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The Biomechanics Behind Extreme Osteophagy in Tyrannosaurus rex; Paul M. Gignac, Gregory M. Erickson. Scientific Reports, 2017; 7 (1) DOI: 10.1038/s41598-017-02161-w
Topic Started: May 18 2017, 08:12 PM (163 Views)
Taipan
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T. Rex Could Pulverize Bones with a Force of Nearly 8,000 Pounds

By Laura Geggel, Senior Writer | May 17, 2017 07:13am ET
Posted Image
Jaw muscles in Tyrannosaurus rex helped it generate an almost 8,000-lb. bite force and an astounding 431,000 lbs. per square inch of bone-crunching tooth pressures.
Credit: Gignac & Erickson/Scientific Reports

Tyrannosaurus rex could gnash and chomp its teeth together with such force that it could easily pulverize the bones of its prey, a new study finds.

The king of dinosaurs could bite down with a force of 7,800 pounds-force (34,522 newtons), a force equal to the weight of three small cars, the researchers found.

But the real damage T. rex inflicted came from its teeth, each of which could exert pressures reaching 431,000 pounds per square inch (2,974 megapascals), "which allowed T. rex to bite through and even shatter bone before consuming it," said lead study researcher Paul Gignac, an assistant professor of anatomy and vertebrate paleontology at the Oklahoma State University Center for Health Sciences.

This is hardly the first time scientists have investigated the mighty tyrannosaur's bite force. For instance, scientists reported in 2012 that they had used digitally scanned T. rexskullsto make computer models, finding that the beast could bite with forces ranging from 7,868 to 12,814 pounds-force (35,000 to 57,000 newtons), Live Science previously reported.

However, the new study includes several advancements. For starters, it is the first published study on the pressure exerted by T. rex teeth, Gignac said. What's more, Gignac and co-researcher Gregory Erickson, a professor of biological science at Florida State University, used a novel method that involved studying the living descendants of dinosaurs (birds), and living cousins of dinosaurs (alligators and crocodiles) to learn more about T. rex's chomping abilities.

Biting research

Most extinct dinosaurs did not have this bone-splintering ability, nor do modern reptiles. Today's carnivores, such as gray wolves and spotted hyenas, can break and eat bone, though they have specialized teeth for the feat.

"In this study, we show that Tyrannosaurus rex is the exception, and we sought to explain how this was possible," Gignac told Live Science in an email.

To begin, the researchers developed and tested a 3D anatomical model that predicted the bite forces of the American alligator (Alligator mississippiensis). "Once we understood how to build such models accurately, we constructed a similar one for T. rex," Gignac said.

They based the T. rex model on a computed tomography (CT) scan from a scaled replica of one of the best-preserved skulls. Then, they inferred the dinosaur's muscle arrangement using a combination of crocodile- and bird-like features, as well as cues from the giant dinosaur's own bone structure.

This model allowed them to estimate the bite force at any tooth position along the jaw, as well as across the known adult size range for the tyrannosaur group, Gignac said.

The results illustrate just how much damage T. rex could inflict with its teeth.

"Through incredible, nearly 8,000-pound bite forces and record-breaking, 431,000 pounds per square inch tooth pressures, T. rex regularly scored, deeply punctured, and even sliced through bones," Gignac said.

The dinosaur "managed these feats, in part, because of its large size but more so because a specific set of tooth traits — extraordinarily large, conical and strongly rooted teeth that were replaced after being worn biennially," he said.

Extraordinary teeth

T. rex's teeth were up to 7 inches (18 centimeters) long, and were replaced about every two years, Gignac said.

Posted Image
This Triceratops pelvis has nearly 80 T. rex bite marks. The bracketed region shows where the carnivore repetitively removed sections of bone.
Credit: Gignac & Erickson/Scientific Reports

"They were toothy," he said. "For example, the upper jaw alone had more than 30 teeth. Three of these teeth (on each side) were particularly large and typically engaged the tissues of prey or scavenged carcasses first to invoke damage to bone."

