Paleontologists have long wrestled with how to differentiate between male and female dinosaurs based on their fossils.

But new research may bring scientists closer to identifying the sex of one group of dinosaur.

Hadrosaurs, also known as duck-billed dinosaurs, were common during the Late Cretaceous Period (100.5 to 66 million years ago), and the bones of these herbivores have been found across multiple continents.

Some hadrosaur fossils show evidence of healing from traumatic bone injuries, all in the same location: on their vertebrae past the base of the tail.

No soft tissues preserving evidence of dinosaur reproductive organs have been found in the fossil record, and differences observed in fossils are often thought to be due to species or age, rather than sex. Additionally, evidence of dinosaurs containing fossilized eggs has been hard to come by.

The authors of a new study published Tuesday in the journal iScience believe the injuries occurred during mating — and they could be used to indicate which fossils belong to female hadrosaurs.

“This will be a game changer since it will enable other questions to be answered about differences between male and female dinosaurs,” said lead study author Dr. Filippo Bertozzo, a researcher at the Royal Belgian Institute of Natural Sciences’ Operational Directorate Earth and History of Life.

Identifying a pattern in fo