
he diminutive Stegoceras dinosaur is thought to have engaged in head-to-head combat with sexual competitors. Artist's impression: Richard T. Nowitz/Corbis
A small, two-legged dinosaur that browsed leaves and berries in the forests of the late Cretaceous fought off rivals by unleashing some of the most formidable head butts ever seen, say scientists.
Stegoceras validum, a beast no bigger than a goat, was engaging in head-to-head combat to overpower its sexual competitors 72m years ago in what is now North America.
Brain scans of skulls belonging to Stegoceras and modern animals that practise head-ramming, such as bighorn sheep and musk ox, revealed that they share cranial features that allowed the animals to withstand eye-watering clashes.