Temporal range: Late Cretaceous
Reconstruction of Tyrannosaurus by Mark Witton
Scientific classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
Clade: Dinosauria
Order: Saurischia
Family: Tyrannosauridae
Genus: Tyrannosaurus
Osborn, 1905
Type species
Tyrannosaurus rex
Osborn, 1905
Other species
  • T. mcraeensis (Dalman, 2024)

Genus synonymy

  • Manospondylus (Cope, 1892)
  • Dynamosaurus (Osborn, 1905)
  • Nanotyrannus (Bakker, Williams and Currie, 1988)
  • Stygivenator? (Olshevsky, 1995)

Species synonymy


Approximate distribution range of Tyrannosaurus rex

Tyrannosaurus (Greek for "tyrant lizard") is an extinct genus of tyrannosaurid theropod dinosaur that flourished during the Maastrichtian age of the Late Cretaceous, 72-66 million years ago. The type species is T. rex (Greek for "Tyrant Lizard King"), named in 1905. A second, older species; T. mcraeensis, was named in 2024.

Ever since its discovery, Tyrannosaurus has become one of if not the most popular of not only its family, but non-avian dinosaurs as a whole; as over 50 individuals of this taxon have been unearthed. The most complete specimen of the T. rex was nicknamed "Sue" (located at Chicago's Field Museum of Natural History, which is roughly 90% complete), measuring approximately 12.3+ meters (40+ feet) in length, around 3.9 meters high at the hips, and an average weight of 10 tonnes, making it among the biggest terrestrial carnivores & biggest theropods that ever existed. There are other specimens estimated to be larger than Sue but this information is debated. However, one specimen, known as "Scotty", measured 12.4 meters (40.6 feet) in length, stood 3.9 (12.8 feet) meters at the hips, and weighed nearly 11 tonnes, making Tyrannosaurus currently the biggest theropod and fully-terrestrial carnivore known to science.

Fossils have been uncovered in North and South Dakota, Texas, Montana, Colorado, Wyoming, and Saskatchewan within a depositional formation known as the "Hell Creek". It was among the last non-avian dinosaurs to live prior to the K-T mass extinction event.

A rather recent, although controversial study indicates that there could be three differentiated and varied species of Tyrannosaurus and proposed two new species: Tyrannosaurus imperator and Tyrannosaurus regina.[1][2] They are considered as invalid by most paleontologists, because the difference between these species can be explained with either individual variation or sexual dimorphism.


Tyrannosaurus by RJ Palmer


Tyrannosaurus skeleton-0

An outdated skeletal restoration of the T.rex depicting the classic upright tail-dragging stance.

Although teeth and indeterminate fragments had been discovered prior, in 1892, paleontologist Edward Drinker Cope described the first known T. rex specimen, which he dubbed "Manospondylus gigas" (Greek for "Giant Thin Vertabrea"). The specimen was originally believed to have belong to that of a ceratopsian, but is currently considered a Nomen oblitum. This was heavily and inaccurately restored with a plaster using Allosaurus as the model, and has since been disassembled. When Barnum Brown and his crew made an expedition to Montana in 1900, they stumbled upon the first partial T.rex skeleton, and then a second one in 1902 that would be properly represented as the neotype specimen. In 1905, Henry Fairfield Osborn named the skeleton "Tyrannosaurus rex", which is the name that has prevailed since.

Tyrannosaurus rex skeletal reconstruction by randomdinos ddqrrq4-pre

A recent, up to date skeletal reconstruction of the Tyrannosaurus specimen "Sue". Artwork by RandomDinos on DeviantArt.

Many more individuals of the dinosaur have been discovered since, including ones that are nearly complete, show numerous ontogenetic stages, skin impressions, and even soft tissue. Brown's 1902 discovery of "Dynamosaurus imperiosus", has also been synonymous with Tyrannosaurus rex, as the Dynamosaurus holotype was reported showing osteoderms that belonged to Ankylosaurus, which the T.rex lived alongside with in Late-Cretacous North America. Tarbosaurus was also, at one point, categorized as a second Asian species of Tyrannosaurus. However, despite similarities between the two, there were enough distinct traits between the two taxa that Tarbosaurus is now usually referred to as its own species, Tarbosaurus bataar (although some scientists classify it as a junior synonym).

In 2024 the new Tyrannosaurus species Tyrannosaurus mcraeensis was described based on fossils found in the Campanian-early Maastrichtian Hall Lake Formation in New Mexico, which are 6-7 million years older than fossils attributed to T. rex. The two species are of similar size and are distinguished by characteristics of the skull.


Tyrannosaurus was one of, if not the largest carnivorous theropod, and by extension largest terrestrial carnivore of all time. The largest known specimen, RSM P2523.8 (AKA "Scotty"), measures around 12.4 meters in length, stood 3.9 meters tall at the hips, and weighed 10-11 tonnes although most fully-grown adults would have averaged 7-9+ tonnes in weight and 11-12+ meters (36-39+ feet) in length. Despite its colossal proportions, theropods such as Spinosaurus and Giganotosaurus may have potentially surpassed T. rex in length. It is believed that Sue and Scotty are among the oldest of their kind, currently known at 28 years old (in comparison, the average T. rex lifespan is estimated at about 25 years old).

Trex skull

Skull of T. rex type specimen located at the Carnegie Museum of Natural History.

T. rex's skull was capable of growing over five feet (1.5 meters) in length and was extremely robustly-built. The base was significantly wider than the snout, providing it with excellent binocular and stereoscopic vision, even greater than that of a human as studies suggest. Its mouth was broad compared to that of most other theropods and resembled a U-shape, increasing the amount of surface area it could chomp down on with a single bite. The skull retained several openings in it, known as "fenestra", that lightened the head and likely held soft tissue such as muscle or blood vessels, and the fenestra on top of its head may have served as a cooling mechanism, as seen in crocodiles.

Additionally, The T. rex's jaws averaged four feet (1.2 meters) in length and were very muscular, compensating for the animal's devastating biting strength. Analysis has shown that Tyrannosaurus was capable of opening its jaws up to approximately 63-80 degrees wide, maximum. The neck of the T. rex formed a natural S-shaped curve, similar to that of other theropods, but was relatively short, and would have been immensely robust in order to support its massive head. Tyrannosaur's often-ridiculed forelimbs were only around the size of an adult human's arms, but were anchored to powerful muscles (the T. rex's arms were capable of bench pressing 400 pounds each), and, unlike dinosaurs such as Carnotaurus and its relatives, were not vestigial and would have had some use in life, although the exact purpose for them is not entirely known. Unlike more basal theropods, Tyrannosaurus hands bore only two usable digits that were tipped with sharp claws, the third being undeveloped and was too small to have shown through the skin. In contrast to the forelimbs, the hind limbs were among the longest in proportion to body size of any theropod and incredibly muscular in order to support the animal's massive bulk. Its feet resembled those of terrestrial birds, with three longer toes that would have impacted the ground, and one vestigial hallux "dewclaw" that would have never touched the ground; each toe was tipped with massive slightly hoof-like claws.

