Science Blast: Slash, T-Rex! Slash!

Tiny T. rex arms were built for combat

 Far from lame and puny, they would have been powerful slashers CAROLYN GRAMLING NOV 29, 2017 — 6:45 AM EST

T. rex

This dino may have been one of the ultimate slashers — if any beast was unfortunate enough to get too close. PARA827/ISTOCKPHOTO
SEATTLE, Wash. — No question, Tyrannosaurus rex had small arms. Still, this dino was no pushover.

It is best known for its giant head, powerful jaws and overall fearsome appearance. And then there were those comical-looking arms. One scientist now argues that they weren’t funny when it came to combat. Those roughly meter- (39-inch-) long limbs weren’t just sad reminders of a longer-armed past, concludes Steven Stanley. He’s a paleontologist at the University of Hawaii at Manoa. Those forelimbs were well-adapted for vicious slashing at close quarters, he says.

Stanley shared his assessment October 23, here, at the Geological Society of America’s annual meeting.

T. rex ancestors had longer arms, which they used for grasping. But at some point, T. rexand other tyrannosaurs began to rely on their giant jaws for grasping. Over time, their forelimbs evolved into shorter arms.

Many scientists had suggested the tinier arms were, at best, useful in mating or perhaps for pushing the dino up off the ground. Others suspected they might at this point have had no role at all.

Those arms remained, however, quite strong. With robust bones, they would have been able to slash out with forceful power, Stanley notes.

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