An international group of scientists from South Korea and other countries have discovered the world’s first fossil evidence of mating among carnivorous dinosaurs.

The Cultural Heritage Administration’s National Research Institute of Cultural Heritage(NRICH) said Friday that researchers from four countries, including South Korea, United States and Canada, studied the stratum during the Cretaceous Period.

The institute revealed that researchers unearthed in the U.S. state of Colorado around 50 fossils that showed traces of carnivorous dinosaurs digging the ground.

The NRICH presumed the ground-digging was done by large male carnivorous dinosaurs in an attempt to seduce their female counterparts.

The institute said it is the first time such fossils were discovered in the world, adding that its researchers led the whole excavation and research procedures.

The finding was published in the renowned scientific journal, Scientific Reports, a sister journal of Nature.