Once upon a time, a long, long time ago there were these big, scary dinosaurs called tyrannosaurs. People were very interested in learning about them so they started to do research to find out more.
First, in the early 1900s, a man named Henry Fairfield Osborn found some bones that he thought were from a new kind of dinosaur. He named it Tyrannosaurus rex, or T. rex for short. This was very exciting because T. rex was one of the biggest and strongest dinosaurs ever!
For a while, people didn't know much about T. rex because there weren't many fossils to study. But in the 1990s, some very important discoveries were made by a woman named Sue Hendrickson. She found a nearly complete T. rex skeleton which helped scientists learn even more about these giant dinosaurs.
Over time, scientists also began to learn more about the behavior of tyrannosaurs. They discovered that some types of tyrannosaurs were smaller and faster than T. rex, and ate different things. They also learned that T. rex may have had feathers, which is kind of surprising because they always thought it was just scaly.
Today, scientists are still studying tyrannosaurs and learning more all the time. They use new technology like CT scans and 3D printing to make models of the bones and learn even more about how these creatures lived so long ago. So who knows what they will discover next!