When the Whales Walked

Growing up, I rarely encountered any books aimed at children that explained evolution in comprehensive terms. It often got a mention in books on paleontology I read, but dedicated books on the subject seemed somewhat lacking, aside from a few token books on individual discoveries such as Lucy and the like. Now, I grew up a creationist, so perhaps I simply wasn’t looking, but as libraries tend to place books on evolutionary topics next to paleontology books, I feel like I would’ve have at least been aware of whatever titles were out there.

All this has changed in the last decade or so, as a wave of visually interesting, kid-friendly books have become available that provide accessible overviews on evolutionary theory. I’ve already reviewed Grandmother Fish here before, but there are many other excellent books out there, in both strict nonfiction formats like Amazing Evolution, and in a more storybook style like One Day a Dot. The Annabelle & Aiden series has an entire range of storybooks exploring evolutionary biology and the origins on the universe (see my reviews of The Story of Life and This World Was Made For Me).

After I reached out to them, Quarto Publishing was kind enough to send me a copy of today’s book under review, When the Whales Walked, by Dougal Dixon & illustrated by Hannah Bailey. (I have also received Amazing Evolution and Kaleidoscope of Dinosaurs and Prehistoric Life from them as well.) I’m sure a certain portion of my readers will perk up at the author’s name: paleontologist Dougal Dixon has authored several dinosaur books over the years, but is probably most famous as the father of “speculative evolution” in popular literature, with his books After Man, The New Dinosaurs, and Man After Man considered by many to be the foundational books in the genre. (For some extra background on Dixon, see Darren Naish’s recap of the on-stage interview he hosted with him last year, which gives some nice background details on Dixon’s work.)

fish to tetrapods

Well, that was a lot of preamble. Suffice it to say, When the Whales Walked is probably in some of the best hands it could be on this particular subject. While many books on evolutionary topics aim for broader overviews of the theory, When the Whales Walked instead takes several evolutionary lineages and examines their development through time with various fossil species that represent important transitional stages.

when whales walked on land compilation
A compilation of the whale series in this book.

Incidentally, I think it’s important to note that this book deals more with the question of “What Happened”, rather than the “How” of Grandmother Fish, or much in the way of “Why” we know what we know. It’s perfectly fine for the aims of this book, but just know it may have limited effect on anyone with a significant misunderstanding of evolution. (It does however do a far better job than  This Chicken is a T-REX!, another book ostensibly about evolution that seems to be trying to go for something roughly similar to When the Whales Walked.) The book opens with a timeline of earth history, an explanation of cladograms, and a brief introduction to Cambrian fauna, but the information remains relatively surface level. I regret to report the cladograms have a few errors. These range from the oversimplification of grouping plesiosaurs and ichthyosaurs under “sea reptiles”, to the more significant errors of depicting whales as more closely related to Carnivorans than to hoofed mammals, and even getting the entire Archosaur family tree completely backwards. One would merely need to move a few images around to fix it, so hopefully this is corrected in future printings. This doesn’t really affect the main focus of the book however, and thus does not detract from it overall.

The tree on the left corrects the error in the Archosaur line present on the right, though the other issues remain. I get the sense that the errors likely stem from a simple mistake during editing.

On a more positive note, I found myself particularly impressed with the diversity of prehistoric animals featured in this book. Every lineage features some of the usual suspects in discussions of transitional forms, like Archaeopteryx, Ambulocetus, and Tiktaalik. Interspersed with these however, we see some rather more obscure species get their moment in the sun as well, including an entire double page spread in which early Cenezoic birds take center stage, without even having to share the page with any “terror birds”! (They and other flightless birds get their own page later on.) I’d never even heard of many of these ancient avians, and was fascinated to learn about these often overlooked prehistoric creatures. Of course, as the Dino Dad, I was pleased to see that plenty of Mesozoic birds and bird-line dinosaurs made the cut as well, though I’m mildly disappointed to see an out-of-date Epidexipteryx, which should have bat-like wings similar to its relatives Yi qi and Ambopteryx.

cenezoic birds
In discussing bird evolution after the end of the Mesozoic, most books of a similar caliber would mention terror birds and then jump straight to chickens. Kudos for discussing the actual diversity of forms through this large span of time!

Hannah Bailey‘s illustrations really make this book, turning what might have been a typical prehistoric children’s encyclopedia into a very approachable and aesthetically pleasing experience. The creatures are generally reasonably restored based on what scientists know about their body fossils, but in my opinion, Bailey truly shines in her use of color. Naturalistic and never over-the-top, she nevertheless manages to make them vibrant and eye-catching so that there is never a dull page in the book.

Crocodilians…. “unchanged” for millions of years???

I would highly recommend When the Whales Walked to anyone interested in the evolutionary history various animal lineages. I’ve definitely got a bit of a collector’s mindset, and so seeing a bunch of related animals organized by family groups appeals directly to some deep, underlying part of my brain. Speaking of collections, this book actually became the basis for a series of evolution themed books from Quarto after its release, including When We Became Humans & When Dinosaurs Conquered the Skies, which I can also recommend. For now though, I happily give When the Whales Walked the Dino Dad Stomp of Approval, and encourage you to check out more of Dougal Dixon’s work!



  1. Wow, that Cenozoic bird spread rocks! (Although “Neocathartes” is now considered a synonym of Bathornis.)

    I hope too that those cladogram gaffes are fixed in future editions, though to be fair, a marine reptile clade encompassing both plesiosaurs and ichthyosaurs has been supported by some recent studies (and a few not-so-recent ones).


    1. Yeah, I suppose it may not necessarily be entirely wrong, just a big oversimplification; especially if the label “sea reptiles” leads some readers into thinking mosasaurs and turtles are included.


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