Yet, in the last 25,000,000 years, the dinosaurs' most infamous predator has appeared. The meanest and scariest of them all. The most terrifying predator that has ever walked the Earth - Tyrannosaurus rex, the ultimate predator, the most notorious flesh-eater ever known, a 7 ton, 15-meter long carnivore, specifically and perfectly evolved to kill and eat even other giant dinosaurs.
— Allen Johnson, about Tyrannosaurus Rex
in Fall of a Kingdom II: Return of the King

Tyrannosaurus (name meaning "Tyrant Lizard"), often referred to as its full name Tyrannosaurus rex or commonly abbreviated simply to T. rex for short, is a genus of tyrannosaurid theropod dinosaur that originated during the Middle Cretaceous period in what is now North America. A large, territorial, and powerful bipedal carnivorous dinosaur that measured 15 meters long, stood 6 meters tall, and weighed roughly around 18 tons, Tyrannosaurus was the largest terrestrial carnivore of all time, dwarfing other predatory dinosaurs and was also the largest of the tyrannosaur family of dinosaurs. The undisputed "King of the Dinosaurs", Tyrannosaurus is arguably the world's most famous and popular dinosaur ever to live on Planet Earth, known for its cultural impact amongst prehistoric creatures, let alone, dinosaurs.

In the Series 2 finale "Fall of a Kingdom Part II: The Return of the King", a family of Tyrannosaurus were brought back to the park from prehistoric Montana of 65 million years ago. Having chased the team around the landscape several times, the pair and their chicks currently reside in the Tyrannosaur Alpine region of the park. They hold the mantle of being perhaps the park's most iconic prehistoric animal. The female Tyrannosaurus named Sue is the leader of her pack.


Era & Discovery

Perhaps the most well-known dinosaur in the world and the undisputed king of the dinosaurs, Tyrannosaurus rex first appeared in North America during the Middle Cretaceous period and lived up until the very end of the Late Cretaceous period around 90 – 65 million years ago, living alongside dinosaurs and other creatures like Ornithomimus, Dromaeosaurus, TroodonDeinosuchus, QuetzalcoatlusPteranodon, Nyctosaurus, DidelphodonDinilysia, Edmontosaurus, Triceratops, Parasaurolophus, Torosaurus, Ankylosaurus, Pachycephalosaurus, and Thescelosaurus. Ruling the Earth for 25 million years as the apex predator of the world, it died out with all the other dinosaurs and other prehistoric creatures at the end of the Cretaceous Period. It was among the last dinosaurs to exist prior to the Cretaceous-Tertiary extinction event.

Henry Fairfield Osborn, president of the American Museum of Natural History, discovered Tyrannosaurus rex by Arthur Lakes near Golden, Colorado in 1874 and named the dinosaur in 1905. Since their first discovery, more than 50 specimens of Tyrannosaurus rex have been identified, some of which are nearly complete skeletons, which has allowed significant research into many aspects of its biology, including its life history and biomechanics. Over the years since they were first discovered, Tyrannosaurus rex has been regarded as the best known and most famous of all prehistoric creatures, let alone dinosaurs, in the world.

Physical Attributes

WWD Tyrannosaurus
The largest member of the tyrannosaur family of dinosaurs, Tyrannosaurus rex was among one of the largest, if not, the largest theropod dinosaur ever to walk the Earth, reaching various large sizes. On average, a fully grown individual Tyrannosaurus weighed up to 7 – 14 tons (15,000 – 30,000 lbs.), stood approximately 12 – 18 feet (3.7 – 5.6 m) tall, and measured over 40 – 47 feet (12.3 – 14.5 m) in length, rivaling the sizes of the earlier Giganotosaurus from South America as well as the Spinosaurus and Carcharodontosaurus of North Africa. However, the largest Tyrannosaurus ever discovered weighed in at up to a staggering 18 tons (39,000 lbs), grew up to reach a height of 20 feet (6.2 m) tall at the hips, and reached a staggering measurement of 50 feet (15.3 m) in length from its snout to the tip of its tail, therefore making Tyrannosaurus larger than any other theropod dinosaur as well as arguably the largest terrestrial carnivore of all time. Tyrannosaurus rex was a deadly predator a massive, 5 foot (1.52 m) long skull that had a standard tyrannosaur build: small two-fingered and clawed forearms; a strong, muscular body balanced by a long, heavy tail; two, very large, strong, and powerful legs; and a large and powerful head with banana-sized teeth.

