Rosa Rubicondior: Creationism Crushed - By Big Biting Dinosaurs

Dinosaur bite illustrations.

Rowe and Rayfield, Current Biology (2025)

Gigantic, meat-eating dinosaurs didn’t all have strong bites | EurekAlert!

Creationists will likely dismiss the recent paper in Current Biology because, as is common in creationist psychology, any scientific evidence contradicting their fundamental beliefs is either ignored, misrepresented, or actively denied—particularly if it suggests their views should be reconsidered.

The study by Andre J. Rowe and Emily J. Rayfield of the University of Bristol (UK) demonstrates that, during the long stretch of Earth’s history predating creationist timelines, giant carnivorous dinosaurs evolved markedly different jaw mechanics to tackle prey—leading to distinct ecological roles. For example, crushers such as Tyrannosaurus rex developed jaws optimised for forceful crushing, akin to crocodilians, whereas slashers - other large theropods such as allosaurids or spinosaurs - developed weaker jaws tailored to ripping and slashing flesh, like modern Komodo dragons [1.1].

This divergence in feeding mechanics underscores a fundamental principle in evolutionary biology: adaptive radiation and allopatric speciation — whereby offspring inheriting intermediate jaw characteristics (neither fully adapted for crushing nor ripping) would likely be at a disadvantage, reducing their reproductive success. Over time, this selective pressure fosters reproductive barriers and drives lineages apart.

Timeline for the evolution of large carnivorous dinosaurs: We can place the evolution of large carnivorous dinosaurs into a clear time-line within the Mesozoic Era, showing how they diversified over ~170 million years. Here’s a simplified chronological outline (dates approximate, in millions of years ago, “mya”):

Triassic Period (252–201 mya) – Origins of Theropods

~230 mya: Earliest small theropods (e.g., Herrerasaurus, Eoraptor) appear in South America. These are bipedal carnivores, typically under 6 m long.
~215–201 mya: Coelophysoids (e.g., Coelophysis) diversify; relatively small and lightly built predators.
End-Triassic extinction (~201 mya) clears ecological space, setting the stage for larger forms in the Jurassic.

Jurassic Period (201–145 mya) – Rise of Large Predators

Early Jurassic (~195–180 mya): Medium-sized theropods (e.g., Dilophosaurus, ~6 m) dominate.
Middle Jurassic (~170 mya): Megalosaurids (e.g., Megalosaurus) emerge, among the first truly large carnivores (8–10 m).
Late Jurassic (~155–145 mya): Allosaurids (Allosaurus, Saurophaganax) become apex predators on land, reaching 8–12 m. Coexist with large sauropods.

Cretaceous Period (145–66 mya) – Apex Diversification

Early Cretaceous (~130–110 mya): Spinosaurids (Baryonyx, Spinosaurus) diversify, with adaptations for fish-eating and semi-aquatic lifestyles. Carcharodontosaurids (Carcharodontosaurus, Mapusaurus) rival allosaurs in size.
Mid-Cretaceous (~105–90 mya): Carcharodontosaurids dominate in Africa and South America; spinosaurids peak.
Late Cretaceous (~83–66 mya): Tyrannosaurids (Tyrannosaurus rex, Daspletosaurus) become apex predators in Asia and North America.

These are among the most massive land predators ever (T. rex up to 12–13 m long, ~9 tonnes).
Allosaur relatives (abelisaurids) dominate in Gondwana (e.g., Carnotaurus).

66 mya – End-Cretaceous Mass Extinction

An asteroid impact (and associated climate collapse) wipes out all large non-avian dinosaurs, including every giant carnivore.
Surviving theropods are the smaller, feathered maniraptorans — the ancestors of modern birds.

A news release via EurekaAlert, based on this Bristol study, succinctly summarises how these biomechanical differences correlate with divergent predatory strategies and ecological niches.

Gigantic, meat-eating dinosaurs didn’t all have strong bites
A new analysis of the bite strength of 18 species of carnivorous dinosaurs shows that while the Tyrannasaurus rex skull was optimized for quick, strong bites like a crocodile, other giant, predatory dinosaurs that walked on two legs—including spinosaurs and allosaurs—had much weaker bites and instead specialized in slashing and ripping flesh.
Reported in the Cell Press journal Current Biology on August 4, these findings demonstrate that meat-eating dinosaurs followed different evolutionary paths in terms of skull design and feeding style despite their similarly gigantic sizes.

Carnivorous dinosaurs took very different paths as they evolved into giants in terms of feeding biomechanics and possible behaviors. 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.

