I just finished reading the first nonfiction book I know of devoted entirely to the prehistoric shark Otodus megalodon, Big Meg: The Story of the Largest and Most Mysterious Predator that Ever Lived, by Tim and Emma Flannery. (Doubleday, 2023, 200 pp.)
The text is excellent, clear and highly readable, as one would expect from Tim Flannery. Emma is his scientist daughter, and they don't separate sections by author, so kudos to both of them: however they divided or blended the work, it succeeded in producing a consistent and engaging tone. The terminology is precise enough for paleontology buffs but not over the head of a smart high schooler. I didn't know from reading Flannery's earlier work (my favorite is his book Throwim Way Leg), that Meg teeth stimulated Flannery's interest in paleontology from an early age. Here he describes finding his first tooth and how his efforts to seek out more contributed to his career.
Five chapters summarize what we know and don't know about the fish. What we know is not as much as we'd like, so that it takes up less than half the book. The authors could have gone into more scientific detail, but the book is clearly meant, in text and in length, for a wide audience. They discuss shark evolution (with a very good short introduction to dating methods), the features of Meg and where they came from, and so on. We learn how the fish lived in the chapter "The Miocene: The Meg's Heyday."
The book finishes this section by examining the Meg's likely time of extinction on and the theories involved. The authors choose as the likeliest explanation of extinction a mix of two factors: the general reduction in the productivity and thus prey available in the oceans in the late Pliocene and the Meg strategy, usual in sharks, of the females being larger than the males. The Flannerys suggest that having the females be the smaller, as seen in cetaceans and particularly sperm whales, means the latter have a cushion in hard times because the most critical sex for reproduction eats less and thus does not need to find as much prey. (I'm not sure whether they figured in the rise in female consumption when pregnant, or whether that is enough of a factor to matter.) The Meg made it to 2.6 MYA at best and may have gone extinct much earlier than that.
On everyone's favorite question, how big the largest Megs grew, the book does not offer a definitive answer, noting that we never have remains of the largest or smallest member of any fossil species. The book ventures that the largest Meg tooth ever found, 18 cm high, "almost certainly came from an individual that exceeded 15 meters in length" and mentions estimates up to 20 m. The text says a couple of times the Meg may have been the largest predator ever, if one excludes the baleen whales on a technicality, which most people do. The only contenders offered are the modern sperm whale and its predecessor Livyatan melvilli. The authors apparently consider the ichthyosaurs out of contention, although one species of Shonisaurus has been estimated at 21 m and 81.5 metric tons. The influential 2015 paper "Sizing Ocean Giants" (see URL below) grants the sperm whale 20 m, though I've read of higher claims.
The authors set the Meg material in context with chapters on the unfortunate interactions of sharks vs. humans (in both directions), shark fossil collecting, and the use of shark fossils in arts and crafts. Oddly, they don't discuss the fake Meg teeth swamping the fossil-selling industry: Steve Alten, who knows a good bit about the Meg and popular culture, thinks 85 percent of teeth marketed from the current hot spot of Indonesia are fakes. (There's an interesting real v fake discussion here.) A particular strength is that book offers many stories of fossil discoveries I'd never read elsewhere. A chapter titled "The Imaginary Meg" considers, very fairly, and dismisses claims the fish still exists. It savages the film Meg but doesn't examine Steve Alten's or other Meg books.
There are good chapter references and an index, something frustratingly absent in too many books these days.
The serious weakness is the lack of illustrations: except for a single page before Chapter 1, there are no photos of fossils or locations, no maps, no timelines, nothing. Regardless, all those interested in sharks in general or Meg in particular will devour this book.
References:
The ichthyosaur figure is from https://faculty.umb.edu/liam.revell/pdfs/Sander_etal_2021.Science.pdf
Matt Bille is a writer, historian, and naturalist living in Colorado Springs. He can be reached at mattsciwriter@protonmail.com. Website: www.mattbilleauthor.com.
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