The dinosaur's ferocious bite would have helped it splinter the carcasses of large horned dinosaurs and duck-billed hadrosaurs, whose bones were rich in mineral salts and marrow, Gignac said.

The finding, published online today (May 17) in the journal Scientific Reports, also shows how sophisticated eating systems, such as the ability to break bone, were present during the dinosaur age, he said.

http://www.livescience.com/59134-tyrannosaurus-rex-bite-could-pulverize-bones.html




Journal Reference:
Paul M. Gignac, Gregory M. Erickson. The Biomechanics Behind Extreme Osteophagy in Tyrannosaurus rex. Scientific Reports, 2017; 7 (1) DOI: 10.1038/s41598-017-02161-w

Abstract
Most carnivorous mammals can pulverize skeletal elements by generating tooth pressures between occluding teeth that exceed cortical bone shear strength, thereby permitting access to marrow and phosphatic salts. Conversely, carnivorous reptiles have non-occluding dentitions that engender negligible bone damage during feeding. As a result, most reptilian predators can only consume bones in their entirety. Nevertheless, North American tyrannosaurids, including the giant (13 metres [m]) theropod dinosaur Tyrannosaurus rex stand out for habitually biting deeply into bones, pulverizing and digesting them. How this mammal-like capacity was possible, absent dental occlusion, is unknown. Here we analyzed T. rex feeding behaviour from trace evidence, estimated bite forces and tooth pressures, and studied tooth-bone contacts to provide the answer. We show that bone pulverization was made possible through a combination of: (1) prodigious bite forces (8,526–34,522 newtons [N]) and tooth pressures (718–2,974 megapascals [MPa]) promoting crack propagation in bones, (2) tooth form and dental arcade configurations that concentrated shear stresses, and (3) repetitive, localized biting. Collectively, these capacities and behaviors allowed T. rex to finely fragment bones and more fully exploit large dinosaur carcasses for sustenance relative to competing carnivores.
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bone crusher
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The sheer brute strength and destructive power of this animal is ridiculous. At 8.5 ton and built like a tank from nose to tail, coupled with a crushing bite of 8000 pound pressure, no wonder its forearms are gimped due to too OP for its ecosystem. Mother nature knew she's done f***ed up when Sue showed up to the party.
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Mammuthus
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bone crusher
May 19 2017, 12:56 AM
At 8.5 ton
Can you please give evidence of trex averaging 8.5 tonnes?..
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Ceratodromeus
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The thing there is he can't because they don't average such as mass. ~7-7.5 tons is closer to the average of the sample we have.
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Ausar
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He never said it averaged at that size......
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Mammuthus
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Ausar
May 19 2017, 04:34 AM
He never said it averaged at that size......
Well the way he said it sounded as if he was meaning an average trex in my opinion.
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Ausar
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He even said "Mother nature knew she's done f***ed up when Sue showed up to the party". Sue is more or less at 8.5 tonnes (8.4 tonnes to be exact, as estimated by Scott Hartman, perhaps even more going by what Eric Snively supposedly said to someone I know from another site), so he could have been referring to it in particular.
Edited by Ausar, May 19 2017, 05:12 AM.
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Mammuthus
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Oh, I didn't realise Sue was around 8.5 tonnes, my bad.
Edited by Mammuthus, May 19 2017, 05:33 AM.
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bone crusher
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Mammuthus
May 19 2017, 02:59 AM
bone crusher
May 19 2017, 12:56 AM
At 8.5 ton
Can you please give evidence of trex averaging 8.5 tonnes?..
Never said they averaged 8.5 ton as others have pointed out for you already. In fact no one at this point can confidently put an average figure for them without enough specimens for 25-30 yr olds. Yeah I was more specifically referring to Sue, you could include Trix and Scotty into the mix too.
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DarkGricer
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bone crusher
May 19 2017, 11:12 AM
In fact no one at this point can confidently put an average figure for them without enough specimens for 25-30 yr olds.
The average T.rex likely did not live to those ages.
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