Another alleged grizzly-polar bear hybrid shot but it’s not a sign of climate change

CBC News this morning (“Grolar or pizzly? Experts say rare grizzly-polar bear hybrid shot in Nunavut: Expert says interbreeding may be happening more frequently due to climate change“) suggests that a putative grizzly x polar bear hybrid bear shot outside Arviat in Western Hudson Bay is a sign of climate change, based on an interview with a black bear expert from Minnesota.

This bogus claim has been busted so many times it’s a wonder it still arises – even polar bear specialist Ian Stirling has said flat out that such hybrids are not due to climate change. On top of that, some of the details regarding this putative hybrid make me want to wait for confirmation from DNA testing before adding it to the roster of known hybrids.
Location of Arviat, courtesy Google maps:

The CBC story reported:

“An odd-looking bear shot last week by a hunter in Nunavut has turned out to be a grizzly-polar bear hybrid — a rare find that a researcher says is becoming more common.

Hunter Didji Ishalook, 25, spotted the animal on top of a hill near his home community of Arviat, about 260 kilometres north of Churchill, Man. From a distance he thought it was either an Arctic fox or a small polar bear.

…

Dave Garshelis, a research scientist from the Minnesota Department of Natural Resources and one of the world’s foremost bear experts, agrees with Ishalook. He believes the bear is a grizzly-polar bear hybrid, and not an albino grizzly bear.

“An albino bear would have a light-coloured or pink-coloured nose, and no pigmentation in the eyes and the claws,” Garshelis said.

“This bear has a black nose, and normal dark-coloured eyes and claws. So, it’s not an albino.“

Grashelis [sic] said polar bears and grizzly bears have similar genetics and have a history of interbreeding. He believes that interbreeding is happening more frequently due to climate change.

“With climate change, grizzly bears are moving further north, so there is more overlap between grizzly bears and polar bears in terms of their range,” Garshelis said.

“There are even American black bears that are moving further north. And a few black bears have been spotted outside of Arviat.” [my bold]

Read the rest here.

Actually, while it may be true that the black bears that Garshelis knows so well are moving north, grizzlies in Nunavut are moving south as their numbers increase after decades of overhunting. This is a natural response of a growing population looking for suitable habitat, not a sign of climate change.

As I reported last year:

“4) A few more grizzlies were recently seen in along western Hudson Bay, where polar bears spend the summer. A compliant CBC (18 June) asked no tough questions of researcher Doug Clark (University of Saskatchewan), who claimed that a few grizzlies seen in Wapusk National Park (see map below) are a sign of global warming – “early winners in the climate change lottery” is the way he put it. Grizzlies in the prairies (Alberta, Saskatchewan, and Alberta) were extirpated years ago (pdf here) but the bears seen recently have moved south from Nunavut. There have been sightings along Hudson Bay since 2008 and these have been getting more frequent, so last week’s report is nothing new. This “invasion” by grizzlies is not an effect of global warming, it’s a healthy northern species expanding its range south into regions with suitable habitat (not north, as you might expect with warming).”

See my previous post here summarizing what we know about polar bear hybridization, with maps and references.

Is it really a hybrid?

It seems a bit odd to me that this animal was shot on land – hybrid polar bears found in the wild have so far turned out to be crosses between male grizzlies and female polar bears (and thus, would be “grolars” using the unofficial vernacular for naming hybrids – the male animal goes first). As a result, they are raised by polar bear mothers and live like polar bears out on the sea ice.

This bear was said to have been shot “last week” (May 9-13) which is a bit early for a polar bear to be ashore but about right for a grizzly just emerged from its winter den. It also seems rather thin for a polar bear that should have been feeding heavily at this time of year – but typical condition for a grizzly in spring.

So, either this animal was a young hybrid that was suffering from typical young polar bear feeding troubles (hadn’t yet learned how to hunt effectively and/or had its seal kills taken away from it by larger, older polar bears) or, given the location, was actually a pale-coloured grizzly.

Such animals do exist, despite the assertion by Garshelis that because the Arviat bear is not an albino it cannot be a grizzly (see photo below, from the US National Parks Service) – these pale bears have dark noses as well as dark paws. That’s why putative grizzly x polar bear hybrids are subjected to DNA tests before an identification of “hybrid” is concluded with certainty. Under the circumstances, I’d wait to see the DNA test results.

UPDATE 28 May 2016: See these 24 May 2016 updates (Five facts that challenge polar bear hybridization nonsense as well as Polar bear hybrid update: samples sent for DNA testing to rule out blonde grizzly) – and this 27 May 2016 follow-up post (Most polar bear hybrids said to exist have not been confirmed by DNA testing) for details on unconfirmed sightings or reports of hybrids (2007-2012).