Jurassic size surprise: T. rex may have been a 15-ton terror, says study

Dinosaurs, the huge beasts that once inhabited the planet, still amaze us. However, there is a huge mystery surrounding them: just how big did they really get?

A new study is challenging our understanding of these prehistoric giants. Dr. Jordan Mallon and Dr. David Hone, leading paleontologists, used computer modeling to explore the maximum possible size of the iconic Tyrannosaurus Rex (T. rex).

And it turns out that T. rex was bigger than we thought. Surprisingly, the model estimates that the largest T. rex could have been a whopping 70% heavier and 25% longer than the largest specimens identified thus far.

“Our study suggests that, for big fossil animals like T. rex, we really have no idea from the fossil record about the absolute sizes they might have reached. It’s fun to think about a 15 tonne T. rex, but the implications are also interesting from a biomechanical or ecological perspective,” said Mallon from the Canadian Museum of Nature.

Computer modelling

Fossilized remains offer paleontologists valuable insights into the lives of these giant carnivores and the lost prehistoric world. However, with limited fossils discovered, scientists lack sufficient data to determine the maximum size of a T. rex, or even other dinosaur species.

That’s why, Mallon and Hone turned to computer modeling to figure this out.  The model accounted for several factors, including population size, growth patterns, lifespan, and the fossil record gaps. T. rex was chosen as the subject of the model because it is a widely known dinosaur with numerous defined traits.

The computer simulations indicate that a T. rex exceeding the size of any discovered fossil by 70% in weight and 25% in length might have existed. Although such an individual would be exceptionally rare, occurring in only one out of 2.5 billion animals.

They found that “the largest known T. rex fossils probably fall in the 99th percentile, representing the top 1% of body size.”

To unearth the largest T. rex in the extraordinarily uncommon 99.99th percentile, scientists would have to excavate at the current rate for another 1,000 years.

The model estimates that the T. rex with a potential weight of 15 tonnes, significantly heavier than the current record of 8.8 tonnes, and a length of 15 meters compared to the known maximum of 12 meters from fossil records.

Rare to find such massive fossils

The authors highlight that there is a long-standing debate over the largest fossil animals. It is complex due to the scarcity of complete dinosaur remains.

Many dinosaur species are recorded by only one or a few individuals, making it impossible to determine their usual size range. This can create a misleading impression of a species’ overall dimensions.

“It’s important to stress that this isn’t really about T. rex, which is the basis of our study, but this issue would apply to all dinosaurs, and lots of other fossil species. Arguing about ‘which is the biggest?’ based on a handful of skeletons really isn’t very meaningful,” said Hone from Queen Mary University of London.

Despite the impressive size of dinosaur skeletons showcased in museums, evidence suggests that even larger individuals of these species existed. “Some isolated bones and pieces certainly hint at still larger individuals than for which we currently have skeletons,” said Hone in the press release.

However, the likelihood of paleontologists finding the absolute largest individuals of a dinosaur species is extremely slim.

The findings were published in the scientific journal Ecology and Evolution.