The tail was long and heavy, occasionally containing over 40 vertebrae in order to balance the large head and torso. To compensate for its immense size, many bones throughout the skeleton were hollow (similar to birds and other theropods), reducing its weight without major loss of strength. The torso was wide and deep, resembling a "barrel-chest". This body would have supported most of the animal's internal organs, with aid from the gastralia (belly ribs). Since Tyrannosaurus was a saurischian dinosaur, the pubis in the hips would have pointed forward and away from the backward-facing ischium.

The teeth of T. rex displayed some heterodonty (differences in shape). The teeth in the premaxilla (front upper jaw) were relatively small and closely packed, D-shaped in cross-section, possessed reinforcing ridges on the rear surface, were incisiform (their tips were chisel-like blades) and curved backwards, which all would have decreased the risk of the teeth breaking when animal bit and pulled. The remaining teeth were robust with a blunter shape compared to the dagger teeth of basal theropods, more widely spaced and also possessed reinforcing roots. The teeth in the middle of the maxilla were the largest in its jaws; the biggest Tyrannosaurus tooth discovered currently was recorded as measuring 30.5 cm (12 inches) in length, including the root, making it the largest tooth of any carnivorous dinosaur and easily one of the most immense teeth in the animal kingdom, excluding tusks.



Various members of tyrannosauridae.

Tyrannosaurus is a genus of coelurosaurian theropod, as well as the type genus of the superfamily Tyrannosauroidea, the family Tyrannosauridae, the subfamily Tyrannosaurinae, and the tribe Tyrannosaurini.










T. rex and T. mcraeensis


The anatomy of tyrannosaurs, showing the variety of skeletal and cranial morphology in the group from Brusatte et al (2010).

The first tyrannosauroids discovered were relatively small and coated with feathers. They were not the top predators of their period, since they were dwarfed by the considerably larger allosauroids. Proceratosaurus, the earliest of this family, inhabited what is now Europe during the Jurassic period, 167 million years ago. As time progressed and the carnosaurs were driven to extinction, the tyrannosauroids took over as apex predators of their environment, evolving to be larger as they traveled west into Asia and finally North America. Yutyrannus is perhaps the most well-known of these basal tyrannosauroids, famed for being the largest confirmed feathered animal; this sparked the thought that Tyrannosaurus and its near cousins may have been possessed feathers as well, however skin impressions show that Tyrannosaurus was actually mostly, if not completely, scaly[3].

Screen Shot 2020-04-26 at 1.38

The Tyrannosauroidea family tree showing geographical and geological range.

Charles W. Gilmore discovered a small tyrannosaur skull from the Hell Creek formation, assigning it as a species of Gorgosaurus. However, following closer examination, the skull was determined to be too unique to represent a Gorgosaurus species, and thus was so given its own name, Nanotyrannus lancensis; as the specimen revealed evidence of immaturity, it was suggested that it was a juvenile of Tyrannosaurus rex, the only other tyrannosaur known from Hell Creek. This hypothesis would be further suspected to be the case with the discovery of BMRP 2002.4.1 (AKA Jane), a six meter (20 feet) T.rex from Montana, whose skull showed similar traits to the Nanotyrannus holotype. When histology was conducted on Jane, it was found that its bones didn't show skeletal maturity and the study came to the conclusion that Jane was in fact a juvenile Tyrannosaurus, making Nanotyrannus at best a Nomen dubium.

Nevertheless, cases have been issued that perhaps Jane and the holotype skull are in fact juveniles, but may pertain to a completely different species of tyrannosaur that just hasn't been uncovered yet in the Hell Creek, a similar case to Alioramus in the Nemegt Formation, and would therefore "Nanotyrannus" was reasserted as a valid taxon. The Nano-morphs follow a similar pattern of characteristics including a long, narrow snout, less binocular vision, blade-like teeth, long, slender hind limbs, a slimmer body plan in general compared to its potential adult counterparts, and 15 or more teeth in its lower jaw compared to the typical 12-13 found in adult T. rex.


Tyrannosaurus rex was one of the largest of the theropod dinosaurs and easily the largest predator in its environment. It had a massive skull with reinforced banana-like teeth. Recent studies have estimated that T. rex was capable of biting down with 64,000 - 94,000N (over 6 tonnes) of force, making it one of the most powerful bites ever known. This amount of force was capable of not only piercing, but completely shattering bone and armor, which would explain why its teeth were so robust, reinforced, and relatively blunt, used for attacking large prey, and crushing smaller prey like ornithomimosaurs. It likely formed such devastating features in order to prey on well-defended herbivores such as the three-horned Triceratops and Torosaurus, which would in turn evolve more defenses and make a vicious cycle of an evolutionary arm's race. While it was originally hypothesized that T. rex might have had flexible parts of its skull like modern relatives such as parrots and lizards, recent studies involving 3D imaging compared stresses on its head revealed that the bones in its skull would instead have been fused like a crocodile in order to reinforce it and keep it from breaking apart due to the massive amount of force its jaws could deliver.

Tyrannosaur charge by alexandernevsky-d59vlvs

Alexander Lovegrove's illustration depicting a young Tyrannosaurus as a fleet-footed ambush predator.

In life Tyrannosaurus would have had eyes the size of softballs and were capable of seeing long distances with very good depth due to them being forward-facing, giving it binocular vision. CAT-Scans of the skull have revealed that much of the brain was dedicated to its sense of smell, giving T. rex one of the strongest senses known in any modern or extinct taxa. The structure of bones around its ear would have been well suited to picking up low-frequency sounds like modern-day elephants do, indicating that T. rex and its prey were making deep low-frequency noises. Because Tyrannosaurus lacked a larynx like modern mammals such as lions and even likely lacked a syrinx such as those found in modern birds, it is unlikely that it was capable of roaring in a traditional sense as is often depicted in pop culture. Instead, it is believed that T. rex would have done low, deep rumblings and hisses, along with the occasional bellows and "roars" similar to living crocodiles. However, with a bird-like larynx recently being found in another dinosaur, though distantly related, Pinacosaurus, it is possible this trait was also present in theropods. This would allow for a far broader range than rumbles as previously believed, but the vocals of theropods are still under debate.

