T. rex evolved into a monster predator by dumbing down its brain

Tyrannosaurus

Big head but a simple brain

Dimitri Carol / Alamy

Tyrannosaurus rex has a reputation for being one of the biggest and fiercest dinosaurs ever to have lived. But it probably wasn’t the brightest: it had a simpler brain than an earlier, smaller tyrannosaur. The change could be a consequence of growing so large.

Fossils suggest that T. rex could reach 12 metres in length and between 8 and 14 tonnes in weight. It belonged to a family of dinosaurs called the tyrannosaurs – but not all of them were large. For example, Dilong paradoxus – …