It used to be thought that many dinosaurs achieved such huge sizes because they grew slowly and continuously, like crocodilesandiguanas do, for a century or more. We now know this wasn’t the case, and that dinosaurs generally grew fast and died fairly young.
We can tell the age of dinosaur fossils by cutting open their bones and counting growth lines; that’s because, similar to a tree, dinosaurs laid down one ring of bone growth every year. This technique tells us thatTyrannosaurus rexreached full size in about 16to22 years, and usually diedat27to33 yearsold.
OtherbigcarnivorescalledCarcharodontosaurids lived to between 39and53 years old. The verylargestdinosaurs,thelong-necked sauropods like Brontosaurus and Diplodocus, seemed to have reached a similar age, although some could have lived maybe a decade or two longer – perhaps up to 70 years old.
Read more:
- What was the first dinosaur?
- How did dinosaurs mate?
- How long did it take dinosaur eggs to hatch?
- How did dinosaurs sleep?
Asked by: Alex Carlson, via email
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