CITY EXPERTS SOLVE MYSTERY OF T-REX’S CRUSHING BITE
T-REX’S notorious bone crushing bite was more than 160 million years in the making, according to new research.
Its jaws became stronger as the creature evolved – allowing it to eat tougher food.
The ‘king of the dinosaurs’ had the most powerful bite of any land animal that has ever lived.
Its lethal dagger-like teeth – shaped like bananas – chomped down on prey with a force of over seven tons.
How T-Rex performed the feat without smashing its own skull has baffled scientists for decades.
Now a Birmingham-led team has solved the mystery using computer modelling and simulations.
The rear of the jaw gradually expanded in all dinosaurs, including flesh and plant eaters.
It also became deeper and upturned in the carnivores, but downturned in herbivores.
The phenomenon fuelled their diversification and led to the emergence of modern birds, which descended from dinosaurs.
Biomechanical analysis showed the changes made jaws mechanically more stable, minimising the risk of bone fracture during biting.
Lead author Fion Waisum Ma, a PhD student at the University of Birmingham, said: “Theropod dinosaurs are always depicted as fearsome predators in popular culture.
“But they are, in fact, very diverse
in terms of diets. It is interesting to observe the jaws becoming structurally stronger over time, in both carnivores and herbivores. This gives them the capacity to exploit a wider range of food items. Theropod dinosaurs underwent extreme dietary changes during their evolutionary history of 165 million years.
“They started off as carnivores,
later on evolving into more specialised carnivores, omnivores and herbivores.
“Studying how their feeding mechanics changed is key to understanding the dietary transitions in other vertebrate animals, too.”
T-Rex first appeared 69 million years ago, becoming extinct 2.5 million years later. Its earliest ancestor dates back 230 million years.
The researchers created digital versions of more than 40 lower jaws from five different types of theropods.
They included T-Rex and
Velociraptor along with lesserknown herbivores such as ornithomimosaurs, therizinosaurs and oviraptorosaurs.
In carnivores like tyrannosauroids, an early form like Guanlong had a relatively slender and straight jaw.
But Tyrannosaurus, Tarbosaurus and other later members evolved more cavernous jaws with the front bending up – which increases strength.
Plant-eating counterparts experienced considerable stress from repetitive munching on coarse vegetation.
The jaws of herbivores like Erlikosaurus and Caudipteryx bent sharply downwards – helping dissipate such pressure.
Senior author Dr Stephan Lautenschlager, also from Birmingham, said: “It is fascinating to see how theropod dinosaurs had evolved different strategies to increase jaw stability depending on their diet.
“This was achieved through bone remodelling, a mechanism where bone is deposited in regions of the jaw that experience high stresses during feeding.”