What killed the woolly rhino?

FROM THE moa in New Zealand to the dodo in Mauritius, the arrival of humans has often spelled extinction for tasty but previously isolated animals. Many scientists had assumed that the woolly rhinoceros, a shaggy beast that sported an enormous horn, suffered the same fate. The animal was common in northern Europe and northern Asia 30,000 years ago, when the first humans arrived. Shortly after, it disappeared.

But Love Dalén, a professor at the Centre for Palaeogenetics in Stockholm, and Edana Lord, one of Dr Dalén’s PhD students, are not so sure. In a paper published in Current Biology, they use data from ancient DNA to argue that, this time at least, humans might be innocent.

Until recently, information on the fate of the great ice-age mammals had been limited to what could be gleaned from fossilised bones. While useful, bones can only tell you so much. They can reveal the number of animals of different ages present at a specific location at a specific time. With some species sex can be determined. Occasionally the cause of death can be detected.

In the past couple of decades, though, scientists have learned to tap another, richer source of information: ancient genomes. By itself, DNA degrades quickly, attacked by water and sunlight. But DNA encased within bones and teeth can survive for...