for National Geographic News
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Footprints impressed on the Earth millions of years ago are energizing the field of dinosaur paleontology which until recently has mostly relied on piles of old bones dug up from ancient sediments.
"Of course, there is much to be learned from a corpse, even one that has been dead for millions of years, but there is a limit after which you leave science and are left with speculation," said Rich McCrea, a paleontologist at the University of Alberta in Canada.
McCrea is a member of a small but growing field of scientists who have dedicated themselves to the study of fossilized dinosaur tracks. "Tracks, even those millions of years old, represent the activity of animals that were living," he said.
Researchers who study them say tracks are the closest a human can get to understanding dinosaurs as breathing, functioning animals. They show where and how dinosaurs walked, their posture, and gait. They show which dinosaurs roamed solo and which in groups.
Each year more and more scientists like McCrea leave the study of dinosaur bones sitting inside museum exhibit halls around the world for the excitement of discovering and interpreting dinosaur tracksites out in the field.
Martin Lockley, a professor of geology and curator of the fossil footprint collection at the University of Colorado at Denver and pioneer in the field of dinosaur track research, says the field has grown significantly in the past 20 years.
"At the last national meeting of the Society of Vertebrate Paleontology there were 57 papers on the subject of fossil footprints. Five to ten years previously there had never been more than one or two a year, and 20 years ago there were many years without any," he said.
Learning from Tracks
The study of tracks has led to discoveries that range from the skin structure and padding of dinosaur feet to the fact that brontosaurs, one of the largest dinosaurs to ever live, were amongst the most gregarious dinosaurs, often traveling in herds.
"They are the real fossil record for dinosaurs," said Anthony Martin, an ichnologist (one who studies tracks) at Emory University in Atlanta, Georgia. Tracks tell scientists more about the environment and behavior of dinosaurs than do bones, he said.
For example, McCrea spends much of his time studying tracks out in the field near the mining town of Grand Cache, Alberta. He has learned several things about the life of dinosaurs that roamed the Rocky Mountain wilderness more than 100 million years ago.
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