This short BBC video shows why polar bears are so often unsuccessful in their summer hunts – adult bearded seals are the species most often available on the ice. These seals are not only predator-savvy but there are lots of escape routes in the melting ice, and this has always been so.
“Hungry polar bear surprises a seal – The Hunt: Episode 2 Preview – BBC One”
Melting ice in summer is not a new phenomenon (e.g. NASA photo below from mid-July 2016) – Thomas Grenfell and Gary Maykut described the process of melt pond development back in the 1970s:
“Melt ponds reach the maximum extent shortly after the disappearance of the snow, when they may cover upwards of 50% of the ice.”
Melting summer ice has always made it challenging for polar bears to catch seals, as this quote from Ian Stirling (1974) show, based on his work in the Central Canadian Arctic in the summer of 1973 (July and August):
“There is a great abundance of natural holes in the ice during summer, anyone of which a seal could surface through. “
This is still true in areas like the Southern Beaufort Sea today (e.g. Whiteman et al. 2015): the ice melts and in some areas, disappears completely in summer.
It’s why polar bears – unlike other species of bears in summer – depend on their stored fat to see them through until the ice reforms in the fall.
The meme “If there’s no ice, there’s no ice bear” is political-style rhetoric, not science.
[When polar bear scientists say “sea ice” or “ice” – they mean summer sea ice. Sea ice in winter and spring are not predicted to decline by 2100 to any appreciable degree and that has been true since sea ice predictions began]
Polar bears in Hudson Bay and Davis Strait routinely go 4-5 months without sea ice in the summer and have done since studies on them began. Yet, all of the polar bear subpopulations in Hudson Bay and Davis Strait are stable or increasing.
Posted in Life History, Sea ice habitat
Tagged bearded seals, Davis Strait, facts, Hudson Bay, hunting, no ice, no ice bear, platform, polar bear, sea ice, seals, summer
At least a dozen polar bears that besieged a remote Russian weather station on an island in the Kara Sea during the first two weeks of September prompted a few media pundits to suggest that loss of summer sea ice due to global warming may be forcing polar bears to hunt humans for food. Headlines like the one below, from the IB Times, fueled such notions:
Eye-catching though such headlines might be, this is more sensationalism than reality. These particular bears have been onshore since early July this year (about the time some Western Hudson Bay bears come ashore) and sea ice conditions have been similar this time of year since 2007. In other words, despite what some writers are claiming, sea ice conditions this year are nothing new.
A few bears usually visit this station each summer when the sea ice leaves – but this year there were more than a dozen bears rather than a few. My opinion as a scientist is that more bears – more bears that are increasingly unafraid of people – are likely the cause of the sudden increase in numbers of bears being a problem at this location. Note that of the 14 bears, four were cubs, which is a good crop of youngsters.
In addition, hunting polar bears is banned in Russia and this incident shows to what lengths people must go to avoid killing them – the population must be booming and may be higher yet than the last population count (in 2013) of about 3,200 bears. More bears means more competition for food, which means more assertive bears get the goods. None of these bears were described as thin or starving – see more photos, like the one below, from the Russian weather station (Daily Mail, 18 September 2016).
While polar bears are always on the look-out for food (and thus always a potential threat to humans), they are most apt to be truly dangerous in winter (when they are at their lowest body weight) and in spring if seals are in short supply.
That’s why my new polar bear attack thriller EATEN is set in early spring, in a year when seals happen to be scarce. Imagine the damage those Russian polar bears could have done if they’d been truly desperate for food – a mere door or window would not have stopped them.
Imagine if dozens of truly ravenous polar bears stalk and ambush people across a great frozen landscape, taking them by complete surprise because no one considers a bear attack in spring to be a real possibility. What if dozens of people have been killed and eaten by hungry polar bears and there is no end in sight? That is the premise of EATEN – a science-based novel set in Newfoundland that will scare your pants off.
This is a great read for fall, when polar bear encounter stories abound. Hopefully the reports this year won’t include the kind of serious mauling that happened in 2003.
Posted in Polar bear attacks
Tagged attacks, besieged, climate change, facts, global warming, Kara Sea, polar bear, Russia, scientists, sea ice, weather station
This new effort by the BBC would make the PR department of the Center for Biological Diversity proud, with it’s prominent use of animal tragedy porn pretending to be science. In contrast, the actual science shows something quite different: though summer sea ice since 2007 has declined to levels not predicted until 2040-2070, there has been virtually no negative impact on polar bear health or survival, a result no one predicted back in 2005.
Bizarrely entitled “A 3-million-year ice age is coming to an end“ (15 September 2016), this slick video pretends it’s promoting the recently released paper by Harry Stern and Kristen Laidre (2016) that got a lot of media attention last week (see here and here).
