You are in the tundra forests of Alaska, 73 million years ago.

The wind howling through the Cretaceous Alaskan conifers was loud, but it wasn't enough to drown out the low, resonant huffing. You froze, crouching behind the icy trunk of a conifer, your breath turning to instant frost. Through the blinding flurries, something was moving.

It wasn't a giant T. rex, but in this world of twilight, it was still king.

A Nanuqsaurus emerged from the snow, a fluffy, feather-covered nightmare roughly 20 feet long. Its plumage was dense, a mix of white and pale gray that blended perfectly with the snowy landscape, insulating it against the freezing temperatures. It was hunting, its long snout swinging back and forth, nostrils twitching, catching the scent of potential prey nearby.

It stopped about thirty feet away, its head tilting. Its large, intelligent eyes—adapted for hunting in months of darkness—settled right on your hiding spot...