Scientists have suggested a possible use of seemingly unimpressive and stunted arms of the ferocious Tyrannosaurus Rex (T-Rex) – for slashing prey ruthlessly.
For a long time it was believed that there was almost no use for T-Rex’s stunted arms; however, paleontologist Dr. Steven Stanley from the University of Hawaii in Manoa believes that’s not the case and that these tiny arms were actually among the dinosaur’s ruthless weapons.
Previous studies have suggested the use of the tiny arms for grasping struggling prey. Some studies have also suggested that these front limbs were likely used to help resting dinosaurs push themselves up from the ground, or even get a tight grip around their mates during sex.
But Dr. Stanley believes that these tiny arms had a much more vicious use – slashing at close quarters. Dr Stanley says that the forelimbs had large claws and they would have enabled the dinosaur to inflict four gashes a meter (three feet) or more long and several centimeters (more than an inch) deep in a matter of just a few seconds. The scientists went on to say that the T-Rex would have made use of the claws on its tiny arms to inflict deep wounds on its prey in quick succession.
Furthermore, Dr. Stanley noted that the T-Rex possessed an unusual quasi-ball-and-socket joint, which would have been ideal for slashing since it could move in several directions.
He also noted that the creature’s ancestors most likely had longer limbs, but evolved to support the massive weight of the rest of its upper body.
“No longer being selected for, the arms were selected against: the expansion of the head deprived them of nutrition in a zero-sum game,” said Stanley. “Then, as the arms approached their final size, natural selection kicked in opportunistically and put them to good use for slashing at close quarters.”
He added: “It might be that the arms were actually more functional in young T. rex, and became reduced in function as it became older,” he explained.
“The strike zone would be proportionately larger in a young T. rex – and going after smaller prey would mean the force required to kill the victim would be less.”