Protoceratops is a genus of sheep-sized herbivorous ceratopsian dinosaur, from the Upper Cretaceous Period (Campanian stage) of what is now Mongolia. It was a member of the Protoceratopsidae, a group of early horned dinosaurs. Protoceratops was a quadrupedal dinosaur that was partially characterized by its distinctive neck frill at the back of its skull. It was approximately 6 feet in length and 2 feet high at the shoulder. A fully grown adult would have weighed less than 400 pounds. The large numbers of specimens found in high concentration suggest that Protoceratops lived in herds. There is speculation that Protoceratops fossils were the basis of griffin myths.