How Dinosaur Footprints Are Preserved
When dinosaurs walked through the mud they left footprints, just like you do on a muddy trail. Over time these footprints were filled with sand or small pebbles and eventually hardened into rock. The footprints were preserved for millions of years until erosion brought them to the surface where people can see them.
The most common tracks found in the park were made by theropods and hadrosaurs. Theropods ranged in size from one to 50 feet, or the height of a five story building! They were bipedal (walked on two feet) and carnivorous. Theropods include dinosaurs like Tyrannosaurus Rex, but the largest Theropod that roamed in Denali was Albertosaurus, which was 30 feet long and weighed as much as a car. Theropod prints have three long, skinny toes and often show claw marks at the tips of the toes.