The Dinosaur Heresies - Robert T. Bakker

The Dinosaur Heresies is another of those books I loaned to Alex he never got around to. Must remind myself to not loan him so many next time.

The book was originally published in 1986, though this is a later reprint since it has "By the Consultant to the Film Jurassic Park" stamped on the cover. Bakker's goal is to address many of the notions concerning dinosaurs that he considers incorrect, and discuss the evidence that works against them, and supports his ideas. This generally involves the debate of whether dinosaurs were warm-blooded like birds and mammals, or cold-blooded like reptiles and amphibians*. This ranges from examinations of bone structure and fossilized footprints, to comparisons to current creatures as examples of similar evolutionary paths. It also includes debates about whether the sauropods, like Brontosaurus (I thought it had been changed to Apatosaurus. Maybe I've got it backwards), really did spend all their time in water to support their bulk (Bakker argues no), how dinosaurs managed to eat enough to keep themselves going if they were warm-blooded, their relationship with birds and flowering plants, and touches on what may have lead to their extinction. He's not a big fan of "the meteor did it!", except as a finishing touch.

The book's written well, at not too high a level of comprehension. I think someone who only had biology in high school could follow the arguments he makes pretty easily, because Bakker tries to lay things out clearly, and critically, he draws lots of comparisons to living creatures, rather than relying solely on fossil evidence. I think being able to compare animals you only see in books, or as deceased remains, to something that's actually alive and moving about helps make the point sometimes. Also, the book is full of illustrations Bakker did himself, in two varieties. Some are extremely detailed, usually meant to either show some anatomical/physiological feature, or to show the dinosaurs in motion, to give some idea of how he perceives them: energetic, lively, bounding, running, and fighting, rather than shuffling along slowly. The others are vastly more simplified, and usually part of some larger diagram where he's trying to illustrate some concept like the different food requirements for warm vs. cold-bloods, or the phylogenetic trees. They aren't always placed the most precisely - they may be related to something a page or two farther ahead or behind - but they are informative.

Rereading the book now, it's hard to think this was ever a debate. To the extent I keep up with discussions of dinosaurs these days, the idea they were energetic and warm-blooded seems widely accepted. So the idea that maybe 30 or 40 years ago it would have flown in the face of what was commonly agreed upon seems strange. This even though I can remember more than one book on dinosaurs I had in the '80s that stuck to many of the ideas Bakker's trying to refute. It's interesting though, because Bakker points out that the assertions he and many others began making in the 1960s and 1970s were widely accepted in the late 19th Century. Many people then did believe dinosaurs were warm-blooded and energetic. In the 1920s, this idea was dispatched, at least partially because a scientist argued birds could not be descended from dinosaurs, and this apparently relegated dinos to a sort of sideshow. An interesting diversion, but ultimately unimportant, which caused people to regard them as slow, dimwitted lizards instead. Strange how that works.

* The better terms are probably endothermic versus exothermic. Body heat generated internally like us, or externally like a lizard. It could also be homeothermic (us) vs. heterothermic (lizards), but there are large reptiles capable of homeothermy simply because their size limits their heat loss, rendering them somewhat more resistant to temperature fluctuations than smaller animals.