The long and short of it

Why did the T-Rex have such short arms? A study published in the journal Acta Paleontologica Polica suggested that the T-Rex evolved short arms because they fed in packs - and by having short arms it meant they wouldn’t bite off each other’s arms. Or was it a matter of the arms didn’t get shorter but that the legs got longer - that’s a suggestion put forward by John Hutchinson at London’s Royal Veterinary College who is an expert in the biomechanics of movement in large terrestrial animals - both living and extinct - who also noted that there was no way we could really know what was involved or the triggering factors. It is interesting to think about this piece of evolution differently though - because we do tend to think of T-Rex anatomy and the short arms that way.