Evolution

Only the great dinosaurs were unperturbed. The comet light made no difference to the air temperature, and when true night had fallen they slipped into their usual torpor. On the last night of a reign that had lasted nearly two hundred million years, the rulers of the Earth slept untroubled.

If not for the tyrannosaur eggs, the young giganotosaur would have spotted the disturbed troodon earlier. In the lee of the mountains, he stalked silently through the green shadows. His name meant Giant.

The forest here was sparse, spindly araucaria and tree ferns, scattered over a ground littered with sharp-edged volcanic rocks. Nothing moved. Anything that could hide had already hidden; anything else lay still, hoping for the shadow of death to pass by.

He came to a pile of moss and lichen. Superficially it looked like a heap of debris piled up at random by wind or the passage of animals. But Giant recognized the characteristic scrapings, the lingering smell of meat eater.

It was a nest.

With a rumble of anticipation, he fell on the nest and began to dismantle it with his stubby forearms. When he had exposed the eggs, Giant dug his clawed thumb, with a surgical precision, into the top of the largest. He pulled out the embryo head first. As the mucus and yolk drained from it, lurid colors bright, Giant saw the chick squirm feebly, even saw its tiny heart beat.

Just as the embryos of chimps, gorillas, humans would all be disturbingly similar, so dinosaur fetuses all looked alike. There was no way to know that this chick would have been a female tyrannosaur. Blind, deaf, immature, the embryo struggled to open her mouth, dimly imagining the hulking shape of a mother who would feed her. Giant flicked the embryo into his mouth and swallowed it without chewing. The chick’s life ended in crushing, acidic darkness.

It didn’t matter. Even if no predator had come this way, her egg would have been destroyed before she could have hatched by a monster even more terrible than a giganotosaur.

Giant was descended from South American stock that had crossed a temporary land bridge into this continent a thousand years earlier.

In a world of slowly separating island continents, the dinosaur fauna had become diverse. In Africa there were archaic-looking long-necked giant herbivores and creatures like hippos with fat, low-slung bodies and powerfully clawed thumbs. In Asia there were small, fast-running horned dinosaurs with noses like parrots’ beaks. And in South America large sauropods were hunted by giant pack-hunting predators; there it was like a throwback to earlier times, to Pangaea. The giganotosaurs had cut their evolutionary teeth hunting the great South American titanosaurs.

Giant was an immature male, and yet he already outmassed all but the very largest carnivores of the era. Giant’s head, in proportion to his body, was larger than a tyrannosaur’s — and yet his brain was smaller. The giganotosaurs were less agile, less fast, less bright; they had more in common with the ancient allosaurs, equipped to kill with teeth and hands, whereas the tyrannosaurs, all their evolutionary energy funneled into their huge heads, specialized in immense, sharklike bites. Where the tyrannosaurs were solitary ambush hunters, the giganotosaurs were pack animals. To bring down a sauropod fifty meters long and weighing a hundred tons, you didn’t need brains as much as raw strength, rudimentary teamwork — and a kind of reckless frenzy.

But, coming across that land bridge into a new country, the giganotosaurs had been forced to confront an established order of predators. The invaders had quickly learned that their takeover of a region could not succeed unless they first mounted a bloody coup against the ruling carnivore.

Which was why this young male giganotosaur was munching slippery tyrannosaur embryos. Resolutely Giant cracked one egg after another. The carefully constructed nest turned into a mess of shattered eggs, scattered moss, and chunks of dismembered chick. Giant was feeding well — and issuing a challenge.

It would be a transfer of power. The tyrannosaur had been the top predator, mistress of the land for a hundred kilometers around, as if the whole elaborate ecosystem was a vast farm run for her benefit. The prey species had come to terms with the formidable presence that lived amongst them: with their armor or weapons or evasive strategies, each of the hunted had reached a point where their losses to predators were not a threat to the endurance of the herd.

Given time, all that would have changed. The impact of the invaders’ hunger would have rippled down the food chain, disturbing creatures large and small, before a new equilibrium could be established. It would have taken longer still for the prey species to learn new behaviors, or even evolve new coping systems or armor to deal with the giganotosaurs.

But none of that would happen. There would not be time for the giganotosaur clan to exploit their triumph. Not in the few hours left.