Crrack!

"What the hell was that?" Klicks brought the Jeep to a halt. We were on a steep slope, having broken out of the forest halfway up the side of a mountain. The cumulonimbus overhead now covered two-thirds of the sky.

Crrack!

"There it is again!" I said.

"Shhh."

We listened intently. Suddenly I caught a blur of orange motion out of the corner of my eye. "My God!" I shouted. "They’re going to kill each other!"

Crrack! Crrack!

Off to our right, two individuals of the genus Pachycephalosaurus were butting heads. These two-legged giants were the big-horned sheep of this time. Holding their backs and necks parallel to the ground, they charged at each other, smashing the tops of their skulls together.

At first glance, pachycephalosaurs looked like the intellectuals of the dinosaurian era. They had high domed heads and a fringe of knobby horns around the back of the skull that gave the impression of being a balding professor’s remaining hair. But the erudite appearance was misleading. The domed skull was almost solid bone, more than twenty centimeters thick.

Crrack!

These must be males, for nearby a larger bonehead, darker rust in color, was using the bumpy knobs on its snout to dig up roots. This one seemed indifferent to the head-bashing going on nearby, but I was sure that it was the female prize the males were fighting for. At six meters in length, the male on the left was a good meter longer than the one on the right — and with reptiles, bigger meant older. The old guy was probably the female’s mate and here was being challenged by a young buck, ready to test his prowess in the way prescribed by his genes. I brought my binoculars to bear on the contest. The challenger was losing ground. Since we’d started watching, he had been forced to back away almost fifty meters.

Klicks pointed to the sky. A large pterosaur was circling above the fight, looking like a vulture waiting for the kill. I doubted that the boneheads routinely fought to the death, but this battle had gone on much longer than I would have anticipated a normal territorial challenge to last.

Time for both pachycephalosaurs to catch their breaths. They straightened, rising to their full heights, tilting their heads up and down in a ritualized display of their skullcaps. Although the tops of both their heads were now partially obscured by blood, I could see that there were bright display markings in yellow and blue on each pate.

The head-bobbing continued for a few minutes. Finally, the one who had been losing ground backed off a bit more, then charged forward at full speed, its three-toed feet throwing up divots each time they kicked off the soil. There was no roar to go with the charge, though. Each beast had its jaw locked shut, presumably to minimize the damage done by the impacts.

Old Guy stood his ground, his horizontally held back ramrod-straight, five-fingered hands at the sides of his head to steady it even more. When the impact came, the glass in our windshield rattled. I saw three chunks of the keratin veneer that sat atop the beasts’ skullcaps go flying. Old Guy had been knocked on his behind, his thick tail bending at an awkward angle. But he rose quickly, while the challenger staggered back and forth, dazed.

In the distance, we could hear more cracking sounds. Somewhere another pair of pachycephalosaurs were jousting. But the contest we’d been watching seemed to at last be over, the most recent impact finally proving too much for the challenger He raised his head and looked at his foe. Old Guy looked up too, and bobbed once, showing his display colors. Then he lowered his head again, ready for another charge. The challenger didn’t return the display. Instead, he turned tail and staggered away. Overhead, the frustrated pterosaur flapped its wings and headed off in search of something else to eat.

Old Guy made his way over to the foraging female and began rubbing his neck against hers, the bony nodes on the rears of their skulls making a sound like a washboard as they clicked together. The female seemed indifferent to the male’s attentions, but I suspected she was in heat and probably her scent had prompted the unattached younger male to make his challenge. Old Guy continued to rub necks with her, but she simply went about her feeding. After a while, though, she dug up a few more choice roots and, instead of eating them, left them on the ground for the male. He tipped his snout down and gobbled them quickly, obviously famished after his fight. This leaving of the roots was apparently a signal that the female was now ready. Old Guy moved in behind her and she went to her knees. The coupling only lasted a few minutes.

I guess they’d been mated a long time.

As a boy, I’d read a short story by Ray Bradbury called "The Sound of Thunder." It told of a time-traveler who had stepped on a butterfly in the Mesozoic, and that one event — the loss of that butterfly — had cascaded down the eons to result in a different future.

Well, we knew now that small events like that do have big consequences. Chaos theory tells us that the flapping of a butterfly’s wing in China really does determine whether it later rains in New York. This sensitivity to initial conditions is even called the Butterfly Effect. I got a kick out of the fact that Bradbury had beat the physicists to the punch. He had known how important butterflies were long before they did. In a way, he was the real father of chaos theory.

But Ching-Mei said we didn’t have to worry about any of that. The Sternberger was anchored to its launch point back in the sky over the Red Deer River. Her equations said that it would return there, regardless of what we did back here. She’d talked in terms I only half understood about the many-worlds interpretation of quantum physics, saying that our future would be safe.

And so we got to hunt dinosaurs with impunity…

"That’s the one," said Klicks, pointing.

"Pardon me?"

"That pachycephalosaur, the challenger. That’s the one we should kill. It’s exhausted by that head-butting contest, so it should be easy to take down. Besides, it obviously doesn’t have a mate depending on it."

I thought for a moment, then nodded. Klicks throttled the engine and we drove off in the direction the challenger had headed. It didn’t take us long to catch up with him. He was indeed looking bedraggled, but still, at about the same length as our Jeep, I doubted that he would be quite as easy to fell as Klicks hoped.

Klicks stopped the Jeep long enough to fire a shot from his elephant gun out his window. It hit the dinosaur in the shoulder. The beast yelped and turned on us. It apparently had no preprogrammed response for dealing with an attack by humans in a Jeep Iroquois. It bobbed its head at us, showing the blue and yellow display colors on its pate. Klicks swung the car around and fired again. This time the creature broke from instinct. It lowered its head and ran straight for us, a biological battering ram.

Klicks pulled hard on the wheel, but that just succeeded in bringing us broadside to the beast. It hit the passenger door, little shards of safety glass showering me, the metal bending as if we’d been in a high-speed automobile collision. We were sent spinning across the clearing and rammed into a tree. The air bags on the dash inflated. Klicks shifted to reverse and pulled us back a distance.

The air bags should have deflated automatically, but they hadn’t — so much for Chrysler’s quality control. Feeling like Patrick McGoohan in The Prisoner, I pushed against the white sheeting until I managed to find my dissection kit, sitting on the hump supporting the stick shift, and dug out a scalpel. I slit my bag first, then Klicks’s, the hot wind that spewed out as they deflated blowing things around the cab.