T. Rex Probably Didn't Use Its Tiny Arms Much

Sue the Tyrannosaurus rex — the most complete and best-preserved T. rex skeleton ever found — temporarily surrendered her arm to science. Tests on Sue's arms at Argonne National Laboratory in Illinois showed few signs of stress, according to The Field Museum in Chicago, where this giant beast dominates the museum's main hall. T. rex's comically small front limbs have long stumped scientists.