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Lonely at the Top?

Part of the Dinosaurs: Ancient Fossils, New Discoveries exhibition.

This is the only known footprint of the huge meat-eater Tyrannosaurus rex. Its one-of-a-kind status may be a clue to the ecology of these enormous dinosaurs.

Modern animals at the top of the food chain--lions, eagles, great white sharks--tend to be rare. And only about 30 T. rex skeletons have ever been found--in contrast to hundreds of remains of many other dinosaur types, such as plant eaters. In other words, the rarity of T. rex footprints and the scarcity of T. rex fossils all suggest that there simply weren't that many of the fearsome carnivores around.

Tyrannosaurus rex "negative" footprint.
AMNH FR 30237 (cast)


One of a Kind

Displayed here is a cast of the only documented footprint of Tyrannosaurus rex, discovered in the 1980s by a geologist doing a mapping survey in northeastern New Mexico. It is the largest print of a meat-eating dinosaur ever found.

The original was what track experts call a negative: It was formed by the sediment that filled the depression left by the dinosaur's foot.

The magnified detail is the imprint of the first toe of T. rex. Because of its position, high on the foot, it would only be visible when the animal stepped in deep mud.

Fun Fact

Sometimes what we call a fossil footprint is really the sediment that filled the hollow left by the animal's foot--turned to stone!