Earlier in the week, I posted some theories regarding the function of T. rex’s diminutive arms. I just thought I would add some recent research before I closed the topic:
Matt Smith (Museum of the Rockies) and Ken Carpenter (Denver Museum of Natural History) began examining the wrist, hand and finger bones of the T. rex forelimb and used wax to hold the bone joints together. This led them to figure out that the forelimb's two claws have an unusual feature: unlike the opposable human thumb and forefinger combo, which can grasp objects, the two dinosaur claws face away from each other like the barbs of a fishing hook.
What does this mean? Perhaps these claws embedded themselves into the prey’s flesh and immobilized it while T. rex used his jaws to finish the job. .
Matt Smith says, "People had been looking at [forelimb] function based on proportionate size. I don't think that's appropriate."