The seasonal loss of ice in the Arctic which scientists believe will eventually lead to ice-free summers could have both beneficial and negative effects for the mammals that have over millennia adapted to life in the cold and harsh environment, according to a new research paper published in the December 15 issue of the journal Nature.
Bears, whales, seals and other mammals have for a long time been locked behind the ice, away from cousins who never developed the necessary traits to survive in the Arctic climate.
Marine mammalogist and first author Brendan Kelly of the National Oceanic and Atmospheric Administration’s marine mammal lab in Juneau, with conservation geneticist Andrew Whiteley of the University of Massachusetts Amherst and evolutionary biologist David Tallmon of the University of Alaska, looked at the effect the extinction of the sea-ice would have on the inhabitants of the once ice-locked region. They found that some mammals could disappear entirely, while others would lose the adaptive gene combinations which allowed them to thrive.
While hybridization — the intermixing of gene combinations between two similar but different species of animal — might have immediate beneficial effects for the first generation of offspring, later generations will be the ones to suffer as they lose the ability to live in the climate their ancestors had once lived in.
Already there are hybrid mammals wandering the Arctic, like the white bear with brown patches that was shot by hunters in 2006 and was later confirmed to be a polar bear-grizzly bear hybrid.
Enough of this sort of breeding, however, can eventually lead to a new species which is unable to live in the Arctic and, as a result, is forced to migrate south and contend with the species of animal which have been at home there longer.
Additionally, extinction is a very real possibility. The researchers note the possibility of the North Pacific right whale — which is believed to have fewer than 200 individual whales left — mating with the more numerous bowhead whales. If this was to occur, it is more than likely that the North Pacific right whale would be bread out of existence.