An early description of the karkadann comes from the 10th century Persian scholar Abū Rayḥān al-Bīrūnī (Al-Biruni, 973-1048). He describes an animal which has "the build of a buffalo...a black, scaly skin; a dewlap hanging down under the skin. It has three yellow hooves on each foot...The tail is not long. The eyes lie low, farther down the cheek than is the case with all other animals. On the top of the nose there is a single horn which is bent upwards." A fragment of Al-Biruni preserved in the work of another author adds a few more characteristics: "the horn is conical, bent back towards the head, and longer than a span...the animal's ears protrude on both sides like those of a donkey, and...its upper lip forms into a finger-shape, like the protrusion on the end of an elephant's trunk." These two descriptions leave no doubt that the Indian Rhinoceros is the basis for the animal. But the future confusion between the rhinoceros and the unicorn was already in the making since the Persian language uses the same word, karkadann, for the mythological animal as it does for the rhinoceros, and this confusion is evident also in the illustrations of the creature.
The Persian physician Zakariya al-Qazwini (Al-Qazwini, d. 1283) is one of the writers who, at the end of the thirteenth century, links the karkadann's horn with poison, in his ʿAjā'ib al-makhlūqāt wa gharā'ib al-mawjūdāt. He lists a few beneficial effects: holding the horn opens up the bowels to relieve constipation, and it can cure epilepsy and lameness.
In the 14th century Berber Sunni Islamic Scholar Abu Abdullah Muhammad Ibn Battuta documented describes it as a ferocious beast, driving away from its territory animals as big as the elephant; this is the legend that is told in "One Thousand and One Nights", in the Second Voyage of Sinbad the Sailor.
Another description said to be the size of a bull with a somewhat wolf like appearance and process two horns which protruded from atop its skull. The first horn, said to resemble an ivory spike, stuck straight up from the creature’s cranium and was said to be used as a means of gouging the Karkadann’s victims. The second horn jutted out from just above the animal’s nose and was said to be curved and bone like, this horn was reportedly used only as a means of self defense. This description is very different than its original depiction.
EvidenceFossils of a very similar animal, the Elasmotherium, have been found in Eastern China and Southern Russia, causing some scientists to speculate that a population of Elasmotherium may have found there way to India, Persia and Northern Africa, though at this time there is no fossil record to back up these claims. This giant rhinoceros like creature stood roughly 6 to 7 feet high and possessed a nearly 6 foot horn atop its head and although it is thought to have gone extinct nearly 1.6 million years ago, a sighting documented by Berber Sunni Islamic Scholar Abu Abdullah Muhammad Ibn Buttuta of a creature that resembled the Elasmotherium may indicate otherwise. Could this prehistoric giant have survived long enough into modern times to be the source of the Karkadann legend, some researchers believe so, while others believe that the Karkadann was nothing more than the misidentification of the rhinoceros.
The Karkadann itself is believed to be entirely based in myth, however there are some that believe that the Elasmotherium could have survived long enough to be the base for this myth. At any rate there is not physical evidence to support the existence of the Karkadann at this time.