T. Rex’s short arms could reduce the risk of bites during rabies feeding

T. Rex is probably the most famous dinosaur of all, but for many years the key question remains about his anatomy – why were his arms so short?

An American paleontologist claims that the scary creature had dull hands to keep them aside during rabid feeding.

Having short arms may have reduced the risk of being bitten by other hungry adult T. rex when they devoured the carcass.

The tiny hands on the mighty tyrannosaurus rex are one of the greatest and enduring mysteries in paleontology.

For example, a 45-foot T. Rex could have a skull five feet long, but arms only three feet long – the equivalent of a 6-foot man with 5-inch arms.

T. rex and other tyrannosaurids first appeared in the Late Jurassic and reached their peak in the Late Cretaceous before becoming extinct about 65.5 million years ago.

The new study was led by paleontologist Kevin Padiana, a professor at the University of California, Berkeley and curator of the University of California Paleontology Museum (UCMP).

Professor Padian noted that the predecessors of tyrannosaurids had longer arms, so there must have been a reason that they decreased in both size and mobility of the joints.

The answer came to him after other paleontologists found evidence that some tyrannosaurids hunted in flocks rather than individually, as depicted in numerous paintings and dioramas.

“What if a few adult tyrannosaurs converged on the carcass?” he said. “You have a bunch of massive skulls with incredibly powerful jaws and teeth that tear and bite flesh and bone right next to you.

“What if your friend thinks you’re too close?” They can warn you by cutting off your hand, ”he said.

“So it would be helpful to reduce the forelimbs, because you still don’t use them in predation.”

While studying in a freshman seminar called The Age of Dinosaurs, students always asked Professor Padian why T. Rex’s hands were so ridiculously short, but the answer was always, “Nobody knows.”

When the great dinosaur hunter Barnum Brown discovered in 1900 the first fossils of T. Rex, he felt that his hands were too small to be part of the skeleton.

At the time, his colleague Henry Fairfield Osborne, who described and named T. Rex, suggested that short arms could be “pectoral fasteners” – limbs that hold the female in place during mating.

This is similar to the pelvic latch of some sharks and stingrays, which are modified fins.

But Osborne presented no evidence, and Professor Padian remarked that T. Rex’s arms were too short to bypass the other T. Rex, and certainly too weak to exert any control over the partner.

For more than a century, other proposed explanations of short arms included swinging to attract a partner or social signals that serve as an anchor to T. Rex to rise from the ground, holding back prey, stabbing enemies and even pushing through sleeping triceratops at night like a cow rushes.

In addition, some paleontologists have suggested that the hands did not perform the function at all, so we should not worry about them.

In his work, Professor Padiana expresses his new hypothesis – T. Rex’s arms were shortened in length to prevent accidental or intentional amputation when a pack of T. Rex fell on the carcass with their massive heads and teeth that break bones.

Perhaps the hands have shrunk in a couple of million years that there was a species to get out of the way while feeding the flock.

In particular, young T. Rex would be wise to wait until the larger adults finish eating.

It is similar to the largest of the existing species of lizards, the giant dragon lizard Komodo (Varanus komodoensis) from Indonesia.

This surviving species hunts in groups, and when it kills prey, larger dragons converge on carcasses and leave leftovers for smaller ones.

Professor Padiana acknowledged that any hypothesis, including his own, would be difficult to substantiate 66 million years after the last T. Rex became extinct.

“Several important quarries found over the past 20 years hold together adult and young tyrannosaurs,” he said.

“We can’t assume they lived together or even died together. We only know that they were buried together.

“But if you find multiple sites with the same animals, it’s a stronger signal. And the probability that other researchers have already expressed is that they hunted in groups. ”

Further research could re-analyze the fossils of T. Rex’s hands for bites.

“Wounds from bites on the skull and other parts of the skeleton are well known in tyrannosaurs and other carnivorous dinosaurs,” said Professor Padiana.

“If fewer bite marks were found on the reduced limbs, it may be a sign that the reduction has worked.”

The study is published in the journal Acta Palaeontologia Polonica.