Tyrannosaurus rex lived longer and took more time to reach its maximum size than previously thought, according to a new study.Scientists have long counted annual growth rings in fossilized Tyrannosaurus rex leg bones to calculate both their age at death and how fast they grew to adult size. These dinosaurs typically stopped growing around 25 years old and lived to around 30, research has shown.However, a new study published in the journal PeerJ on Wednesday details how a team of scientists used polarized light to reveal previously unseen growth rings from 17 individual specimens. T. rex wouldn’t have reached its maximum size of around 8 tons until it was 35 to 40 years old, the analysis found.AdvertisementAdvertisementAdvertisementAdvertisementUnlike tree growth rings, dinosaur growth rings only capture the final 10 to 20 years of an individual’s life.But because the specimens ranged in age from early juveniles to adults, researchers were able to put together a picture of their growth using a new statistical approach that combines records from individuals of different ages.A diagram shows the percentage of a Tyrannosaurus rex’s adult size that it would have reached at different life stages. – Dr. Holly Woodward BallardDrawing on the largest dataset ever put together for Tyrannosaurus rex, researchers were able to reconstruct their growth history year by year and found that the dinosaurs grew much more slowly than previously thought.“Instead of growing quickly, T. rex spent most of its life in the mid-body size range rather than achieving a total body length of 40 feet quickly,” lead study author Holly Woodward, a professor of anatomy at Oklahoma State University, told CNN on Thursday.AdvertisementAdvertisementAdvertisementAdvertisement“Additionally, we found that growth ring spacing varied within individuals, with some years showing substantial growth and others very little,” she said. “Thi …