Andre J Rowe, first author
School of Earth Sciences
University of Bristol, UK.

Rowe has always been fascinated by big carnivorous dinosaurs, and he considers them interesting subjects for exploring basic questions in organismal biology. In this study, he and co-author Emily Rayfield wanted to know how bipedalism—or walking on two legs—influenced skull biomechanics and feeding techniques.

It was previously known that despite reaching similar sizes, predatory dinosaurs evolved in very different parts of the world at different times and had very different skull shapes. For Rowe and Rayfield, those facts raised questions about whether their skulls were functionally similar under the surface or if there were notable differences in their predatory lifestyles. As there are no massive, bipedal carnivores alive today—ever since the end-Cretaceous mass extinction event—the authors note that studying these animals offers intriguing insights into a way of life which has since disappeared. 

To examine the relationship between body size and skull biomechanics, the authors used 3D technologies including CT scans and surface scans analyze the skull mechanics, quantify the feeding performance, and measure the bite strength across 18 species of therapod, a group of carnivorous dinosaurs ranging from small to giant. While they expected some differences between species, they were surprised when their analyses showed clear biomechanical divergence.

Tyrannosaurids like T. rex had skulls that were optimized for high bite forces at the cost of higher skull stress. 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.

Andre J Rowe.

Skull stress didn’t show a pattern of increase with size. Some smaller therapods experienced greater stress than some larger species due to increased muscle volume and bite forces. The findings show that being a predatory biped didn’t always equate to being a bone-crushing giant. Unlike T. rex, some dinosaurs, including the spinosaurs and allosaurs, became giants while maintaining weaker bites more suited for slashing at prey and stripping flesh.

I tend to compare Allosaurus to a modern Komodo dragon in terms of feeding style. 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.

Andre J Rowe.

Publication:
Rowe & Rayfield
Carnivorous dinosaur lineages adopt different skull performances at gigantic size.
Current Biology 35(15), 3664 - 3673.e3; DOI: 10.1016/j.cub.2025.06.051

Highlights

Large theropods evolved distinct biomechanical strategies for feeding
Tyrannosaurids prioritized bite force, leading to higher skull stress
Megalosauroids and allosauroids maintained low-stress skull designs
Skull stress patterns reflect ecological divergence in carnivorous dinosaurs

Summary
Theropoda is one of the most extensively studied dinosaur clades, including iconic carnivores such as Tyrannosaurus rex and Spinosaurus aegyptiacus. The clade includes the largest terrestrial bipeds ever described, including three lineages that independently achieved giant size: Megalosauroidea, Allosauroidea, and Tyrannosauroidea. Here, we investigate how increasing size influenced feeding performance by quantifying feeding-induced mechanical performance across numerous large theropods using 3D finite element analysis. Unexpectedly, we discovered a divergence in functional strategy among the three lineages that led to gigantic top predators: in non-tyrannosauroid theropods, skull stress generally did not increase with size, in contrast to tyrannosauroids, which experienced greater stress due to increased muscle volume and bite forces. When skulls were scaled to equivalent size, smaller theropods, particularly basal taxa, experienced higher stresses. Despite similar scaling constraints, theropods adopted two distinct functional and likely ecological strategies: increased size with reduced stress or increased skull size, muscle volume, and bite force at the cost of higher stress. Giant tyrannosaurids uniquely maximized bite force despite elevated cranial stress, a strategy perhaps driven by the demands of subduing increasingly large and mobile prey in the Late Cretaceous. Alternatively—or additionally—this shift may reflect ecological displacement by coexisting predators such as smaller theropods and giant crocodyliforms. Whatever the cause, tyrannosaurids pursued a high-risk, high-reward feeding strategy unlike any seen in their Early Cretaceous counterparts, underscoring a profound shift in mega-carnivore evolution near the end of the Mesozoic.

