The Tyrannosaurus rex dinosaur, renowned for being one of the most fearsome creatures to have ever lived on Earth, evolved a bite that was less impressive in relation to its body size than a tiny Galapagos ground finch, according to a study. New analysis by scientists at the University of Reading and the University of Lincoln in the UK has shown the evolution of T rex was not led by a strong need for a bone-crushing bite to kill its prey.
Instead, it had a bite force of 57,000 Newtons (N) that was completely average for its body mass of eight tonnes and which evolved gradually over tens of millions of years, according to the study published in the Royal Society journal Proceedings B. Comparatively, a Galapagos large ground finch was found to have the most powerful bite in relation to its body size of all the animals in the study, packing an impressive 70N of force, despite weighing just 33 grammes. This makes the bite force of the finch about 320 times more powerful, pound-for-pound, than T rex. Moreover, the finch evolved its mega-bite relatively quickly, in less than one million years. The research also suggests human intelligence may have led to us having an extremely weak bite.
This is owing to the evolution of our larger brains taking up space in our heads where the muscles critical for hard biting would otherwise be. "The image of T rex with its fierce jaws has helped it become the most iconic of dinosaurs, but our research shows its bite was relatively unremarkable," said Manabu Sakamoto, a biological scientist at the University of Reading. "Bite force was not what gave T rex its evolutionary advantage, as was previously presumed," Sakamoto said. "Large predators like T rex could generate enough bite force to kill its prey and crush bone just by being large, not because they had a disproportionately powerful bite.
"This counters the idea that an exceptionally strong need for a powerful bite drove these ancient beasts to evolve bone-crushing bite forces," Sakamoto said. "Our research provides new insight into the latest theories about the speed and drivers of evolution. It also allows us to create some fascinating hypothetical match-ups," said Chris Venditti from the University of Reading. "The proclaimed 'King of the Dinosaurs' would be no match for a finch in a fight, if they were the same size," Venditti said. The researchers argue that the study shows the course of evolutionary history should not be ignored when looking at how animals developed distinctive traits. The scientists used supercomputers to analyse the largest ever collection of bite force data from 434 species both extinct and surviving, including reptiles, birds and mammals.
They investigated the theory that animals with more powerful bites were forced to rapidly evolve that way owing to changes to their diets. They instead found that the bite power of most of these animals developed proportionally to evolutionary changes to their body size over time, with only some seeing their bite forces develop at a faster rate than other changes. Accelerated bursts of bite power evolution were seen in some animals, especially finches -- a species famously first noted as an example of natural selection by Charles Darwin. However, expected increases along with body size during the passage of time was seen to be the most common driver of this trait. The team even observed more dramatic reductions in bite forces during evolution than increases. This was true for early humans, whose bite power decreased rapidly despite their body size increasing over time.
(With inputs from agencies.)