A readable and quirky discussion of dinosaur ichnofossils. Paleontologist Anthony Martin makes the interesting point that a dinosaur bone can be transported from its place of origin before fossilization, but a dinosaur footprint was made right there right then. And dinosaur trackways are the only way we can get any insight into the social behavior of the animals.

Tracks and trackways are the most common dinosaur ichnofossils, but Martin also documents nests, burrows, toothmarks, gastroliths, coprolites, mating scrapes, vomit, and urine stream traces (although this last requires some speculation). Martin notes that the dinosaur “stampede” seen in the movie Jurassic Park was based on an actual trackway from Australia.

Well worth the reading time. A nice selection of plates. There are endnotes, but they are by page number; no bibliography but references are included in the relevant endnotes. ( )

Summed up by the last sentence: "Place your hand on a dinosaur track, and you connect with the breathing essence of its maker, leaving your own fingerprints on it: life traces intersecting through time." Inspiring as that quote, but also incredibly funny, awe inspiring, and just plain fun to read! As a child of the 80s who was only averagely interested in dinosaurs, I had a lot of catching up to do to understand the terms, types and names of dinosaurs discussed here. But I know that if I had read this book at the age of 17, deciding where to go to college and what to study, geology/paleontology/ichnology, somewhere near dinosaur bones, would have been at the top of the list. ( )

One of the best books of science for the non-scientist I have read. ( )

Fascinating stories about dinosaur trace fossil paleontology. Especially toward the end, Martin gets overly speculative and the book becomes more about modern birds than non-avian dinosaurs. Still, the writing is enthusiastic, delightfully punny, and almost always interesting.

> paleontologists who study dinosaur tracks first assume they are looking at undertracks, and only modify these realistic expectations if confronted by the delightful details of skin.

> dinosaur tail impressions are quite rare, with fewer than forty reported from the entire geologic record, and many of these are associated with resting traces.

> The traces showed the positions of the theropod’s hands with its “palms” turned inward toward the center of the body, almost as if it were measuring the width of the trackway. For too many years, paleontologists have cringed at reconstructions of theropods walking around limp-wristed, palms down: a posture sometimes derisively labeled as “bunny hands.” In fact, skeletal evidence indicates this was anatomically impossible, and that the hands must have been held with the palms turned inward, not downward. Thus these two handprints vindicated critics’ previous assertions of theropod hand positions.

> we needed much more information before declaring that this was the world’s first known dinosaur burrow. It was time to take a closer look at the dinosaur found in the burrow, and find out whether it had died in a burrow of its own making or not. … An adult with a half-grown juvenile in a burrow was not only evidence of denning—a previously unknown behavior in dinosaurs—but also of extended parental care.

> The long-held assumption is that huge sauropods, many of which only had puny, pencil-like teeth, used gastroliths to grind their food. However, this idea is now seriously doubted

> In this coprolite was recognizable muscle tissue, some of it preserved in three dimensions. In their analysis, the paleontologists were astonished to see: striated cell-like structures revealed in thin sections; bundles closely resembling muscle cells and connective tissues in SEM photographs; and high concentrations of carbon in and around these structures.

> Other sizeable birds on islands included: the giant swans of Malta (Cygnus falconeri); the moa-nalo, consisting of four species of ducks in the Hawaiian Islands; the Viti Levu giant pigeon (Natunaornis gigoura), which was on one of the Fiji islands; and the giant cursorial owl (Ornimegalonyx sp.) of Cuba. All of these birds were flightless, and as one might guess from the adjective “giant” applied to their common names, they were significantly larger than any of their living relatives; for instance, imagine a 1.2 m (4 ft) tall owl prowling the forests of Cuba. All of these birds had something else in common, which was their rapid extinction soon after humans came in contact with them

> birds and flowering plants expanded and diversified at about the same time, which was in the middle of the Cretaceous Period (about 100–125 mya). ( )

It’s sometimes difficult to tell whether Dinosaurs Without Bones is about dinosaurs or about paleontologists. Both turn out to be fascinating, and one of them can still be seen in the field today (Jurassic Park notwithstanding). The stated theme of the book is dinosaurs beyond mere bones. That is, every shred of evidence, from footprints to bathtub-like constructs that indicate where a dinosaur “took a leak” all add to our collective knowledge of how flesh and blood dinosaurs lived.

But from that (scant) knowledge, flights of fantasy emerge. Paleontologists aren’t mere scientists; they are fantasists, dreaming up scenarios if not whole novels about what their stony discoveries mean. To be sure, they have their lists of reality checks, if only to weather potential criticisms better, but their imaginations are where they really show off. And Dinosaurs Without Bones flies freely, leveraging every bodily function that fossil traces afford us. Every bodily function.

Paleontologists need to be expert in an incredible range of fields. They need to understand everything from digestion to physics. They need to know that a T-rex could not possibly run around at 45 mph as in the movies, because if it ever slipped or tripped, its massive weight and height would most surely have killed it in its fall, which is not a very effective evolutionary trait or strategy. The book is filled with such observations. It makes for a potentially realistic vision of what actually took place on planet earth 200 mya (million years ago, a lovely abbreviation used throughout).

There is a great deal of data on birds - modern birds – which for Martin represent the living embodiment of dinosaurs. His appreciation of them dominates the last quarter of the book. And he makes excellent arguments for his positions.

The one batch of theories I wanted but did not see was numbers. How many dinosaurs were there? Billions? Did they overpopulate the planet, or were they scattered? How dominant were they in the landscape? How much territory did a T-rex need, and how much for a brontosaurus? It matters in topics like how dinosaurs might have affected the environment, promoting flowers over dense foliage for example, or filling the air with exhaust gases and therefore warming it. I was left with absolutely no feel for how prevalent dinosaurs were.

Martin peppers the setting with humor: self-effacing, punning, and cultural (eg. hoping for an appearance on Comedy Central, the highest form of acknowledgement for scientists in the USA). It makes the book all the more readable, and, well, human. Basically, Martin is an incurable romantic, but an exhaustively fair and thorough one.

David Wineberg ( )