Category Archives: Evolution

NY Times pushes an implausible story of polar bear evolution and what makes a species

Carl Zimmer over at the New York Times penned a misleading story of speciation, using the polar bear as an example. It explains polar bear evolution based on a genetic interpretation that ignores the fossil record, bear behaviour, and geological history. [h/t Kip Hanson].

In my opinion, this kind of ‘science communication’ 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.

Polar Bear Evolution does a better job for those who are really interested in the process: it doesn’t hide the complicated nature of speciation or polar bear evolution. It doesn’t pretend to present “the truth” but explains how a good scientist gets to a plausible explanation that best fits the evidence.

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Tom Nelson interview with me about the failed polar bear narrative and rapid evolution

You can watch my interview with Tom Nelson about the latest issues in polar bear conservation and highlights of my latest book, Polar Bear Evolution.

On Youtube:

Tom tells me, “It’s also up on other video sites such as Rumble and BitChute, and will soon be available on other podcast apps such as Apple Podcasts (most, but not all, of those are audio-only).  It should also be on Spotify, Google Podcasts, Pocket Casts, Podvine, Overcast, Amazon Music podcasts, Audible podcasts, Castbox, RadioPublic, Twitter, etc.”

Summary: Susan Crockford, a zoologist, discusses the challenges in accurately estimating polar bear populations and the ongoing debate between Inuit communities and polar bear specialists regarding population sizes. She also shares her theory on the role of thyroid hormones in polar bear evolution and the quick adaptation of species to new environments using the example of the Russian foxes.

A list of topics covered, by time-stamp in the interview, is listed below.

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Walrus and polar bear population size changes in the N. Atlantic over the last 20k years

This is a lesson in how to assess the potential worth of scientific papers. One of two similar Arctic evolution studies got media attention, at least in Canada — about the polar bears, of course — but in my opinion the walrus research conclusions are much better supported, less biased by climate change rhetoric, and lack the hubris present in the polar bear paper.

Both studies use similar sample sizes for the regions they had in common (North Atlantic) and used computer models to determine genetic diversity and population size changes since the LGM. However, the tone of the walrus paper was less emotionally-charged and the caveats of the work were appropriately stated. In my opinion, papers like the polar bear example contribute to eroding the public’s trust in science.

The last Ice Age peaked between about 27,000 and 19,000 years ago. At this time the Arctic was buried under kilometers of glacial ice sheets, and so marine mammals were pushed southwards to areas of ice floes and more open water. Walrus survived in some areas of the Atlantic located further to the south, and as soon as climates warmed again, the ice edge retreated and walrus populations pushed quickly northwards again. This combination of warming and climate-driven dispersal led to local walrus populations becoming more genetically differentiated. Walrus study, Lund University press release 27 September 2023

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Polar Bear Evolution pre-Christmas book sale: discounts on all formats!

I have reduced prices on all formats of my Polar Bear Evolution book for four weeks starting today (8 November-6 December 2023), in time for holiday gift-giving. The ebook version has the largest price reduction (60% of regular price, to US$17.40) but the other discounts are also substantial. This sale is a time limited offer: don’t miss out! Links below.

This is the book for those who are really interested in how grizzly bears could have turned into polar bears and why the story of polar bear evolution could not be told without discussing climate change.

One Amazon reviewer said this about Polar Bear Evolution:

The author of Polar Bear Evolution, Susan Crockford, is a good, credentialed scientist. Her writing is clear; her thinking is also. She has a broad understanding of biology and an informed paleo perspective. Crockford condenses a very large literature on polar bear biology and evolution in this book which will help readers understand the science related to the evolution of an Arctic species. Perhaps the most important aspect of this book is its synthesis of information from the fields of wildlife biology, molecular evolution, paleontology, and climate. Her original ideas and hypotheses on thyroid hormone’s role in evolution are very important and add a credible mechanism of phenotypic change which complements the literature on molecular genetic evolution. Polar Bear Evolution is an important contribution to science and its application in evolutionary biology and wildlife biology. Matthew A. Cronin, Ph.D.

Available at the links below (others also available):

USA https://www.amazon.com/dp/1778038328

UK https://www.amazon.co.uk/dp/1778038328

Canada https://www.amazon.ca/dp/1778038328 [shipping delay for hardcover version is 4-5 weeks]

Australia https://www.amazon.com.au/dp/1778038328

Germany https://www.amazon.de/dp/1778038328

Evolution Earth documentary comments on polar bear survival & adaptation: let’s see how they do

Just a heads-up that this week, PBS in North America will broadcast the “polar” episode of a new documentary called “Evolution Earth.” In my area, it’s scheduled for Wednesday, September 27 at 10:00 PM. It remains to be seen whether this is really about evolution or (given those involved in its production) simply more climate change propaganda similar to that promoted by Attenborough, but I intend to watch and report back.

About the Show: “Evolution Earth embarks on a global expedition to reveal the animals keeping pace with a planet changing at superspeed. Heading out across the globe to distant wilds and modern urban environments, five episodes track how animals are moving, using ingenuity to adapt their behavior, and even evolving in unexpected ways.

We follow heart-warming tales of resilience that redefine our understanding of evolution, and hint at how nature can show us a path towards a sustainable future for Planet Earth. The series is narrated by Dr. Shane Campbell-Staton, who guides us through each episode in an intimate narrative style, drawing on his background as an evolutionary biologist.”

Episode 4 | IceAt the planet’s frozen extremes, shifts in animal movement and behavior reveal vital information about our future world. Examine polar bears in the Arctic, penguins in Antarctica and other animals surviving in icy worlds.

Find tips for watching outside the US here.

