Study Suggests Mating Injuries Could Reveal the Sex of Duck‑Billed Hadrosaurs

A new study published this week in the journal Science proposes a compelling method for inferring the sex of at least one group of dinosaurs. Paleontologists have long struggled to determine sex from fossilized bones because most skeletal features do not clearly indicate male or female.

The research team focused on hadrosaurs, the familiar duck‑billed dinosaurs, noting a recurring pattern: many hadrosaur skeletons show healed fractures on vertebrae near the base of the tail. After testing multiple explanations for these traumatic bone lesions, the authors conclude the pattern is most consistent with injuries sustained during mating behavior.

"The mating hypothesis is the one that, at the moment, best explains our observations and data," said lead author Dr. Filippo Bertozzo of the Royal Belgian Institute of Natural Sciences in an interview with CNN.

If the injuries were indeed caused by mating interactions, the affected individuals were most likely female, according to the study. The authors emphasize that this interpretation is specific to hadrosaurs and that additional research is needed before the approach can be generalized to other dinosaur groups.

Limitations and next steps

While the analysis is thorough, the team plans to expand the dataset by including hadrosaur fossils from China and South America to test whether the pattern holds across broader geographic and taxonomic samples. The authors also note alternative explanations—such as intraspecific combat or accidental injury—cannot be completely ruled out without further data.

This study offers a promising avenue for paleontologists seeking to answer long‑standing questions about dinosaur biology and behavior, but the conclusions remain tentative pending expanded sampling and further testing.