Tyrannosaurus Rex Facts



Modified: 27 Jan 2022

Tyrannosaurus Rex Facts, T-Rex

Mention the word dinosaur, and it’s likely that the Tyrannosaurus Rex comes to mind. Also known as “T-Rex”,  the Tyrannosaurus Rex is practically the poster child for dinosaurs around the world. And in over 65 million years, no other predator has become as successful as the T-Rex. Learn more about this king of dinosaurs with these 40 Tyrannosaurus Rex facts.

  1. Scientists estimated that the T-Rex could grow up to a height of 6 meters.
  2. Their bodies could also grow over 12 meters long.
  3. A T-Rex’s skull alone could measure over 1 meter long.
  4. They could also weigh as much as 14 metric tons.
  5. A T-Rex’s bite could exert up to 35,000 Newtons, compared to a human’s maximum bite force of only 300 Newtons.
  1. Scientists first found T-Rex’s fossils, specifically teeth, in 1874, at the Arthur Lakes in Colorado.
  2. Barnum Brown found the first incomplete T-Rex skeleton in 1900.
  3. He later found a second, also incomplete T-Rex skeleton in 1902.
  4. WWI, the Great Depression, WWII, and the Korean War, all caused studies into the T-Rex to decline until the 1960s.
  5. William MacMannis’ discovery of another incomplete T-Rex skeleton in 1967 revived the study of the dinosaur.
  6. Charles Pillmore discovered the first fossilized T-Rex footprint in 1983.
  7. Sue Hendrickson discovered the most complete, at around 85%, T-Rex skeleton thus far in 1990, and which scientists named after her.
  8. Jack Horner discovered 5 T-Rex skeletons in a single site in 2000.
  9. Phil Manning discovered another fossilized T-Rex footprint in 2007.
  10. Possible fossilized T-Rex footprints later became discovered in 2016, but remain debated among scientists today.
  1. Tyrannosaurus Rex literally means Tyrant King of Lizards.
  2. Scientists now consider the name as inaccurate, as dinosaurs became the ancestors of modern birds.
  3. Scientists estimate that the T-Rex could travel on average at a walking speed of 5 kph.
  4. When running, they estimate the T-Rex could reach speeds of up to 27 kph.
  5. Scientists now think that the T-Rex both actively hunted prey, as well as scavenged the corpses of dead dinosaurs.
Table of Contents

T-Rex lived across what would become the west of modern North America.

At the time, it formed an entirely separate continent, which scientists call Laramidia. Today, this includes an area stretching from Canada in the north, to New Mexico in the south. Fossil evidence also suggests that Laramidia had a varied climate, ranging from subtropical coastal and inland regions, as well as semi-arid plains. This made T-Rex a very adaptable species, especially as newer evidence suggests they may not have evolved on Laramidia at all. Instead, they originated from what would become modern Asia, only migrating to Laramidia at some point before the Cretaceous Period.

Scientists today debate on how large the T-Rex population became before their extinction.

Based on fossil evidence, most scientists think T-Rex had no more than an estimated 20,000 adults at any one time. The total population itself varies, with computer estimates ranging from as low as 1,200, or as high as 328,000. Scientists usually disregard the lower number, as it falls far too low from the average suggested by the fossil evidence. Fossil evidence has also suggested that the T-Rex flourished for around 127,000 generations, leading scientists to total the T-Rex population from their evolution to extinction at 2.5 billion animals. Out of those, only 1 in 80 million became fossils after their deaths.

T-Rex may have had feathers.

Here’s an interesting example of Tyrannosaurus Rex Facts. As we mentioned earlier, scientists have discovered that dinosaurs like the T-Rex weren’t reptiles like they long believed. But instead, dinosaurs counted as prehistoric, wingless birds, and from which all modern birds evolved. This has led scientists to question whether or not they had scales like reptiles do, but had feathers instead. Fossil evidence suggests that T-Rex actually had both, with scales covering most of its body. Feathers, however, may also have grown around its neck, but fossil evidence of this remains circumstantial to this day.

They may also have had lips as mammals do.

Evidence for this exists in the enamel coating that scientists found on fossilized T-Rex teeth. Enamel requires the teeth to stay constantly wet, which would require the T-Rex to have lips to keep the mouth properly sealed. Many scientists disagree, though, pointing to fossil evidence that the T-Rex had scales on its mouth. Study into the question continues in the paleontological community to this day.

