{"id":303706,"date":"2024-02-21T15:59:16","date_gmt":"2024-02-21T14:59:16","guid":{"rendered":"https:\/\/climatescience.press\/?p=303706"},"modified":"2024-02-21T15:59:19","modified_gmt":"2024-02-21T14:59:19","slug":"ny-times-pushes-an-implausible-story-of-polar-bear-evolution-and-what-makes-a-species","status":"publish","type":"post","link":"https:\/\/climatescience.press\/?p=303706","title":{"rendered":"NY Times pushes an implausible story of polar bear evolution and what makes a species"},"content":{"rendered":"\n
\"\"
TPOTY 2014<\/figcaption><\/figure>\n\n\n\n

<\/p>\n\n\n\n

From polarbearscience<\/a><\/p>\n\n\n\n

Carl Zimmer over at the\u00a0New York Times<\/em>\u00a0penned a\u00a0misleading story of speciation<\/a>, using the polar bear as an example. It explains polar bear evolution based on a\u00a0genetic interpretation<\/a>\u00a0that ignores the fossil record, bear behaviour, and geological history. [h\/t Kip Hanson].<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

In my opinion, this kind of \u2018science communication\u2019 is more misleading than enlightening because it fails to alert readers to the fact that the topic is actually more complicated and gives the impression that the author considers readers too stupid to understand a more accurate explanation.<\/p>\n\n\n\n

Polar Bear Evolution<\/a><\/em> does a better job for those who are really interested in the process: it doesn\u2019t hide the complicated nature of speciation or polar bear evolution. It doesn\u2019t pretend to present \u201cthe truth\u201d but explains how a good scientist gets to a plausible explanation that best fits the evidence.<\/p>\n\n\n\n

What is a species?<\/strong><\/p>\n\n\n\n

From the Zimmer article, \u201cWhat is a species, anyway?<\/a>\u201d (New York Times, 19 Feb 2024):<\/p>\n\n\n\n

In the 1940s, Ernst Mayr, a German ornithologist, tried solving this problem with a new definition of species based on how animals breed.<\/em> If two animals couldn\u2019t breed with each other, Mayr argued, then they were separate species.<\/em><\/p>\n\n\n\n

By \u201cbreed with each other,\u201d he meant hybridize. But Mayr also acknowledged that occasional hybridization between species does not negate his concept that good species generally don\u2019t interbreed, which Zimmer doesn\u2019t bother to say or doesn\u2019t know. The issue for polar bears and brown bears (as for many other good species pairs), is how often hybridization actually happens.<\/p>\n\n\n\n

What we know through observation and genetic analysis is that hybridization between polar bears and brown bears is not only very rare but it only goes one way.\u00a0In the wild,\u00a0<\/strong>hybridization always involves a male brown bear (aka grizzly) and a female polar bear, even in second-generation hybrids (see image below) and\u00a0this photo essay<\/a>. In\u00a0Polar Bear Evolution<\/a><\/em>, I explain this in detail, which comes down to differenced in dominance behaviour between the two closely-related species. Similar \u201cone-way\u201d hybridization is common in many species pairs for the same reason: the less dominant species is virtually always the female partner when two otherwise good species come together at mating time.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Shared genes don\u2019t always mean hybridization<\/strong><\/p>\n\n\n\n

The next part of Zimmer\u2019s article gets into the genetic basis of speciation, which has been recently confounded by claims of widespread hybridization, which he begins with an example from polar bear evolution (my bold):<\/p>\n\n\n\n

You don\u2019t have to be a mammalogist to understand that polar bears and brown bears are different. Just one look at their white and brown coats will do.<\/em><\/p>\n\n\n\n

The difference in their colors is the result of their ecological adaptations. White polar bears blend into their Arctic habitats, where they hunt for seals and other prey. Brown bears adapted for life on land further south. The differences are so distinct that paleontologists can distinguish fossils of the two species going back hundreds of thousands of years.<\/em><\/p>\n\n\n\n

And yet the DNA inside those ancient bones is revealing an astonishing history<\/a> of interbreeding between polar bears and brown bears. After the two lineages split about half a million years ago, they exchanged DNA for thousands of years. They then became more distinct, but about 120,000 years ago they underwent another extraordinary exchange of genes.<\/strong><\/em><\/p>\n\n\n\n

