How Subtle Climate Change Wiped Out The Prehistoric ‘Siberian Unicorn’

Unicorns have been depicted as graceful creatures, resembling horses. Except of course, for that fabled horn. And, in a sense, they did exist but they didn’t look anything like that mythical creature of the Middle Ages. Elasmotherium, an ancient rhinoceros, is one such beast. But it’s a “unicorn” that’s perhaps suffered a few smacks from the ugly stick. At 9,000-lbs, this massive creature lived alongside our distant ancestors.

And no, it didn’t look like the unicorn featured in this gorgeous medieval tapestry:

This colorful tapestry, depicting Medieval unicorns, hangs in Stirling Castle, Scotland. Image license CC SA 2.0 by dun_deagh via Flickr

It looked more like this:

Elasmotherium sibericum. Image license CC SA 4.0 International by ДиБгд via Wikimedia Commons

However, recent research has come to light that suggests climate change played a significant role in the extinction of this ancient rhinoceros that had a face only a mother could love. Currently, three species of Elasmotherium are recognized, but the one I’m focusing on is the so-called Siberian unicorn (Elasmotherium sibiricus). Scientists originally believed this truly enormous rhinoceros (which was as large as some mammoths) became extinct about 200,000 years ago,  Yahoo! Lifestyle reports. But recently a team of international researchers began analyzing Elasmotherium’s DNA for the first time. And when they did, they realized the creature continued to roam Eastern Europe and Central Asia until 39,000 years ago.

Ancient artwork from a cave in Rouffignac, France, depicting what is believed to be an Elasmotherium. Image license Public Domain, U.S. France, by The Rhino Resource Center via Wikimedia Commons

For millions of years, things had been pretty rosy for the Elasmotherium lineage. Previously thought to be a close relative of living rhinos, scientists studied 23 bone specimens from the “Siberian unicorn,” and now know that it split from the line that led to modern rhinos at least 40 million years ago, ScienceAlert reports. This genetic analysis, coupled with radiocarbon dating gave scientists a more precise idea of how this animal lived and when it became extinct, TheConversation reports.

Predation by humans didn’t cause this creature’s extinction. Neither did the peak of the last Ice Age, which occurred about 25,000 years ago, the study’s authors believe.

Instead, subtle climate changes that reduced the grasslands in Eastern Europe and China appear to be the cause. These grasslands were crucial for this great beast, and unlike the Saiga antelope, which also coexisted alongside it and still lives today, Elasmotherium wasn’t able to adapt. Many fascinating and diverse rhino species appeared over a period of millions of years, but sadly, there are only five extant species of rhino. And all of them are in trouble, thanks to humans. This includes the Javan rhino, which is critically endangered, as is the Sumatran rhino, and the white rhino, which is near threatened.

And the scientists note that humans really should take a good long look at the extinction of this ponderous animal.

“If we look at timing, it’s during a period of climate change, which wasn’t extreme, but it did cause a bunch of much colder winters that we think really altered the extent of the grassland in the area,” said Alan Cooper of the Australian Center for Ancient DNA, in an interview with ScienceAlert.

Elasmotherium shared its’ home with mammoths, the aforementioned Saiga antelope, and the woolly rhino. As the grasslands shrank and permafrost took over, many herbivores adjusted their diets accordingly — relying on herbs, shrubs and any other vegetation they could eat. But the scientists believe this huge rhino wasn’t able to do that. Instead, they think it continued to eat grass until the encroaching permafrost finally caused its extinction.

The skull of Elasmotherium sibiricum. Image license CC SA 3.0 by FunkMonk via Wikimedia Commons

And they think the creature’s huge head, which was likely equipped with an absolutely enormous horn, may have contributed to the problem. An intact horn hasn’t been discovered yet, but scientists say that recovered skulls show that the base where the horn was located was absolutely massive. Based on comparisons with living rhinos, that horn may have been one meter (3.3 feet) long. That’s lead some scientists to question whether this animal could even raise its head.

“It looks this unicorn was so specialized to eat grass it couldn’t survive,” saidCooper, one of the authors of the study.

He added:

“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 it’s 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.”

The researchers are still aren’t sure why this cooling event, which was mild, seemingly led to Elasmotherium’s demise. They say further research is needed, but add that we should take note.

“The worrying thing about it is it shows you don’t have to have major climate change to have vegetation responses that can wipe out a species — and this is before humans had restricted animals’ ranges,” Cooper said. “Can you imagine what will happen today?”

It’s one reason why scientists are now looking to grasslands, in places like Africa, and how something like mild climate change can affect food production, he notes. Tragically, if this situation doesn’t change, many species face dire situations. And like the Siberian unicorn, they too may vanish.

The research team’s study was published on November 26 in the journal Nature, Ecology & Evolution. 

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