Unique Polar Bears in Greenland

A genetically distinct population of polar bears (Ursus maritimus) has been documented living in southeastern Greenland.  Their access to sea ice is limited, which may account for their genetic difference.  The survive on the freshwater of the Greenland ice sheet,.  The lead author of a Science journal article said  indigenous people know if the bears, but the population had not been studied before.

They are still able to catch and consume seals on the sea ice between February and late May, after that they hunt the coastline using ice that has broken away land. The glacial ice makes the area a small refuge from the effects of climate change, which is rapidly causing sea ice to melt rapidly or not form at all. The glaciers that make a home for these bears exists elsewhere, such as in Svalbard and other inlets of the Greenland coast, but the combination of geological factors and abundant glaciers make this southeastern Greenland a redoubt for polar bears.  They provide an example of how polar bears may persist when sea ice has largely vanished.  Southeast Greenland's sea ice now resembles the conditions predicted for much of the Arctic by late this century.

Researchers collected thirty years of historic data from eastern Greenland with seven years of data from the remote and rugged southeastern region.  They also consulted with subsistence hunters, and tacked bears from the air.  They found the bears trekking over mountainous terrain to reach fjords filled with glacial ice.  Of the twenty-seven bears tracked by the study half of them floated down the coast for one hundred and twenty miles before hopping off their iceberg and returning home by land.  Scientist say while the newly documented habitat provides some hope for polar bear survival, it his too limited to support a large population of bears.  Glacial bear females are smaller than other females and have fewer cubs. a condition that may be related the rugged terrain and long searches for mates. These bears are so distinct that researchers have proposed this population to be the 20th polar bear subspecies. [glacial bear and cubs, credit: K. Laidre]

Polar bears are taking matters into their own paws as they spend increasing amounts of time on shore. As they move south in search of food, they meet the grizzlies that are moving north due a warming climate. Thus the number of polar bear and grizzly bear hybrids are increasing.  The first documented hybrid was shot in 2006.  DNA testing confirmed it was a "prizzly" bear--a hybrid.  The two species only diverged genetically 600,000 years ago, so they are able to produce viable offspring, which are also fertile. A 2017 study confirmed eight hybrid bears produced by a single polar bear mother and two male grizzlies.  It remains to be seen if these hybrids are able to adapt successfully to a rapidly warming environment,  Polar bear populations are expected to decline by 30% in the next thirty years.