Dr. Susan Crockford
My open-access, peer-reviewed paper on the ecology of ancient polar bears in relation to sea ice has just been published in Open Quaternary. It’s called ‘Polar Bear Fossil and Archaeological Records from the Pleistocene and Holocene in Relation to Sea Ice Extent and Open Water Polynyas’.
A unique compilation of more than 104 polar bear skeletal records from the Holocene and late Pleistocene shows that most ancient remains are associated with existing or ancient open water polynyas or the expansion of sea ice during past cold periods. This big-picture analysis indicates that as they do today, polar bears were most commonly found near polynyas throughout their known historical past because of their need for ice-edge habitats.
Read my longer summary below and download the paper here. This is a much-updated and expanded analysis based on an informal study I did in 2012.
Polar Bear Fossil and Archaeological Records from the Pleistocene and Holocene in Relation to Sea Ice Extent and Open Water Polynyas
No Arctic animal is more iconic than its apex predator, the polar bear (Ursus maritimus). However, its distribution across time and space has not previously been reported. Natural death skeletal specimens of this species (‘fossils’) are rare but archaeological remains are much more common. This historical compilation presents the record of known ancient polar bear remains from fossil and archaeological contexts before AD 1910.
Most polar bear remains date to the Holocene (the last 11,700 years) and come from human habitation sites within the modern range of the species. Specimens found outside the modern range (extralimital) have been documented in the north Atlantic during the late Pleistocene (ca. 115,000- 11,700) and the southern Bering Sea during the middle Holocene (ca. 8,300-4,200 years ago), in conjunction with natural expansions of sea ice during known cold periods.
Surprisingly, the single largest assemblage of this species is also the oldest archaeological site with polar bear remains. Zhokhov is one of the northern-most islands in the East Siberia Sea, Russia which polar bears females still use today as a denning area. The site was occupied primarily during a short period (ca. 8,000-7,900 years ago) near the beginning of the Holocene Climatic Optimum (about 9,000-5,500 years ago), when the Arctic was warmer than today. Almost 6,000 polar bear bones were recovered from Zhokhov Island, which represented about 28% of all the animal remains identified at the site.
In virtually all other archaeological sites worldwide, less than 3.5% of identified remains were polar bear. The Zhokhov Island assemblage is also our first evidence of the return of polar bears to the western Arctic after extraordinarily thick sea ice during the Last Ice Age (ca. 30,000-19,700 years ago) drove seals and bears into the north Pacific.
This study shows that polar bear remains are most often found in proximity to areas where polynyas (recurring areas of thin ice or open water surrounded by sea ice) are known today and which likely also occurred in the past. As a consequence, the oldest known fossil (dated to about 130-115k years ago) and the oldest known archaeological specimens (dated to about 8,000 years ago) were likely associated with polynyas as well. This pattern indicates that as they do today, polar bears may have been most commonly found near polynyas throughout their known historical past because of their need for ice-edge habitats at which to hunt seals, their primary prey.
Citation: Crockford, S. J. 2022. Polar bear fossil and archaeological records from the Pleistocene and Holocene in relation to sea ice extent and open water polynyas. Open Quaternary 8(7): 1-26. https://doi.org.10.5334/oq.107
Thanks, Doc! Already emailed the link to original article to a dozen people. Yea, email. People actually do still use it. Weird, I know.
Susan Crockford, once again shows that the polar bear is a much more complicated creature. The so-called current climate emergency is small beer compared to what this supreme predator has had to put up with in the past.
Keep up the good work. Eventually.the deluded alarmists will have to concede.
Aw, what does she know?
She knows there is always a lot more to know.
One who doesn’t claim her conclusions are “settled”.
Which is what makes her such a superb scientist.
Dave was channeling griff without the apparently necessary/sarc tag
Yeah I got that too.
The down votes were from readers who misinterpreted what Dave meant.
Hardly an expert like Dr. Crockford. But dug up some interesting polar bear stuff for essay Polar Bears in ebook Blowing Smoke.
DNA single nucleotide polymorphisms (SNPs) show they ‘fully diverged’ from brown bear ancestors about 600kya. Indicia include webbed paws for swimming and white fur for springseal hunting. ‘Fully’ is relative, because they can still (rarely) interbreed. The Inuit terms for the hybrids translate to Pizzly and Growler (both puns depend on who mom was, as browns are also known as grizzly bears).
Later whole genome analysis shows the divergence actually started about 2mya, about when the present glacial era started. Makes sense. And present DNA from both says there was a lot of interglacial mixed interbreeding up until about 600kya.