Between 25,000 and 10,000 years ago, the bears interbred in several parts of their range. The exchanges have left a significant imprint on bears today: About 10 percent of the DNA in brown bears comes from polar bears.<\/strong>\u201d<\/em><\/p>\n\n\n\n

Zimmer is citing the work of Ming-Shan Wang and colleagues (2022) as his sole reference to explaining polar bear evolution. As I explain in my book, Wang and colleagues should have admitted that the evidence of shared genes they found in polar bears and brown bears could mean that ancient hybridization events took place OR that both species retained some genes from a recent ancestor they both have in common (e.g. Cronin et al. 1991, 2014; Kutchera 2014; Kumar 2017). They preferred the hybridization interpretation because it makes a more interesting and dramatic story but that doesn\u2019t make it true.<\/p>\n\n\n\n

And as Zimmer\u2019s additional examples show, this \u201chybridization\u201d story is becoming the preferred explanation much more often, including for some groups of birds, which is creating a confusing situation. It appears more and more geneticists are conveniently forgetting or ignoring the fact that shared genes do not necessarily mean ancient hybridization.<\/p>\n\n\n\n

When shared genes crop up, you need to look at more evidence to get the bigger picture, as I\u2019ve done in for polar bears my book, summarized in this blog post.<\/a> You need to look at dominance behaviour, as explained above, as well as the fossil record and geological history.<\/p>\n\n\n\n

I show that polar bears could not have evolved 500 thousand years ago (kya) because at that time brown bears did not exist in most areas of Eurasia and it was also an interglacial period, so there were no continental ice sheets to push brown bears offshore onto sea ice. The fossil evidence of brown bears is excellent and we know it was not until about 200kya, after a long warm interglacial period, that brown bears were living across Eurasia from Britain to Kamchatka, which set up conditions during the next severe Ice Age for polar bears to split off as a new species when continental ice sheets moved down from the Arctic.<\/p>\n\n\n\n

The evidence suggests the most plausible time for the rise of the polar bear as a new species was about 140kya at the height of the severe MIS 6 glacial period (see below, from Crockford 2023a).<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

The genetic evidence for timing precisely when polar bears arose varies greatly among more than a dozen distinct studies, and Zimmer cites only the most recent one (Wang et al. 2022) as if it must necessarily be the most accurate. He could at least have acknowledged that different studies existed. The chart below, from my book, summarizes the suggested timing of polar bear speciation from these studies (\u201cT & S\u201d is Talbot and Shields 1996):<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Geneticists have recently made some very bold statements about polar bear evolution, see here<\/a> and here<\/a>, often to support an interpretation that implicates future predictions of catastrophic global warming. My research over more than 20 years shows that while genetics has been able to give us some critical insights into evolution, it still cannot provide any kind of plausible explanation for exactly how or why speciation actually happens (Crockford 2023b).<\/p>\n\n\n\n

Distinguishing species from subspecies, as Zimmer explains<\/a>, is a contentious issue but it isn\u2019t likely to go away any time soon.<\/p>\n\n\n\n

References<\/strong><\/p>\n\n\n\n

Bidon T., Janke, A., Fain, S. et al. 2014. <\/strong>Brown and polar bear Y chromosomes reveal extensive male-biased gene flow within brother lineages. Molecular Biology and Evolution<\/em> 31(6):1353\u20131363.<\/p>\n\n\n\n

Bidon, T., Schreck, N., Hailer, F., et al. 2015. <\/strong>Genome-wide search identifies 1.9MB from the polar bear Y chromosome for evolutionary analysis. Genome Biology and Evolution <\/em>7(7):2010-2011.<\/p>\n\n\n\n

Cahill, J.A., Green, R.E., Fulton, T.L., et al. 2013.<\/strong> Genomic evidence for island population conversion resolves conflicting theories of polar bear evolution. PLoS Genetics<\/em> 9(3): e1003345.<\/p>\n\n\n\n

Crockford, S.J. 2023a. <\/strong>Polar Bear Evolution: A Model for How New Species Arise<\/em>. Amazon Digital Services, Victoria.  https:\/\/www.amazon.com\/dp\/1778038328<\/a><\/p>\n\n\n\n

Crockford, S.J. 2023b.<\/strong> The species problem and polar bear evolution. ResearchGate preprint<\/em>, DOI: 10.13140\/RG.2.2.20218.06089 https:\/\/www.researchgate.net\/publication\/372160076_The_Species_Problem_and_Polar_Bear_Evolution<\/a><\/p>\n\n\n\n

