More than dinosaurs

Pterygotus, the T. rex of the Silurian (about 1.5 m long). Diorama previously at the Field Museum.

It happened again today. I was asked what it is do and when I said I was a paleontologist, the response was “cool.” This is the common reaction, often followed by (if we are not confused with archeologists), asking how many dinosaurs I have discovered. I then have to explain that although I study fossils, I don’t work on dinosaurs and have never discovered one.

Dinosaurs are the “charismatic megafauna” of the fossil record. Just like pandas and whooping cranes exemplify the vast number of animals threatened with extinction, dinosaurs epitomize those that are long gone. Scarcely a week goes by without a news article about a new dinosaur discovery, inevitably with reference to Tyrannosaurus rex (almost as big as…., chased by…, ancestral to…, etc. etc.). Even when a significant new invertebrate fossil is discovered, the dinosaur comparisons are de rigueur (the T. rex of the Silurian!). This fascination with dinosaurs, of course, goes back to many of our childhoods, with innumerable dinosaur books and toys. Unfortunately, it obscures a very simple fact about fossils; almost none of them actually are dinosaurs. And it creates the unfortunate impression that all fossils are rare and valuable.

Fossils, on the whole, are really amazingly common. Limestone, one of the most common rocks on Earth, is usually comprised of the remains of marine organisms. These are often visible as fossils in the rock. To a first approximation, therefore, we build many of our buildings out of fossils. Many other sedimentary rocks also contain fossils. These fossils, however, are rarely if ever dinosaurs. Instead, they are the remains of the innumerable other kinds of organisms that have ever lived on Earth. In terms often used today, dinosaurs are the 1% (actually far less); the rest of the fossil record is the other +99.99…. % This is why Sue the Tyrannosaurus cost millions of dollars, whereas you can buy a brachiopod at a rock shop for $0.50.

It should not be surprising, therefore, that most paleontologists don’t study dinosaurs or even fossil vertebrates, such as ancient mammals. Instead, we investigate the history of life that is documented by all of the other fossils. Some of these groups are charismatic in their own right; nothing excites one of my students like collecting a trilobite or a plant leaf. Others are of abiding interest only to their specialists but are nevertheless important parts of life’s story. Many are critical to unraveling ancient climates or helping tell geological time. And many fossils give ecological and environmental context to those darn dinosaurs since they lived at the same time. One of my fondest memories is walking though the Badlands of South Dakota with my colleague Gale Bishop, looking for the remains of Cretaceous crabs and lobsters that lived in a shallow ocean near where dinosaurs made their home.

To be sure, I have nothing against dinosaurs; I am actually fond of them. They do “pay the bills;” the public interest in dinosaurs has greatly aided the survival of the field. My simple point is that they do not define paleontology; we are a discipline as diverse as the ancient life we study. Discovering any previously unknown fossil is very exciting and important. That said, I would still like to discover a dinosaur…