Book Review by Kip Hansen — 11 June 2023
If you are interested in a book that will explain to you, your family or your friends that, “No, polar bears are not endangered by so-called climate change”, then this book is not the one you want. If that’s your interest and your purpose, then you’d be better off with one of Susan Crockford’s other books:
Polar Bears: Outstanding Survivors of Climate Change
The Polar Bear Catastrophe That Never Happened
or
Polar Bear Facts & Myths: A science summary for all ages
or maybe, for a fictional tale, her science thriller:
Her latest book, Polar Bear Evolution: A Model for How New Species Arise, is not that simple explainer, but rather a deep science book delving into the question: How did the Brown Bear turn into the Polar Bear? Let me warn you – Susan Crockford does not give the usual evolutionist “Just So” story in reply.
You know what a “Just So” story is, right? :
“In science and philosophy, a just-so story is an untestable narrative explanation for a cultural practice, a biological trait, or behavior of humans or other animals. The pejorative nature of the expression is an implicit criticism that reminds the listener of the fictional and unprovable nature of such an explanation.” [ source: wiki ]
How brown bears turned into polar bears, in a geologically-short time period, cannot be reduced to the usually-relied-on “then something happened”. As she says “However, without an explanation for precisely how and why such changes occurred, we are no further ahead than we were with the myth. “Something happened” is simply not good enough.”
Dr. Crockford is a “bone whisperer” — she works at her company, Pacific IDentification, which “offers biologists and archaeologists the most complete analysis of bone and shell from western North America. The identification of whole or fragmentary skeletal elements (both cranial and postcranial) from marine and freshwater fish, land and sea mammals and birds from western North America are our specialty.” For us, that means she knows her behind from her elbow when it comes to identifying and dating bones including the fossil remains of brown bears and polar bears.
In reading this book you’ll discover that the polar bear is not just a grizzly-bear-with-a-new-white-winter-coat – there are far too many physical, physiological and behavioral differences between the two species to think that. Crockford leads readers through the fossil record of world’s bears, a record that has brought us to the present situation in which we have brown bears (grizzlies), black bears (like those that appear in my backyard) and the iconic polar bear – the color-names don’t do justice to the differences, they are just easier to remember. That path may sound easy, but it’s no walk in the park.
More importantly, Susan Crockford returns to the subject of her doctorate thesis, Animal Domestication and Vertebrate Speciation: A Paradigm for the Origin Of Species (1976) [pdf], and her first book, Rhythms of Life: Thyroid Hormone & the Origin of Species(2006). Further illuminating and expanding her hypothesis concerning the effects of thyroid hormone rhythms on development and growth of nearly all animals and the effects that these rhythms, and their changes, can have on a species, including both domestication and the creation of a new species over rather short periods of time.
Dr. Crockford writes:
“Thyroid rhythm theory assumes that individually unique thyroid rhythm variants exist within species-specific patterns for animal populations and that these thyroid rhythm variants are the actual characteristics targeted by natural selection for adaptation and colonization.”
and
“…that daily rhythmic thyroid hormone secretion profiles in any vertebrate species are individually variable and that these variations between individuals can be correlated with discernible physical, reproductive, or behavioral differences, which are the thyroid rhythm phenotypes.”
I have been simultaneously reading Charles Darwin’s On the Origin of Species and find that Crockford’s thyroid rhythm hypothesis is not in conflict with Darwin, but supplies the possible physiological explanation which is lacking in Darwin. The biologists who are stuck with nothing but the gene theory – all variation is caused by gene mutation and expression – will just have to hold their ire in check — many of their colleagues are speaking out about that view’s deficiencies. The battle is currently carried on in the “new” field of epigenetics — “Epigenetics is the study of how your behaviors and environment can cause changes that affect the way your genes work.” Crockford’s thyroid rhythm theory may supply one of the missing pieces in epigenetics as well.
Crockford offers a series of possible tests for her hypothesis — and it is testable. The tests are not easy, and may require some advances in biological testing of living animals, but they are at least feasible.
In the end, whether her thyroid rhythm hypothesis is correct as she has laid it out, or if it is found to be mostly correct with caveats and corrections, readers will find the evidence compelling if not convincing. In either case, it is fascinating.
This is not a book for the “only mildly curious” who wish to learn it all by a quick leaf-through. It is a serious book of serious science presenting a novel concept.
If you are interested in evolution, speciation, domestication or the biological history of polar bears: Then this is the book for you.
Bottom Line:
I liked this book – it made me think, re-think and think again. It made me do the type of intellectual work that refreshes the mind and brings new understandings. It just can’t get better than that!
Highly recommended for the brighter and more open minds wishing to get a new perspective on evolution. Information on ordering available here.
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Author’s Comment:
Susan Crockford was kind enough to send me a digital, pre-publication nearly-final proof copy of this, her tenth (I believe) book. It was a good thing I got it early – this is the second book I have reviewed recently that challenged me to really THINK. The first was Judith Curry’s Uncertainty which I reviewed here. With Curry’s book, I was already deeply familiar with the general topic – one which about which I write extensively as a journalist.
With Susan Crockford’s Polar Bear Evolution: A Model for How New Species Arise, I mentioned above, several months ago, something prompted me to re-read Darwin. Reading the two books, simultaneously, has been quite a ride.
And, yes, Crockford talks about Climate, Climate Change, and the connection between climate change and polar bears in her new book. As she says “The story of polar bear evolution could not be told without discussing climate change”.
Get Crockford’s new book — open that door in your mind dedicated to letting in new ideas — open to the first page and let’er rip!
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