Climate change killed "Siberian unicorn", study finds

Weighing more than 7,700 pounds and wearing what was probably the largest rhinoceros horn of all time, Elasmotherium sibiricumpopularly known as "Siberian Unicorn" – must be an incredible sight to behold.

But despite the spectacular appearance of this extinct rhinoceros, we know very little. This changed Monday with the publication of an article in Nature Ecology & Evolution presenting the first DNA analysis of Siberian unicorn fossils.

Under the leadership of Pavel Kosintsev, paleontologist of the Ural branch of the Russian Academy of Sciences, a team of researchers concluded to the death of the Siberian unicorn some 39,000 years ago, suggesting that modern humans and Neanderthals shared Eurasia with this epic beast on Earth. According to previous estimates, the rhinoceros disappeared 200,000 years ago.

Although humans have been implicated in the extinction of many species of megafauna, such as woolly mammoths and giant sloths, Kosintsev and his colleagues believe that our ancestors have kept their distance from this rhino and that climate change was probably the main factor of his disappearance.

"Human presence is unlikely to be a cause of extinction," said co-author Chris Turney, climate scientist at the University of New South Wales, in a statement. "The Siberian unicorn seems to have been severely affected by the beginning of the ice age in Eurasia, when a precipitous drop in temperature caused an increase in the frozen surface of the soil, reducing the hard and dry grasses on which it lived and affecting populations in a large area. "

The traditional chronology of the extinction of the Siberian unicorn was challenged for the first time by a E. sibiricum Skull discovered in Kazakhstan in 2016. The skull was dated 29 000 years ago, but the measure was not considered reliable because its collagen composition was not ideal for radiocarbon dating. .

Kosintsev and his colleagues decided to follow up the strange measure with multiple data sources. The team performed radiocarbon dating on 23 E. sibiricum specimens, extracted DNA from six specimens and conducted an ecological assessment of rhinoceros habitat from geological and fossil evidence.

The specimens were dated between 39,000 and 50,000 years ago, a period associated with the emergence of anatomically modern humans across Eurasia. It also coincides with the late Quaternary extinction, a period that lasted from 50,000 to 4,000 years and included profound climate change. According to the study, about 40% of the mammal species of North Eurasia weighing more than 45 kg died during this climatic event.

There is heated debate about the extent to which natural climate change or human pressures have pushed some of these species out of harm's way.

Read more: This ecologist finds clues about the survival at the Anthropocene extinctions of the ice age

To inform the impact of climate change on the Siberian unicorn, researchers carried out isotopic analysis of E. sibiricum fossils of teeth to replenish its probable food sources, and discovered that these animals were highly specialized breeders in the steppes. Eurasian herbivores with more diverse diets, such as the saiga antelope, have survived the 40,000-year-old climate change. But as grasslands have declined as a result of these disturbances, the Siberian unicorn may have been slowly threatened with extinction.

It is still possible that humans played a role in the eventual end of this animal. But E. sibiricum is rarely described in human rock art and there is no trace of its bones in the human settlements of that time; therefore, the two species probably did not interact much, according to the study.

It is incredible to think that humans were there to witness the last days of the Siberian unicorn, one of the most majestic megafaunes of the Pleistocene.

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