Stegosaurs are a group of dinosaurs characterized by the possession of two rows of plates and spines that extend from the neck to the end of the tail. They are known from Jurassic rocks, and have been found on all continents except Australia and Antarctica. Stegosaurs are part of a larger group of armoured dinosaurs, which also includes the ankylosaurs. Stegosaurs were four-legged plant-eaters that weighed about the same as a rhino. They were probably slow-moving, and not capable of running. They had very small teeth and do not appear to have chewed, but despite this, their bite forces indicate they could have eaten tough vegetation and small twigs. Several hypotheses have been put forward about the function of the plates of stegosaurs, but these have proven difficult to test. Different species appear to have had differently shaped plates, suggesting a role in display, and perhaps to deter predators. Join Dr. Susannah Maidment as she provides an overview of this unique and diverse group of dinosaurs.