Monarchs of the Sea The Extraordinary 500-Million-Year History of Cephalopods

Cephalopods, the group of molluscs that include the octopus, squid, cuttlefish and nautilus, are some of the most fascinating invertebrates to live in the world’s seas. Especially the octopus is famed for its intelligence and mind-bending acrobatics, being able to squeeze through the smallest hole. There have been some fantastic popular books on cephalopods recently, from William’s entertaining Kraken: The Curious, Exciting, and Slightly Disturbing Science of Squid to several works focusing on the octopus (Godfrey-Smith’s Other Minds: The Octopus and the Evolution of Intelligent Life, Montgomery’s touching The Soul of an Octopus: A Surprising Exploration of One of the World’s Most Intriguing Creatures, which made me tear up in more than one place, Mather et al.‘s Octopus: The Ocean’s Intelligent Invertebrate, and Harmon Courage’s Octopus! The Most Mysterious Creature in the Sea). But, as marine biologist Danna Staaf remarks, what’s been missing is a popular book on the evolution of cephalopods. Having been fascinated with them since childhood, she eventually decided to write Squid Empire. All hail the squid!

Cephalopods have a long and illustrious evolutionary history, stretching back some 500 million years. The fact that they are still here means they have lived through their fair share of mass extinctions. After some basic morphology, Staaf quickly introduces us to the three groups on the family tree, as these are the main protagonists whose fate we will follow here.

A large chunk of the book deals with the now-extinct group of Ammonoids whose familiar whorled fossil remains are so numerous that they can be used to date rock strata. Although many species went extinct at the end of the Devonian, Permian and Triassic, some members of the lineage managed to survive, allowing the group to thrive, again and again, all the way until the end-Cretaceous. With Brannen’s recent The Ends of the World still fresh on my mind I was quite familiar with the details, but if you’re not, Staaf does an excellent job in giving a balanced picture of the various mass extinctions. She is equally capable of giving a short history of the Alvarez impact hypothesis, as she is able to explain anoxic events or large igneous provinces and flood basalts.

The second group are the slow-and-steady (evolutionarily speaking) Nautiloids who seem never to have diversified terribly much, but have kept on keeping on to this day. And, finally, there are the Coleoids who radiated to become today’s cuttlefish, squid and octopuses.

And yes, I said octopuses rather than octopi. Staaf provides the best overview I have read so far of the whimsical discussion around how to pluralise this word. But far from mere whimsy, this book provides page upon page of fascinating insights. Whether it’s the intricacies of evolving buoyancy mechanisms allowing cephalopods to float, the way Coleoids internalised and in some groups virtually eliminated their shell, the continued confusion around the lower jaw or aptychus of the Ammonoids, or the arms race between cephalopods and their predators (first fish, then whales)... who knew there was so much fascinating research buried in the scientific literature?

Being a marine biologist herself, she is well-situated in these academic circles and has interviewed many scientists including Christian Klug, Dieter Korn, Kenneth de Baets, and Isabelle Kruta, all of whom are editors on the 2nd edition of the Ammonoid bible Ammonoid Paleobiology. Interesting findings and insider insights into ongoing academic discussions are combined with Staaf’s narrative which is fiendishly readable. In my opinion, her writing style strikes just the right balance between informative and understatedly entertaining (I sniggered throughout the book), without feeling forcedly funny. Admittedly, I have a soft spot for these squishy invertebrates, but I tore through this book in the space of a single seven-hour sitting! Squid Empire is a shining example of good use of illustrations supporting the text. Especially the cephalopod family tree on page 46 is something you’ll be referring to time and again and has some clever details. Next to that, the book is also beautifully designed with stylised chapter headings and a beautiful Haeckel lithograph gracing the cover.

Dinosaurs may have time and again stolen the limelight, but Staaf shows an accessible book on the evolutionary history of cephalopods has been long overdue. With Squid Empire – which, can you believe it, is only her first book – she has established herself as cephalopod-champion par excellence. I know that 2018 has only just started, but already this book will be a strong contender as my book-of-the-year. This, ladies and gentlemen, is how you write a good popular academic book.