Who exactly suggested the profound prophesy stated in their chosen title, the BBC Earth folks don’t say: the Stern and Laidre paper certainly does not. And the use of a bear that appears to drown before our eyes is Hollywood-style emotional manipulation. Note the careful use of “might” (above) and “could” (below).
Watch the videos below and weep not for the plight of the polar bear, but for the downfall of science journalism. Continue reading
Posted in Sea ice habitat
Tagged Arctic, BBC, Center for Biological Diversity, declining sea ice, endangered, facts, Laidre, polar bear, sea ice, Stern, summer sea ice, terminal threat, threatened, tragedy porn, video
The annual Arctic sea ice minimum for 2016 is imminent and the hand-wringing about polar bear survival has already begun. While this year is shaping up to be another very low sea ice minimum in the Arctic – not as low as 2012 but
lower than as low as 2007 (previously the 2nd lowest since 1979) – contrary to predictions, several recent studies show that such low sea ice coverage in summer has had no (or very limited) negative effects on polar bear health and survival. In fact, for polar bears in some areas low summer sea ice has been quite beneficial (although these are not the populations that polar bear specialists predicted would do better).
Since low summer extents of recent magnitude (3.0 – 5.0 mkm2) are clearly not any sort of threat to polar bears, it seems improbable that even an ice-free (≤ 1.0 mkm2) summer (e.g. Wang and Overland 2015) would be devastating to the species [don’t forget Cronin and Cronin 2016: they’ve survived such conditions before] – as long as conditions in spring allow for the necessary concentrated feeding on young seals.
Above: Top, minimum at 2012 (16 Sept, 3.41 mkm2, lowest since 1979); Center, 2007 (18 Sept, 4.17 mkm2); Bottom, 2015 (9 Sept, 4.50 mkm2), from NSIDC. Below: sea ice at 10 Sept 2016, 4.137 mkm2 – minimum not yet called).
Recall that in 2006, the IUCN Polar Bear Specialist Group based their conservation status of ‘vulnerable’ (likely to become threatened within the next 45 years due to reduced habitat) on the predictions of sea ice specialists (see 2008 update here).
Sea ice experts in 2005 predicted such low summer sea ice extents as polar bears have endured since 2007 (3.0 – 5.0 mkm2) would not happen until 2040-2070, at which time PBSG biologists said that >30% of the world’s bears would be gone.
Evidence to the contrary comes from polar bear specialists working in the Chukchi, Beaufort, and Barents Seas – and in Southern Hudson Bay – since 2007. Overall, the latest IUCN Red Book assessment (2015) put the global population size at 22,000-31,000 (or about 26,500).
All of this means that those polar bear experts were wrong: polar bears are more resilient to low summer sea ice conditions than they assumed.
Posted in Conservation Status, Population, Sea ice habitat
Tagged ACIA, arctic sea ice, Barents Sea, bearded seals, Beaufort Sea, body condition, Chukchi Sea, endangered, extinction, extirpation, facts, IUCN Polar Bear Specialist Group, NSIDC, polar bear, population size, predictions, productivity, ringed seals, sea ice, Southern Hudson Bay, summer ice minimum, survival, threatened
It appears that the male polar bear with a too-tight satellite radio collar that was photographed late last year near Kaktovik on the North Slope of Alaska has been captured and his faulty collar removed, says a statement posted on the University of Alberta website 25 August 2016. The animal was reported to be healthy and behaving normally.
As far as I can tell, no press release was issued and no media interviews have been conducted despite the strong interest in the fate of this bear last fall (previous reports here, here, and here) – I found the notice by accident while looking for something else.
Andrew Derocher and his research team from U of A have admitted they collared this bear and the Polar Bear Facts webpage where this recent statement appears was developed to deal with the many inquiries about the status of this bear (dubbed “Andy” by some).
Note the statement, copied below, does not confirm that this is indeed the same bear as was photographed last year – they just assume it is. No photo is provided of the rescued bear, although clearly some were taken. However, if it is not the same bear, then another subadult male spent the winter of 2015-2016 on the ice of the Beaufort Sea with a tight and non-functioning collar that was not about to fall off by itself.
Only three females with collars are still being tracked by USGS researchers in the Beaufort Sea and all of them spent August 2016 on the sea ice in the eastern portion, off the coast of Banks Island.
Meanwhile, as Arctic sea ice nears the annual low, NSIDC predicts that 2016 will likely not set a new record but may bottom-out below 2007 (the second-lowest since 1979). The impact of low September sea ice on polar bear health and survival, based on recent research reports, will be the topic of an upcoming post.
Posted in Life History, Sea ice habitat
Tagged Beaufort Sea, females, NSIDC, polar bear, satellite collars, sea ice, September minimum, summer, tracking, USGS