A Nunavut hunter has killed what many believe to be a grizzly bear/polar bear hybrid, one of only a handful identified during the last decade and another sign of a changing environment in the North.
On May 15, Didji Ishalook from Arviat, 250 kilometres north of Churchill, Manitoba, posted photos on social media of the animal and has since been interviewed about the kill, while DNA samples of the bear have been sent to a lab in British Columbia for confirmation.
Grizzlies and polar bears have enough genetic similarity to allow for interbreeding – they are thought to have split off from the same genetic line no more than 500,000 years ago – but scientists have yet to determine if a hybrid bear can reproduce or what their survival rate might look like. What is known is that young male grizzly bears have been extending their range in recent years, so much that the two species‘ habitat zones are now overlapping in places.
“We have reports from hunters on occasion that grizzly bears venture on to sea ice in the spring to scavenge from polar bear kills or hunt newborn seals,” says biologist Malik Awan from Igloolik.
The extended range of the grizzly seems to have been spurred on by a number of factors – warmer temperatures in more northern climes, for one, but also because of better population management and stricter hunting quotas. Andrew Derocher, biology professor at the University of Alberta says their habitat has been spreading eastward from the Northwest Territories and western Nunavut. “We have very healthy populations with improving conditions. We’re probably getting more young dispersing males. They just pick a direction and go,” says Derocher. “But they aren’t finding females to mate with, which means they tend to roam farther and farther.”
The polar bear has taken centre stage in the public’s consideration of the effects of climate change – consider the image of an anxious polar bear balancing on an ever-shrinking chunk of floating ice. But even as the Arctic’s sea ice continues to melt, effectively causing the polar bear’s traditional hunting environment to disappear, researchers are now predicting that the polar bear’s chances of survival are not as poor as previously estimated.
“Polar bears are opportunists and have been documented consuming various types and combinations of land-based food since the earliest natural history records,” says Robert Rockwell of the American Museum of Natural History. While earlier studies had predicted mass starvation of polar bears by mid-century, new evidence points to the likelihood that polar bears will adapt by changing their diets to include land resources such as snow geese, their eggs and caribou, rather than seals.
Researchers gauged the caloric requirements needed for the bears to ward off starvation during ice-free periods in the North and found that there are more than enough calories available on land to meet the polar bear’s needs even as the ice-free seasons in the Arctic grow longer. “If caribou herds continue to forage near the coast of Western Hudson Bay when bears come to shore earlier each year, they are likely to become a crucial component of the bears’ summertime diet,” says Rockwell.