Protoceratops is a genus of sheep-sized (1.8 m long) herbivorous ceratopsian dinosaur, from the Upper Cretaceous Period (Campanian stage) of what is now Mongolia. It is a member of the Protoceratopsidae, a group of early horned dinosaurs. Unlike later ceratopsians, however, it is a much smaller creature that lack well-developed horns and retained some primitive traits not seen in later genera. One was seen fighting against Blue Brow before it was buried alive under the collapsing sand.