Natural Science

Ever since the first dinosaur fossil was unearthed by Robert Plot in 1676, dinosaur fever has infected almost everyone. Dinosaurs captivate us not only because of the enormous size that some of them attained, but because of their extraordinary diversity. Encompassing such astonishing creatures as the fearsome Tyrannosaurus rex, the majestic Triceratops and the cunning raptors, dinosaurs are truly fascinating.

From such fascination many questions arise. How were the dinosaurs able to survive for such a long period of time? Why did they become so large? Just what was their everyday existence like?

These questions have puzzled scientists for years. But by looking at fossils, paleontologists have been able to learn much about the dinosaurs. They can infer the appearance of these creatures in life-like detail as they existed millions of years ago. They can investigate their diet. And they can find out about the way dinosaurs interacted both among themselves and with their environment.

Despite the frequent media attention given to discoveries of dinosaur bones, especially skulls, the truth is that such fossils are rare, much rarer than fossils of most plants and invertebrate animals. Thus, although bones are of great interest, if we had no other evidence, we would have a much less accurate picture of the dinosaurs than we in fact possess.

How, then, has it been possible to learn so much about these terrible lizards when we have so few bones to study? The answer lies in trace fossils. As the name implies, a trace fossil is a "trace" of an ancient organism such as a footprints, a tooth or bite mark, or a coprolite.

Footprints and tooth marks, yes, but coprolites? As any paleontologist will tell you, a coprolite is a piece of fossilized dung. Why would anyone study fossilized dung? Well, if you really want to know, you would do well to ask Karen Chin, visiting scientist with the U.S. Geological Survey, Menlo Park, CA, who is the world's foremost expert on...