T rexes grew much more slowly than previously thought, taking several decades to reach their full size of around eight tonnes, a comprehensive new fossil study revealed. Until now, researchers counted ...

The largest-ever analysis of Tyrannosaurus rex fossils suggests the giant and fierce Cretaceous predator was a late bloomer, taking 35 to 40 years to reach maturity. The findings also further the ...

For decades, scientists have been counting annual growth rings—similar to tree rings—inside fossilized leg bones of Tyrannosaurus rex to estimate how old the giant carnivores were when they died and ...