From specimens such as Jane and B-Rex (MOR 1125), researchers were able to make a growth chart of Tyrannosaurus rex and found that once it hit its pubescent years, T. rex gained an average of 600 kg (1,300 lbs) a year until it hit adulthood at around 18 years of age. No eggs or hatchlings have been found of T. rex yet so what exactly it would have looked like at this stage of its life is not currently known. Because of this some scientists have suggested that this was because these animals rarely died during this age, though others have pointed out that this could simply be due to bias in the fossil record, which doesn't preserve small animals as well as larger ones. The oldest confirmed age for any Tyrannosaurus is currently 28 and belongs to Sue. At this age Sue was already showing signs of age due to arthritis and suggests that even though it didn't die due to old age it still was getting close to the end of its lifespan. It's unlikely T. rex lived much older than 30 years of age, suggesting they lived fast, hard lives.

For some time it was unknown just what Tyrannosaurus' integument consisted of. The classic depiction is that of lizard-like scales entirely covering its body, just like all dinosaurs were thought to have been like at the time. However, as time went on and more fossils were found that depicted dinosaurs with feathers, the question started to arise as to whether all dinosaurs would have had feathers in some way, including Tyrannosaurus rex. This seemed to become more possible when a decently-sized relative of T. rex, Yutyrannus, was found to in fact have been covered in feathers. This lead to the influx of paleo artists challenging the past depictions of the tyrant lizard by covering it from head to toe in downy feathers.

Resting tyrannosaurus rex by fredthedinosaurman d91km60-fullview

A Tyrannosaurus relaxing in the sunrise by Fred Wierum.

However, a study in 2017 showed that skin impressions of several derived tyrannosaurs, including T. rex itself, depict not the downy feathers that many experts had been expecting, but in fact small, reticulated scales. Although the skin impressions have only been in scattered patches among several species, the researchers concluded that there are enough scale impressions among so many different parts of the individual bodies that it's more likely that scales covered the entire animal instead of feathers only covering places that happened to not be preserved. This was further explained to be the case due to the animal's large body, which at its size any extra integument would have been a detriment rather than a benefit, especially since it lived in such a warm environment. There was a hypothesis for a while that perhaps the young tyrannosaurs would have had feathers when they were hatched and gradually lost them as they aged and grew in size. However, several researchers have pointed out that no animal today completely changes integument as it ages. Even birds today such as turkeys and vultures don't gain scales when they grow out of their facial feathers, it's just bare skin, so that hypothesis has been abandoned. If T. rex did have any feathers in life it would have been light downy feathers along its back similar to elephant hair. Many patches along Tyrannosaurus' skull show extended patches of grooved, rugose bone, indicating that thick keratin would have covered much of the animal's face in life. These are most prevalent along the top of the snout, the crest ridges above the eye, and on the cheek of the upper jaw. It is believed this would have served as extra protection against rivals since bite marks show that these animals would have regularly bitten each other in the face during confrontation. Like all other theropods, Tyrannosaurus walked on two legs (known as "bipedalism") that were very well muscled and were made to support and balance the animal as it stood, walked or ran. Unlike the classic upright depictions of when it was first found, paleontologists now know that T. rex and most other theropods would have had vertical bodies in a neutral pose and used its tail and head to balance each other.

Rjpalmer trex 016 by arvalis d9wgjrd by arvalis-daj1or5

A featherless Tyrannosaurus reconstruction by RJ Palmer.

Tyrannosaurus rex had long been believed to be a hyper carnivore, the apex predator of Hell Creek. It certainly seemed to have the size and teeth to fill that role. However, all of this came to contention when in the 1990s, renown paleontologist Jack Horner proposed that T. rex was a lumbering scavenger that scoured the land for carcasses or bullied smaller predators away from their kills instead of hunting for themselves as had been the traditional view. He based these claims on observations to the animal's anatomy such as the tiny arms which he claimed would have been too useless in taking down large animals, its massive size which would keep it from chasing down potential prey, the fact its sense of smell was so strong which is only comparable to vultures which are known scavengers, its bone-crushing bite which carnivores that are typically depicted as scavengers like hyenas are known to have, and that its eyes would have been too small to properly hunt. Horner also noted that a specimen of Triceratops showed many bite marks on its pelvis and suggested that since it clearly took its time picking apart the carcass, the T. rex must have scavenged it.

This hypothesis was met with near immediate backlash. Rebuttals to Horner's claims were met by fellow paleontological and tyrannosaur experts such as Philip J. Currie, Thomas Holtz, Thomas Carr, and Robert T. Bakker, who noted that Horner misinterpreted several things about T. rex and the analogs he used. Tyrannosaurus did have small forearms, but they wouldn't have been necessary in killing its prey since it had a massive jaw that was more than capable of taking down large game, and even noted that not all predators kill with help from their arms, such as crocodiles and raptorial birds. Further, one of the comparisons used, the Hyena, also use their bone-crushing bite to hunt. While Tyrannosaurus was a very massive animal, it would still have been able to move fast enough to keep up with its rather slow-moving prey items such as Triceratops.

This was perhaps due to its unique arctometatarsus arrangement, which is the condition found in tyrannosaurs where the upper part of the middle ankle bone was pinched between the other two and would have allowed for greater agility and speed. The most recent estimates have found that T. rex could have moved anywhere from 20 km/h (12 mph) to 34 km/h (21 mph). It was also noted that elephants, which are of similar size to T. rex, are more than capable of being surprisingly fast when they want to be. However, due to its massive size alone, biomechanics researchers have noted that Tyrannosaurus would not have been capable of running.[4][5]

New simulations based on tail movement showed that T. rex wasn't even a speedy walker! In a matter of fact, its preferred or most resonable walking speed clocked in at under 3 mph (5 km/h), about half the speed of earlier estimates. To put that into perspective, that's about the average walking speed for an average human, according to the British Heart Foundation.[6][7][8][9][10]

T. rex's sense of smell was astounding but that in no way indicated that it was a scavenger in nature since many modern day predators such as wolves and bears have great senses of smell as well. The massive bite compared to hyenas is also misunderstood since hyenas actually hunt their food far more often than they scavenge. As for its eyes, when scans of T. rex's skull revealed its braincase, it was found that a decent amount of it was dedicated to eyesight. Couple that with great binocular vision, and it would have allowed T. rex to locate prey at a great distance and been very useful for hunting prey. Not only that, but it was completely impractical that the only large carnivore in the area wouldn't have been hunting the massive herbivores in the ecosystem and keep a healthy population in the area. Horner's colleagues have pointed out that the next biggest carnivores in Hell Creek would not have been capable of taking down the multi-tonne prey on their own. There was also a fossil of Edmontosaurus found with a healed bite taken out of one of the tail vertebrae, indicating that it had escaped the attack and survived long enough for the wound to heal, and the only animal that was capable of making a bite like that was Tyrannosaurus rex.


