Britannica
Sources used in this answer
How quickly did Tyrannosaurus rex reach adult size?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
tyrannosaur
The fossilized remains of Sue, the most complete Tyrannosaurus rex skeleton in the world, on display at the Field Museum of Natural History, Chicago.
By analyzing the annual growth rings preserved in their long bones, paleontologists have determined that Tyrannosaurus rex effectively reached its full adult size in less than 20 years.12
This growth rate is notable because, while it spans a period similar to that of human beings, T. rex attained a significantly larger body mass during that time. However, this growth was not as rapid as that of some other dinosaurs; for instance, sauropods reached most of their massive size in approximately 14 years, and some hadrosaurs reached full maturity in as little as seven or eight years.1