Elasmotherium

Elasmotherium or giant unicorn was a two meter high, and six meter long Rhinoceros with a single two meter long horn in the forehead. Its habitat was the steppes south of the range of the woolly rhinoceros. It may have weighed up to 5 tonnes. Its legs were longer than those of other rhinos and were designed for galloping, giving it a horse-like gait. It was probably a fast runner, in spite of its size. Its teeth were similar to those of horses, and it probably grazed low herbs.

Due to a lack of fossils, it is usually regarded as having gone extinct together with the rest of the megafauna ca: 10.000 years ago.

Possibly extinct later

It is not known when it died out, but according to Nordisk familjebok, and to Willy Ley, the animal may have survived long enough to be remembered in Evenks legends (a huge black bull with a single horn in the forehead). There is also a testimony by Ibn Fadlan (who is usually considered a reliable source) which indicates that it may have survived into historical times. It is also sometimes regarded as the source of the unicorn myth, and fits well the Persian karkadann unicorn, and the Chinese zhi unicorn.

Ibn Fadlan's account:

There is nearby a wide steppe, and there dwells, it is told, an animal smaller than a camel, but taller than a bull. Its head is the head of a ram, and its tail is a bull’s tail. Its body is that of a mule and its hooves are like those of a bull. In the middle of its head it has a horn, thick and round, and as the horn goes higher, it narrows (to an end), until it is like a spearhead. Some of these horns grow to three or five ells, depending on the size of the animal. It thrives on the leaves of trees, which are excellent greenery. Whenever it sees a rider, it approaches and if the rider has a fast horse, the horse tries to escape by running fast, and if the beast overtakes them, it picks the rider out of the saddle with its horn, and tosses him in the air, and meets him with the point of the horn, and continues doing so until the rider dies. But it will not harm or hurt the horse in any way or manner.

The locals seek it in the steppe and in the forest until they can kill it. It is done so: they climb the tall trees between which the animal passes. It requires several bowmen with poisoned arrows; and when the beast is in between them, they shoot and wound it unto its death. And indeed I have seen three big bowls shaped like Yemen seashells, that the king has, and he told me that they are made out of that animal’s horn.