'That's the interesting thing,' says Lord.

This stability lasted until well after humans began living in Siberia, contrasting the declines that would be expected if the woolly rhinos went extinct due to hunting. 'We found that after an increase in population size at the start of a cold period some 29,000 years ago, the woolly rhino population size remained constant and that at this time, inbreeding was low.' 'We examined changes in population size and estimated inbreeding,' says co-first author Nicolas Dussex, a postdoctoral researcher at the Centre for Palaeogenetics. 'We sequenced a complete nuclear genome to look back in time and estimate population sizes, and we also sequenced fourteen mitochondrial genomes to estimate the female effective population sizes,' says co-first author Edana Lord, a PhD student at the Centre for Palaeogenetics.īy looking at the heterozygosity, or genetic diversity, of these genomes, the researchers were able to estimate the woolly rhino populations for tens of thousands of years before their extinction. To learn about the size and stability of the woolly rhinoceros population in Siberia, the researchers studied the DNA from tissue, bone, and hair samples of 14 individuals. If anything, we actually see something looking a bit like an increase in population size during this period.'

'So, the decline towards extinction of the woolly rhinoceros doesn't coincide so much with the first appearance of humans in the region. But recently, there have been several discoveries of much older human occupation sites, the most famous of which is around thirty thousand years old,' says senior author Love Dalén, a professor of evolutionary genetics at the Centre for Palaeogenetics, a joint venture between Stockholm University and the Swedish Museum of Natural History. 'It was initially thought that humans appeared in northeastern Siberia fourteen or fifteen thousand years ago, around when the woolly rhinoceros went extinct.

Woolly rhinoceros