Artist's reconstruction of dinosaurs engaging in scrape ceremony display activity, based on trace fossil evidence from the Dakota Sandstone, Colorado. Scientific Reports/Xing Lida
Fancy footwork similar to that of modern birds may have been involved in some prehistoric mating rituals, researchers say.
Physical evidence of large scrapes made by the feet of theropod dinosaurs has been discovered at four sites at Dakota Sandstone, a single Cretaceous rock unit in Colorado.
The scrapes are similar to those made by some modern ground-nesting birds — including Atlantic puffins and ostriches — during breeding season.
The behaviour, known as nest scrape display, involves males showing off their ability to provide for females by excavating fake nests.
The largest site discovered by the team, led by palaeontologist Martin Lockley from the University of Colorado Denver, was about 750 square meters and contained at least 60 traces of scrapes.
The display arenas contained marks of different sizes and depths, meaning they were likely used by different species of therapods.
"These are the first sites with evidence of dinosaur mating rituals ever discovered, and the first physical evidence of courtship behaviour," Professor Lockley said.
"These huge scrape displays fill a missing gap in our understanding of dinosaur behaviour."
The discovery supports theories about the nature of dinosaur mating displays, which, until now, scientists could only speculate about.
"This is physical evidence of pre-historic foreplay that is very similar to birds today," Professor Lockley said.
The findings were published in Scientific Reports.
