T. rex could have been 70 per cent bigger
There’s no denying that Tyrannosaurus rex was one of the biggest dinosaurs to ever walk the planet. But how big could this dinosaur get? In a new investigation, researchers attempted to answer that. Palaeontologists from the Canadian Museum of Nature in Ottawa estimated that the largest T. rex may have tipped the scales at a whopping 15,000 kilograms, making it heavier than an average school bus, which weighs about 11,000 kilograms.
Currently, the heftiest T. rex on record is a specimen nicknamed ‘Scotty’, which weighed 8,870 kilograms when it was alive, about as much as 6.5 Volkswagen Beetles. According to the new research, the largest T. rex “would have been about 70 per cent bigger” than Scotty, said Jordan Mallon, a research scientist and head of palaeobiology at the Canadian Museum of Nature. “That almost doubles the size of T. rex,” Mallon adds.
To reach this weighty conclusion, the scientists rst examined the fossil record, which shows that approximately 2.5 billion T. rex once lived on Earth. However, only a small fraction – just 32 adult fossils – have ever been discovered, giving the scientists a limited amount of information to pull from. Mallon and David Hone, a senior lecturer and deputy director of education at Queen Mary University of London, also looked at population numbers and average life spans to
create a model of the largest possible T. rex. They also considered variations in body size based on sexual dimorphism, size dierences between the sexes of animals within a species. “We wound up building two models, one exhibiting zero dimorphisms and one with strong dimorphism,” Mallon said. “If T. rex was dimorphic, we estimate that it would have weighed up to 24,000 kilograms, but we rejected that model because if it were true, we would have found even larger individuals by now.”
The scientists were able to model T. rex’s growth curve throughout its lifetime and estimate how big an adult might have grown. Mallon cautioned that until a T. rex is found that is comparable in size to the one in the model, the model’s conclusions are speculative. “This is a thought experiment with some numbers behind it. It’s something fun to think about,” Mallon said. Indeed, the investigation highlights how challenging it is for palaeontologists to draw conclusions about dinosaur species from a very limited fossil record. “This reminds us that what we know about dinosaurs isn’t much at all, since the sample sizes are so small,” said Thomas Carr, a vertebrate palaeontologist from Carthage College in Kenosha, Wisconsin. “Right now, we are nowhere near the sample size needed, especially when compared to other species of animals.”