So polar bears evolved to thrive in both glacial and interglacial conditions over several such cycles since ‘final’ divergence. And recent multiyear field studies of the West Hudson population shows that after ice out when polar bears come ashore, they will still hunt snow geese chicks and eggs, scavenge caribou, and even forage berries just like their brown bear cousins further south in Alaska when they are not gorging on salmon. Spring welping season seals only comprise about 80% of the West Hudson polar bear annual calorie diet.
So almost everything Sterling and Derocher have predicted for decades about global warming polar bear disaster has been wrong. As Dr. Crockford points out often, polar bears depend on spring ice edges to hunt seals during welping, not summer ice. And nobody ever modeled the Arctic to lose its spring ice after a cold dark winter.
Actually more recent mitochondrial DNA analyses suggest that polar bears split from brown bears about 4-5 MYA … long before the Pleistocene epoch began, making polar bears one of the most adaptable to wildly varying climates and polar ice extents of any existing mammalian species, having survived at least 24 major glaciation/interglacial cycles.
Th notion that the tiniest bit of warming experienced over the last 170 years is threatening their very existence is simply preposterous balderdash.
Also her bitch was with CliSciFi modeling. Even the Feds said it was no good for endangerment findings.
Sterling is an a**hole. So is Desocher.
That period corresponds with the Eemian that according to Wiki ‘was on average, around 1 to 2 degrees Celsius (1.8 to 3.6 Fahrenheit) warmer than that of the Holocene’ although other estimates for Greenland have been as high as ‘around 8 degrees C warmer than today’.
Cool.
When Hippos swam the Thames in London .
https://secretldn.com/hippos-lions-used-run-wild-london/
” This pattern indicates that as they do today, polar bears may have been most commonly found near polynyas throughout their known historical past because of their need for ice-edge habitats at which to hunt seals, their primary prey.”
Like Yogi said “They’re smarter than the average bear!” Since bears are smart enough to adapt to
differing ice conditions, I bet us humans can adapt to temperature changes that are << daily temperature
ranges. The banal stupidity reeks! 🙁
It seems rather apparent that for any given apex predator in any given environment to which they are adapted, the predator population is proportional to the prey population.
So what do the fossil data tell us about polar bear prey populations throughout the Pleistocene and Holocene epochs? Seals, and any other prey?
It appears that Dr. Crockford’s work includes investigations of seal/walrus dynamics over time.
“It seems rather apparent that for any given apex predator in any given environment to which they are adapted, the predator population is proportional to the prey population.”
While it may seem apparent to you it isn’t in fact the case they usually fluctuate in an oscillatory manner. The first development of the theory behind this was by Lotka, below is one of the first cases that he studied:
Recently, I haven’t noticed as many stories in media about Polar Bears
being on an extinction path. Further, I haven’t figured out if they have
a new creature to be worried about.
Secondly, when media folks realized rifles, snow mobiles, and airplanes had disrupted bear population dynamics and numbers stopped declining while CO2 increased, they needed to find a new creature. I think it was Puffins and then Monarch butterflies. Picas made a brief appearance. Your memory may differ.
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Thanks Susan.
“ Recently, I haven’t noticed as many stories in media about Polar Bears
being on an extinction path.”
That’s because Polar Bears don’t buy into the trans delusion. They’ll eat you regardless.
I saw a begging ad by WWF about saving the ‘endangered penguins’ in Antarctica. They shamelessly will always try anew.
They’re also begging on behalf of koalas, populations of which have increased since settlement.
Like when they had to change Global Warming into Climate Change. They also tell us that Slavery is Freedom.
Great catchy title …
“‘Polar Bear Fossil and Archaeological Records from the Pleistocene and Holocene in Relation to Sea Ice Extent and Open Water Polynyas’.”
… Just trips of the tongue !
But it’s … Proper science from a proper scientist.
Who know, Polar Bears have have to live near to their food source.
Dr. Susan Crockford,
Congratulations for your hard work and successful efforts to advance polar bear science.
Polar bear fossils near London, how interesting.
Finally, I have finished reading your book about the walrus deception – Fallen Icon -a diabolical story and tangled web of deceit created by an ignominious clique of scheming opportunists. You could have been a high-level criminal investigator, but I will guess that mammal science is more enjoyable.
Woke biologists have forgotten that many, if not most, species are capable of adaptation to changing environmental conditions.
https://nsidc.org/arcticseaicenews/