You are in the dry floodplains of western North America, 66 million years ago.

The heat in the Late Cretaceous was suffocating and the air was humid, smelling of ferns and damp earth. You have been trekking along the dry plains when you spot a small group of Pachycephalosaurus grazing near several scattered trees. You crouched behind a fallen, fossilized redwood to document the herd. One of the bone-headed dinosaurs was seen ramming its head against a tree, causing several fruits to fall upon impact, allowing the herbivore to feed.

Just then, there is a commotion when you hear a series of low-frequency grunts. You looked up to see one male Pachycephalosaurus—easily six feet tall at the hip and fifteen feet long—walking parallel to your hiding spot. It wasn't looking at you, but at another male of its kind nearby. Both are magnificent: bipedal, heavily built creatures, each with a massive, ten-inch thick dome of bone topping its skull, rimmed with spikey knobs.

The two males began a tense, circular dance, lowering their bony heads as they lock eyes onto each other and make shrill, screeching grunts, sizing up with each other. The rest of the herd look on.

It looks like a fight between these males may be inevitable, you realized as you held your breath in your hiding spot.