Isbjørnen ble hvit for bare 480.000 år siden, og er derfor mye yngre som art enn tidligere antatt, har forskere funnet. Nettsiden til Arctic Research Centre i Århus skriver:
We compared genes between brown and white bears and were surprised. First and foremost, the polar bear as a species is less than 480,000 years old. It is thus significantly younger than previously thought,” says Professor Rune Dietz from the Arctic Research Centre, Department of Bioscience, Aarhus University.
The researchers believe that the brown bear migrated to the north during a warmer climate period and when a cold period subsequently set in, a group of brown bears may have become isolated and therefore forced to quickly adapt to the new colder conditions.