Researcher Says He's First to Tell Male, Female Dinos Apart

If the sight of broad, wide plates along the back of a stegosaurus fails to drive you wild with desire, that's probably because you're not a female stegosaurus. In what the University of Bristol calls the "first convincing evidence for sexual differences in a species of dinosaur," researcher Evan Saitta says you can tell the male stegosauruses from the ladies by their plates. He tells Reuters that in males, the "broad, wide plates likely made a continuous display surface along the animal's back to attract mates," serving much the same showoff function as a peacock's feathers. Females had taller, narrower plates that probably served to ward off predators, he says.

Some paleontologists have their doubts about the conclusion of the study, which is published in the journal PLoS ONE, but Saitta tells the Verge he studied enough specimens to rule out other explanations, like age or variations within the species, for the differences in plates. And the study may be just the beginning of dinosaur sexing, as researchers take a fresh look at features like nose horns: The stegosaurus finding "suggests that many dinosaurs used sexual display, as birds and mammals do today, usually the males displaying or mock fighting to attract attention of females," a fellow University of Bristol paleontologist tells Reuters. (New research suggests the brontosaurus really did exist.)