Tuesday , December 1 2020

How Climate Change Deletes "Siberian Unicorn"

A mysterious mysterious giant rhino – called Siberian unicorn because of its huge horn – appears to have survived in Western Russia just 36,000 years ago, according to a study published today in Nature Ecology & Evolution. This date of extinction means that the last days of the Siberian unicorn were shared with early modern humans and Neanderthals.

Previously, little was known about the creature that was thought to have disappeared for more than 200,000 years. But genetic analysis and radiocarbon dating begin to reveal many aspects of how he lived and when he disappeared.

The main conclusion is that the Siberian unicorn has not disappeared due to the modern human hunt, nor is the peak of the last ice age about 25,000 years ago.

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Instead, it has succumbed to a more subtle climate change that has reduced meadows from Eastern Europe to China.

Our new results show that the Siberian unicorn relied on these grasslands and, unlike other species in the area, such as the Saga Antelope, could not adapt to the changes.

"The Siberian Unicorn"

Siberian unicorn (elastomotors) had a large horn rated up to one meter long. This was one of the many different types of rhino that ever existed.

In addition to the extinct wavy rhinoceros (which is still found as frozen mummies), there are five species of live rhinoceroses. All these beings are now sadly in trouble, including the white rhinoceros (almost threatened)
knight Javan (critically endangered) and the Sriman rhinoceros (critically endangered).

The loss of the Siberian unicorn provides a valuable case study demonstrating the low resistance of rhinoceroses to environmental changes.

The animal on which we worked was found in modern Russia, although its scope extends to areas that now include Kazakhstan, Mongolia and northern China, where it inhabited a steppe-like habitat dominated by herbs and herbs.

The Siberian unicorn shares this environment with saga antelope and other glacier species, including the wavy rhinoceros and the mammoth.

But most evidence so far indicates that the Siberian unicorn disappeared 200,000 years ago, while the wavy rhinoceros and mammoths disappeared 13,000 and 4,000 years ago, respectively.

Why then did the Siberian unicorn disappear, while other species living in the same habitat held for thousands of years longer, or even sagas, still survive today?

Saiga antelope in the sanctuary of Stepnoy, Russia. Its impressive nose acts as a dust and reverse filter that reduces the loss of water in a dry environment.
Wikimedia / Andrey Gilyov, CC BY-SA

A gun for smoking

Several unconfirmed evidence recently suggested that the Siberian unicorn survived to the present, similar to the wavy rhinoceros. So we studied the age of 23 animal bone samples held in museum collections in Russia and the UK.

More than 200,000 years ago, the new dating found that the Siberian unicorn actually disappeared recently just 36,000 years ago.

Then we looked at how he might have disappeared at that time.

Climate change seems likely to be a contender, but 36,000 years is well before the height of the ice age that occurred 20,000-25,000 years ago.

But this date coincides with the time of the obvious change to a cooler summer in northern Europe and Asia. This seasonal change has led to lower growth of grasses and herbs, as well as an increase in plant species of the tundra, such as mosses and lichens.

Vulnerable specialist

Then why did climate change 36,000 years ago drive the Siberian unicorn disappeared, but not the woolly rhinoceros or sagitt?

To answer this question, our study has fossilized bones from the Siberian unicorn, the wavy rhinoceros and the saga, and looked at the nitrogen and the carbon they contain – because the differences in these elements reflect the animal's diet.

We found that 36,000 years ago the site and the Siberian unicorn behaved very similarly, eating grass almost exclusively. After this point, the carbon and nitrogen in the bones of the bones show significant dietary change to other plant species.

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But shifting from a herb diet turns out to be too difficult for a Siberian unicorn, with its special folded wear-resistant teeth and low head just above the grass. Relatives like the woolly rhinoceros have always eaten a more balanced set of plants and have been much less affected by habitat change.

It is important that the climate change that led to the extinction of the Siberian unicorn was actually much less pronounced than those that occurred during the glacial era. Or the changes we will face in the near future.

The story of Siberian unicorn is a timely reminder that even minor changes in plant distribution can have devastating consequences for large animal species.

It is alarming that this is a dangerous risk for many animals, such as the surviving Siberian unicorn cousins ​​who, thanks to people, already have very limited ranges.

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