An artistic rendering of a drowned group of tyrannosaurs and a crocodilian scavenging in the background. Illustration by: VICTOR LESHYK

Some paleontologists have suggested that perhaps Tyrannosaurus lived in familial groups where a pair of adults would raise a bunch of juveniles until they were old enough to leave and make families of their own. The main catalyst for this theory is from a close relative of T. rex, Albertosaurus has been found in large groups of varying aged individuals together. It's believed if this was the case, the smaller, faster juveniles would have acted as the pursuers who would drive weaker individuals away from their herds and chased them into the slower but stronger adults, who would end the job with a quick, powerful bite to a vital area. Whereas. more recent publication might have supports this group behavior for Tyrannosaurus, the publication studies a group of tyrannosaur fossils were found buried together at the “Rainbows and Unicorns Quarry” in Grand Staircase-Escalante National Monument. A skull of the same tyrannosaur species, depicted here, was found about two miles north of the group site. Titus even thinks that the site could be evidence that tyrannosaurs worked together as cooperative pack hunters. “Now you’ve got these giant terrestrial predators behaving in a group, much more akin to a pack of wolves and a pride of lions, [which] is staggering,” he says; but as he and other experts note, true pack hunting is rare among living predators. And social behavior among predators ranges from the barest tolerance of another individual to coordinated pack attacks. The new fossils are not the first example of tyrannosaurs discovered in the same place, but a meticulous reconstruction of the area’s geologic history provides strong evidence that they died in a group. The more elusive question is what they were doing together.

The 75-million-year-old site—named Rainbows and Unicorns Quarry by Titus’s colleague for its apparently incredible specimens—is the first of its kind in the southern U.S. However, it’s far from the only to hint that tyrannosaurs gathered in groups. One bonebed in Alberta, Canada, contains the bodies of 12 to 14 Albertosaurus that were seemingly concentrated together during a flooding event. In Montana, an area about half the size of a tennis court contains the remains of at least three Daspletosaurus. Even the site in South Dakota that yielded the famous T. rex fossil Sue contained remains of other T. rex individuals. Fossil tracks also add to the picture. In 2014, scientists announced that rocks in British Columbia preserve footprints of three tyrannosaurs that walked in the same direction within a short time of each other, if not at the same time. Researchers argued that the site could point to social behavior, even suggesting a collective noun for a tyrannosaur group: a “terror.” Thomas Carr, a paleontologist at Carthage College in Kenosha, Wisconsin, who wasn’t involved with the new study, says that finding more signs of social dinosaurs shouldn’t necessarily come as a surprise. Extinct dinosaurs belong to a bigger group called the archosaurs, which includes social animals such as modern birds, alligators, and crocodiles.[11][12][13]

In the mid 2000s, a hypothesis arose that suggested since Tyrannosaurus had serrated teeth like today's Komodo Dragon, it would have had a septic bite that would infect victims that had initially escape its jaws due to the bacteria that would fester in its mouth due to the small pieces of rotting meat that would get caught between the serrations. However, this theory fell through for a few reasons. As it turned out, Komodo dragons don't have a deadly bite due to bacteria in its mouth but instead used venom to make its target bleed to death overtime if it escaped, so that analogy couldn't be used for T. rex. It was also found that serrations are in fact not capable of holding small pieces of meat in them, and if this was the case it was more likely the host itself would get its mouth infected by being constantly in contact with the bacteria. And finally, there would be no need for Tyrannosaurus to have evolved such large and powerful jaws if it was constantly relying on using a septic bite to take down its prey.

Sexual dimorphism is notoriously hard to distinguish in the fossil record. For a while, it was believed that female tyrannosaurs were the larger ones between the males, though recent analyses suggest there's no known reliable correlations to make this assumption. There is only one confirmed specimen of Tyrannosaurus to show sexual dimorphism, known as "B-Rex", and it was only found by breaking its femur and finding traces of soft tissue that resembles medullary bone like those found in modern-day birds when they're ovulating in order to provide extra calcium for the eggs.

In 2021, a paper by Charles Marshall et al. set to find the survival rates of Tyrannosaurus infants reaching adulthood, a process which had him attempt to find the approximate number of individuals who could have existed on earth. At the end of the study, it was revealed 2.5 billion individual adult Tyrannosaurus may have existed in total, meaning the species was one of the last "evolutionary supernovas" before the K-PG impactor. Tyrannosaurus assumed the role of a morphospecies, meaning the animal took many different niches until adulthood, where it reached apex predator. They compared Tyrannosaurus to many extant predators like lions and komodo dragons, comparing blood temperature, range, population density and growth curves to determine a likely number.

They found that among the 2.5 billion, only about 20,000 individuals could be supported at one time. They estimate that for every one fossilized individual, 80,000 others did not preserve, and every 1 in 16,000 for the famous Hell Creek Formation. In the paper, they state the models are only a "ballpark estimate" and not data, but such information could be further revised in the future.[14][15][16]

Tyrannosaurus Species T. rex, T. regina, T

Tyrannosaurus Species: T. rex, T. regina, T. imperator

Soichiro Kawabe et al. (2021) confirmed this. They found a complex network of sensory organs in the snout of Tyrannosaurus. Nerves are the most complexly distributed of all dinosaurs. They found it was able to recognize different areas, materials and movement with great accuracy. This would have enabled it to have eaten bodies depending on the situation. Neurovascular canals branched through the anterior of the dentary. Because it may have lacked the thick integument seen in crocodilians, it was likely more sensitive; and ornithischians, when compared, did not match the level seen in Tyrannosaurus. However, the team was not able to fully study the mandible and compare enough dinosaurs to be seen as sufficient, so their findings are seen as "a reasonable estimate"[17].

T. rex, T. regina, T

The specimens of: T. rex, T. regina and T. imperator

A recent analysis concluded that the Tyrannosaurus had nerve sensors in the tips of its jaws that could recognise the varied parts of its prey. Researchers from Japan's Fukui Prefectural University scanned a fossil T. rex jaw From this they were able to reconstruct the blood vessels and nerves from within They found that the 'tyrant lizard kind' most likely had a very sensitive mouth It may have been able to use its mouth to help build nests and care for young.[18][19][20][21][22][23]

An updated study claims that there could be several differentiated species of Tyrannosaurus. New analysis, based on a dataset of over three dozen specimens, finds that Tyrannosaurus specimens exhibit such a remarkable degree of proportional variations, distributed at different stratigraphic levels, that the pattern favors multiple species at least partly separated by time; ontogenetic and sexual causes being less consistent with the data. Variation in dentary incisiform counts correlate with skeletal robusticity and also appear to change over time. Based on the current evidence, three morphotypes are demonstrated, and two additional species of Tyrannosaurus are diagnosed and named. One robust species with two small incisors in each dentary appears to have been present initially, followed by two contemporaneous species (one robust and another gracile) both of which had one small incisor in each dentary, suggesting both anagenesis and cladogenesis occurred.[24][25][26][27][28][29][30][31][32]

Although the study itself remains highly controversial and should better be not taken seriously at all. The distinction between T. rex, T. imperator and T. regina can easily be explained by the individual variation of T. rex. Most experts and Paleontologists don't agree with the hypothesis by Gregory S. Paul at all.[33][34][35]


Hell Creek Formation Size Chart

Size chart of Hell Creek Formation fauna including Tyrannosaurus

Tyrannosaurus rex would have served the role as apex predator in its environment. In this case, the environment of Hell Creek during the Maastrichtian would have resembled northern Florida as a warm, moist delta ecosystem with tropical plants growing in swamps and floodplains. During this point in Earth's history the Western Interior Seaway was receding and where there was once ocean a few million years earlier there was now only river systems and a coastal plain.

