Biology: 7 Mind-boggling Myths About the T-Rex debunked!

Note: The following article was written by Zuhair Bilal L6C (20BilalZ@students.watfordboys.org)

Tyrannosaurus (meaning “tyrant lizard”) is unquestionably the Earth’s most iconic prehistoric animal, a theropod dinosaur of giant proportions. Any scientist who has dealt with Tyrannosaurus fossils and any child who has watched Jurassic Park has come to have either fear or respect for this colossal killer of the Cretaceous period. Tyrannosaurus Rex, the only universally recognised Tyrannosaurus species, is suggested to have lived from 68 to 66 million years ago, its reign ending with the Cretaceous-Paleogene extinction event. A possible new Tyrannosaurus species, Tyrannosaurus mcraeensis, is theorised to have predated Tyrannosaurus Rex by 3 to 7 million years. Fossils belonging to the tyrant lizard king were first discovered in 1874 in Colorado, and the first partial skeleton was found in 1900, Wyoming. Over time, we have developed our understanding of the bipedal beast thanks to many specimens being discovered over the years. However, an array of myths still surround the king of the dinosaurs. In this article, I will tackle seven myths and dispel any related falsehoods regarding Tyrannosaurus.

1 - Did Tyrannosaurus Roar?

We’ve all watched “Jurassic Park” and heard the infamous T. Rex roar, an epic, loud and majestic sound. This roar was further popularised by its presence in the second and third Jurassic Park movies, as well as all three movies in the “Jurassic world” trilogy. Gary Rydstrom, the leader of the team that created this sound, explained in a 2013 interview that the roar was created by mixing the sound made by multiple animals such as a tiger, an alligator and a baby elephant. In reality, Tyrannosaurus’s roar most likely sounded completely different, and perhaps even more terrifying. Scientists use multiple ways to theorise what sounds Tyrannosaurus Rex made. First of all, it is highly unlikely that the beast produced any sort of “roar” like what we have seen on television. Animals like lions and tigers roar, but T. rex is not at all closely related to these animals. T. rex is much more closely related to members of the archosaur group, of which many species still exist today. For example, birds and crocodiles. Therefore, it is much more likely that T. rex produced a sound more similar to that of modern-day archosaurs than to that of modern-day mammals such as tigers. Upon examination of T. rex anatomy, it has been found that their ears and brain likely emphasised low frequency sounds, suggesting that T. rex heard low frequency sounds from other T. rexes. This not only aligns with the archosaur theory, but also makes sense when accounting for T. rex behaviour. Low frequency sounds can travel long distances through air, water and solids, allowing for long-distance communication between rexes without alerting prey. Quite clearly, it is much more probable that T. rex made low, ominous rumbles or hisses rather than a loud, majestic roar.

2 - Could Tyrannosaurus see you if you stood still?

“Keep absolutely still. Its vision is based on movement.” These words about T. rex come from Alan Grant in Jurassic Park. He suggests that the giant reptile would leave you alone if you stood still as its bad vision meant it wouldn’t be able to see that you are alive. It was reported in a 2006 study in the Journal of Vertebrate Paleontology that T. rex had a binocular vision range of 55 degrees, wider than modern hawks, and had vision 13 times more precise than that of a human. For comparison, an eagle only has vision 3.6 times that of a human. This means that T. rex had one of the best pairs of eyes in the history of the animal kingdom. Consequently, it follows that T. rex, having such vision, could easily see stationary objects and identify them. Alan Grant’s advice in our favourite dinosaur movies would probably get quite a few people eaten.

3 - Did Tyrannosaurus have feathers?