Tyrannosaurus Rex Facts, T-Rex Skull with Teeth
Photo by A.E. Anderson from Wikipedia

Their body size also required a warm-blooded metabolism.

Even before the discovery of dinosaurs counting as birds, many scientists wondered how supposedly cold-blooded animals could have grown such big bodies. Fossil evidence also suggests fast growth rates for young T-Rexes, something impossible with a cold-blooded metabolism. The discovery of dinosaurs as birds resolved all this issue, as the powerful hearts of warm-blooded animals would explain how T-Rex could grow so big and so quickly.

Some T-Rex fossils include the remains of soft tissues in addition to bone.

Ironically, scientists discovered it entirely by accident when they broke a fossilized T-Rex bone to make it easier to transport. This led them to discover that the marrow inside had also undergone fossilization. This, in turn, allowed scientists to have a good look at the structure of T-Rex’s blood vessels, and even at their cells, with a small number of fossilized blood cells still in the marrow. Scientists later concluded based on this evidence that T-Rex blood and circulatory systems strongly resembled those of ostriches. It also provided even more evidence of the T-Rex’s, and by extension, other dinosaurs’ relation to birds, as well as having warm-blooded metabolisms.

T-Rex had small arms.

So much so that scientists once thought that their only use involved holding prey or meat in place while T-Rex ate. However, computer simulations of reconstructed T-Rex muscles have now shown that the arms actually had more use than previously thought. In particular, T-Rex could have used them for fighting up close, whether for dominance against another T-Rex or against struggling prey. The arms could have swung hard enough to let T-Rex’s claws dig deep gashes into their target. They could also grip with surprising delicateness, such as during sexual intercourse between two T-Rexes.

Tyrannosaurus Rex Facts, T-Rex’s Small Arms
Photo by Roy Buri from Pixabay

They also had very good senses.

Computer simulations and studies of the T-Rex’s skull have led scientists to think a T-Rex had superior eyesight compared not just to humans, but even to modern birds. In fact, they think a T-Rex could see clearly up to 6 km away, and that despite popular belief claiming T-Rex couldn’t see something that didn’t move, they actually could. They also had highly-developed noses, at least comparable to modern vultures. Surprisingly, though, a T-Rex had at once a very developed sense of hearing but limited in other ways. While they could hear further away than humans can, a T-Rex’s ears seem to hear low frequency sounds better than they would with high-frequency sounds.

They also had a fairly large brain.

Talk brainy Tyrannosaurus Rex Facts. T-Rex had the biggest brain out of most dinosaurs. Most scientists, however, question just how intelligent it made them. They point out that a T-Rex’s brain remains smaller than those of modern birds, if still comparable to those of modern reptiles. Other scientists, though, think that the T-Rex may have had intelligence comparable to chimpanzees today. Again, most scientists question this, as brain size between mammals and non-mammals do not accurately predict intelligence values.

Scientists once debated how the T-Rex stood and walked.

Scientists once thought that the T-Rex walked like a kangaroo, with its body angled at 45°, and its tail dragging against the ground. However, reconstructions of T-Rex proved this wrong, and that T-Rex instead stood parallel to the ground and held its tail in the air. This would become accepted as the dinosaur’s standard appearance in various fictional appearances over the course of the 20th Century onward.

Scientists today still debate whether or not T-Rexes hunted in packs.

Evidence exists in the form of three T-Rexes whose fossilized skeletons scientists found together. Additional evidence also exists in the form of similarly large, predatory dinosaurs like Tarbosaurus and Albertosaurus, which hunted in packs. The large, herbivorous dinosaurs they preyed on, such as Triceratops and Stegosaurus, also featured heavy defenses. Hunting in packs would have made taking them down easier, and many scientists argue further supports the idea of T-Rexes hunting in packs.

Fossil evidence also points to T-Rexes suffering from certain diseases.

Specifically, small holes in the fossilized jaws of several T-Rex skeletons point to parasites similar to the modern Trichomonas that can affect birds today as the cause. In fact, scientists have noticed that the fossil’s state of infestation meant the T-Rex couldn’t move its jaw by the time of death. This, in turn, led them to conclude that the T-Rex had died of starvation and that other T-Rexes could have suffered the same fate. Talk about grisly examples of Tyrannosaurus Rex Facts.