Of all the known fauna in the area, Tyrannosaurus makes up around a quarter of all fossils found in Hell Creek, which is surprisingly high for an apex predator, though there could be bias in the fossil record with larger animals preserving better than smaller ones. Living alongside Tyrannosaurus in these fluvial habitats were the iconic three-horned Triceratops, which were the most plentiful animal in the area and would have been the main source of nutrition for Tyrannosaurus. The large hadrosaur Edmontosaurus would have migrated into Hell Creek fairly regularly and served as another favorite prey item for the local tyrannosaur. Other dinosaur residents would have included the armored club-tailed Ankylosaurus, the dome-headed Pachycephalosaurus, the ostrich-like Ornithomimus and the more nimble Thescelosaurus. Among T. rex's carnivorous dinosaur competition, there was the dromaeosaur Acheroraptor, the large oviraptorosaur Anzu, and the troodontid Pectinodon.

Upper Cretaceous Hell Creek dinosaur census

Faunal distribution in the Hell Creek Formation.

While mammals were relatively rare in the area, Didelphodon was a relatively large one that lived alongside all of these dinosaurs. Because the environment was so tropical, Hell Creek would also have supported many animals that require a more warm environment such as crocodilians, turtles, and fish such as gar, sturgeon and even freshwater rays. Specimens of a freshwater mosasaur have also been described to have come from the same deposits as T. rex. Although it didn't live in Hell Creek itself, the gigantic sauropod Alamosaurus was contemporaneous with Tyrannosaurus and fossil evidence suggests that they would have even fed on these massive animals if given the opportunity, as bite marks and tyrannosaur teeth have been found with Alamosaurus bones. As top predator, it would have been T. rex's job to make sure the weak and sick individuals of these herbivores were taken out so the herd populations would be healthy and not overrun the entire ecosystem, so it would have acted as a keystone species.


A Tyrannosaurus brain

There would have been many deciduous and coniferous trees and made dense forests in Hell Creek. These large plants would have made good places for hiding from prey to ambush (as Tyrannosaurus was suspected to do) or rest in the shade on a hot day. It is believed that instead of four distinct seasons like in modern-day western North America, there would only have been a dry season and a rainy season similar to the African Savannah. The average temperature for Hell Creek would have been much warmer and wetter than the average climate in the same region today. Because the environment was a fluvial one, most fossil remains found have been disarticulated. Tyrannosaurus and its cohorts were among the last non-avian dinosaurs, as Hell Creek goes all the way to the Cretaceous-Paleogene boundary where it is believed an asteroid the size of Mt. Everest crashed into the Yucatan Peninsula and set off a chain of events that would ultimately end in the mass extinction.

Notable Specimens[]

Sue the Trex Barthdry

The "Sue" specimen, stored in the Field Museum of Natural History, Chicago

Sue (FMNH PR2081):[]

Perhaps the most famous and most complete T. rex specimen, Sue is also among the largest and was known to be 12.35 m (40 ft) long. It was found in the badlands of South Dakota in 1990 by Susan Hendrickson (who the animal was named after) and is over 90% complete. After years of legal disputes between the paleontologists who found the skeleton and the owner of the land it was found on, Sue sold for over $8 million to the Field Museum of Chicago and is now where it currently resides on display for the world to see. Along with being one of the largest and most complete T. rex specimens, Sue is also one of the oldest at 28 years of age. By now it was already showing signs of aging with arthritis being visible in the caudal (tail) vertebrae. Other pathologies found on Sue include healed rib fractures, healed infected broken leg bones, bites taken out of its vertebrae by other tyrannosaurs, and even a disease that caused unnatural holes to form in its jaw, which would have made eating incredibly painful and is believed to be the cause of its death. All of this indicates that even the most infamous predator in history would have struggled to survive.

Scotty (RSM P2523.8):[]


Reconstruction of Scotty by Dan Folkes

Scotty was discovered in Saskatchewan, Canada in 1991 by Robert Gebhardt. Phillip J. Currie and his team excavated the rest of the skeleton and started preparation in the Royal Saskatchewan Museum from there. Scotty was named after the bottle of scotch that was for celebration once the bones had been identified as belonging to T. rex. Once the matrix had been completely cleaned from the bones, analysis was able to be done on them and found that the skeleton was around 70% complete and likely belonged to a Tyrannosaurus that was bigger than any that had been seen before. Estimates put Scotty slightly outsizing Sue at 10-11 tonnes in weight, 12.4 m long and 3.9 m tall. Scotty is also significant for Canada because not only is it the biggest T. rex found from there, it's the biggest dinosaur found in the country period.

B-Rex (MOR 1125):[]

Tyrannosaurus Rex skeleton in Carnegie Museum of Natural History

T.rex skeleton in Carnegie Museum of Natural History

In 2000, experienced paleontologist Bob Harmon from Museum of the Rockies was digging in Charles M. Russell National Wildlife Refuge in Garfield County, Montana when he saw a bone sticking out of a steep cliffside. When it was found that the bones belonged to a Tyrannosaurus, it was nicknamed "Bob Rex" or "B-Rex" after the paleontologist who found her. Unfortunately, the fossil had to be split in order for it to be transported, however this allowed for some interesting discoveries to be made. Paleontologist Mary Schweitzer decided to take other opportunity of this situation and tried dissolving a piece of the fossilized bone in acid to see what would happen. As it turned out, when inspected under a microscope, Schweitzer found out that some of the fossils were elastic and resembled soft tissue such as blood vessels. This was the first sign of soft tissue in dinosaur fossils of any kind that had been found. Later on after further study, it was found that the soft tissue was actually medullary tissue, which is what is found in female birds that are about to lay eggs, indicating that B-Rex was female. This also was further indication of how closely T. rex, and by extension dinosaurs, were to birds. Interestingly, histology showed that B-Rex was only a subadult when she died, which suggested that T. rex didn't have to be skeletally mature to be sexually mature, and also that B-Rex was in the middle of laying eggs when she mysteriously died. Only about 37% of the skeleton was found (including nearly a complete skull), and what was found doesn't seem to indicate any injuries that would indicate how she passed away prematurely.