Cronin, M.A., Amstrup, S.C. and Garner, G.W. 1991.<\/strong> Interspecific and intraspecific mitochondrial DNA variation in North American bears (Ursus<\/em>). Canadian Journal of Zoology<\/em> 69:<\/strong>2985-2992.<\/p>\n\n\n\n

Cronin, M.A., Rincon, G., Meredith, R.W., et al. 2014.<\/strong> Molecular phylogeny and SNP variation of polar bears (Ursus maritimus<\/em>), brown bears (U. arctos<\/em>), and black bears (U. americanus<\/em>) derived from genome sequences. Journal of Heredity<\/em> 105(3):312\u2013323.<\/p>\n\n\n\n

Davison, J., Ho, S.Y.W., Brayk, S.C., et al. 2011.<\/strong> Late-Quaternary biogeographic scenarios for the brown bear (Ursus arctos<\/em>), a wild mammal model species. Quaternary Science Review<\/em> 30:418\u2013430.<\/p>\n\n\n\n

Edwards, C.J., Suchard, M.A., Lemey, P., et al. 2011. <\/strong>Ancient hybridization and an Irish origin for the modern polar bear matriline. Current Biology<\/em> 21:<\/strong>1251\u20131258.<\/p>\n\n\n\n

Hailer, F. 2015. <\/strong>Introgressive hybridization: Brown bears as vectors for polar bear alleles. Molecular Ecology<\/em> 24(6):1161\u20131163.<\/p>\n\n\n\n

Hassanin, A. 2015.<\/strong> The role of Pleistocene glaciations in shaping the evolution of polar and brown bears. Evidence from a critical review of mitochondrial and nuclear genome analyses. Comptes Rendus Biologies<\/em> 338:494-501.<\/p>\n\n\n\n

Kumar, V., Lammers, F., Bidon, T., et al. 2017. <\/strong>The evolutionary history of bears is characterized by gene flow across species. Scientific Reports<\/em> 7:46487<\/p>\n\n\n\n

Kutschera, V.E., T. Bidon, F. Hailer, J.L. et al. 2014. <\/strong>Bears in a forest of gene trees: Phylogenetic inference is complicated by incomplete lineage sorting and gene flow. Molecular Biology and Evolution<\/em> 31:2004\u20132017.<\/p>\n\n\n\n

Kurt\u00e9n, B. 1968.<\/strong> Pleistocene Mammals of Europe.<\/em> Weidenfeld and Nicolson, London.<\/p>\n\n\n\n

Lan, T., Lepp\u00e4l\u00e4, K., Tomlin, C., et al., including Lindqvist, C. 2022. <\/strong>Insights into bear evolution from a Pleistocene polar bear genome.Proceedings of the National Academy of Sciences USA 119(24):e2200016119.<\/em><\/p>\n\n\n\n

Lindqvist, C., Schuster, S.C., Sun, Y., et al. 2010.<\/strong> Complete mitochondrial genome of a Pleistocene jawbone unveils the origin of polar bear. Proceedings of the National Academy of Sciences USA<\/em> 107:<\/strong>5053-5057.<\/p>\n\n\n\n

Liu, S., Lorenzen, E.D., and Fumagalli, M. 2014<\/strong>. Population genomics reveal recent speciation and rapid evolutionary adaptation in polar bears. Cell<\/em> 157:<\/strong>785-794.<\/p>\n\n\n\n

Miller, W., Schuster, S.C., Welch, A.J., et al. 2012. <\/strong>Polar and brown bear genomes reveal ancient admixture and demographic footprints of past climate change. Proceedings of the National Academy of Sciences <\/em>109(36):E2382\u2013E2390.<\/em><\/p>\n\n\n\n

Talbot, S.L. and Shields, G.F. 1996. <\/strong>Phylogeography of brown bears (Ursus arctos<\/em>) of Alaska and paraphyly within the Ursidae. Molecular Phylogenetics and Evolution<\/em> 5:477\u2013494.<\/p>\n\n\n\n

Wang, M.-S., Murray, G.G.R., Mann, D., et al. 2022.<\/strong> A polar bear paleogenome reveals extensive ancient gene flow from polar bears into brown bears. Nature Ecology and Evolution<\/em> 6:936\u2013944.<\/p>\n\n\n\n