T-Rex specifically refers to just one species out of many.

Specifically, Tyrannosaurus Rex, but other tyrannosaurs existed, with T-Rex simply the most famous out of the Tyrannosaurid Family. Other members of the family include Alioramus, Daspletosaurus, Gorgosaurus, Tarbosaurus, and Zhuchengtyrannus. They all had the same body structure but generally grew smaller than the T-Rex, which remained the biggest of them all. Other differences include their origin, with Alioramus and Zhuchengtyrannus both living in prehistoric Asia instead of migrating to Laramidia as the T-Rex did.

Tyrannosaurus Rex Facts, Alioramus
Photo by Texas A&M University-Commerce Marketing Communications Photography from Wikipedia

They have the distinction of the most well-known dinosaur in the world.

No dinosaur other than T-Rex has its scientific name, Tyrannosaurus Rex, become part of everyday vocabulary. Its common nickname of T-Rex also comes as a unique distinction, with no other dinosaur having such a widespread nickname of its own. Even scientists commonly call the Tyrannosaurus Rex by its nickname, without any stigma from their peers. As American paleontologist Robert Bakker noted, T-Rex just comes off as too irresistible to use even for scientists.

The T-Rex first appeared on film in 1918.

Specifically, the silent film The Ghost of Slumber Mountain, directed by Willis O’Brien. Part of the film has become lost today, but the plot involves an explorer, Jack Holmes, who gets convinced by a ghost to use a machine that lets him look back into the past. This lets him watch a pair of triceratops fighting each other, only for the victor to get attacked and eaten by a T-Rex. The T-Rex then notices Holmes, but just as it attacks, Holmes wakes up, with his past experience apparently all part of a dream.

They later also made an appearance in the 1933 film King Kong.

In fact, many dinosaurs feature as antagonists in the film, with King Kong having to fight and kill them. The T-Rex that appeared in the film, though, counts as scientifically inaccurate, featuring the inaccurate kangaroo-like stance we mentioned earlier. Its 3-fingered claws also belong to Allosaurus, where T-Rex only has 2 fingers on each claw. In fact, T-Rex would not make a scientifically accurate appearance on film until the late 20th Century.

movie, T-Rex vs King Kong
Photo by Lothar Dieterich from Pixabay

Their most famous media appearance is in the Jurassic Park film franchise.

Based on the novel of the same name by Michael Chrichton, the T-Rex and other dinosaurs in the franchise were given birth through cloning. The InGen Corporation intended them feature attractions for a theme park, but they soon become deadly predators when the park failed.

In the first film, the T-Rex starts out as some sort of an antagonist, hunting the humans, only to heroically save them in the end by fighting a pack of raptors. The second film features two T-Rexes hunting the humans after one of them kidnaps their baby. A T-Rex appears in the third film, only to quickly get killed by a Spinosaurus which infuriated many fans.

Their glory returned in Jurassic World where the aging T-Rex from the first film reappears, fighting and killing a new threat, the Indominus Rex.

They’ve also appeared in many other films.

These include the animated children’s film series, The Land Before Time, while a toy T-Rex, literally named Rex, appears as a supporting character in the Toy Story franchise. The Night at the Museum also features a T-Rex, but with a unique twist. Instead of a living dinosaur, the T-Rex appears as a literal reanimated skeleton.

The T-Rex is also featured in various novels and TV series.

As we mentioned earlier, Michael Chrichton wrote the novels which later inspired the Jurassic Park films. However, even he based his work on Arthur Conan Doyle’s 1912 novel, The Lost World. There, explorers find a mysterious, undiscovered plateau in South America, where dinosaurs have survived. On television, Barney from the TV series of the same name probably counts as the most famous T-Rex of them all. The Power Rangers franchise from Japan also usually features at least one T-Rex-like robot in every reincarnation of the show.

Many other forms of entertainment feature the T-Rex.

Many video games feature the T-Rex, including the Jurassic Park tie-in games. Other games where the T-Rex appears include the Tomb Raider and even the Super Mario franchise. T-Rex toys remain popular worldwide, and the dinosaur has also appeared in various comics. The long-running comic Calvin and Hobbes has a story arc dedicated to the T-Rex, with Calvin writing a report on the dinosaur. The T-Rex has also appeared many times in the weekly British comic serial, 2000 AD.