HMN 2025: How Gigantic, meat-eating dinosaurs didn’t all have sturdy bites

A model new analysis of the chew power of 18 species of carnivorous dinosaurs reveals that whereas the Tyrannosaurus rex skull was optimized for quick, sturdy bites like a crocodile, completely different massive, predatory dinosaurs that walked on two legs—along with spinosaurs and allosaurs—had rather a lot weaker bites and instead specialised in slashing and ripping flesh.

Reported in Current Biology, these findings show that meat-eating dinosaurs adopted fully completely different evolutionary paths in terms of skull design and feeding vogue no matter their equally gigantic sizes.

“Carnivorous dinosaurs took very fully completely different paths as they superior into giants in terms of feeding biomechanics and doable behaviors,” talked about Andrew Rowe of the University of Bristol, UK.

“Tyrannosaurs superior skulls constructed for power and crushing bites, whereas completely different lineages had comparatively weaker nonetheless further specialised skulls, suggesting quite a lot of feeding strategies even at big sizes. In completely different phrases, there wasn’t one ‘best’ skull design for being a predatory massive; a lot of designs functioned fully successfully.”

Rowe has on a regular basis been fascinated by massive carnivorous dinosaurs, and he considers them attention-grabbing subjects for exploring main questions in organismal biology. In this study, he and co-author Emily Rayfield wanted to know how bipedalism—or strolling on two legs—influenced skull biomechanics and feeding methods.

It was beforehand recognized that no matter reaching associated sizes, predatory dinosaurs superior in very fully completely different parts of the world at fully completely different situations and had very fully completely different skull shapes.

For Rowe and Rayfield, these info raised questions on whether or not or not their skulls had been functionally associated beneath the ground or if there have been notable variations of their predatory life. As there are no big, bipedal carnivores alive within the present day—ever as a result of the end-Cretaceous mass extinction event—the authors phrase that studying these animals presents intriguing insights proper into a way of life which has since disappeared.

To study the connection between physique measurement and skull biomechanics, the authors used 3D utilized sciences, along with CT scans and ground scans, to analyze the skull mechanics, quantify the feeding effectivity, and measure the chew power all through 18 species of theropod, a bunch of carnivorous dinosaurs ranging from small to massive. While they anticipated some variations between species, they’d been shocked when their analyses confirmed clear biomechanical divergence.

“Tyrannosaurids like T. rex had skulls that had been optimized for prime chew forces on the worth of bigger skull stress,” Rowe says. “But in one other giants, like Giganotosaurus, we calculated stress patterns suggesting a relatively lighter chew. It drove dwelling how evolution can produce a lot of ‘choices’ to life as a giant, carnivorous biped.”

Skull stress didn’t present a pattern of improve with measurement. Some smaller theropods expert greater stress than some greater species as a consequence of elevated muscle amount and chew forces.

The findings present that being a predatory biped didn’t on a regular basis equate to being a bone-crushing massive. Unlike T. rex, some dinosaurs, along with the spinosaurs and allosaurs, turned giants whereas sustaining weaker bites further suited to slashing at prey and stripping flesh.

“I tend to examine Allosaurus to a up to date Komodo dragon in terms of feeding vogue,” Rowe says.

“Large tyrannosaur skulls had been instead optimized like fashionable crocodiles with high chew forces that crushed prey. This biomechanical selection implies that dinosaur ecosystems supported a wider differ of massive carnivore ecologies than we steadily assume, with a lot much less opponents and further specialization.”