Biomechanical Stabilization by the Forelimbs of Tyrannosaurus rex

The markedly reduced forelimbs of Tyrannosaurus rex have generated a longstanding debate concerning whether they were functionally important, secondarily reduced but still functional, or effectively vestigial. Previous hypotheses have proposed roles including prey restraint, close-range slashing, and other forms of prey manipulation. Here, I propose a biomechanical hypothesis in which the forelimbs functioned primarily as auxiliary stabilizing structures, rather than as the principal offensive apparatus. The proposed Biomechanical Stabilizer Model consists of two complementary functional contexts. First, during feeding, the forelimbs may have provided short-range stabilization of a carcass or accessible tissue while the jaws and cervical musculature performed the principal work of tissue removal. Second, during close-range predation on large-bodied prey, the forelimbs may have provided transient contact with the prey or adjacent body surfaces, potentially reducing lateral displacement and rotational instability generated by prey resistance. Under this interpretation, the forelimbs need not have been capable of independently restraining or overturning large prey. Instead, their functional contribution would have consisted of relatively small but strategically positioned forces that complemented the much larger mechanical contributions of the jaws, neck, trunk, and hindlimbs. This model predicts that the short forelimbs of T. rex could have retained selective functional value despite their reduced length. The hypothesis is testable through three-dimensional musculoskeletal reconstruction, joint-range-of-motion analysis, contact modeling, and experimental assessment of the effects of forelimb contact on predator-prey rotational dynamics.