New Study Finds That T. Rex Could Have Been 70 Percent Larger Than Fossils Suggest

Published November 18, 2022

New research estimates that the T. rex may have weighed as much as 33,000 pounds — more than two African elephants.

T Rex Skeleton

Liang Sen/Xinhua via Getty ImagesPaleontologists in Canada estimate that the T. rex may have reached weights of up to 33,000 pounds.

The Tyrannosaurus rex is arguably one of the most famous dinosaurs, but new discoveries are constantly changing our understanding of these massive, prehistoric creatures.

For instance, take new research from a team of paleontologists at the Canadian Museum of Nature in Ottawa, Ontario, which suggests that we’ve vastly underestimated the size of T. rex ever since its discovery in 1902.

According to Live Science, the team presented their findings at an annual conference held by the Society of Vertebrate Paleontology on November 5, where they told those in attendance that they estimate the T. rex may have been nearly 70 percent larger than previously thought.

The largest T. rex specimen on record, nicknamed “Scotty,” weighed just under 20,000 pounds when it was alive, but the study’s authors say that other T. rexes may have weighed as much as 33,000 pounds.

For reference, that’s heavier than two African elephants.

Study co-author Jordan Mallon told Live Science that he and the team came to this conclusion by examining the fossil record, which estimates that around 2.5 billion T. rexes once roamed the Earth.

Of those 2.5 billion, only 32 adult fossils have ever been discovered, meaning researchers’ knowledge of the dinosaur is based on incredibly limited information.

It’s possible — and quite likely, Mallon and co-author David Hone figured — that these undiscovered T. rexes were a fair bit larger than the small fraction researchers have found. Mallon and Hone looked at population numbers and average lifespans to create a model of what could have been the largest T. rex.

“We wound up building two models — one exhibiting zero dimorphisms and one with strong dimorphism,” Mallon said. These dimorphisms account for variations in size between the sexes.

“If T. rex was dimorphic, we estimate that it would have weighed up to 53,000 pounds,” Mallon continued, “but we rejected that model because if it were true, we would have found even larger individuals by now.”

T Rex Skeleton

ScottRobertAnselmo/Wikimedia CommonsA Tyrannosaurus rex specimen at the Carnegie Museum of Natural History.

Based on this data, they were able to create a growth curve model for the T. rex and estimate the largest possible size for an adult. They did, however, offer the reminder that until a fossil is found that can substantiate their estimate, the conclusion is nothing but speculation.

“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 paleontologist from Carthage College in Wisconsin. Carr was not involved with the new study, but he attended the conference and agreed that there is a possibility T. rex was much bigger than we tend to think.

“Right now, we are nowhere near the sample size needed, especially when compared to other species of animals,” he said. “It’s truly a stupendous animal. To imagine a T. rex of that magnitude is extraordinary, and I think an animal of that size is within reach statistically.”

Indeed, there is still much researchers don’t know about the T. rex, and their understanding of it changes every day. In fact, earlier this year, the Daily Mail reports, some researchers put forth the idea that T. rex was actually three separate species, including T. regina, or the “queen of the dinosaurs,” and T. imperator.

The idea was largely refuted by other scientists, but it stands as another example of the ever-changing nature of paleontology.

Other misconceptions about T. rex have been called into question in recent years as well, such as the notion that the dinosaur’s long legs helped it run quickly to chase prey. As it turns out, those long legs were used for extended periods of walking and stalking — not sprinting through the jungle.

Mallon said on Twitter that he and Hone are still tweaking their final manuscript, but he feels that the 33,000-pound model is “mechanically feasible.”

After learning about this new discovery, meet the T. rex’s Canadian cousin, the “Reaper of Death.” Then, learn about the biggest dinosaur of all time — that was 10 times bigger than the T. rex.

Austin Harvey
A staff writer for All That's Interesting, Austin Harvey has also had work published with Discover Magazine, Giddy, and Lucid covering topics on mental health, sexual health, history, and sociology. He holds a Bachelor's degree from Point Park University.
Cara Johnson
A writer and editor based in Charleston, South Carolina and an assistant editor at All That's Interesting, Cara Johnson holds a B.A. in English and Creative Writing from Washington & Lee University and an M.A. in English from College of Charleston and has written for various publications in her six-year career.
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Harvey, Austin. "New Study Finds That T. Rex Could Have Been 70 Percent Larger Than Fossils Suggest.", November 18, 2022, Accessed May 25, 2024.