LONDON, Dec. 15 (UPI) -- Loss of sea ice in the arctic is leading to hybridization of animals, threatening the extinction of many species as they are presently known, researchers say.
With ongoing reductions in the amount of summer sea ice in the arctic predicted through the end of the century, polar bears will spend even more time in grizzly bear territories, and species of seals and whales currently living in different oceans separated by ice will soon share the same northern waters, an article in the journal Nature said.
Isolated populations will come into contact and mate, and some, like the North Pacific right whale, could be driven to extinction, the authors say.
Many arctic hybrids have already been seen. In 2006, arctic hunters shot a polar bear-grizzly bear mix, a white bear with brown patches. In the late 1980s, a skull thought to be that of a narwhal-beluga whale mix was found in west Greenland, and in 2009, an apparent bowhead-right-whale hybrid was photographed in the Bering Sea.
Porpoises and seals are known to be hybridizing, researchers say, and this year another polar-grizzly hybrid was killed.
The authors of the Nature piece call for a monitoring program to see how much cross-breeding is going on, so the International Union for the Conservation of Nature can develop better protection plans.
"The rapid disappearance of sea ice leaves little time to lose," the authors write.