UPDATE 27 September 2023: Well, as I expected, this show was full of Attenborough-style nonsense about starving polar bears waiting for sea ice to form along Western Hudson Bay, the bears presented as “canaries in a coal mine” indicators of climate change, with an activist scientist saying she’s “pissed” about climate change. They used charts of the very distinctive pattern of sea ice formation that took place in November 2020 to illustrate how freeze-up was “later and later each year” even though 2020 was one of the earliest freeze-ups on record (bears were successfully hunting from shorefast ice as early as 30 October). A waste of 15 minutes: I couldn’t bear to watch what they did with the penguins.

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Natural flexibility explains W Hudson Bay polar bear movements at breakup better than climate change

Hudson Bay in early July this year is a mosaic of more-than-average and less-than-average sea ice coverage but apparently, only the less-than-average ice areas constitute the “early breakup” caused by climate change, and only “deniers” would say otherwise.

I say some folks are cherry picking the ice conditions that support a story line they prefer, forgetting that polar bears know better than they do when to come in off the ice.

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No evidence polar bears survived Eemian warmth because they were not yet fully ice-dependent

Is evolution primarily fast or slow? Does it take hundreds of thousands of years or a few generations to produce a new species? Ignoring vast evidence to the contrary, most geneticists insist that evolutionary change is imperceptibly slow and one of them is using this misconception to support the human-caused climate change narrative.

For polar bears, the question is this: could brown bears (aka grizzlies) have survived for hundreds of thousands of years living in a completely different habitat–the perpetually-frozen world of Arctic sea ice–before significant biological changes took place? I contend the answer is no. Moreover, if I am correct that polar bears arose ca. 140,000 thousand years ago (140kya) during the height of an extreme glacial period, the fossil evidence concurs. Analysis of fossil remains show that by about 115-130kya at the latest (after perhaps 10k years), polar bears were primarily eating seals as their modern counterparts do and their bones had lost the distinctive features of their grizzly ancestors.

But that’s the maximum time frame: research on other animals indicate that such critical changes almost certainly took place long before that, within the first few generations of life on the sea ice. If coordinated changes had not taken place very quickly, within ecological time, brown bears would simply not have survived the harsh life on Arctic sea ice.

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Claims of interspecies hanky-panky have unfairly sullied polar bear & Neanderthal reputations

One big question I asked before writing my book on polar bear evolution was this: did interbreeding with grizzlies, aka brown bears, profoundly impact polar bear history, as geneticists insist? Or is something else going on?

Polar bear hybrid, 3/4 grizzly (offspring of a hybrid female backcrossed to a grizzly male), Ulukhaktok, Victoria Island, Canada, 2010.

Virtually all genetic studies done in recent years, which I review in my book, conclude that hybridization with grizzlies has happened to various degrees over the course of polar bear history (e.g. Cahill et al. 2013, 2018; Cronin et al. 1991; Edwards et al. 2011; Hailer 2015; Kumar et al. 2017; Miller et al. 2012). Two of the most recent studies claim the most complicated hybrid ancestry for polar bears yet, invoking tales of “extensive” past hybridization events between the two species (Lan et al. 2022; Wang et al. 2022).

But does their interpretation of the genetic data represent reality or does it simply fit the authors’ preferred but false narrative that climate change is to blame for recent hybridization events and therefore likely to happen more often in a warmer world? And if, as I argue in my book, grizzly hybridization isn’t needed to explain polar bear evolutionary history, what does that say about similar claims that there has been a significant amount of Neanderthal interbreeding with humans in our past? Put another way, are geneticists everywhere going overboard with claims of interspecies hanky-panky?

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New evidence that polar bears survived 1,600 years of ice-free summers in the early Holocene

New evidence indicates that Arctic areas with the thickest ice today probably melted out every year during the summer for about 1,600 years during the early Holocene (ca. 11.3-9.7k years ago), making the Arctic virtually ice-free. As I argue in my new book, this means that polar bears and other Arctic species are capable of surviving extended periods with ice-free summers: otherwise, they would not be alive today.

Money quote: Here we show marine proxy evidence for the disappearance of perennial sea-ice in the southern Lincoln Sea during the Early Holocene, which suggests a widespread transition to seasonal sea-ice in the Arctic Ocean. [Detlef et al. 2023: Abstract]

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How grizzlies evolved into polar bears: The first book to tell the whole story is now available

Polar Bear Evolution: A Model for How New Species Arise is the fascinating story of the origin of polar bears. It reveals not just when and where the species came to be, but how it happened and why the bears were able to survive repeated cycles of sea ice change, some of unimaginable severity.

No other book like this exists. Despite decades of serving as an icon for the catastrophic climate change narrative, the polar bear has never had its evolutionary history explained so completely, never mind in a fully-referenced, plain-language style. And I couldn’t have done it without the financial help of my many supporters, so I thank you all again for your assistance in getting this important work completed.

One Amazon reviewer said this about Polar Bear Evolution:

The author of Polar Bear Evolution, Susan Crockford, is a good, credentialed scientist. Her writing is clear; her thinking is also. She has a broad understanding of biology and an informed paleo perspective. Crockford condenses a very large literature on polar bear biology and evolution in this book which will help readers understand the science related to the evolution of an Arctic species. Perhaps the most important aspect of this book is its synthesis of information from the fields of wildlife biology, molecular evolution, paleontology, and climate. Her original ideas and hypotheses on thyroid hormone’s role in evolution are very important and add a credible mechanism of phenotypic change which complements the literature on molecular genetic evolution. Polar Bear Evolution is an important contribution to science and its application in evolutionary biology and wildlife biology. Matthew A. Cronin, Ph.D.

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