Tumblr n0qfz2yrRU1rp96zgo1 500

Tyrannosaurus as it appeared in Jurassic Park

In popular culture[]

  • Tyrannosaurus is the most famous of all prehistoric animals, ever since its description in 1905, it's been extremely popular, and it's almost always the first dinosaur that comes to mind when the word "Prehistoric Animal" or "Dinosaur" is mentioned, being one of the few dinosaurs where nearly everyone fully knows its full scientific name.
  • It is shown in nearly every single dinosaur movie. It was first depicted by Stop Motion Animation in the two short films The Ghost of Slumber Mountain and Monsters of the Past. The first full length dinosaur film that the Tyrannosaurus Rex had appeared in was the 1925 film The Lost World, where it battles an Agathaumas, T. rex appeared in the 1956 Film The Animal World where it fights a Triceratops then they see the Volcano erupted which brought the reign of the Dinosaurs to an end. Then T. rex appeared in the 1978 Film Planet of Dinosaurs where it was the Main antagonist through the entire Film, It also appeared In the 1985 Touchstone/Disney Production My Science Project, It was seen as a living Skeleton fighting a Mastodon Skeleton in the FullMoon film Doctor Mordrid, There was a baby T. rex named Elvis from the Prehysteria! (film series) films & the same Stop Motion studio that created Prehysteria T.rex recycled it for the first two part films of the six part film Josh Kirby... Time Warrior!.
  • Tyrannosaurus rex has arguably made its most iconic role in the movie Jurassic Park (1993) and all of its sequels such as The Lost World: Jurassic Park (1997), Jurassic Park III (2001), Jurassic World (2015), Jurassic World: Fallen Kingdom (2018), and Jurassic World: Dominion (2022) as well as both of the original novels by Michael Crichton. It has acted as a powerful carnivore that often saves the main protagonists (most notably near the end of the movie) and occasionally fights another carnivore that is typically portrayed as a villain (examples include Giganotosaurus and Indominus rex). The most notable Tyrannosaurus from the Jurassic series is Rexy, appearing since the first installment all the way to Dominion, with the only movies she wasn't featured in being The Lost World and Jurassic Park III. Other notable Tyrannosaurus characters are Buck, Doe, and a baby Tyrannosaurus all from The Lost World, and Bull, a younger adult from Jurassic Park 3 most popular for dying against the Spinosaurus. There are also two Tyrannosaurus recurring characters in the Netflix tie-in show Camp Cretaceous, a mother-daughter duo known as Big Eatie and Little Eatie.
  • It also starred in an episode of the renowned documentary series Walking with Dinosaurs where a female Tyrannosaurus tries her best to find a mate and reproduce, but dies at the end along with her two offspring after her leg is broken by an Ankylosaurus.
  • Tyrannosaurus rex appears in the Discovery channel show, Prehistoric: Denver where it battles Triceratops.
  • Tyrannosaurus rex appeared in the well-known documentary When Dinosaurs Roamed America, where a juvenile Tyrannosaurus and it’s four siblings are taught by their parents on how to hunt.
  • 56BC3307-4189-4E7C-BBAB-EE5087DF98FA
  • In the Magic School Bus episode The Busasaurus, based off the book of the same name, a Tyrannosaurus rex is the main antagonist.
  • Tyrannosaurus rex appears in the BBC series, Prehistoric Park where two youngsters that are brother and sister are named Terrence & Matilda.
  • Tyrannosaurus rex appears in the History Channel show, Jurassic Fight Club where in the second episode a pair of Tyrannosaurus rex parents go on a hunt, leaving their two juveniles unattended, but contained within a clearing marked with urine. A predatory Nanotyrannus is depicted using these scent trails to hunt, and attacks the Tyrannosaurus children, killing one. but before it can finish off the other one, the mother T.rex comes back and kills the Nanotyrannus in a rage. In the 11th episode, a Tyrannosaurus, attracted by the noise of a battle between a lone Edmontosaurus and a pack of Dromaeosaurus, takes the Edmontosaurus that was killed by the Dromaeosaurus, leaving them with just the tail.
  • Tyrannosaurus rex appears in the show Dino Dan, Dino Dan: Trek’s Adventures, and Dino Dana.
  • It also appeared in several other documentaries like Animal Armageddon, Dinosaurs Decoded, Truth About Killer Dinosaurs, T. rex: New Science, New Beast, Dino Gangs, Ultimate Guide: Tyrannosaurus rex, Clash of the Dinosaurs, and Last Day of the Dinosaurs.
  • Another documentary it's been in is Dinosaur Revolution, where episode 4, titled "Endgame" showed how a family of tyrannosaurs named Stumpy, Tinkerbelle & Junior lived until the K-Pg Extinction. Another individual, named Jack Palance, is the main antagonist of the episode, and engages in frequent territorial disputes with Stumpy. At around the start of the episode, Jack killed two of the pairs initial hatchlings while they were playing. Jack is eventually killed by impalement on a Triceratops carcass. Junior, the teenage individual, survives the initial asteroid impact, but he gets carried away chasing a mammal and falls off a small cliff, killing him. A Troodon later nests inside Junior's gaping mouth, keeping it alive in the cold.
  • Tyrannosaurus rex is the very first dinosaur to appear in BBC's Prehistoric Planet, in the first and third episodes. This animal is depicted with a light coat of elephant hair, lips, and is very bulky as is shown in fossil skeletons of Tyrannosaurus. Trace fossils left on seabeds are used to support the scene in episode 1 where a Tyrannosaurus father, nicknamed Hank, takes his group of children to an offshore island to scavenge a turtle carcass. One infant is killed by an unnamed mosasaur before the family reaches the island. In the third episode, a fully-grown, heavily scarred male kills a Triceratops off-screen, and rinses his wounds in river water. A smaller female appears, and after a quick display, the male and her mate in the cover of the surrounding forest.
  • Tyrannosaurus makes an appearance in the 2022 Animated Short, "The Last Tyrant," uploaded to YouTube by the creator Dead Sound. A mating pair of Tyrannosaurus is depicted with lips and keratinous crests above their eyes, but no fur or feathers of any kind. After the famous asteroid strikes, the male scavenges his mate, and notices a chick who has died while hatching out of its egg.
  • Multiple Tyrannosaurus appear in the 2019-2022 Television series Primal. One individual named Fang, is one of the show's protagonists, living alongside the human named Spear, the other main character. Fang is named due to the tusk-like tooth in the right side of her mouth on her lower jaw. Their adventures together began when Spear helped fend off three other unnamed theropods, who had killed and ate Fang's children. These other theropods have enlarged facial ornaments, so it is unclear if they are actually Tyrannosaurus. In the second season, Fang runs off with a male named Red, and eventually kills him after one too many close calls with Spear. In later Second Season, it Appears that Fang and Red we're mating before Red's Death. Later, Fang produce a three eggs, one was killed, and the other two were hatched: One with blue- colored body just like Fang with a red stripe on it's head, while the other Other One is a grey-colored body with teal-colored head and with the small horn on it's snout. At the end of Season 2, The same offspring has fully grown and they have a snaggletooth like their Mother, And Other one with red-colored face was ridden by Spear and Mira's Daughter
  • In the film 65, a Tyrannosaurus skeleton is seen. Later, there are two Tyrannosaurus that attack Mills and Koa, both being killed by the end of the film. This creature design makes the animal semi-quadrupedal.
  • Tyrannosaurus named T-Rex appears in the Disney show season 2 of Gigantosaurus, behaving as a show-off to the other predator.
  • Tyrannosaurus rex appearances in 2 episodes of the 4 part PBS documentary program The Dinosaurs! "Flesh on the Bones" & "The Death of the Dinosaurs".
  • It also appeared on 2 episodes of the Six part PBS NATURE Program Triumph of Life It was seen in the 1st episode & was seen as a skeleton ghost next to a pride of lions in the last episode.
  • It was the first creature to be featured in Jeff Corwin's Giant Monsters, where it briefly chased Jeff who in turn explained how it may have hunted or scavenged (possibly both) by studying turkey vultures.
  • A Tyrannosaurus named Heart serves as the main protagonist of the 2010 anime film You Are Umasou.
  • It served as antagonists in the books and TV show of Dinotopia.
    Tyrannosaurus new

