Another Kind of Bigfoot
When dinosaurs walked in Zion National Park they left imprints in moist, muddy sediments near watercourses. These tracks remained exposed for a short while, allowing them to become drier and harder. Then the imprints slowly filled with contrasting sediments and eventually were preserved in rock. Subsequent erosion over millions of years removed rock layers exposing tracks like the one shown here.
Dinosaur tracks are rarely found in a location with fossil skeletons of the same animal. Paleontologists give different names to tracks than to dinosaurs, because it is very difficult to link the two. Also, identical tracks were made by several species of dinosaur and individual species determination is rarely possible.
Zion’s museum collection includes the Grallator track shown here and documentation of many additional tracksites in the park. The most probable dinosaur for the creation of the Grallator track is, Megapnosaurus, a lizard-like, 70-pound, carnivorous biped about 10 feet long from the tip of the tail to nose.
Dinosaur tracks provide clues to behavior and paleo-environments. A recent discovery west of Zion contains dozens of parallel trackways heading in the same direction, indicating migratory behavior of several species of dinosaurs along an ancient lakeshore. The tracks helped confirm the presence of Lake Dixie that existed nearly 200 million-years ago.
Brad Wolverton/Utah Geological Survey
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