It's an animal that has captured our imagination ever since remains were first unearthed in Siberia: the so-called "Siberian unicorn" (Elasmotherium sibiricum), a massive beast that once sported a singular horn like no other.

Although not as dainty and majestic as the mythical horse-like unicorns we're all familiar with, these rhinoceros-like behemoths are more than worthy of the title. They would have been a sight to see: Imagine a creature the size of a woolly mammoth, with a 3-foot-long horn and brawny musculature.

And now, it turns out, there may have been humans who got to lay their eyes on these intimidating beasts. Scientists recently recovered intact DNA from an E. sibiricum specimen, and the analysis has just come in. There are some pretty big surprises, to say the least, reports Science Alert.

For one, Siberian unicorns didn't go extinct around 200,000 years ago, as scientists once presumed. Rather, they survived at least until around 36,000 years ago. That's recent enough to have co-existed with modern humans, who had started populating the steppe of Russia, Kazakhstan, Mongolia and Northern China by this time, within the habitat range of the unicorns.

Furthermore, the DNA analysis shows that unicorns were the descendants of a long-lost, ancient rhinoceros lineage, with a far more distant common ancestor to modern rhinos than anyone had predicted. In fact, they are at least 40 million years removed from the lineage that would come to produce modern rhinos. Though not quite as mythical as their namesakes, Siberian unicorns were special indeed.

Researchers were also able to narrow down what drove the animals to extinction, and it probably wasn't humans.

The problem with that 'magical' horn

"If we look at timing [of their extinction], it's during a period of climate change, which wasn't extreme, but it did cause a whole bunch of much colder winters that we think really altered the extent of the grassland in the area," explained Alan Cooper of the Australian Centre for Ancient DNA, to ScienceAlert. "We can also see the change in the isotopes in the bones of the animals — you can see and measure the carbon and the nitrogen in the bones and we can see that it was only eating grass."

In other words, unicorns were exclusively grass-eaters that simply couldn't adapt at a time when grasslands were disappearing and the tundra was encroaching. It's even possible that their massive horns were partly to blame for this; the weight of the appendage might have made reaching for higher shrubs and bushes laborious, keeping the animal with its mouth to the ground.

"It looks like this unicorn thing was so specialized to eat grass it couldn't survive," Cooper said. "Its head was a whopping great big thing, it was kind of extended really really low, sitting right at grass height, so it really doesn't have to lift its head up. There's question of whether it could even lift its head at all! It was highly specialist so once the environment shifted it appears to have died out."

There's more research that will need to be done before anything definitive can be said about why these ancient beasts truly died out when they did, but these are some important first clues. It's rare to be able to find intact DNA from such a long-extinct animal. The more we learn, the more unique (and dare we say, "magical") these captivating creatures tend to seem.

'Unicorn' DNA has been collected and analyzed for the first time
Elasmotherium sibiricum, the so-called 'Siberian unicorn,' is not as closely related to modern rhinos as once thought.