With a weight of up to 7,700 pounds, Elasmotherium sibiricumIt was believed that an extinct furry rhino known popularly as the "Siberian unicorn" disappeared 200,000 years ago. An updated fossil analysis suggests that this formidable species was still around 39,000 years ago, and that the conditions of the Ice Age, not the human hunters, contributed to its demise.
Paleontologists know about 250 species of rhinos, of which only five exist today. Among the most spectacular of these rhinoceroses was Elasmotherium sibiricum-The Siberian unicorn. For Neanderthals and modern humans who lived next door and possibly hunted this massive creature in Eastern Europe and Central Asia, it must have been an impressive and deeply intimidating sight. Fossil evidence suggests Elasmotherium Weighed more than 3.5 tons, was covered by a thick layer of hair and sported a horn of Biblical portions, possibly up to three feet (1 meter) in length.
However impressive it may have been, the Siberian unicorns eventually became extinct. The previous fossil dating suggested an expiration date sometime between 200,000 and 100,000 years ago, long before the large-scale extinction of the Quaternary megafaunal, which began 40,000 years ago. New research published this week in Nature Ecology & Evolution now offers a more reliable estimate, dating from the demise of Elasmotherium Sometime between 39,000 and 35,000 years ago. The extinction of the Siberian unicorns, therefore, can now be connected to the extinction of the megafauna of the Quaternary, an event that witnessed the end of the woolly mammoth, the Irish elk and the saber-toothed cat.
Writing in their new study, led by Adrian Lister of the Natural History Museum in London, the researchers said that "there is no absolute dating, genetic analysis or quantitative ecological assessment of this species." [had] performed, "which explains why the previous extinction estimate was so far away, the new study overcomes these shortcomings and includes the use of updated fossil dating techniques.
For the study, an international team of researchers from the United Kingdom, the Netherlands and Russia examined more closely 23 Elasmotherium specimens, including a pristine skull stored in the Museum of Natural History. An improved radiocarbon dating technique resulted in the revised extinction dates; Many of the samples were mixed with preservation materials, which required careful preparation for carbon dating.
"Some of the samples we studied were highly contaminated, which made radiocarbon dating a challenge," Thibaut Devièse, a researcher at the Oxford School of Archeology and co-author of the study, said in a statement. "For this reason, we use a novel method of extracting a single amino acid from bone collagen to guarantee highly accurate results."
In addition, the researchers managed, for the first time, to extract DNA from the Elasmotherium fossils The resulting genetic analysis showed that Siberian unicorns separated from modern rhinos about 43 million years ago, "solving a debate based on fossil evidence and confirming that the two lineages had deviated from the Eocene," the researchers wrote in the study. . These rhinos from the ice age they are the last species of a "very distinctive and ancient lineage," according to the research.
The Siberian unicorns lived next to anatomically modern humans and Neanderthals. The fact that ancient hominids have taken advantage of these large rhinos is not as outrageous a proposition as it may seem. The first humans, probably a form of Homo erectus, they hunted rhinos in the Philippines about 700,000 years ago. But while rhinoceroses were on the menu of hominids, this new research suggests that climate change, and not hunters, was responsible for ElasmotheriumThe disappearance of
These rhinos, as we now know from the new research, lived during the Ice Age just before the Last Glacial Maximum, the stage at which the ice sheets covered their largest area, approximately 26,500 years ago. The Earth was prone to dramatic climate changes during this period, producing droughts, desertification, a drop in sea levels and the constant invasion of glaciers. These climatic interruptions were fatal for many species, Elasmotherium among them.
For the Siberian unicorn, this meant a loss of habitat and, consequently, the disappearance of a critical food source, as the new study suggests. In experiments, Lister and his colleagues analyzed stable isotope ratios of fossilized rhinoceros teeth. The researchers tried to link several plants with the levels of carbon and nitrogen isotopes in their teeth. The Siberian unicorns, as this analysis revealed, lived in a dry steppe environment where they stung in hard, dry grasses. The study suggests that rhinos, with their highly specialized grazing lifestyle and a naturally low population number, could not adapt quickly enough to rapidly changing conditions.
A changing climate, and not humans, were responsible for the disappearance of E. sibiricum. Interestingly, it is a conclusion that agrees with similar, but unrelated, investigations in which scientists claim that humans were not responsible for many megafaunal extinctions of the Ice Age. Unfortunately, the same can not be said of the sixth mass extinction in progress, which is undoubtedly our fault.[Nature Ecology & Evolution]