    Dinosaur Island Tyrannosaurus

  • It also appeared in Jurassic: The Hunted Where It was encountered twice in the campaign, once in its respective mission "Tyrant Lizard King" and once more in "Enter: Spike", where it falls victim to the game's Spinosaurus antagonist.
  • A giant robotic "Tyrannosaurus Zord" is piloted by the red ranger in both the Mighty Morphin' Power Ranger series and the Dino Thunder series.
  • Tyrannosaurus is also the antagonist of nearly every episode of The Land Before Time.
  • It also starred in a Hollywood parody called T. rex: A Dinosaur in Hollywood, where they talk about how T. rex gained its fame throughout its discovery to modern-day movies.
  • It starred in the Disney movie Fantasia where it fought a Stegosaurus to the orchestra of "The Rite of Spring".
  • Tyrannosaurus rex was mentioned in the documentary series River Monsters on fish files.
  • T

    T.Rex in Animal Crossing New Horizons on the Nintendo Switch

    It was also a main source for evolution in many episodes of the History Channel show Evolve.
  • It also served as the main dinosaur in a documentary called Tyrannosaurus Sex, where they talked about how T. rex and other dinosaurs may have reproduced.
Tyrannasaurus Spitter

Tyrannosaurus from Walking with Dinosaurs

  • Tyrannosaurus was also an antagonist in the comedy show Land of the Lost, a Hannah-Barbera show Dink, the Little Dinosaur named Tyrannor and the Korean film Speckles: the Tarbosaurus, where it was named "One Eye" and killed the family of the main character "Speckles", a Tarbosaurus.
  • Jack Horner also talked about T. rex and why he believes it's mostly a scavenger in the documentary Valley of the T. rex, despite the theory already being disproven by then. The creature was depicted as a large lumbering animal reliant on carcasses, with Horner claiming it was too slow and weak to catch live prey.
  • T-Rex from Fossil Fighters
    Tyrannosaurus also appeared in five episodes of Planet Dinosaur, but it was only was shown in a database.
Tumblr nq609cj6zQ1rrgw5no3 540

Tyrannosaurus as it appeared in Jurassic World

  • T. rex is one of the main dinosaurs in the Dinosaur themed restaurant T.rex Cafe located in Disney World and Kansas City. It's mascot is also a T. rex named Dexter.
  • A T.rex nicknamed "Grumpy" by the characters appeared in the 2009 film Land of the Lost.
  • Tyrannosaurus rex is seen as The Disneyland train travels to the Primeval World diorama. In it, he is seen reenacting his battle from Fantasia.
  • In Walt Disney World's Epcot there was a ride known as Ellen's Energy Adventure where several dinosaurs could be seen that are similar to the ones during Fantasia's The Rite of Spring. Most notably, there was a large Tyrannosaurus attacking a Stegosaurus over a cliff.
  • At Disney's Animal Kingdom DINOLAND USA, there's a life sized statue of T. rex seen in Cretaceous Trail. Another statue of the head and neck is found near the entrance of the ride, DINOSAUR. At Downtown Disney's T.rex Cafe, there is a large Tyrannosaurus with his young.
Ice Age 3 Dawn of the Dinosaurs

Momzilla in Ice Age 3

  • A family of Tyrannosaurus (Momma Dino & her babies Egbert, Shelly and Yoko) appeared in the 2009 Blue sky studios film Ice Age: Dawn of the Dinosaurs as the protagonists and support characters.
  • Three Tyrannosaurus (Butch, Nash and Ramsey) appeared in the Disney/Pixar film The Good Dinosaur.
  • Tyrannosaurus made some appearances in Dino-Riders.
  • In blue's clues and you-Blue's Dino clues-a T. rex waitress and T. rex customer appear
  • In Histeria, Miss Information interviews two T. rexes
  • Tyrannosaurus makes in appearence in the 2014 movie "Dinosaur Island." While the Tyrannosaurus in this movie is somewhat anatomically accurate, it is coated in vibrant blue and red feathers with wattles around the eyes and throat.
  • A Tyrannosaurus rex and leader of the Tyrannos named Gangus Rex appears in various episodes of Dinosaucers, Gangus Rex devolves back into his ancestral appearance in only a couple episodes.
  • You are umasou

    Heart from you are umasou

    Tyrannosaurus made some appearances in Cadillacs & Dinosaurs. "Both Some Comic Books & a few episodes nicknamed a Shivet".

Tyrannosaurus and most others of its kind appeared in several episodes of Kong: The Animated Series. A couple made a cameo appearance in the movie Kong King of Atlantis & only One was seen on the other Film Kong Return to the Jungle.

