Scientists May Have Finally Figured Out What T-Rex Did With Its Stubby Little Arms

The function of the tiny limbs has remained a mystery to scientists.

A model of the Tyrannosaurus rex.
Marco Rubino / Shutterstock

The function of the tiny limbs has remained a mystery to scientists.

It turns out that the stubby arms on the Tyrannosaurus rex may have actually been quite useful.

Researchers studying the gigantic predator believe that they have determined the function of the tiny arms, which resemble the limbs of some modern animals like the domestic turkey and the American alligator. As Live Science reported, two researchers studied the modern relatives of the T-Rex and found out that the little limbs may have actually served a purpose.

The co-researchers — Christopher Langel and Matthew Bonnan from Stockton University in New Jersey — determined that the T-Rex could rotate its arm inward and upward so that the palm could face the chest. This range of motion meant that the arms were actually functioning and could help the ferocious predator to eat.

“We might speculate that such a movement (rotating the forearm and hand in toward the chest) could allow some theropods to bring prey in close for a bite,” the researchers told Live Science.

If true, then the arms may have been key in the evolution of the T-Rex, giving it a slight advantage over other predators.

This is not the first team to attempt to determine what function the T-Rex’s tiny arms could have served. Last year, a paleontologist from the University of Hawaii suggested that they could have aided the dinosaur in killing its prey. As Time reported, Steven Stanley posited that the ultra-sharp claws helped the dinosaur to slash deep into the flesh of its prey while it was hunting. Much like the talons of the modern hunting birds, these claws could have helped kill smaller animals.

“Its short, strong forelimbs and large claws would have permitted T. rex, whether mounted on a victim’s back or grasping it with its jaws, to inflict four gashes a meter [three feet] or more long and several centimeters [more than an inch] deep within a few seconds,” said Stanley. “And it could have repeated this multiple times in rapid succession.”

As the report noted, there have been other guesses as to what T-Rex did with its small arms — with some theorizing that they were used to help the dinosaur to stabilize and to stand up after falling over. Others believe that they were used to grip a mate during mating.

The researchers from Stockton University say that there is still more work to do to figure out exactly how the T-Rex used its stubby little arms, and they plan to examine the shape of its forelimb bones — comparing them to those of alligators and turkeys.