A 40-foot-long predator stomps through a forested valley in what’s now western North America, following its nose: The animal sniffs a tasty Triceratops nearby. Moving quickly—about 12 miles an hour—the carnivore catches up to its prey. With one powerful bite, it rips off a hundred pounds of meat. Then it throws its head back, tosses the flesh 15 feet into the air, and catches it to swallow it whole.
Other species of tyrannosaurs existed for a hundred million years before T. rex appeared, but these dinos were puny compared to other giant predators at the time, like allosaurs, ceratosaurs, and spinosaurs. (The smallest tyrannosaur, Dilong, was only about five feet long and weighed about 11 pounds.) But Tyrannosaurus rex was one of the fiercest predators of all time.
T. rex had a massive body; a mouth full of 60 eight-inch-long, supersharp teeth; and the strongest bite of any land animal—ever. Its jaws could have crushed a car. Even more fearsome? T. rex had a brain about twice as large as other dinosaur noodles, suggesting that it might have been more intelligent, with better vision and sense of smell, than its fellow dinosaurs.
Its name comes from the Greek words meaning “tyrant lizard king.” This “king” ruled over what’s now North America and Asia some 68 million years ago, during the Cretaceous period. But T. rex was no match for the giant asteroid that slammed into Earth 66 million years ago, causing the extinction of the dinosaurs.
Scientists have known about T. Rex for more than a hundred years, but it wasn’t until the 1980s that the most complete fossil was discovered in South Dakota. Named Sue after the fossil hunter who found it, the 13-foot-tall dino measures 42 feet from end to end.
Although a baby T. rex would be about the size of a small turkey, adults grew way beyond these feathered creatures. Sue’s skull weighs 600 pounds; when it was alive, the dino probably weighed about 18,000 pounds—about as much as an RV. Want to see for yourself? You can visit Sue at the Field Museum of Natural History in Chicago, Illinois.