Tyrannosaurus rex was the dinosaurs most infamous and ultimate predator that appeared in the last 25,000,000 years of the Cretaceous Period. They were giant carnivorous dinosaurs that stalked the landscape and, being the most notorious flesh-eaters ever known, they were specifically and perfectly evolved to kill and eat even other giant dinosaurs, even ones larger than T. rex itself. The brain of Tyrannosaurus rex was well developed, which gave it excellent senses sight (comparable to that of a bird of prey), great hearing, and advanced olfactories that allowed Tyrannosaurus to efficiently smell prey from over four miles away.

Like their smaller cousin, Albertosaurus, T. rex was a very hard dinosaur to outrun. Despite their immense size and heavy-weight, T. rex were relatively fast and agile dinosaurs and could break into surprising bursts of speed, often achieving speeds of over 25 – 35 (40 – 56 km/h), even reaching 45 mph (72 km/h) if they needed to, thanks to some of its bones being hollow, and were also capable of catching fast-moving prey including Ornithomimus and Edmontosaurus as well as tackling large and sturdy dinosaurs like Triceratops. Relative to the large and powerful hind limbs, Tyrannosaurus forelimbs were small and retained only two digits. Recent specimens have shown the tiny arms to have been well-muscled, presumably to enable the animal to anchor itself to the ground as it attempted to straighten its hind legs and stand up from a prone position.

Additionally, T. rex also had another advantage over other carnivorous dinosaurs of a similar size: its bite. It has been discovered that Tyrannosaurus rex also possessed a biological weapon. Its bite could cause infections and diseases like septicemia, therefore their bites induced a vast amount of bacteria onto its victims, much like that of a Komodo dragon. The primary weapon of a Tyrannosaurus was their mouth. Their arms were rather small so they could carry a massive jaw and remain balanced on their legs. 

The heavily reinforced skull of T.rex suggests that it was a devastating predator, with bone-crushing bite strength. T. rex had massive mussels in their jaws that gave them a bite force of 4 – 6.5 tons (8,000 – 14,000 lbf), over 10 times more powerful than that of a lion's bite force, therefore making it among the strongest bite force in the animal kingdom. Its jaws alone were 1.2 meters long and 1 meter wide filled with 50 sharp, serrated bone-crushing teeth that were like thick pegs, larger than a human hand, some being close to 13 inches (150mm) in length (with the root included) that could go through most prey, including their bones. The teeth were used to grip prey, breaking bones, puncturing arteries, and rupturing many organs. Tyrannosaurus could have also had toxic spit that it used to bring down animals. These jaws could crush bone and tear off up to 70 kilograms of meat in a single bite at a time. This could be very dangerous, though, as it could potentially choke to death. It had jaws strong enough to crush even the armor of an Ankylosaurus.

Capabilities and Weaponry

  • Raw Strength: In addition to being physically a tremendously strong dinosaur, T. rex could lift over 5 tons with its powerful jaws. They could charge their own body weight against their enemies, ramming them like a freight train.
    • Jaw Strength: Having the bite force of 8,000–14,000 pounds PSI, the teeth and jaws of T. rex are perfectly designed to crush armor and bone.
  • Speed: Despite their giant size, T. rex was considerably fast, able to reach speeds in excess of 25–35 mph (40–56 km/h) by using their long, powerful, and muscular legs. However, if they were hungry or determined enough, they can also reach speeds as fast as 45 mph (72 km/h) if they ever needed to.
  • Agility: In addition to their relatively quick speed, T. rex is quite agile for their size, able to make sharp turns within a couple of seconds.
  • Senses: T. rex relies strongly on its powerful sense of smell and hearing to find prey. They have also had powerful binocular eyesight, comparable to that of a bird of prey.
  • Bacterial Bite: In addition to their remarkably powerful jaws and bone-crushing teeth, T. rex, much like the Komodo dragon, was said to have a mouth full of diseases that could kill its victims.
  • Intelligent: T. rex is said to be as smart as a hawk, if not smarter, and to have the brain size of a gorillas brain. Knowing of their large size, packs of smaller predators will leave the baby rexes alone. The cerebrum of T. rex was larger than most dinosaurs, indicating that they were able to think through things more efficiently, identical to raptors.
  • Roar: The roar of a Tyrannosaurus rex can be heard over 7 miles away while being rooted.
  • Hunting: T. rex can hunt by themselves or in a family group and occasionally scavenge.
  • Combat Abilities: Mostly, T. rex used their powerful jaws to bite its enemy or prey. It can also use its long powerful legs to kick and their large tail to whip as well if the enemy is near the tail. T. rex's head can be useful as a headbutt. They can even use their own body charge at its enemies, like a 7-ton battering ram.
  • Durability and Stamina: T.rex, large size and fully grown, are able to take many blows from other dinosaurs that are able to still fight back because of their tough skin.

