The discovery of a fossilized skull in Kazakhstan is making paleontologists rewrite the timeline of the Siberian unicorn, Elasmotherium sibiricum. This impressive animal was a real-life unicorn, though it didn’t match the image most of us have for the fairytale creature.

Closer to a rhino than a horse in appearance, it was similar in stature to the mammoth. Measuring up to 6.5 feet tall and almost 15 feet long, it weighed up to 9,000 pounds. Its most recognizable feature was its single horn, which is thought to have been much longer than a rhino’s, up to multiple feet long. Its habitat was the vast territory from the Don River in Russia to east of modern Kazakhstan.

Here's a reconstructed Siberian unicorn skull at the London Natural History Museum. Note how sword-like the horn is, very different from the horn of a modern rhino.

A Siberian Unicorn's reconstructed skull and horn.A Siberian unicorn's reconstructed skull and horn. (Photo: Ghedoghedo/Wikipedia)

The Siberian unicorn, which first emerged in the fossil record around 2.5 million years ago, was thought to have disappeared 350,000 years ago. But the discovery made by researchers from Tomsk State University in Siberia, Russia, seems to show that E. sibiricum might have stuck around much longer. In fact, the beast and humans might have met, since our ancestors began spreading across Asia more than 50,000 years ago and likely went to Siberia around 35,000 years ago.

The well-preserved skull found in the Pavlodar Priirtysh region of northeast Kazakhstan was dated using the radiocarbon Accelerator Mass Spectrometry method and found to be about 29,000 years old. "Most likely, it was a very large male of very large individual age. The dimensions of this rhino are the biggest of those described in the literature, and the proportions are typical," Andrey Shpanski, a paleontologist at Tomsk State University, said in Phys.org. These findings are described in the American Journal of Applied Science.

It’s not yet clear why a Siberian unicorn was alive so long after the rest of the species was thought to be extinct, but scientists have some theories: "Most likely, the south of Western Siberia was a refúgium, where this rhino persevered the longest in comparison with the rest of its range. There is another possibility that it could migrate and dwell for a while in the more southern areas," said Shpanski.

First published restoration (1878) of E. sibiricum, by Rashevsky, under supervision of A.F. Brant.This is the first published restoration of Elasmotherium sibiricum. (Photo: Wikimedia Commons)

Michael Graham Richard ( @Michael_GR ) Michael writes for MNN and TreeHugger about science, space and technology and more.