About 190 million years ago, a large predatory dinosaur was walking along the shore of a river when it suddenly stopped in its tracks. It turned, and then broke into a run, perhaps in a dash for prey. How do we know this? Because its footprints became fossilized. Dinosaur tracks can give us an amazing glimpse into the behavior of the animals that left them.
These prints are couple of about 2,000 that were found at Dinosaur State Park in Connecticut. No remains of the dinosaurs were found, but scientists think they may have been Dilophosaurus or something similar. The animals seem to have been crossing an ancient mudflat.
POSITIVE OR NEGATIVE?
Fossil footprints can be positive or negative. Positive prints are simply impressions in rock and look like ordinary footprints. Negative prints look like the underside of a dinosaur foot, as though viewed from below.
They form when a footprint fills with sand to form a natural cast. Millions of years later, the sandstone cast is all that is left behind.
These tracks look like ordinary footprints.
These tracks look like the bottom of a dinosaur’s foot.
Dinosaur footprints that form a long trail are rare but give us fascinating clues about the way dinosaurs lived. Most tracks do not show drag marks left by the tail, telling us that dinosaurs held their tails up. Parallel tracks (tracks that run side by side) show that some species traveled in herds.
A LONG TRACKWAY
The world’s longest dinosaur trackway is found on a cliff face in Bolivia, South America. The tracks are those of a titanosaur.
Why are they on a cliff face?
The dinosaurs that left these tracks were walking along a sandy shore or a mudflat. Later, the prints became buried and the mud or sand turned to rock. Movements in Earth’s crust have since tilted the layer of rock, so the prints now run vertically.
DID YOU KNOW?
The 100 million-year-old dinosaur footprint below was found on a beach in Portugal. It was made by an iguanodontian—a plant-eater. The dinosaur was walking on its own and its tracks cross those of two meat-eating dinosaurs.
At Olhos de Agua, Portugal, this huge iguanodontian footprint was found.