In the 1990s and early 2000s, paleontologists discovered dinosaur fossils with impressions and bone marks suggesting that they had feathers or feather-like fibres. Among these dinosaurs were some from the genus Yutyrannus, an early relative of T. rex. This led scientists to suggest that other Tyrannosaur species, including T. rex, may have had feathers. Up until now, no direct evidence of feathers or fibres like those found on Yutyrannus have been discovered on a T. rex fossil. In fact, some of the only fossils we have of T. rex’s skin suggest that it was scaly and not feathery. Another reason modern paleontologists believe T. rex was not feathery is, basically, its size. T. rex was an extremely large animal and therefore has a small surface area to volume ratio. This means that the T. rex's body was very good at retaining heat, and therefore did not need feathers for insulation. The same is seen in large animals today, such as elephants, hippopotamuses and rhinoceroses. This is aided by the fact that these animals live in rather warm environments. T. rex lived in Cretaceous North America, in temperatures likely higher than that of the modern day.

4 - Did Tyrannosaurus stomp?

Historically, the T. rex has been depicted as a large rampaging beast that stomped around without its feet flat on the floor. However, recent discoveries have suggested otherwise. Examinations of the feet (and the ligaments within them) of Tyrannosaurus have found that it put a lot of pressure on its front toes as opposed to its heel. This means that, instead of taking large, heavy strides, it took quicker steps on its toes, sort of like a 10-ton ballerina. This aligns with some modern birds, such as ostriches. T. rex is also theorised to have had fleshy pads under its feet. Large animals, such as elephants, often have such feet to absorb the shock of their massive bodies stepping on the ground. For T. rex, this also likely meant that it was surprisingly quiet for a massive carnivorous monster. You couldn’t hear Tyrannosaurus’s footsteps until it was too late, leaving you to be a quick dino-meal.

5 - Was Tyrannosaurus dumb?

In the past, the T. rex has been depicted as a giant, unintelligent brute that only offered aggression. In reality, the case is much more complex. A 2023 study suggested that Tyrannosaurus was more intelligent than even some modern primates due to its forebrain containing 3.3 billion neurons. However, evidence does not support this claim, and the number of neurons alone is not a reliable indicator of intelligence. For example, a giraffe has about 5 times more neurons than a magpie, but displays no intelligent behaviours that magpies display such as imitation or self-recognition in front of a mirror. While T. rex did not have the cognitive power of modern primates, it likely had a similar brain to a crocodile, and had no trouble with basic problem solving. Our giant reptilian friend certainly was not dumb, but was also not as ingenious as some people have suggested.

6 - Did Tyrannosaurus’ teeth stick out of its mouth?

In almost all movies that depict T. rex, the lizard king’s teeth can be seen on the side of its jaw while its mouth is closed. This came from the inaccurate assumption that the T. rex’s had similar stuck-out teeth to a crocodile. In reality, Tyrannosaurus needed to protect its teeth from the outside to prevent the wearing away of its enamel. Crocodiles, on the other hand, often have their teeth submerged in water, preventing them drying out and becoming prone to wear. T. rex, like modern day komodo dragons, probably had scaly lips that covered its teeth when its mouth was closed, allowing the protection of the deadly daggers that lined the beast’s jaws.

7 - Was any other land carnivore bigger than Tyrannosaurus?

