Hoe het verder moet met de populatie ijsberen is ook onzeker.
Onlangs nog een nieuwe studie daarover gepubliceerd. Waarschijnlijk zullen ze opnieuw (meer) kruisen met de bruine beer.
"Rather than polar bears splitting from brown bears a few hundred thousand years ago, we estimate that the split occurred 4 to 5 million years ago."
"This result means polar bears definitely persisted through warming periods during Earth's history," Lindqvist said. She cautions, however, that the species' endurance over several million years doesn't guarantee its future survival.
"We see an increase in polar bears at the end of the Early Pleistocene as the Earth became much colder, and a continuous decline in the size of the population during warmer times. We also found, perhaps unsurprisingly, that polar bears occur in much smaller numbers today than during prehistory," Lindqvist continued. "They have indeed lost a lot of their past genetic diversity, and because of this, they are very likely more sensitive to climate change threats today."
The new analysis uncovered more genetic similarities than previously known between polar bears and ABC brown bears, an isolated group from southeastern Alaska -- suggesting that these animals have exchanged genes since becoming separate species.
