‘Climate change’ not the cause: DNA results prove so-called polar bear hybrid was a ‘blonde grizzly’ – Activists & media, ‘now have egg on their faces’

All the hubris last month about polar bear x grizzly hybrids, based on an unusual-looking bear killed near Arviat, has turned out to be wishful thinking by those who’d like to blame everything to do with polar bears on climate change. An awful lot of “experts” now have egg on their faces. That “hybrid” was just a blonde grizzly, as I warned it might.

grizzly-polar-bear-hybrid_Arviat 2016 Didji Ishalook

According to one report, Nunavut wildlife manager Mathieu Dumond said:

“Some otherwise pretty renown bear biologists jumped on the hybrid bear story without even knowing what they were talking about,” Dumond said.

“I think it was something blown out of proportion, with the wrong information to start.”

Gee, ya think? CBC ran a story too. But the CBC don’t really admit (see below) that they were the first out of the gate on this story and started the media madness. It was the CBC that relied on the opinion of a black bear expert from Minnesota (who likely only saw a picture) – but since he was willing to say it was a hybrid and that its presence was a sign of climate change, they went with it.  See “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” (CBC 18 May 2016).

For background, see these recent posts on this putative hybrid and the issues on hybridization it spawned:
Another alleged grizzly-polar bear hybrid shot but it’s not a sign of climate change

Polar bear hybrid update: samples sent for DNA testing to rule out blonde grizzly

Five facts that challenge polar bear hybridization nonsense

Most polar bear hybrids said to exist have not been confirmed by DNA testing

Blonde grizzlies, like the one pictured below (which I posted the day the story broke), are actually a proven sign of natural variation within species – a critical lesson in biology that should be the take-home message here.

“Paging Professor Derocher”: PBSG biologist and University of Alberta professor Andrew Derocher gave so many interviews to the media on this issue I lost count – he fed the media frenzy almost single-handedly. Well, except for granddaddy of polar bear experts Ian Stirling, who said (via the Toronto Star):

“I think it’s 99 per cent sure that it’s going to turn out to be a hybrid,” said Ian Stirling, an emeritus

New paper shows no harm from more time on land for S. Beaufort polar bears

polarbears-arcticnatlwildliferefuge-suzannemiller-usfws_labeled_smTake-home quote from a new polar bear paper by Todd Atwood and colleagues (2016):

“…there is no causal link between the patterns in polar bear vital rates and increased use of terrestrial habitat…”

In other words, there was no information to link the increased time polar bears spent onshore with either an increase or a decrease in body condition, survival or cub production. The authors did find that polar bears were strongly attracted to the bone piles that accumulated in the fall from 2010-2013 after Inuit bowhead whale (Balaena mysticetus) hunting at Barrow, Cross Island, and Kaktovik. Isn’t that a surprise?

The results also appear to confirm previous work that showed terrestrial (land-based) foods are not important to polar bears – a conclusion I totally agree with and which I discussed last year here. No wonder there was no press release issued by USGS about this study. It’s only “news” because someone the Anchorage Daily News interviewed lead-author Atwood yesterday as a way of promoting the International Bear Conference (see previous post here, now updated with a link to the Talk of Alaska radio podcast). Atwood implied there could be advantages to bears from feeding on the bone piles but admitted he had no data to support that assumption.

Some inconvenient polar bear facts supported by scientific literature

The evidence that polar bears have not been harmed by recent declines in sea ice is contained in the scientific literature, no matter what some researchers say when they talk to the media.

USGS w_polarbearscience_caption 2016

Here’s a few of those facts (not all, by any means), with the references to back them up:

  • Southern Beaufort bear numbers did not fall in the mid-2000s due to global warming or summer sea ice loss but because of thickspring sea ice conditions that were as bad as a similar event that occurred in 1974-1976 – a fact that’s well documented in the scientific literature (Amstrup et al. 1986; Bromaghin et al. 2015; Burns et al. 1975; Lentfer 1976; Harwood et al. 2000, 2012; Pilfold et al. 2015; Smith 1987; Stirling 2002; Stirling and Lunn 1997; Stirling et al. 1980, 1982). See this post: Biggest threat to polar bears reconsidered [especially the appendix]
  • Recent loss of sea ice in the Beaufort Sea (April/May 2016) has been due to the actions of the massively strong current called theBeaufort GyreSee this post (with NASA video) Beaufort Sea fractured ice due to strong Beaufort Gyre action – not early melt
  • The polar bear who swam the longest may have lost 22% of her body weight but that is a meaningless figure – other research shows that 22% was less than she would have lost if she’d stayed on land (Derocher and Stirling 1995; Durner et al. 2011; Pagano et al. 2012; Pilfold et al. 2016 in press). See this post: Longest-swimming polar bear lost less weight than if she had stayed onshore
  • Although it’s true that polar bears that spend the summer on the sea ice of the Arctic Basin don’t catch very many seals, biologists assume most bears eat very little over the summer regardless of where they spend it – on land or on sea ice (Derocher et al. 2002; Pilfold et al. 2015; Hammill and Smith 1991; Stirling 1974; Stirling and Øritsland 1995). See these posts: Polar bears out on the sea ice eat few seals in summer and early fall and Summer habitat for most polar bears is either shoreline or sea ice in the Arctic Basin
  • Starvation is the leading cause of death for young bears, sick or injured bears, and very old bears – it’s just a fact of life for this apex predator with no natural enemies (Amstrup

