You are in the coastlines of North America, 75 million years ago.

The air smelled of salt and rotten seaweed as you crouched low behind a rocky outcrop on the Cretaceous coastline of what would one day be Kansas. The sun was hot, but the water of the Western Interior Seaway was a deep, inviting teal.

Suddenly, a sleek, dark head broke the surface, twenty feet from the shore.

It was a Hesperornis—almost six feet of prehistoric, toothed penguin-like bird. Its body was streamlined, and its neck was long and slender, much like a modern loon.

The creature watched the shoreline with a cold, yellow eye, turning its head from side to side. It was wary. It was too clumsy on land to be comfortable here. It seemed to know that in this environment, it was vulnerable to terrestrial predators, though it was a master of the sea.

You stayed frozen as it slowly paddled in, awkward hind legs pushing it forward, its tiny, vestigial wings pressed tightly against its feathered body. As it got closer, you could see the long, needle-like beak filled with a groove of small, sharp teeth. It wasn’t here to fish; it was looking to bask on the rocks.