Legends and names referring to a special type of unicorn or mysterious beast with one horn, as opposed to the delicate imaginary unicorns of Europe based on narwhal horns, are scattered across the former range of Elasmotherium from China to Eastern Europe. They have been noted there since the first known literature of the Middle Ages.
However there were (and still are) real existing “Unicorns”! They are actually of the same family as rhinoceros.
Elasmotherium (“Thin Plate Beast”) is an extinct genus of giant rhinoceros endemic to Eurasia. Three species are recognized. The best known, E. sibiricum was the size of a mammoth and is thought to have borne a large, thick horn on its forehead which was used for defense, attracting mates, driving away competitors, sweeping snow from the grass in winter and digging for water and plant roots. Like all rhinoceroses, elasmotheres were herbivorous. Unlike any others, its high-crowned molars were ever-growing. Its legs were longer than those of other rhinos and were designed for galloping, giving it a horse-like gait.
http://animals.nationalgeographic.com/animals/mammals/indian-rhinoceros/
12 Second video of baby rhino “skipping”
“He maketh them also to skip like a calf: Lebanon and Sirion like a young unicorn.” Psalm 29:6
The KJB translators also knew this was referring to as can be seen in their marginal notes:
In Isaiah 34:7 in the 1611 edition the AV translators wrote two slashes || in front of the word UNICORN. Those slashes are known as a siglum, and the 1611 edition makes use of sigla throughout. In the adjacent margin – directly across from this siglum – the AV translators repeat that same siglum, i.e., they write the same two slashes ||, and then immediately after that they write – “or Rhinocerots“