Introduction
Theropod dinosaurs are among the most iconic fossil organisms, known for their repeated evolution of large body size and for producing the largest bipedal carnivores in Earth’s history.^1,2,3,4 Unambiguous theropods appeared in the Late Triassic (∼228 Ma),⁵ and by the Early Jurassic, genera such as Dilophosaurus were the largest terrestrial predators.⁶ Multiple theropod clades independently evolved giant forms by the Late Cretaceous, including the ∼5,600-kg allosauroid Acrocanthosaurus^7,8 and the ∼8,000-kg megalosauroid Spinosaurus.9

Body size influences many aspects of organismal biology, affecting predation, energetics, and extinction risk.^10,11,12,13 Although Cope’s rule—size increase over time—is not universal across vertebrates, it appears to apply to several theropod lineages.^3,14 Nonetheless, small-bodied theropods persisted throughout the Mesozoic, reflecting persistent ecological differentiation and functional diversity among carnivorous dinosaurs.^15,16 Such coexistence likely involved partitioning of prey size, hunting strategies, or habitat use, reducing direct competition with their larger counterparts. At least three major theropod clades independently evolved large size: megalosauroids, allosauroids, and tyrannosauroids.^17,18 These shifts occurred across time and geography and involved significant changes in skull morphology. For example, basal tyrannosauroids were lightly built (∼125 kg), whereas Tyrannosaurus reached ∼9,500 kg with deep, massively muscled skulls.^19,20,21,22

Although previous studies have examined how size affects locomotion,^23,24 feeding biomechanics at large size remain less understood. Bite force scales with body mass in extant diapsids,^25,26,27,28 but many prior theropod studies have relied on 2D shape approximations.^{29,30,31,32,33} Modern 3D technologies—computed tomography (CT), surface scanning, photogrammetry—now allow detailed analyses of skull mechanics using finite element analysis (FEA) across a broad taxonomic sample.^{34,35,36,37,38,39,40,41,42} Yet, fundamental questions remain: how does skull performance scale with body size? Do large theropods reduce stress via geometric scaling or do muscle forces increase proportionally, leading to higher stress loads? Does cranial morphology evolve to offset these forces?

Here, we used FEA to test how body size relates to cranial biomechanics across 18 theropods spanning key clades that independently evolved large size (Megalosauridae, Allosauroidea, and Tyrannosauroidea), along with smaller basal taxa such as Herrerasaurus and Dilophosaurus for comparison (Figure 1). We excluded likely herbivorous theropods like therizinosaurs, which possessed specialized tooth and muscle arrangements adapted for herbivory.^43,44

Figure 1 Temporally calibrated theropod dinosaur phylogeny
Phylogeny based on several recent studies (Brusatte and Carr,45 Hendrickx et al.,46 and Tanaka et al.47). Asterisks indicate taxa included in this study. Theropod silhouettes from PhyloPic.

We test three key hypotheses using FEA-based 3D mechanical models: (1) stress reduction with size—larger taxa should experience lower stress under geometric scaling predictions; (2) elevated stress in tyrannosauroids—if bite forces scale disproportionately in tyrannosaurids, they should show higher cranial stress relative to similarly sized taxa; and (3) higher stress in smaller taxa when size corrected—when skulls are scaled to the same size, smaller taxa should show higher stress due to less robust skull geometry.

Figure 2 Finite element stress maps for all theropod skulls modeled at actual size after simulated adductor contraction and biting at the two front teeth
Areas of high stress are indicated by hotter colors, and low stress is indicated by cooler colors. Gray regions indicate regions with the highest probabilities of structural failure. Note the very high stresses occurring in the basal ambiguous theropod Herrerasaurus. For larger stress maps of actual-size skulls, see Figure S1.

Figure 4 Finite element stress maps for all theropod skulls modeled when size corrected
Gray regions indicate regions with the highest probabilities of structural failure. For larger stress maps of size-corrected skulls, see Figure S2.

Rowe & Rayfield
Carnivorous dinosaur lineages adopt different skull performances at gigantic size.
Current Biology 35(15), 3664 - 3673.e3; DOI: 10.1016/j.cub.2025.06.051

Copyright: © 2025 The authors.
Published by Cell Press (Elsevier Inc). Open access.
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)

Creationists will, of course, have to pretend this research doesn’t exist. It shows that for tens of millions of years before they think the Earth was magicked into existence out of nothing, giant carnivorous dinosaurs were busy evolving into specialist “crushers” and “rippers” — each honing a very different approach to dispatching prey.

Far from the static “kinds” demanded by creationist dogma, we see lineages branching, adapting, and diversifying in response to ecological opportunity and mechanical constraint. Crushing-jawed tyrannosaurids and ripping-jawed allosaurids or spinosaurs were not designed to be interchangeable; hybrids would likely have been ill-equipped for either role. This is textbook natural selection and speciation — the very processes creationists insist don’t happen, yet here they are, written in the stone record of deep time.

If creationism were true, such careful, converging specialisations arising in entirely separate lineages over vast stretches of time simply wouldn’t occur. Evolution predicts it; the fossils confirm it; and creationists must either ignore it or invent a fantasy to make it go away.

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