Crushing vs. Slashing: New cranium scans reveal how big dinosaurs killed

“Carnivorous dinosaurs took very different paths as they evolved into giants in terms of feeding biomechanics and possible behaviors,” stated Andrew Rowe of the University of Bristol, UK.

“Tyrannosaurs evolved skulls built for strength and crushing bites, while other lineages had comparatively weaker but more specialized skulls, suggesting a diversity of feeding strategies even at massive sizes. In other words, there wasn’t one ‘best’ skull design for being a predatory giant; several designs functioned perfectly well.”

Rowe has all the time been fascinated by huge carnivorous dinosaurs, and he considers them fascinating topics for exploring fundamental questions in organismal biology. In this research, he and co-author Emily Rayfield wished to understand how bipedalism — or strolling on two legs — influenced cranium biomechanics and feeding methods.

It was beforehand identified that regardless of reaching related sizes, predatory dinosaurs advanced in very completely different elements of the world at completely different occasions and had very completely different cranium shapes. For Rowe and Rayfield, these information raised questions on whether or not their skulls have been functionally related below the floor or if there have been notable variations of their predatory life. As there are not any large, bipedal carnivores alive right now — ever for the reason that end-Cretaceous mass extinction occasion — the authors be aware that learning these animals provides intriguing insights right into a lifestyle which has since disappeared.

To study the connection between physique dimension and cranium biomechanics, the authors used 3D applied sciences together with CT scans and floor scans analyze the cranium mechanics, quantify the feeding efficiency, and measure the chunk power throughout 18 species of therapod, a bunch of carnivorous dinosaurs starting from small to large. While they anticipated some variations between species, they have been stunned when their analyses confirmed clear biomechanical divergence.

“Tyrannosaurids like T. rex had skulls that were optimized for high bite forces at the cost of higher skull stress,” Rowe says. “But in some other giants, like Giganotosaurus, we calculated stress patterns suggesting a relatively lighter bite. It drove home how evolution can produce multiple ‘solutions’ to life as a large, carnivorous biped.”

Skull stress did not present a sample of enhance with dimension. Some smaller therapods skilled better stress than some bigger species as a result of elevated muscle quantity and chunk forces. The findings present that being a predatory biped did not all the time equate to being a bone-crushing big. Unlike T. rex, some dinosaurs, together with the spinosaurs and allosaurs, turned giants whereas sustaining weaker bites extra suited to slashing at prey and stripping flesh.

“I tend to compare Allosaurus to a modern Komodo dragon in terms of feeding style,” Rowe says. “Large tyrannosaur skulls were instead optimized like modern crocodiles with high bite forces that crushed prey. This biomechanical diversity suggests that dinosaur ecosystems supported a wider range of giant carnivore ecologies than we often assume, with less competition and more specialization.”

This analysis was supported by funding from the Biotechnology and Biological Sciences Research Council.