Juvenile T. rexes were light and agile before they leveled up into the adults we’re more familiar with. (The physical discrepancies between younger and older T. rexes can be so vast that experts have argued over whether certain specimens are different species altogether, rather than different ages.) 2021 February 25, Cara Giaimo, “The Outsized Influence of Teen T. Rex and Other Young Dinosaurs”, in The New York Times, New York, N.Y.: The New York Times Company, →ISSN, →OCLC: