
Skull Strength Trumps Tiny Arms: New Study Solves T. rex Arms Mystery
A study published in the Proceedings of the Royal Society B analyzed 85 dinosaur species and found that tiny arms in T. rex and other giant carnivores are an evolutionary trade-off for increasingly large skulls; as skull strength rose to deliver more bite power, forelimbs shrank across multiple lineages around the world over roughly 180 million years, though their exact function remains unclear.

