You are in the forests of North America, 70 million years ago.

The mist of the Late Cretaceous morning still clung to the conifers of what is now Alberta. You kept low in the ferns, your heart hammering against your ribs, watching a massive herd of Pachyrhinosaurus grazing by the riverbank. They were breathtaking, roughly 26 feet long, their skin a mottled, pebbled grey that blended into the temperate landscape further north.

Suddenly, the air split with a deafening, wet grunt.

One of the largest males, its face armored by a monstrous, rough-surfaced bony boss on its snout instead of a horn, swung its head toward a rival. The two bull pachyrhinosaurs lowered their heads, displaying the bizarre, knob-like ornamentation that defined their kind. With a sound like colliding boulders, they slammed their nasal bosses together.

They engaged in a shoving match, their legs digging deep trenches into the muddy riverbank. You watched from the safety of the ridge as the herd continued feeding, accustomed to the raw power of their leaders.