The horn of the monocorn is a formidable weapon when turned on an attacking carnivore like a northclaw. Monocorn herds usually travel with big males on the outside protecting the females and hornless young.
The monocorn, Monocornus occidentalis, is a single-horned, rhino/bison-like ceratopsid, most likely a relative of the centrosaurs, from the prairies and grasslands of the Great Plains in The New Dinosaurs: An Alternative Evolution.
The lightly built sprintosaurs are not the only grazing animals that roam across the vast prairies of North America. Huge slowly-moving grass-eaters also exist here, cropping the grasses down to their roots and moving on in black dusty herds. The huge monocorn is one of several species of ceratopsian that still inhabit the North American continent. It differs in appearance from the members of its ancestral stock, such as Triceratops and Styracosaurus, but the differences are not really profound, and they are a reflection of the life that the animal now leads. The herds of monocorn need to be on the move constantly, for once all the grass in one area is eaten up they have to move on to fresh areas. The legs are therefore longer and more slender then we would expect in such a large animal. The feet are digitigrade, that is they support the weight of the body on the toes rather than on the flat of the foot (the plantigrade condition of the monocorn's ancestors). In common with the ancient ceratopsians the neck and shoulders are protected by a bony frill, and a horn on the nose is used as a weapon.
The bony frill of the monocorn is very long, covering the length of the neck to the high shoulders. It is used when males spar with one another for herd leadership. The contestants push harmlessly against one another until one tires and gives way.
The ceratopsids in general are now no longer confined mostly to the North American continent. Several species are now found in Eurasia where they spread via the land bridge of Beringia between North America and Asia right before the Quaternary Glaciation officially began.