Evolution

The chick’s life was a handful of brief, vivid impressions: the cold air beyond its cracked shell, the blurred glow of the comet, a sense of flying. But now a hot cavern opened beneath it. Its skin still smeared with yolk, the chick died instantly.

Meanwhile more chicks were pushing out of the ground, hatching all at the same time. It was as if the ground were suddenly swarming with baby dinosaurs. The didelphodon, and more predatory mammals, closed in to feed.

An ancient survival strategy had been operating. Dinosaurs were reptiles who laid their eggs on the ground. Though some parents stayed with their brood, there was no way all the vulnerable eggs and chicks could be protected. So dinosaurs laid many eggs, and their hatchings were synchronized. There should have been dozens of broods hatching right now, scattered through this area of forest: hundreds of chicks. The idea was that suddenly the forest floor would be overwhelmed with baby dinosaurs, far too many for even the hungriest of predators. Most of the chicks would die, but that didn’t matter. It was enough that some would survive.

But here, tonight, the strategy had gone wrong — horribly so for the dinosaur chicks. The mother of these chicks was a hunter isolated from her pack. Confused, hungry, scared of predation herself, she had laid her eggs in the old, familiar place — this rookery was millennia old — and covered them with rotting vegetation for warmth. She had done just what she should have done, save that it was the wrong time, and the eggs had been forced to hatch without the cover of hundreds of others.

The air was filled with the stink of blood, the low growls of the predators, and the sad peeping of the doomed chicks. There were many species of mammals represented here at this grisly banquet. The largest was the big didelphodon. There was a pair of deltatheridiums, ratlike omnivores, neither marsupial nor placental, a unique line that would not outlive the dinosaurs. Many of the creatures here had potential far beyond their present standing; one unprepossessing little creature was an ancestor of the line that would lead to the elephants.

But for now, all that concerned them was their empty bellies. Dissatisfied with the slow emergence of the struggling hatchlings, the mammals had already started to dig into the loose silt, seeking unbroken eggs, scattering the cover of moss laid over the nest by the mother dinosaur.

By the time Purga arrived the rookery had become a killing pit, a squirming mass of feeding mammalian bodies. Purga, late to the fray, burrowed eagerly into the dirt. Soon tiny bones crunched in her mouth. And, so deeply did she immerse her head in search of the deep-buried goodies, she was the last to sense the return of the mother dinosaur.

She heard an angry bellow, felt the ground shudder.

Her snout sticky with yolk, Purga pulled her head out of the dirt. The other mammals were already vanishing into the forest’s welcoming green black. For one instant Purga saw the whole creature, an unlikely feathered monster suspended in the air, limbs splayed, mouth gaping. Then a vast clawed hand flashed out of the sky.

Purga hissed and rolled. Too late she learned that this was the nest of a troodon: an agile, fast-moving killer — and a specialist hunter of mammals.

The troodon’s name meant "Wounding Tooth."

Wounding Tooth, the size of a dog, was not the largest of dinosaurs, but she was intelligent and agile. Her brain compared in size to that of the flightless birds of later eras she somewhat resembled. Her eyes were as large and as well night-adapted as Purga’s, and they could see forward, giving her binocular vision, the better to triangulate on her small, fast-moving targets. She had legs that enabled her to spring like a kangaroo, a long sicklelike claw on the second toe of each foot, and hands like spades evolved specifically to dig out and crush scuttling mammals.

She was coated in small sleek feathers, an elaborate development of scales. The feathers weren’t meant for flying, but for warmth during the night’s chill. In the equable climate that swathed the Earth in these times, you didn’t need a hot-blooded metabolic engine to keep warm: If you were big enough, your cold-blooded body would retain its heat right through the night, even if you lived at Earth’s extremes, at the poles. But smaller dinosaurs, like the troodon, needed a little extra insulation.

Small or not, she had one of the largest brains of all dinosaurs. All in all, she was a well-equipped hunter. But Wounding Tooth had problems of her own.