T. rex grew into a giant over four decades, new study finds
A new peer-reviewed study of 17 Tyrannosaurus rex fossils used growth rings revealed by polarized light to map year-by-year growth, showing T. rex took 35–40 years to reach full size and grew for four decades to about 8 tons, with an estimated lifespan of 45–50 years. This large dataset yields a revised growth curve and suggests a lengthy juvenile phase may have helped juveniles occupy varied ecological roles before the species became a dominant late-Cretaceous apex predator.
