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

The mist clung to the riverbanks, blending the early morning light into a soft grey wash. The air smelled of damp ferns and pine needles. Standing on the ridge, you checked the wind—blowing away from you, toward the valley below.

You were looking at a herd of about twenty Parasaurolophus.

They were massive—easily 30 feet long—but moved with a cautious grace. A large male, his six-foot curved crest showing a vivid red hue against his drab green skin, stood upright on his hind legs, using his long tail for balance. He stripped the upper branches of a coniferous tree while the others grazed on shrubs closer to the ground.

The herd wasn’t quiet. Instead of loud calls, they produced a constant, low-frequency hum, a resonant vibration that seemed to tremble through the ground. It was musical, almost like a massive pipe organ echoing through the valley. They were talking—constant social communication, keeping contact while they fed.

It is a good time for you to document the real sounds of the Parasaurolophus…