Tyrannosaurus rex dinosaurs lived during the late Cretaceous period, which was about 65 million years ago, on a continent named Laramidia. Laramidia is now part of North America. The name Tyrannosaurus rex means "tyrant lizard king."
Tyranno is the Greek work for tyrant, saurus is the Greek word for lizard, and rex is the Latin word for king. The dinosaur does appear to have been a fearsome predator, though some biologists speculate that it was also a scavenger. It was not above cannibalism, though it is not certain whether T. rex hunted and killed weaker members of its own species or opportunistically ate their carcasses.
T. rex stood about 13 feet tall at the hips. Its height is not measured at the shoulders because it did not stand upright. It was 40 feet long and weighed as much as 9 tons. Despite its size, it could move quickly. Scientists believe it could run up to 25 miles per hour.
The dinosaur's teeth were serrated and could be up to a foot long. Like human teeth, they had different functions.The front teeth gripped the prey, the side teeth tore it up, and the back teeth chopped the meat and conveyed it into the animal's throat. T. rex's bite was so powerful that it crushed bones as it ate.