After The Dinosaurs: The Age Of Mammals, by Donald R. Prothero

This book is an honest book. That does not make it by any means a perfect book–the author is clearly not intending to write a book that contains a smooth narrative and he assumes (probably correctly) that the audience for books on the Cenozoic Era is not a very large one, at least as of the time the book was written in the early 2000s. There are at least a few occasions where the author pursues what appear to be somewhat personal grudges, the most notable one being his self-evident desire to mock the extremes of those who support the asteroid impact theory for the K-T transition that wiped out the dinosaurs, which is what everyone who writes about the last geological era has to address as the elephant in the room, only larger, like a brontosaurus or something. Had this book been a bit more polished, it would likely be a bit more enjoyable to read and a bit less like it was written for an inside audience of geologists. When someone reads this book without more than a fundamental understanding of the field (only one university course in the subject, aside from plenty of reading), there are a few aspects of this book that come off as somewhat alarming, and that the author would have done well to discuss a bit less bluntly.

This book is a bit more than 300 pages and it is divided into 9 chapters, most of them relating to a part of the Cenozoic Era as a whole. The book begins with a preface and acknowledgements and then contains an introduction that points to the absence of regularly accessible books about its subject matter as providing a reason for this book to exist, which is as good a reason as any, I suppose (1). This is followed by a chapter that argues over several possible reasons for the extinction of the dinosaurs and other sea life as well as the precise timing and which seeks to reduce the importance of the impact crater as well as posit other explanations for the global iridium found at the K-T boundary (2). After this the author talks about the Paleocene, the world in which mammals (and birds) made their bid for dominance with the destruction of the dinosaurs in a world that had been largely cleared for them (3). This is followed by a discussion of the hothouse Eocene world (4), where there was a proliferation of mammals growing in complexity. This is followed by a discussion of the chilly Oliogocene, where the ice that had been absent from the world for a long time came back (5) as a sign of things to come. After this comes a discussion of the Miocene (6), a period of drying that led to the proliferation of savannas instead of the forests that had been previously dominant in many areas. After this came the transition between what had been mostly warm periods to the chill of the more recent epoch, largely due to plate tectonics, it would appear (7). The author spends a chapter talking about the period of the Pleistocene, famous for its proliferation of ice ages and interglacials (8), before talking about a chapter on “our” interglacial as human beings (9), which ends up being mostly about environmental issues relating to mankind and its activity. The book then ends with a bibliography and index.

One of the notable aspects of this book that shines through is the way that just about every example of climate change over the course of history and prehistory has been vigorously argued and debated as far as its etiology. The causes and limits of various environmental mechanisms hangs like a fog over understanding of the past, and the conflict between the results that come out of climate models and the facts that we have at the ground is something that haunts many of the environmental transitions of the last 65 million years ago or so as geologists define it (more on that shortly). The fact that the book ends with a warning call about global warming (which seemingly every book that mentions the Holocene or Anthropocence, as it is sometimes labeled, feels it necessary to do) when a substantial part of the book discusses the inevitable extinctions that occur during transition periods of heating and cooling as the world resets itself and the fact that the earth has been considerably warmer in the past is a reminder that political logic and scientific logic are often at odds with each other, and that writers often feel it necessary to make political points even when the facts are at odds with the claims that they make, and even in works that explicitly acknowledge the dodgy state of information in the field of climatology, to say nothing of geology. The book is also of interest in the way it honestly and forthrightly deals with the immense problems of trying to date rocks, which often involves as process of circular reasoning that makes it hard to resolve the interminable debates that exist about the causes of the extinctions and climate changes that one sees in the geological record.