This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Woolly rhinoceroses (Coelodonta antiquitatis) were fascinating creatures: giant, lumbering Ice Age beasts with thick fur and massive horns that died out about 11,000 years ago. Previous genetic studies had left open the question of whether their genetic diversity emerged in high-latitude areas, like that of woolly mammoths, but a new analysis of ancient DNA and habitat models covering the past 500,000 years has revealed a different story.
It made sense to look to the frozen north. Scientists already knew that woolly mammoths developed much of their genetic diversity in northern Siberia. But for woolly rhinos, the genetic evidence was much more limited, with only three nuclear genomes coming from Northeast Siberia.
Yet this created a major blind spot. With genetic evidence coming almost entirely from the far north, researchers realized they were ignoring vast swaths of Eurasia, the combined landmasses of Europe and Asia. So an international team of scientists led by He Yu from Peking University looked beyond these extremely cold settings.
That meant screening 183 fossils from across Eurasia to find high-quality ancient DNA. They recovered 29 mitochondrial (maternal) genomes and 14 nuclear genomes, which they compared with previously published genetic data from other woolly rhinos and related species. While fossil woolly rhinos have been found in many parts of Eurasia, that only tells us where individual animals died.
To see if these milder regions could have remained suitable habitats over time, the team needed to map the ancient environment. They fed fossil locations and ancient climate and vegetation data into computer models to reconstruct how the environment changed over 500,000 years. The findings, published in the journal Science, had a couple of major surprises in store.
The first was that, unlike woolly mammoths, much of the woolly rhino's genetic diversity emerged in temperate, midlatitude Eurasia rather than far-northern Siberia. "Our results suggest that its maternal genetic diversity mainly evolved in temperate Eurasia around 460,000 to 420,000 years ago during a prolonged glacial-interglacial transition," the study authors said. The second was that the species did not simply expand southward from the frozen north when the climate cooled.
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