TYRANNOSAURUS rex may have grown more slowly and lived longer than previously thought, according to new research published in the journal PeerJ.
Scientists had previously estimated the dinosaur’s age and growth rate by counting annual growth rings in fossilised leg bones, concluding that T-rex stopped growing at about 25 years old and lived to around 30.
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The latest study used polarised light to reveal previously unseen growth rings in 17 individual specimens and found that T-rex did not reach its maximum weight of around eight tonnes until between 35 and 40 years of age.
Researchers noted that, unlike tree rings, dinosaur growth rings record only the final 10 to 20 years of life, prompting them to examine specimens ranging from early juveniles to adults and apply a new statistical method combining data from individuals of different ages.
Lead author Holly Woodward, professor of anatomy at Oklahoma State University, said the findings showed T-rex spent most of its life in the mid-body size range, with growth ring spacing varying within individuals and indicating development was flexible and likely influenced by resource availability and environmental conditions.
