It’s no secret that T. rex arms were small, and those stubby limbs don’t seem very useful for such a fierce predator. The dinosaur couldn’t reach out and grab things while it stood. Likewise, using its claws to swipe at prey seemed unlikely, given the height-to-arm-length ratio. Why did T. rex have such little arms, and how did it use them? We’ll explore the answers to both questions below!
The Reason for Little Arms
The T. rex had little arms because the species evolved that way based on what it ate and how it hunted. Early ancestors of the tyrant lizard rarely used their arms, so the physical structure shrunk as they evolved. Essentially, those forelimbs became a vestigial feature of the T. rex; while its arms weren’t particularly useful, they also didn’t harm the animal.
On the other hand, their heads became more massive to accommodate those enormous teeth to catch and crush prey. If its arms also become tremendous, it may throw off the animal’s balance and make this slow-moving reptile walk even more leisurely.
Some Uses for Little Arms
While its arms weren’t useful for hunting, the animal may have used them in other ways, such as socially. The T. rex may have used its arms and claws to catch the attention of a potential mate. Likewise, those tiny arms may have helped a T. rex push itself up if it fell or got knocked over.
It’s also possible that the T. rex evolved with small arms to avoid hurting itself when it chased and caught its next meal. After all, this apex predator had one of the strongest bites of any land animal; biting its arm could risk accidental amputation. However, those short arms aren’t in any danger of unintentional bites because they aren’t long enough to reach its mouth.
The T. Rex Wasn’t Alone
While many of us wonder why on earth T. rex had such little arms, the creature was by no means the only one with ironically small limbs. Various theropods had relatively small arms compared to their body size:
Similar to the Tyrannosaurus rex, other dinosaurs had small arms because they didn’t use them much.
Shop for Dinosaur Action Figures
Creative Beast Studio sells authentic-looking dinosaur action figures for dino lovers! You’ll find various ceratopsian dinosaurs in collections, such as our Beasts of the Mesozoic Ceratopsian collection. If the T. rex is your favorite prehistoric animal, check out our Tyrannosaur Series and buy an action figure!