T. rex didn't evolve tiny arms because its body got bigger — it evolved tiny arms because its jaws got more powerful, according to a new study of 82 meat-eating dinosaur species that found the same pa

The standard cultural framing of Tyrannosaurus rex’s famously tiny arms has, for over a century, treated them as one of the small jokes evolution has played on an otherwise terrifying animal. The skull is enormous. The teeth are the size of bananas. The body is the size of a city bus. The arms, by contrast, […]