Dino disco: 100-million-year-old giant courtship arena discovered in Colorado

Researchers had previously noted the existence of five fossilized scrape marks at Dinosaur Ridge. After a closer investigation, however, they discovered much more than a few traces of this ritual.

Aerial images revealed 35 marks made by different dinosaurs, making this former wetland home to one of the largest mating destinations in the ancient world.

Where dinosaurs “did the dance” for the continuation of their species

Once upon a time, 100 million years ago, many species walked through this former wetland, such as duck-billed hadrosaurs and ostrich-like herbivores. They left track marks in the soft Earth. Nearby, researchers discovered that they marked solid rock on a slope with a more dynamic set of traces, suggesting they began their mating rituals here.

Paleontologists gathered aerial images of the site, which is, in a humorous twist of fate, closed to foot traffic to preserve and protect the track marks.

They did not expect to uncover what appeared to be a space more like a dance club where dinosaurs would gather and dance, hoping to secure a mate.

Dr. Caldwell Buntin of Old Dominion University, the study’s lead author, told IFLScience that Martin Lockley, who first identified the trace fossils, determined they were likely related to mating displays after ruling out other possibilities such as nesting, foraging, territorial marking, or water-seeking behavior.

Buntin and his team wanted to evaluate the validity of Lockley’s findings that these were, in fact, traces of a mating dance using a data-driven approach.

High-resolution drone imagery revealed 35 Ostendichnus, the scientific name for this specific type of claw marks associated with the dance of sex, according to the study.

The mating dance of the dinosaurs

Buntin told Science that he believed Ornithomimids, or ostrichlike herbivores, and Acrocanthosaurus, which looks like a T.rex, both used this sacred ground to populate their species.

These markings—bowl-shaped and long and thin as if the dinosaurs kicked back their feet—were clustered together at different layers of the rock. Researchers understood that the element of time was present. These dinosaurs returned to this site over generations to put themselves out there—to attract a female.

“These traces were generated by backward kicking movements repeated by both the left and right foot,” Buntin said.

In interpreting the choreography, researchers understood that the dinosaurs turned clockwise and scraped their claws through the sand. The circular markings suggest that, later, they might have nested here.

Though restricted, you can visit the site

Scientists have only found three lekking sites worldwide. Already a rare discovery, the site at Dinosaur Ridge might be “the clearest case yet of a dinosaur display arena,” according to Amy Atwater, the site’s director of paleontology.

Buntin told Science that future work might require the state of Colorado to allow researchers to visit it, so they can study the traces of mating up close, as they still cannot make any definitive statements as to who these markings belong to.

Nonetheless, some of it is open to the public, so dinosaur lovers can visit one of the world’s only and most popular hiking sites. This site stands to contribute to the field and provide new insights into the ancient beasts that once ruled the Earth—the dinosaurs.

The discovery of 35 scrape sites offers new insight into dinosaur courtship, showing they likely performed display behaviors to attract mates.

The study was published in the journal Cretaceous Research.