Giant Jaws, Tiny Arms: Study Links T. rex Arm Reduction to Skull Power

New research argues Tyrannosaurus and related theropods reduced forelimb size as they evolved larger, more robust skulls and jaws, using jaws as the primary weapon against enormous prey. An analysis of 61 theropods shows a strong link between short arms and robust skulls across five families, with skull growth likely preceding arm reduction. Forelimbs retained some function but did not drive the arms’ evolution; the study emphasizes correlation, not direct causation, and was published in Proceedings of the Royal Society B.