For over a century, T. rex has been thought to be not only the largest theropod dinosaur (bipedal dinosaur) to ever exist, but also the largest land carnivore. In recent decades, T. rex’s claim to the throne has been challenged by a few other theropod dinosaurs. First of all, it is noteworthy that “size” in this debate is referring to mass. A snake may be longer than an elephant but it would be preposterous to say that a snake is larger than an elephant. A 1995 study purported that Giganotosaurus (a large theropod that lived in modern-day South America) was a larger animal than T. rex. A bone from an incomplete Giganotosaurus specimen suggested that it had a longer skull than the (at this point) contested king, and the femur from the holotype specimen was longer than that of T. rex. Modern studies have backed up Giganotosaurus being longer than T. rex by a potential few decimetres, but few, if not none, have helped the claim that Giganotosaurus was larger in mass. On the contrary, many studies suggested otherwise. In 2012, a fairly accurate formula was developed to calculate the mass of a theropod dinosaur using the circumference of its femur. The formula suggested that T. rex was larger than any other theropod, with an average mass of about 6.3 to 7.3 tonnes, Giganotosaurus having a mass of about 6.3 tonnes. The largest T. rex specimen at the time, Scotty, had a calculated mass of 8.9 tonnes, and Sue, another large T. rex specimen, was not far behind. Therefore, the formula suggests that it is highly unlikely that Giganotosaurus was a larger animal than T. rex. Carcharodontosaurus, a large theropod dinosaur closely related to Giganotosaurus, has also been posed as a competitor, but is probably inferior in size to its South American cousin. Spinosaurus, an unconventional semi-aquatic theropod,  has also been put forward in the past, its mass being 7 to 8 tonnes. This means it could potentially have been a better competitor for the throne than Giganotosaurus. However, in recent years, scientists have come to realise that we have been underestimating the size of many theropods by depicting them as skinnier than they actually likely were. With new volumetric modelling, we can more accurately predict the mass of theropods based on the volume of their bodies, as flesh is constant in density. This development in paleontology, however, was not a new hope for Giganotosaurus or Spinosaurus to take the throne. Instead, it was the nail in the coffin.

These animals’ bodies are specialised for their roles in the ecosystems they live in. All three are apex predators, but each one performs a different task. Spinosaurus lived both on land and in water, wading in the shallows and fishing for large shark-like creatures. It was longer than both Tyrannosaurus and Giganotosaurus due to its large tail that it used for swimming. Giganotosaurus hunted small dinosaurs and large sauropods (long-necked dinosaurs). Upon engaging a sauropod (potentially in a pack), it would take bites out of its side using its sharp teeth, slowly cutting away at the giants. Giganotosaurus’s more slender build allowed it to run fast and was better suited for this style of hunting. T. rex on the other hand, was completely different. T. rex was not as thin and did not have large spines. Instead, T. rex was a monster of extremely bulky proportions. T. rex’s prey were similarly sized to it, and were often armed. Triceratops, a herbivorous dinosaur with 3 large horns and a large crest on its head, was often hunted by T. rex. Edmontosaurus, a herd dinosaur slightly larger than T. rex, was also a personal favourite for the king. It is also likely that T. rex came into contact with Ankylosaurus, a smaller but heavily armoured dinosaur. Ankylosaurus was covered in bony plates from head to tail, protecting it from attacks everywhere except its underbelly. Even its eyelids were armoured! It had a large club on its tail that it swung to fend off or injure attackers, and was a solitary, territorial animal. When approached by a T. rex, they likely raised their tail, got low to the ground, and prepared for a brutal clash between giants. T. rex, having excellent vision, surprising agility and the strongest bite force of any land animal ever, was adapted for fights with these feisty dinosaurs of Cretaceous North America. Tyrannosaurus was a tank designed to take down other tanks. It is for this evolutionary reason that T. rex was so massive. 

The existence of volumetric modelling, the Campione and evans formula, and the giant skeletons of Sue and Scotty (who are theorised to have been 9-10 tonnes) have all made it unlikely that any other theropod could be bigger than Tyrannosaurus (using this modelling, Giganotosaurus was probably 6.8-9 tonnes). But if all of that wasn’t enough, we found even larger T. rexes. The ED cope (Dubbed “copium rex” by the internet) specimen’s body mass ranges from 11.5 to 12 tonnes (10.6 using the Campione and Evans formula), bigger than any theropod dinosaur previously discovered. In 2024, another T. rex specimen (named “goliath”) was discovered, with an estimated mass of 11.5-12.5 tonnes. It is hypothesised that even a 15 tonne T. rex could exist, and it is possible that we find larger T. rex skeletons in the future. But even with what we have now, it is fairly safe to say that the king’s claim to the throne is undisputed.