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Birds do some wacky mating dances—and turns out, they learned it from their ancestors. A reveals that some dinosaurs showed off to their potential mates by dancing, too. 

Scientists recently discovered long, fossilized scrape marks that date back 100 million years—give or take a million—at an excavation site in western Colorado. Because the scrapes were clustered in one area, the researchers realized they were more than just footprints: They think the deep, repeating gashes resulted from some incredibly forceful mating displays. The gashes were likely made by the dinosaurs' claws as they made moves similar to the rituals modern birds, including sage-grouse and snipe, perform.

The dancing dinos were likely large non-avian theropods (basically two-legged, flightless carnivores). The top candidate is the Acrocanthosaurus, which first popped up in the early Cretaceous period, says Martin Lockley, lead author and paleontologist at the University of Colorado, Denver. “It was a process of elimination,” he says. “We looked at what animals were known at this point in time [in the western United States] and this animal seemed like the most suitable candidate.” (The prints found in the area also seemed to match the size of the Acrocanthosaurus.) The rituals might have been an attempt to demonstrate nest-making ability, since theropods are thought to have . 

As to which gender was dancing, birds might offer a clue, Lockley says. “We do know these dinosaurs are the ancestors of birds. And generally speaking, the male is the player and the female is the onlooker. So the odds are that the scrapes are of a male trying to attract a mate.”

Whoever was dancing, birds seem to have carried on the tradition—and expanded it. Several species of birds, including the , the Whooping Crane, and the moonwalking Red-capped Manakin (see below), are known for their unique mating moves.