‘Nonesense’: Polar Bear researcher rips media reports of Grizzlies & Polar Bears mating due to ‘climate change’

Five facts that challenge polar bear hybridization nonsense

It was inevitable, I suppose, that the putative hybrid shot in Arviat,Nunavut last week (see my post here) would initiate the global warming blame game.

Hybrids again_Washington Post 23 May 2016_title screencap

Washington Post, 23 May 2016, Adam Popescu: “Love in the time of climate change: Grizzlies and polar bears are now mating

Here are the five points you need to know about polar bear hybridization, as there are several nonsense statements contained in this Washington Post article.


1) POLAR BEAR TERRITORY IS NOT CONTRACTING

Steven Amstrup, head spokesperson for Polar Bears International (“Save Our Sea Ice!”)

“[Steven Amstrup], like other experts, characterizes this “new” bear relationship as more beneficial to grizzlies than polar bears. That’s because there are more grizzlies than polar bears and because grizzly territory is expanding while polar bear territory is contracting. What that adds up to is a good chance grizzlies could essentially dilute the polar bear population until it doesn’t exist at all, they say.”

Polar bear territory is contracting” is a nonsense statement that is totally false. I dealt with a related claim here.

Territory might be prophesied to contract decades from now but so far,i t hasn’t changed a bit as a result of sea ice changes since 1950.The regions where hybridization has been documented (Doupé et al. 2007, see map in refs. below) are still polar bear territory, as is the region where the latest putative hybrid was shot (still not confirmed by DNA). All of the polar bear regions adjacent to grizzly populations in Canada have stable or increasing polar bear populations.

EC_PolarBearStatusMapCanada_Oct 26 2014

2) GRIZZLIES INVADING THE W. HUDSON BAY COAST ARE MOVING SOUTH

Derocher:

It shouldn’t be a big surprise that grizzlies are moving north — everything is.

Map below shows where grizzly populations are found in Central and Northern Canada (according to the SARA Registry, 2012 – see table copied below). If a grizzly male met a polar bear female along western Hudson Bay (which is the most recent putative hybridization event took place and where more grizzlies have been seen in recent years), it could only have come from the north.

Nunavut and other provinces_grizzly presence_Gov dot ca

The population table below is from the SARA Registry about grizzlies in Canada, which shows “few” grizzlies

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 ablack bear expert from Minnesota.

Hybrid pb shot in Arviat_CBC 18 May 2016

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:

Arviat with Churchill_Google maps

Climate Hustle knows: Ten dire predictions that have failed as global polar bear population hits 20-31k

https://polarbearscience.com/2016/05/01/climate-hustle-knows-ten-dire-predictions-that-have-failed-as-global-polar-bear-population-hits-20-31k/

While polar bears may be negatively affected by declines in sea ice sometime in the future, so far there is no convincing evidence that any unnatural harm has come to them. Indeed, global population size (described by officials as a “tentative guess“) appears to have grown slightly over this time, as the maximum estimated number was 28,370 in 1993 (Wiig and colleagues 1995; range 21,470-28,370) but rose to 31,000 in 2015 (Wiig and colleagues 2015, pdf here of 2015 IUCN Red List assessment; range 20,000-31,000).…

Scientists Find No Evidence Polar Bears Are Undergoing A ‘Climate Crisis’

http://dailycaller.com/2016/03/28/scientists-find-no-evidence-polar-bears-are-undergoing-a-climate-crisis/

A new study by Canadian scientists once again debunks the notion polar bears are currently being harmed by global warming. Researchers with Canada’s Lakehead University found “no evidence” polar bears are currently threatened by warming.

“We see reason for concern, but find no reliable evidence to support the contention that polar bears are currently experiencing a climate crisis,” Canadian scientists wrote in their study, published in the journal Ecology and Evolution.

Scientists looked at 13 polar bear subpopulations and found “much of the scientific evidence indicating that some polar bear subpopulations are declining due to climate change-mediated sea ice reductions is likely flawed by poor mark–recapture sampling.” This means researchers aren’t able to put together accurate “demographic parameters.”

Read more: http://dailycaller.com/2016/03/28/scientists-find-no-evidence-polar-bears-are-undergoing-a-climate-crisis/#ixzz44FUvff73…