A couple of weeks ago in Arviat, Nunavut (CA), a local Inuit was out to hunt polar bears. However, what he had hunted was not an ordinary polar bear but a polar bear – grizzly hybrid. This is the third confirmed sighting of this hybrid and scientists now debate over the future of polar bears in the face of climate change.

Polar bears and grizzlies are closely related and thus hybrids have been known from zoological gardens. These hybrids are either grolar (grizzly father) or pizzly (polar bear father) bears. Picture by Corradox, Wikipedia
Polar bears and grizzlies are closely related and thus hybrids have been known from zoological gardens. These hybrids are either grolar (grizzly father) or pizzly (polar bear father) bears. Picture by Corradox, Wikipedia

Polar and grizzly bears have been mating across the circumpolar Arctic for thousands of years, says University of Alberta bear biologist Andrew Derocher. "These are two species that are very closely related," he says. "Polar bears evolved from a grizzly bear ancestor. We knew for a long time from experiments done in zoos in Europe and in Russia that polar bears and grizzly bears could hybridize in captivity but it wasn't until 2006 that we found the first one in the wild in the N.W.T." Recent grolar or pizzly bear occurrences have been the result of a male grizzly mating with a female polar bear. Male grizzlies can travel long distances looking for a mate while female grizzly bears tend to stay farther south.

In Canada and Alaska, female bears have to go ashore to give birth because of the missing multi-year ice and the loss of caves, like this one in Arviat. This puts them in the range of wandering male grizzlies. Picture: Michael Wenger
In Canada and Alaska, female bears have to go ashore to give birth because of the missing multi-year ice and the loss of caves, like this one in Arviat. This puts them in the range of wandering male grizzlies. Picture: Michael Wenger

Derocher says the biggest threat to the polar bear population is climate change and receding sea ice. But he says the hybrid bears could also have an impact if polar bear populations dwindle. "At some point, it's conceivable that the genetic information in both species would just sort of gobble up what's left of polar bears if [polar bears] do become that uncommon over time," he says. "But it's hard to say and predicting that far into the future is a challenge and it really depends on what we do about global warming as a whole."

Polar bears are made for a life on ice. Hybrids are most likely less adapted to ice and could have less chances of survival. Picture: Michael Wenger
Polar bears are made for a life on ice. Hybrids are most likely less adapted to ice and could have less chances of survival. Picture: Michael Wenger

Dave Garshelis, a research scientist with the Minnesota Department of Natural Resources, agrees that there are many threats to polar bear populations but he says he doesn't believe hybrid bears will usurp pure-bred polar bears. "There have been hybrids throughout our evolutionary history and yet they've never really taken off," he says. "In order for that to happen, the hybrid animal would have to be more adapted to the environment than either the pure-bred polar bear or pure-bred grizzly bear, which is very unlikely." Garshelis says polar bears have adapted to survive and hunt on ice and in Arctic waters, and grizzly bears have adapted to live on land. He says a hybrid bear with traits from each species would most likely not have the proper traits to live mainly on sea ice or mainly on land. "If the hybrid that we see now was very adaptive to this kind of environment we would have seen that in the past. There have been warming periods in the past, yet hybrids haven't taken over," Garshelis says. "It seems unlikely to me that we're going to have this giant influx of hybrids." But Derocher and Garshelis both agree that as climate change continues, more of them will be popping up.

Canadian Inuit have the right to hunt polar bears and have a set limit for their tradition. They use the fur, the meat and even the bones. But polar bear products are all banned in Europe and thus no trade is allowed. Hybrids could bring potentially more money because they are much rarer.
Canadian Inuit have the right to hunt polar bears and have a set limit for their tradition. They use the fur, the meat and even the bones. But polar bear products are all banned in Europe and thus no trade is allowed. Hybrids could bring potentially more money because they are much rarer.

Source: Canadian Broadcasting Company