If you had to guess, at what point on the timeline do you think a book about prehistoric mammals would begin its tale? Most of us, I suspect, would imagine that book to start at the end of the Cretaceous, when the asteroid wiped out the dinosaurs and ushered in the so-called Age of Mammals. But surprise! Steve Brusatte’s latest book, The Rise and Reign of the Mammals, doesn’t do that. In fact, the asteroid strike shows up halfway through the book. In other words: the entire first half of a book about prehistoric mammals covers the period before the Age of Mammals. The first half is the rise, the second the reign: get it?

That’s because The Rise and Reign of the Mammals isn’t about the Age of Mammals, i.e. the Cenozoic; it’s about the mammals. And their origin predates the dinosaurs by a lot. And like Brusatte’s previous book, The Rise and Fall of the Dinosaurs (reviewed here), the focus is on evolution. What makes a mammal? (It’s not about the semi-eponymous mammary glands, which don’t fossilize in any event; it’s mostly about the jaw.) When did mammal characteristics evolve? What kinds of mammals evolved, and where, and what happened to them?

And again like the previous book, that evolution is presented in context: with the state of the climate in particular, and what mammals were competing against. It’s a paleontological shibboleth that the presence of dinosaurs suppressed mammalian evolution, in that mammals were kept small; Brusatte argues that mammals kept dinosaurs big—at least the non-avian kind. It’s that context—time, climate, habitat, other species—that made The Rise and Fall of the Dinosaurs stand out, and the same is true here: if you liked the last one, you’ll like this one too.

Add to that the fact that, at least as far as popular culture is concerned, mammal evolution is somewhat overlooked of late. This book remedies that, and in spades.


The Rise and Reign of the Mammals
by Steve Brusatte
Mariner, 7 Jun 2022 | Picador, 9 Jun 2022 (UK)
Amazon (Canada, UK) | Apple Books (UK) | Bookshop