Tag Archives: cannibalism

Tracking polar bears in the Beaufort Sea and the issue of open water in May

A map posted by USGS shows that the 13 polar bears with tags or collars tracked during April 2016 in the Beaufort Sea were down to 9 in May (7 females with collars, 2 subadult or adult males with tags). As two rather large patches of open water formed last month in the Beaufort – mostly due to winds and currents, rather than melt (see animation below, original post here) – a reasonable question is this: how have polar bears dealt with this somewhat unusual condition?

Polar_Bear_Biologist_USFWS_working_with_a_Bear_Oct 24 2001 Amstrup photo

Beaufort Sea breakup in April due to the effects of the Beaufort Gyre (NASA video):

There is also fairly extensive open water in Hudson Bay, so the same question can be asked for that region as well – but fortunately, we have data on tagged bears from both regions to give us a clue as to how the bears are faring.
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Cannibalism video shot in 2015 did not involve a starving polar bear

National Geographic has just posted an exclusive video shot mid-summer of 2015 of a male polar bear killing and eating a young cub.

National Geographic 2015 cruise Cannibalism video screencap_Feb 23 2016

It’s worth watching (23 February 2016; Polar bear cannialzies cub) [update: Youtube version posted below]. It was filmed in 2015 in Baffin Bay at mid-summer (during either their July 28-Aug 9 or Aug 7- 19 cruise; pdf of itinerary, dates and prices – oh my god, the prices! here). [Summer is 1 July-30 September]

You’ll soon realize the male bear was not thin or starving (as was true of a much-publicized 2011 event captured on film off Svalbard).

It is also obvious based on the dates listed above that this incident debunks the explanation that cannibalism by adult males is driven primarily by their desire to mate with the mother of the consumed cub: this incident occurred sometime between August 7 and August 19 (as I was informed via email, by a reader on one of those two cruises), which is well past the breeding season for polar bears. A male bear would not still have viable sperm by August and a female could not be forced into estrus. [added 26 February 2016]

National Geographic is already hyping this incident as more evidence of climate change harming polar bears, as the article accompanying the video suggests. However, this is just the typical oversell that accompanies much to do with polar bear these days.

The bear was not “driven to desperation” : he simply took advantage of a rare chance to eat during the summer:

“Without the ability to hunt seals, polar bears may be driven to ever more extreme cannibalism, if they’re not already.”

It’s clear to me that this was an opportunistic kill made at a time of year when few seals are available, as even Stirling admits. It reiterates the point I’ve made many times before, that polar bears on the sea ice in summer have few feeding opportunities.

Incidents of cannibalism cannot be said to be increasing because there is no scientific baseline for which recent occurrences can be compared. Scattered anecdotal reports of any behaviour cannot be touted as evidence for a trend even though they may be of interest and worth recording.

UPDATE 23 February 2016: Video now posted on Youtube, see it copied below:

Twenty good reasons not to worry about polar bears

PB  logo coloured Here’s a new resource for cooling the polar bear spin, all in one place. I’ve updated and expanded my previous summary of reasons not to worry about polar bears, which is now two years old. In it, you’ll find links to supporting information (including previous blog posts of mine that provide background, maps and extensive references), although some of the most important graphs and maps have been copied into the summary. I hope you find it a useful resource for refuting the spin and tuning out the cries of doom and gloom about the future of polar bears — please feel free to share. Pdf here of the text below.

This is the 1st anniversary of Canada providing population estimates and trends independent of the pessimistic prognostications of the IUCN/SSC Polar Bear Specialist Group (PBSG) — so let’s celebrate the recent triumphs and resilience of polar bears to their ever-changing Arctic environment.

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Polar bears and melting ice: three facts that shouldn’t surprise you

If I was invited by USA TODAY to discuss how climate change is affecting polar bears now – summed up in three talking points – this is what I’d say. I’d use some meaningful images rather than cute pictures of cuddly bear cubs and I’d provide links to my work with references and details to back up my answers.

Compare my responses to those supplied by Steve Amstrup in his capacity as spokesperson for Polar Bears International (“Save our sea ice!”) to Jolie Lee at USA TODAY last week, who’s word is expected to be taken as gospel.

