The Tyrannosaurus rex, commonly known as T. rex, was a large carnivorous dinosaur that lived during the late Cretaceous period, around 68 to 66 million years ago. It is one of the most well-known dinosaurs, characterized by its massive skull, powerful jaws, and tiny arms. T. rex could grow up to 40 feet long and weigh over 9 tons, making it one of the largest land predators of its time. Fossils of T. rex have been found primarily in North America, providing valuable insights into its anatomy and behavior. This dinosaur likely hunted other large dinosaurs and scavenged for food. Its keen sense of smell and strong legs allowed it to be an effective predator in its environment.