A New Explanation for the T-Rex's Stubby Arms
Sue the Tyrannosaurus rex, sporting the dinosaur's tiny arms. (Source: Field Museum of Natural History)
Certain debates persist across paleontology, but perhaps none as thorny as the evolutionary function of the T-Rex’s arms. To this day, no definite consensus has arisen to explain the fearsome predator’s miniscule appendages, with a host of theories circulating through the scientific community.
The theories run quite the gamut, from the idea that the arms functioned as weapons to trap prey while feeding, or that they were used during group feedings over a carcass. Other more contentious ideas suggest they were used in mating or simply to help the T-Rex stand up from a resting position, but both of these present problems: there are no meaningful differences in the arms between males and females, and the arms would not be long enough to help the T-Rex fully stand.
A more recent theory makes no attempt to explain the arms’ function, rather it suggests that the arms served no purpose at all and were simply holdovers from an earlier stage of evolution. This suggests that had T-Rexes not perished along with the other dinosaurs, they may have eventually lost their arms altogether. Evolution is always at work, constantly refining species into new forms. The fossils we uncover only tell part of the story, who knows what other innovations evolution might’ve spawned from the dinosaurs had their story not been cut short.
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