Rage of the Dinobots

Grimlock with his crew

  • The Tyrannosaurus appeared in Dino Hunter: Deadly Shores in Region 1. It also has a Trophy Hunt variant named "Tyrannos", which appears to be a young, but wreckless Tyrannosaur.
  • A female Tyrannosaurus appeared in the Film Dino Time "Back To The Jurassic".
  • Grimlock of the Transformers franchise transforms into a robotic fire breathing T. rex.
  • A male Tyrannosaurus rex appears in the science fiction action adventure horror comedy film Raptor Ranch (known as The Dinosaur Experiment) where it fights a mated pair of Megalosaurus.
    Jurassic Mario

    Mario being chased by a Tyrannosaurus Rex

  • A Tyrannosaurus appears in the video game named Parasite Eve as an boss, in one of the cutscenes it is shown that the T.rex is reanimated by Eve's Neo mitochondrial powers.
  • Tyrannosaurus rex also appears in the mobile game Jurassic World Alive as an Epic dinosaur, and is a vital ingredient for the Indominus Rex.
  • Tyrannosaurus rex made an appearance in the ROBLOX game called "Dinosaur Simulator" where it is given as a free dinosaur.
  • Tyrannosaurus rex appeared in a Nintendo Switch game named "Super Mario Odyssey", where it is portrayed as a large enemy. Mario can use the ability of his friend, Cappy, to control this Tyrannosaurus. It appears in 3 separate worlds in the game, being Fossil Falls, Deep Woods, and New Donk City.
  • Tyrannosaurus appeared in the 2018 Roblox game Dinosaur World Mobile as a gamepass creature.
  • Tyrannosaurus rex appeared in Granblue Fantasy as Unite and Fight January 2021 raid boss.
  • Tyrannosaurus rex appeared in the 2000 mockbuster film Dinosaur Adventure.
  • It will appear in the upcoming video game Saurian as a playable dinosaur.
  • Tyrannosaurus ex appeared in Jurassic Benny.
  • Tyrannosaurus appeared in the game, Plants VS Zombies 2, donning a green and purple-striped color pattern and acting like a dog. By roaring loud, it scares all zombies in its lane and increases their speed.
  • Tyrannosaurus rex appears in Prehistoric Kingdom. Tarbosaurus, a close relative of Tyrannosaurus, is one of the Tyrannosaurus's skins.
  • Clash of the Dinosaurs.
  • T. rex: New Science, New Beast.
  • Dino Gangs
  • Ultimate Guide: Tyrannosaurus rex
  • T. rex: A Dinosaur in Hollywood
  • Evolve
  • T. rex: Warrior or Wimp?
  • Dinosaur 13, a documentary on how Sue was found.
  • Jurassic Benny
  • The Complete Guide To Prehistoric life; by Tim Haines and Paul Chambers
  • Ultimate Book of Dinosaurs; by Paul Dowswell, John Malam, Paul Mason, Steve Parker
  • Dino Wars; by Jinny Johnson, consulted by Michael J. Benton
  • The Marshall Children's Dinosaur Encyclopedia, consulted by Michael J. Benton
  • Vertebrate Paleontology; by Michael J. Benton
  • How do We Know Dinosaurs Existed; by Mike Benton
  • The Audubon Society Pocket Guides Familiar Dinosaurs; by Alfred A. Knopf
  • Uncover T. rex; by Dennis Schaz
  • The Dinosaur Heresies; by Robert T. Bakker
  • Life-Sized Dinosaurs; David Bergen
  • Rise and Fall of the Dinosaur; Joseph Wallace
  • Tyrannosaurus Sue; Steve Fi


Other Wikis[]


  1. https://link.springer.com/article/10.1007/s11692-022-09561-5
  2. https://www.theguardian.com/science/2022/mar/01/tyrannosaurus-rex-may-have-been-three-species-scientists-say
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5493735/
  4. https://www.businessinsider.com/T.rex-discoveries-hunted-walked-growth-2021-4?amp
  5. https://phys.org/news/2017-07-tyrannosaurus-rex-couldnt.html
  6. https://www.livescience.com/T.rex-slow-walker-tail.html
  7. https://www.sciencetimes.com/articles/30805/20210422/could-you-outrun-a-T.rex-dinosaur-heres-what-experts-say.htm
  8. https://www.news18.com/news/buzz/on-your-mark-humans-can-probably-outwalk-a-tyrannosaurus-rex-reveals-study-3663092.html
  9. https://www.forbes.com/sites/davidbressan/2021/04/23/tyrannosaurus-rex-was-not-a-fast-runner-more-a-slow-walker-simulation-shows/?sh=113d28bf64be
  10. https://nautil.us/issue/102/hidden-truths/T.rex-was-a-slacker-rp
  11. https://www.nationalgeographic.com/science/article/did-tyrannosaurs-live-in-groups-experts-discuss-new-fossil-clues
  12. http://www.sci-news.com/paleontology/social-tyrannosaurs-09576.html
  13. https://www.newscientist.com/article/2275060-tyrannosaurs-may-have-hunted-together-in-packs-like-wolves/
  14. https://gizmodo.com/2-5-billion-T.rex-may-have-roamed-earth-1846691923?utm_medium=sharefromsite&utm_source=gizmodo_twitter
  15. https://wbng.com/2021/04/15/study-about-2-5-billion-T.rex-roamed-earth-but-not-at-once/
  16. https://abcnews.go.com/Technology/wireStory/study-25-billion-rex-roamed-earth-77098450
  17. https://phys.org/news/2021-08-rex-jaw-sensors-fearsome-predator.html
  18. https://www.dailymail.co.uk/sciencetech/article-9919241/Fossils-T-rex-complex-nerve-sensors-tips-jaws-study-finds.html
  19. https://www.sciencedaily.com/releases/2021/08/210824083443.htm
  20. http://www.sci-news.com/paleontology/tyrannosaurus-rexs-jaw-tactile-sensor-09986.html
  21. https://scitechdaily.com/t-rexs-huge-jaw-had-nerve-sensors-to-make-it-an-even-more-fearsome-predator/
  22. https://www.labmanager.com/news/-em-t-rex-em-s-jaw-had-sensors-to-make-it-an-even-more-fearsome-predator-26592
  23. https://www.independent.co.uk/news/science/t-rex-jaw-tyrannosaurus-bite-b1907673.html
  24. https://link.springer.com/article/10.1007/s11692-022-09561-5
  25. https://www.theguardian.com/science/2022/mar/01/tyrannosaurus-rex-may-have-been-three-species-scientists-say
  26. https://www.newscientist.com/article/2308160-tyrannosaurus-rex-may-actually-be-three-separate-species/
  27. https://www.reuters.com/business/environment/scientists-propose-tyrannosaurus-had-three-species-not-just-rex-2022-03-01/
  28. https://edition.cnn.com/2022/02/28/world/t-rex-three-different-dinosaurs-scn/index.html
  29. https://www.dw.com/en/scientists-find-tyrannosaurus-had-two-more-species-other-than-rex/a-60954222
  30. https://newatlas.com/biology/tyrannosaurus-rex-three-species/
  31. https://www.dailymail.co.uk/sciencetech/article-10560927/T-Rex-actually-THREE-species-fossil-analysis-reveals.html
  32. https://www.earth.com/news/were-there-three-distinct-species-of-tyrannosaurus-rex/
  33. https://www.nytimes.com/2022/02/28/science/tyrannosaurus-rex-species.html
  34. https://www.nationalgeographic.com/science/article/call-to-split-tyrannosaurus-rex-into-3-species-sparks-fierce-debate
  35. https://www.nhm.ac.uk/discover/news/2022/march/controversial-paper-suggests-there-are-three-tyrannosaurus-species.html