Examining the Size: What was the Size of the Largest Tyrannosaurus rex?

Tyrannosaurus rex stood taller than many other dinosaurs. However, the largest of the dinosaur kings could have been even heavier. More evidence of this is found in fossils.

Only around 80 Tyrannosaurus skeletons have been discovered so far, and not all of them are complete. There are likely millions or billions of Tyrannosaurus that once roamed the Earth, according to paleontologist Jordan Maron from the Canadian Museum of Nature in Ottawa. Due to the incomplete nature of the discovered skeletons, it’s unlikely that the largest Tyrannosaurus has been found yet. Similar to a group of 80 randomly chosen people not necessarily including the tallest person on the planet.

To estimate the maximum potential size of Tyrannosaurus, Maron collaborated with David Horn, a paleontologist at Queen Mary University in London, England.

Scientists speculate that around 2.5 billion Tyrannosaurus once existed on Earth. However, not all of them survived to adulthood. Maron’s team used a computer model to simulate this large group using 140 million pairs as the sample size due to the computer’s limitations.

By applying statistics, researchers could estimate the body sizes and age distribution of Tyrannosaurus, similar to crocodiles which are their living relatives. This statistical approach allowed them to calculate the potential maximum size of the entire 2.5 billion population of Tyrannosaurus.

According to Maron, the largest possible Tyrannosaurus could have been 70% larger than the largest known animal today. The estimated size was around 15 meters in length and 15,000 kilograms in weight. These findings were published in the journal Ecology and Evolution.

However, Maron admits that this size estimation is speculative, as it’s based on a theoretical framework rather than actual fossil evidence.

It may take years to discover fossils supporting this hypothetical giant Tyrannosaurus. The rarity of finding such massive specimens indicates that it might be a long and challenging process to unearth one that surpasses 99.9% of all others of its kind.

Size estimate

Figure A: Fossils reveal information about an animal’s age and weight. For example, bone growth patterns can suggest the age of an animal when it died. The growth curve for Tyrannosaurus was created based on fossil reports to show how weight increases with age.

Figure B: The researchers used a computer model to estimate the distribution of theoretical 140 million Tyrannosaurus individuals of all ages and body sizes. Due to the limited number of discovered fossils, the researchers looked at related species to understand age distribution and body size variations.