Bite of juvenile T. rex was less ferocious than an adult tyrannosaurus

The juvenile Tyrannosaurus rex had a weaker bite than adult counterparts, according to a study by researchers in Britain. File Photo by John Angelillo/UPI
The juvenile Tyrannosaurus rex had a weaker bite than adult counterparts, according to a study by researchers in Britain. File Photo by John Angelillo/UPI
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March 9 (UPI) -- The bites of juvenile Tyrannosaurus rex dinosaurs were less powerful than those of their older counterparts, according to a new study.

The fossil record is rich with the bones of adult T. rex dinosaurs, allowing for detailed analysis of the predator's powerful bite -- a bite strong enough to crush bones and help T. rex take down large, plant-eating dinosaurs.


Previously, scientists determined the adult T. rex was capable of a bite force of 60,000 Newtons. Less is known about the anatomy and bite mechanics of juvenile tyrannosaurs.

For the new study, published Tuesday in the journal Anatomical Record, researchers imaged the jaws of several juvenile T. rex fossils.

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Using the images, scientists developed 3D models to examine the relationship between mandible dimensions and bite forces in both juvenile and adult T. rex dinosaurs.

Prior to their modeling analysis, authors of the new study hypothesized adult tyrannosaurs experienced lower levels of peak stress on their mandible, while juvenile tyrannosaurs expired higher levels of stress and strain on their more slender jaws.

The models showed the opposite, however. Juvenile tyrannosaurs actually experienced lower levels of peak stress and strain on their mandible.


Adults, on the other hand, put lots of absolute stresses on their mandibles during feeding, but because their jaws were so robust, the predators were able to tolerate the tremendous bite forces.

The findings suggest predator behaviors of juvenile tyrannosaurs differed from those of their adult counterparts.

"Tyrannosaurids were active predators and their prey likely varied based on their developmental stage," lead author Andre Rowe, a geology doctoral student at the University of Bristol in Britain, said in a press release.

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"Based on biomechanical data, we presume that they pursued smaller prey and fulfilled an environmental role similar to the 'raptor' dinosaurs such as the dromaeosaurs. Adult tyrannosaurs were likely subduing large dinosaurs such as the duckbilled hadrosaurs and Triceratops, which would be quickly killed by their bone-crunching bite."

In a separate study, published earlier this year, researchers showed the rapid growth and unique predatory behaviors of juvenile tyrannosaurs stunted to the speciation and diversification of other types of medium-bodied dinosaurs.

Rowe and his research partners hope their analysis will inspire other scientists to use CT scans and 3D modeling to more accurately characterize the cranial structures and biomechanics of other groups of dinosaurs.

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"There remains a plethora of unearthed dinosaur material that has not been utilized in studies of feeding and function -- ideally, all of our existing specimens will one day be scanned and made widely available online to researchers everywhere," Rowe said.


"The current lack of 3D model availability is noticeable in dinosaur research; relatively few studies involving 3D models of carnivorous dinosaurs have been published thus far. There is still much work to be done concerning skull function in all extinct animals -- not only dinosaurs," Rowe said.

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