One detail that has long puzzled scientists when it comes to Tyrannosaurus rex, the uncrowned king of the dinosaurs, is its tiny arms and what function they actually served. Scientists now believe they have the answer.
A new study, in which researchers analysed over 80 different species of carnivorous dinosaurs, has revealed a clear pattern. There is strong evidence that as these animals' skulls grew larger, their forelimbs also became smaller. This correlation was observed across several different groups of carnivorous dinosaurs, pointing to a clear evolutionary trend that occurred regardless of species.
The researchers also suggest that these larger dinosaurs—and specifically the carnivorous ones—gradually relied more and more on their powerful jaws and massive heads when hunting and killing prey. So as this became their primary weapon, the need for large, strong arms diminished, which may also have led to their shrinking over the course of evolution.