Yu L., Li Y.-W., Ryder O.A. and Zhang Y. 2007. <\/strong>Analysis of complete mitochondrial genome sequences increases phylogenetic resolution of bears (Ursidae), a mammalian family that experienced rapid speciation. BMC Evolutionary Biology <\/em>7:198\u2013209.<\/p>\n\n\n\n

<\/p>\n","protected":false},"excerpt":{"rendered":"

Carl Zimmer over at the\u00a0New York Times\u00a0penned a\u00a0misleading story of speciation, using the polar bear as an example. It explains polar bear evolution based on a\u00a0genetic interpretation\u00a0that ignores the fossil record, bear behaviour, and geological history. <\/p>\n","protected":false},"author":121246920,"featured_media":303715,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_coblocks_attr":"","_coblocks_dimensions":"","_coblocks_responsive_height":"","_coblocks_accordion_ie_support":"","advanced_seo_description":"","jetpack_seo_html_title":"","jetpack_seo_noindex":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"Carl Zimmer over at the\u00a0New York Times\u00a0penned a\u00a0misleading story of speciation, using the polar bear as an example. It explains polar bear evolution based on a\u00a0genetic interpretation\u00a0that ignores the fossil record, bear behaviour, and geological history. ","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[1],"tags":[691819822,691822681,691827074,691818745],"class_list":["post-303706","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized","tag-brown-bears","tag-endangered-species-act-esa","tag-ny-times","tag-polar-bear","fallback-thumbnail"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2024\/02\/0-polar-bear-feeding.jpeg?fit=2060%2C1323&ssl=1","jetpack_likes_enabled":true,"jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/paxLW1-1h0u","jetpack-related-posts":[{"id":259747,"url":"https:\/\/climatescience.press\/?p=259747","url_meta":{"origin":303706,"position":0},"title":"The story of polar bear evolution could not be told without discussing climate change","author":"uwe.roland.gross","date":"05\/30\/2023","format":false,"excerpt":"Polar bears arose as a new species because the climate changed and forced some brown bears to colonize the sea ice. Polar bears epitomize the story of\u00a0how evolution works\u00a0but perhaps not quite how you imagined it.","rel":"","context":"In \"brown bears\"","block_context":{"text":"brown bears","link":"https:\/\/climatescience.press\/?tag=brown-bears"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/05\/00ykBjTq22Cb3YtMmgLCGdHU-1.jpg?fit=1200%2C943&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/05\/00ykBjTq22Cb3YtMmgLCGdHU-1.jpg?fit=1200%2C943&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/05\/00ykBjTq22Cb3YtMmgLCGdHU-1.jpg?fit=1200%2C943&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/05\/00ykBjTq22Cb3YtMmgLCGdHU-1.jpg?fit=1200%2C943&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/05\/00ykBjTq22Cb3YtMmgLCGdHU-1.jpg?fit=1200%2C943&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":264124,"url":"https:\/\/climatescience.press\/?p=264124","url_meta":{"origin":303706,"position":1},"title":"No evidence polar bears survived Eemian warmth because they were not yet fully ice-dependent","author":"uwe.roland.gross","date":"06\/27\/2023","format":false,"excerpt":"Is evolution primarily fast or slow? Does it take hundreds of thousands of years or a few\u00a0generations\u00a0to produce a new species? Ignoring\u00a0vast evidence\u00a0to the contrary, most geneticists insist that evolutionary change is imperceptibly slow and\u00a0one of them\u00a0is using this misconception to support the human-caused climate change narrative.","rel":"","context":"In \"Arctic sea ice\"","block_context":{"text":"Arctic sea ice","link":"https:\/\/climatescience.press\/?tag=arctic-sea-ice"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/0227472polarbearscute550x412-1200x800-1.jpg?fit=1200%2C800&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/0227472polarbearscute550x412-1200x800-1.jpg?fit=1200%2C800&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/0227472polarbearscute550x412-1200x800-1.jpg?fit=1200%2C800&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/0227472polarbearscute550x412-1200x800-1.jpg?fit=1200%2C800&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/0227472polarbearscute550x412-1200x800-1.jpg?fit=1200%2C800&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":261713,"url":"https:\/\/climatescience.press\/?p=261713","url_meta":{"origin":303706,"position":2},"title":"How grizzlies evolved into polar bears: The first book to tell the whole story is now available","author":"uwe.roland.gross","date":"06\/12\/2023","format":false,"excerpt":"Polar Bear Evolution: A Model for How New Species Arise\u00a0is the fascinating story of the origin of polar bears. It reveals not just\u00a0when and where\u00a0the species came to be, but\u00a0how\u00a0it happened and\u00a0why\u00a0the bears were able to survive repeated cycles of sea ice change, some of unimaginable severity.","rel":"","context":"In \"Grizzlies\"","block_context":{"text":"Grizzlies","link":"https:\/\/climatescience.press\/?tag=grizzlies"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/00polar-bears.jpeg?fit=1200%2C762&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/00polar-bears.jpeg?fit=1200%2C762&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/00polar-bears.jpeg?fit=1200%2C762&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/00polar-bears.jpeg?fit=1200%2C762&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/00polar-bears.jpeg?fit=1200%2C762&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":287347,"url":"https:\/\/climatescience.press\/?p=287347","url_meta":{"origin":303706,"position":3},"title":"Polar Bear Evolution pre-Christmas book sale: discounts on all formats!","author":"uwe.roland.gross","date":"11\/09\/2023","format":false,"excerpt":"This fascinating story finally brings together everything that scientists have learned about the origin of polar bears, in clear language that non-scientists will understand: not just\u00a0when and where\u00a0the species arose, but exactly\u00a0how\u00a0it happened and why the bears were able to survive repeated cycles of sea ice change, some of unimaginable\u2026","rel":"","context":"In \"book\"","block_context":{"text":"book","link":"https:\/\/climatescience.press\/?tag=book"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/11\/image-271.png?fit=840%2C1200&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/11\/image-271.png?fit=840%2C1200&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/11\/image-271.png?fit=840%2C1200&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/11\/image-271.png?fit=840%2C1200&ssl=1&resize=700%2C400 2x"},"classes":[]},{"id":263983,"url":"https:\/\/climatescience.press\/?p=263983","url_meta":{"origin":303706,"position":4},"title":"Claims of interspecies hanky-panky have unfairly sullied polar bear & Neanderthal reputations","author":"uwe.roland.gross","date":"06\/26\/2023","format":false,"excerpt":"One big question I asked before writing my book on\u00a0polar bear evolution\u00a0was this: did interbreeding with grizzlies, aka\u00a0brown bears, profoundly impact polar bear history, as geneticists insist? Or is something else going on?","rel":"","context":"In \"Climate change\"","block_context":{"text":"Climate change","link":"https:\/\/climatescience.press\/?tag=climate-change"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/00RW-COMP-BEARred-1.webp?fit=1200%2C800&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/00RW-COMP-BEARred-1.webp?fit=1200%2C800&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/00RW-COMP-BEARred-1.webp?fit=1200%2C800&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/00RW-COMP-BEARred-1.webp?fit=1200%2C800&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/06\/00RW-COMP-BEARred-1.webp?fit=1200%2C800&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":367834,"url":"https:\/\/climatescience.press\/?p=367834","url_meta":{"origin":303706,"position":5},"title":"No News is Good News on Polar Bear Day: Celebrate With 35% Off Polar Bear\u00a0Evolution","author":"uwe.roland.gross","date":"02\/27\/2025","format":false,"excerpt":"Instead of asking whether polar bears will survive a bit of warming over the next few decades, ask yourself how they survived more than 100,000 years of unimaginable changes in Arctic climate (both much warmer\u00a0and\u00a0colder) before now?","rel":"","context":"In \"Arctic Climate\"","block_context":{"text":"Arctic Climate","link":"https:\/\/climatescience.press\/?tag=arctic-climate"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/02\/0Polar-Bear-Evolution-and-Relatives-4.jpg?fit=1200%2C803&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/02\/0Polar-Bear-Evolution-and-Relatives-4.jpg?fit=1200%2C803&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/02\/0Polar-Bear-Evolution-and-Relatives-4.jpg?fit=1200%2C803&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/02\/0Polar-Bear-Evolution-and-Relatives-4.jpg?fit=1200%2C803&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/02\/0Polar-Bear-Evolution-and-Relatives-4.jpg?fit=1200%2C803&ssl=1&resize=1050%2C600 3x"},"classes":[]}],"_links":{"self":[{"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/posts\/303706","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/users\/121246920"}],"replies":[{"embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=303706"}],"version-history":[{"count":5,"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/posts\/303706\/revisions"}],"predecessor-version":[{"id":303716,"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/posts\/303706\/revisions\/303716"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/media\/303715"}],"wp:attachment":[{"href":"https:\/\/climatescience.press\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=303706"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=303706"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=303706"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}