Elasmotherium, or the "Thin Plate Beast," also known as the Giant Unicorn, is a genus of giant rhinoceros that roamed the Eurasian steppes for millions of years, from about 5 million years ago until around 1.6 million years ago (but one report suggests it may have lived until the 10th century). Elasmotherium had an average height of 2 meters (6.6 ft), length of 6 meters (20 ft), with a single 2 meter (6.6 ft) long horn in the middle of its forehead. The horn had a wide base, sharpening to a point at the tip. With a horn larger than an adult human male, Elasmotherium could kill most would-be predators. Like modern rhinos, it was an herbivore, mostly consuming grasses.
Analysis of Elasmotherium fossils has led scientists to believe that the animal was probably a fast runner, despite its size. A charging specimen may have been able to generate more kinetic energy than any land mammal that ever lived. Like modern rhinos, it probably could have charged at 25 mph (40 km/h) for short periods, and was likely a good swimmer. Its size was similar to that of the largest living rhino today, the Indian Rhino. Its horn is about twice as long as the longest among living rhinos. Since all known specimens are fossilized, however, extant Elasmotherium horns are made out of stone, not keratin.
It has been suggested by the Nordisk familijebok (a Swedish encyclopedia published in the late 19th and early 20th century) and the science writer Willy Ley that Elasmotherium may have existed long enough to be remembered in the cultural consciousness of the Evenk people, who dwell in present-day Russia and China. A "huge black bull with a horn in its forehead" features in some of their legends. A possible reference to Elasmotherium in historic times also appears in the accounts of Ibn Fadlan, a medieval Arab Muslim who traveled as an ambassador from Baghdad to the settlements of the Volga Bulgars in present-day Russia. In his account, the beast had a propensity to toss men from their horses, spearing them in midair with its horn, while leaving their mount alone. It was allegedly hunted by the natives, who shot poison arrows at it from trees.