Paleontologists have described the sixth form of a horned marmots (genus Ceratogaulus, a synonym Epigaulus) on fossil material from Nebraska, reported in the Journal of Systematic Palaeontology. They compared his horns (outgrowths on the nasal bones) with horns other members of the family and came to the conclusion that these structures arose once and initially helped to dig the ground, and was later used as protection from predators. Animals with the largest horns, most likely, spent a lot of time on the surface and often exposed to the attacks of carnivores, therefore, had to have a means of defense.
Although members of the order of Rodents is very diverse in appearance and lifestyle, horned among them was very small — only representatives of the extinct genus Ceratogaulus from the family Mylagaulidae. They are called horned horned marmots or ground squirrels, but they seem closer to the “mountain beaver” of aplodontia from superselective Aplodontoidea. Ceratogaulus — the smallest horned mammals and only animals with antlers, which led an underground life.