Uncovering Dinosaur Behavior What They Did and How We Know

In The Future of Dinosaurs, English palaeontologist David Hone pointed out that dinosaur behaviour is the one area where we see the greatest disconnect between what we know and what people *think* we know. His new book Uncovering Dinosaur Behavior is a sobering reality check for the lay reader, but I suspect that even palaeontologists might come away wondering whether there is *anything* we know for sure. Concise, well-structured, and beautifully illustrated by palaeoartist Gabriel Ugueto, this is a superb book that transcends "merely" being a good popular science work by also addressing professional palaeontologists.

Uncovering Dinosaur Behavior opens with a very clear mission statement: what the book is and is not about, who it is for, and even what its potential weak points are. The book is more than a catalogue of studies, additionally explaining how we figured these things out. He specifically targets palaeontologists interested in animal behaviour and ethologists interested in dinosaurs. Having explicitly laid his cards on the table, Hone follows through with a logically structured book.

Three introductory chapters cater to both palaeontologists and ethologists by providing primers on dinosaurs, the fossil record, and the study of animal behaviour. One of the chapters introduces the basic biology that both determines and limits dinosaur behaviour; topics such as activity patterns, habitat choice, physiology, posture, and locomotion. A final important concept is extant phylogenetic bracketing, that is, looking at the behaviour of the nearest living relatives of dinosaurs. This will help you determine how far back in time a certain behaviour likely evolved. Armed with all of the above, you should be better able to judge whether behaviours inferred for dinosaurs are theoretically possible, plausible, or even likely.

Hone here also lays out his challenge to fellow palaeontologists to produce more rigorous science, giving you a set of eleven guidelines. He has observed several recurrent problems with how data is used, interpreted, and presented, leading to misrepresentation and over-extrapolation of behaviour far beyond what the data supports. His philosophy is to "always favor a degree of uncertainty or lack of confidence in a result, rather than embracing an interpretation confidently that may be wrong" (p. 35).

The remainder of the book examines five broad categories of behaviours. Given above attitude, this is where the sobering reality check comes in. Take the frequently depicted idea that dinosaurs lived in groups, with a certain franchise making hay out of pack hunting. Now, many animals alive today live socially, and there are advantages to doing so, but how do you deduce this from fossils? The problem with bonebeds is that fossils found in groups did not necessarily live or even die together: the taphonomic history (what happened between death and burial) matters. But equally, many groups will have lost members individually: solitary fossils do not exclude social behaviour. Trackways can similarly not be taken at face value. Beyond the challenge of assigning them to species, determining if they were laid down together is challenging, and even if they were, many interpretations are possible beyond social behaviour.

Hone is similarly circumspect when it comes to signalling and reproduction. He highlights what we know and what remains unknown. For instance, dinosaurs likely used visual and auditory signals, and they laid eggs. But did they use touch, taste, or smell? How did they mate? How many eggs did a female typically lay? What amount of care did parents bestow on offspring before and after hatching? We have data and tentative hints for some species, but for many questions, we cannot go much beyond generalities. The situation is better for combat: many species sported implements that intuitively look like weapons, but how and on whom they used them is harder to determine. Studies have furthermore focused on a small number of species while ignoring many others. Feeding biology is the area that has the most robust support, bringing together many independent lines of evidence such as biomechanics, trace fossils, isotope data, tooth microwear analysis, stomach contents, and coprolites. Even here, though, such full pictures are only available for a handful of species.

Overall, interpreting dinosaur behaviour is "profoundly difficult" (p. 152) due to both the limitations of the fossil record and the diversity and plasticity we see in the behaviour of animals alive today. The problem he observes is that "much of the scientific literature tends toward a confidence in interpreting dinosaurian behaviors that probably should not be there [while failing] to recognize alternate possibilities and the inherent uncertainty of interpreting ancient behaviors" (p. 153). That sounds pretty damning but he also recognizes that the field has come a long way from early guesswork and extrapolations to more rigorous methods that take seriously the fact that dinosaurs were once real, living animals rather than mythical monsters.

Uncovering Dinosaur Behavior benefits from an excellent and logical structure that flows very well. All chapters come with a helpful summary and an interesting case study; I thought the one on ankylosaurs and what their tail clubs were used for was particularly compelling. I also have to praise the fantastic illustrations by Ugueto. The colour plate section is mouthwatering eye candy, and there are numerous classy and useful black-and-white drawings and diagrams throughout the book. Some of the black-and-white photos of fossils are harder to decipher, and I would not have minded had some been included in the colour plate section.

Uncovering Dinosaur Behavior was published about a year after Benton's Dinosaur Behavior, meaning Princeton now has two illustrated books on the topic. Which one do you choose? In my review, Benton's is an introductory book for novices that starts from first principles. Hone's work, though very accessible, is more advanced and, for me, hit the sweet spot of the kind of depth I look for in my popular academic books: fairly technical, thought-provoking, never shirking the hard questions, and yet admirably brief at 207 pages. One thing Hone does not do is introduce and explain the various techniques. He assumes that phrases such as isotope data, palynology, and finite element analysis mean something to you and do not require more than a brief definition. If you find your eyes glazing over at these terms, maybe start with Benton's book. For everyone else, however, Uncovering Dinosaur Behavior is a superb book that should be your go-to reference for a thoughtful appraisal of what we know about dinosaur behaviour.