Science

Computer modeling suggests Tyrannosaurus rex was much bigger than previously thought

Computer modeling suggests Tyrannosaurus rex was much bigger than previously thought
The SUE Tyrannosaurus rex skeleton at Chicago's Field Museum
The SUE Tyrannosaurus rex skeleton at Chicago's Field Museum 
View 3 Images
Computer models of an adult Tyrannosaurus rex, a juvenile, and a human (Image: The Royal Veterinary College)
1/3
Computer models of an adult Tyrannosaurus rex, a juvenile, and a human (Image: The Royal Veterinary College)
A variety of the models used to estimate the body mass of Tyrannosaurus rex, starting with a 3D scan of an actual skeleton (Image: The Royal Veterinary College)
2/3
A variety of the models used to estimate the body mass of Tyrannosaurus rex, starting with a 3D scan of an actual skeleton (Image: The Royal Veterinary College)
The SUE Tyrannosaurus rex skeleton at Chicago's Field Museum
3/3
The SUE Tyrannosaurus rex skeleton at Chicago's Field Museum 
View gallery - 3 images

Tyrannosaurus rex, that coolest of all the dinosaurs, may have been even bigger and scarier than originally thought. That's the conclusion that was recently reached by a team of scientists, who used computer modeling technology to estimate the average body mass of the carnivorous dinosaurs. After digitally "fleshing out" existing T. rex skeletons, the researchers now believe that the reptiles grew twice as fast, and reached adult weights up to 30 percent higher than previously assumed.

The research was conducted by scientists at The Royal Veterinary College, in London, and The Field Museum of Natural History, in Chicago.

Previous attempts at estimating dinosaur body mass have used either scaled-down models, or extrapolations based on living animals that don't necessarily have the same body layout as dinosaurs. This study, however, used five actual T. rex skeletons as the starting point.

These skeletons were laser-scanned, to produce 3D computer models. Using the relationships of the soft tissues to skeletons in birds and crocodiles as a guide, digital body cross-sections were then created along the length of each skeleton, with a virtual skin overlaid on each one. The mass of each section was then calculated, with empty spaces such as the lungs and mouth cavity not being included in the final figures.

A variety of the models used to estimate the body mass of Tyrannosaurus rex, starting with a 3D scan of an actual skeleton (Image: The Royal Veterinary College)
A variety of the models used to estimate the body mass of Tyrannosaurus rex, starting with a 3D scan of an actual skeleton (Image: The Royal Veterinary College)

Just as there is no one standard size for homo sapiens, however, there was likely also a considerable variety of body sizes for T. rex. To allow for that margin of error, each body section on each skeleton was modeled at three conceivable levels of fleshiness. In this way, the scientists were left with a general but more meaningful range of sizes, as opposed to one middle-of-the-road size that most tyrannosaurs probably either overshot or never reached.

The results of the study indicate that teenage T. rexes grew as fast as 3,950 pounds (1,790 kg) a year, which is double what was previously believed. One of the large adult skeletons, which resides at the Field Museum and is known as SUE, is now thought to have come from a dinosaur that weighed approximately nine tons (8.16 tonnes) - a 30 percent increase over the former estimate.

Interestingly, however, the models also suggested that the juvenile dinosaur represented by the smallest of the skeletons was probably lighter than previously thought. Additionally, based on muscle modeling of the legs of all five skeletons, the study backs up the existing assumption that large tyrannosaurs slowed down as they grew up, with large adults only managing a top running speed of around 10-25 mph, or 17-40 km/h.

View gallery - 3 images
5 comments
5 comments
Stradric
Sorry, T-Rex is not the coolest dinosaur. There\'s enough evidence to suggest that he was more likely a scavenger than a skilled hunter. He\'s not even the coolest land dinosaur. Velociraptor is way more interesting and Spinosaurus would wreck Tyrannosaurus any day.
T-rex is probably the most iconic dinosaur though. I think you should replace \"coolest\" with \"most iconic\". It makes the article sound more mature.
beethovens9th
The T Rex dude would be useless at table tennis, no matter how big?
Slashpot
Oh stadric, like that supposed tubby panhandler, I must beg... To differ! \'more than enough evidence\' suggests a scientifically accepted concept, which the idea of a Hyena-like T-Rex most certainly is not! Hell, even Hyenas hunt sometimes!
Despite the ongoing debate however, common sense dictates that a nine-ton predator would eat... Well, whatever the hell he wanted! The same common sense also dictates that while able to commit large-scale murders, Rexy would have stolen kills from other predators and certainly taken advantage of any carcasses carelessly left lying around. Most very large predators do just that including Lions, Leopards, crocs, eagles, wolves, and probably Allosaurs, Giganotosaurs, and Utahraptors. Maybe even those little turkey-sized, feathered Jackals called Velociraptors! Although probably not the giant fish catcher Spinosaurus, who would never take on a T-rex for 2 reasons, (a) they lived many thousands of miles apart, and (b) if a Spino fell over he would break his spine-o thanks to those ridiculous vertebral projections, yeah, real cool! Rex rules!!!
Steve Anderson
The \"slowing down as they got older\" thing is interesting, and possibly suggests that T Rex may have been cannibalistic, or at least territorially competitive and evolution made the youngsters quicker both to escape aggressive adults and out-compete for prey.
Maybe.
Brian Hall
Posted on another thread, but relevant here, too:
"Here's a brain-blast fer ya: hypothesis: Air was so thick during the Mezozoic that 2/3 of the dinos' weight was "floating", and they needed powerful hindquarters and narrow fronts to push through it. Explains, e.g., how pterodactyls could fly and catch prey (impossible in current atmo-density). And how brachiosaurs could lift their long necks so high without passing out. And actually support and move their huge bodies.
http://dinosaurtheory.com/index.html (David Esker)"