There is a chance, however, that your competition might not be able to put all that beefy muscle to use. There are dozens of hypotheses about what the T. rex used its arms for, Conrad explains, but the ones taken most seriously involve pushing itself up if it was lying on its belly, tossing big chunks of meat into its mouth, or holding onto females during what scientists suspect was a very vigorous mating routine. These ideas are favored because such actions required Barbie doll–like up-and-down motions of the arm, and fossil evidence indicates that the dino king was incapable of rotating or twisting its arms. "The T. rex probably couldn't have done the arm-wrestling move," Conrad says. "So maybe you could get him on a technicality."