sleeved shirt. Two more troodons appeared from the brush. Each was hopping rapidly from foot to foot for balance, like shoeless boys on hot pavement. Klicks rolled over, trying madly to reach his gun. A three-clawed foot slammed into his chest, pinning him. The dinosaur let loose a sticky hiss, showering him with reptilian spit.

I ran toward Klicks and, approaching from the left side, brought my steel-toed boot up and under the creature, kicking it in the center of its yellow gut. I made no dent in the lean, muscular belly, but, much to my surprise, my kick lifted the thing clear off the ground. It must have massed less than thirty kilos and the reduced gravity magnified my strength. Freed, Klicks scrabbled for the gun again, his fingers clawing dirt.

The recipient of my kick turned on me, moving with surprising agility. I held my arms in front of my body, trying to grab its scrawny throat. Hands shooting forward in a green blur of motion, it seized my wrists with sickle digits. My spine arched back like a limbo dancer’s, trying to avoid the jaws at the end of that dexterous neck. The creature wasn’t built for fighting something more than twice its mass with muscles, such as they were, accustomed to more than double the gravity. I held my own for a good fifteen seconds.

Still gripping my arms, the troodon crouched low, folding its powerful hind legs beneath it, and kicked off the rich soil. The force of its leap knocked me backward and I hit the ground hard, rocks biting into my spine. Straddling my body, the crazed reptile arched its neck, opened its lipless mouth wide, exposing yellow knife-like teeth, and—

Kaboom!

Klicks had found his elephant gun and squeezed off a shot. He’d hit my attacker in the shoulder, sending the beast’s neck and head pinwheeling into the sky. Twin geysers of steaming blood shot from the torso’s severed carotid arteries. No longer balanced, the body tipped forward and the cavity of the open chest, sticky and wet, slammed into my face. Revolted, I rolled away, dirt clinging to the dinosaur blood that covered my face.