A team of Swedish and Russian researchers found part of the answer in DNA fragments from 14 of these prehistoric animals (Coelodonta antiquitatis), their genetic codes revealing that rhino populations had remained stable for millennia in cohabitation with humans , their sharp decline coinciding with warming at the end of the last ice age, at the end of the Pleistocene.
“This makes it more likely that the climate changes of 14,000 years ago were the main cause of the extinction, rather than humans.“Love Dalén, geneticist at Stockholm University who conducted the study, told AFP, published Thursday in the journal Current Biology.
How can DNA strands taken from a few animals found in frozen soil shed light on the number of animals living at a given time?
The size of a population of a species is proportional to its level of genetic diversity and the degree of inbreeding, says Love Dalén. The analysis of the complete genome of a rhinoceros dating from 18,500 years ago, and in particular the comparison between the chromosomes inherited from the mother and those inherited from the father, showed that this genetic diversity was high, and that inbreeding was low.
“An individual’s genome is a mosaic of all of their ancestors“, this Love Dalén.”We come to the conclusion that 18,000 years ago this rhino belonged to a large population, and its ancestors also belonged to large populations, thousands and tens of thousands of years ago.“.
Since humans arrived in this part of Siberia 30,000 years ago, researchers conclude that for about 12,000 years, despite hunting, rhinos survived without declining. Until the so-called Bølling-Allerød warming.
The same team had previously published the genome of the woolly mammoth, and believes that for this other megaherbivore, global warming and not hunting was also at the origin of the extinction (the scientific community continues to debate this, however).
The difference is that the mammoths went extinct twice: the mainland ones disappeared along with the rhinos, but a few hundred survived on Wrangel Island, off Siberia, six millennia longer, before their extinction. definitive.
From Extinction to Extinction: The current closest cousin of the woolly rhino is the Sumatran rhino. It is in danger of extinction, with 80 animals surviving to date. The cause is clearly identified here: it is man (poaching, reduction of habitat).
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