You are in the floodplains of North America, 150 million years ago.

The air in the Late Jurassic floodplain was thick, humid, and smelled intensely of wet ferns and cycads. Hidden behind a dense thicket of horsetails, you watched a herd of Camptosaurus grazing, perhaps a dozen individuals ranging in size from smaller juveniles to adults roughly 20 feet long.

Their movement was a rhythmic, jerky shifting between four-legged browsing and standing on their hind legs to reach higher vegetation. You could hear the grinding of their cheek teeth crushing through tough ferns, a surprisingly loud sound in the humid silence. They were bird-hipped, bird-like in their movements, yet solidly thick-bodied.