During its heyday 66 million years ago, Tyrannosaurus rex was one of the fiercest creatures on Earth. Now, one specimen discovered almost 30 years ago is revealing that the animals grew even larger than fossils have led some to believe.

Scientists estimate the behemoth dinosaur weighed close to 10 tons and was about 30 years old. Its age is likely what allowed it to grow so big, the researchers say. Tyrannosaurs kept growing throughout their lives.

“Tyrannosaurs seem to be an animal th