To meet the oldest creature in our cast of characters - the T. rex - we’d have to go back to a time when people and animals did not co-exist. What we know about this dinosaur, we’ve learned from fossils. (This animation depicts the fossilization process.)
Six years later - in the same Hell Creek, Montana location - Brown found more fossilized remains (follow the link to reconstruct animals from fossil bones) for the American Museum of Natural History. When viewed together, all the findings provided scientists with a good picture of this enormous carnivore.
The first T. rex mount - made in 1915 and incorporating the 1908 skeleton plus casts of missing pieces from the 1902 discovery - revealed a ferocious creature possessing the power to efficiently annihilate its prey. (Scientists have determined that T. rex ate Triceratops, among other things.)
Digging for dinosaurs has resulted in other stunning discoveries. New "finds" have shown that T. rex was not the biggest creature to roam the earth, and its ancestor - Raptorex kriegsteini, or R. kriegsteini - was amazingly small.
Thanks to a relatively recent discovery - near the town of Faith, South Dakota - we can see the skeleton of a nearly complete T. rex. Its name is Sue, and it currently resides in Chicago's Field Museum.
Sue’s 5-foot skull is enormous and heavy. It cannot be displayed with the rest of the skeleton. Instead, a replica sits atop the dinosaur’s fossilized bones while the skull itself is encased, with teeth in place, inside a special glass container. Some of Sue’s serrated teeth are more than a foot long!
Although the brain of this massive dinosaur was not fossilized, its braincase was in remarkably good shape. Scientists have determined Sue’s brain was about a foot (or 30.5 centimeters) long. Scans of Sue’s skull, taken by Boeing’s computerized tomography machine, have allowed scientists to create a digitized version.
Sue (whose sex cannot be determined) has given scientists much more knowledge than they previously had regarding the fearsome T. rex. But unlike Attila the Hun - the next character we will meet - no one can tell why Sue died.