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Polar bear cannibalism and sea ice, the spring of 1976

Remember Ian Stirling’s claim that late freeze up in Western Hudson Bay in 2009 was forcing polar bears to resort to cannibalism (here and here), with gut-wrenching images and video provided for the media? Or Steve Amstrup’s claim for a similar phenomenon in the Southern Beaufort in 2004?

I pointed out that Stirling’s claim was way overblown and that Amstrup’s incidents were almost certainly the result of heavy ice in the spring (not low ice in summer), similar to the heavy ice conditions and polar bear starvation documented in the same region back in 1974-1976.

It turns out that the heavy ice conditions documented in the Eastern Beaufort in the mid-1970s had much broader effects on polar bears and ringed seals than has been appreciated.
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Polar bears have not been harmed by sea ice declines in summer – the evidence

PB  logo colouredThe polar bear biologists and professional activists of the IUCN Polar Bear Specialist Group (PBSG) continue to insist that since 1979 increasingly smaller amounts of Arctic sea ice left at the end of summer (the September ice minimum) have already caused harm to polar bears. They contend that global warming due to CO2 from fossil fuels (“climate warming” in their lexicon) is the cause of this decline in summer ice.

In a recent (2012) paper published in the journal Global Change Biology (“Effects of climate warming on polar bears: a review of the evidence”), long-time Canadian PBSG  members Ian Stirling and Andrew Derocher (both of University of Alberta) summarized their position this way:

“Climate warming is causing unidirectional changes to annual patterns of sea ice distribution, structure, and freeze-up. We summarize evidence that documents how loss of sea ice, the primary habitat of polar bears (Ursus maritimus), negatively affects their long-term survival”

I’ve spent the last year examining their evidence of on-going harm, but in addition, I’ve looked at the evidence (much of it not mentioned in the Stirling and Derocher paper1) that polar bears have either not been harmed by less sea ice in summer or have thrived in spite of it.

This is a summary of my findings. I’ve provided links to my original essays on individual topics, which are fully referenced and illustrated. You are encouraged to consult them for complete details. This synopsis (pdf with links preserved, updated; pdf with links as footnotes, updated) complements and updates a previous summary, “Ten good reasons not to worry about polar bears” (pdf with links preserved; pdf with a foreword by Dr. Matt Ridley, with links as footnotes).

Update 8 September 2013: to include links to my post on the recently published Chukchi population report; updated pdfs have been added above.

Update 22 January 2014: added figure comparing March vs. September sea ice extent using the same scale, from NOAA’s “2014 Arctic Report Card,” discussed here.
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Ian Stirling’s latest howler: “the polar bear who died of climate change”

Will wildlife biologist and Polar Bear Specialist Group member Ian Stirling now say anything – no matter how unscientific – to garner more sympathy and media attention for polar bears? It appears so.  [see followup post published Aug. 11, here]

A tabloid-style picture-is-worth-a-thousand-words article appeared in the environment section of the UK newspaper The Guardian yesterday (August 6, 2013) with a picture of a dead polar bear meant to wring your heart. The picture is a vehicle for statements from Ian Stirling and others that this polar bear died from climate change. A longer article was alongside.

The caption below the photo of a dead polar bear (animal tragedy porn) is this:

This 16-year-old male polar bear died of starvation resulting from the lack of ice on which to hunt seals, according to Dr Ian Stirling.”

Many folks have been asking questions about this and so have I.

I suggest this is what really happened: the polar bear biologists working in Svalbard earlier this year knew this bear was going to die back in April when they captured him – they simply waited, with a photographer on hand, until he died. It was an orchestrated photo-op.

[Update, Aug. 8, 2013: I suggest it was not necessary for anything more to happen to “orchestrate” this photo than for the researchers who captured the bear in April to tell colleagues and local tour boat operators (who always have avid photographers on board) to “keep an eye out for a dead bear, we don’t think this guy is going to make it.” However, very little real information is provided. Who knows when (or from whom) we’ll get the whole story — if ever? That’s why anecdotal accounts like these aren’t “evidence” of anything, in the scientific sense. That’s the real take-home message here.  If this dead bear was being presented as scientific evidence, we’d have been given all the details, including necropsy results, local ice conditions, precise dates, locations, and photos of any other bears that were seen that were in poor condition. In other words, a proper scientific report. ]

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