Study finds Tyrannosaurus rex did not reach full size until age 40

There is no question that Tyrannosaurus rex got big. In fact, this fearsome dinosaur may have been Earth’s most massive land predator of all time. But the question of how quickly T. rex achieved its maximum size has been a matter of debate.

A new study examining bone tissue microstructure in the leg bones of 17 fossil specimens concludes that Tyrannosaurus took about 40 years to reach its maximum size of roughly 8 tons, some 15 years more than previously estimated. As part of the study...