Behavior & Traits

Wwd trex2

Tyrannosaurus pair

Like many predatory dinosaurs, even ones of their immense size (though it has been shown to be a solitary hunter), Tyrannosaurus rex often traveled and hunted in packs, ranging from pairs to a small group of several individuals, including juveniles and even hatchlings. Tyrannosaurus was also a generalist hypercarnivore with no real preferences: its prey consisted of the many herbivores in the area, including ankylosaurs, ceratopsians, pachycephalosaurs, ornithopods, as well as its favorite prey the hadrosaurs, and even the mighty sauropods. Tyrannosaurus hunted its prey using stealth and cunning surprising for such a large animal. Once it locked its sights on a prey item, Tyrannosaurus pursued its victim swiftly and silently despite its large size, with little chance of escape. T. rex was so deadly that its very presence could be disturbing to some smaller animals, who would go into a state of complete silence when the predator was nearby.

Though Tyrannosaurus had enormous territories of hundreds of square kilometers, some T. rex packs usually made their dens in mountain or alpine regions, which is typically full of bones from various dead animals scattered all over. Like modern birds and lions, T. rex brought food back to their territory to avoid potential fights from rivals. In the home of a T. rex, the juveniles (be it hatchlings or adolescents) often fought over the scraps of food.

Though T. rex itself had no predators, the unborn would fall victim to air pollution from nearby volcanoes that prevented their eggshells from forming correctly and nest raiders, like Dromaeosaurus and the mammal Didelphodon. There were no known predators of Tyrannosaurus. However, whilst they were wary of dinosaurs like the armored Ankylosaurus, the only dinosaurs T. rex was truly afraid of was another, larger individual of their own species who were willing to commit cannibalism. Like all reptiles, T. rex, at times, were cannibalistic, eating not only their own kind but hatchlings as well, given the chance. Tyrannosaurus was also very aggressive and territorial, with the females being the largest and most aggressive.

Mating Tyrannosaurus
When it came to mating, females would attract males by emitting loud calls, broadcasting the noise even for weeks for a male. The males responded to these calls by giving the female an animal carcass as a gift to appease her rather than to satisfy their own hunger. Sometimes, the male would have too call the female on certain occasions when he had a kill for her. When the females arrived at those males, they did seem weary at first. If she liked the gift, she would be submissive to the male. The two would then proceed to have a mating period that would last three days with the male being beside his mate at all times to prevent any other male Tyrannosaurus rex from mating with her. Afterward, the female Tyrannosaurus would lay her eggs in a mound-shaped nest, much like modern crocodilians.

Tyrannosaurus females were capable of laying a maximum of 12 eggs, but normally only got one to three chicks at most and rarely more than that, mostly because other eggs are taken by scavengers. Tyrannosaurus eggs were the size of a mango and bird-like. During the incubation period, the Tyrannosaurus mother would camouflage and guard their nests to prevent any nest raiders, such as little Cretaceous mammals, Dromaeosaurus, and Ornithomimus, from eating their eggs, even to the point of denying themselves food or water for two months just to make sure their nest was protected.


Female T. rex with babies

After their young were born, Tyrannosaurus mothers would end their fasting period and would give the juveniles any remains left from their kills. Tyrannosaurus females were highly protective of their offspring and would find food for them, even at the cost of her own life. The young were able to get their mother's attention by chirping. If a juvenile was in any danger, it would call out to its mother for help. Therefore, she would fight off even other members of her species in order to protect her young, even if she was wounded. The mother would still protect her chicks even if it killed her in the process. And the more an adult female T. rex protected her offspring, the better chances they had at survival.

Tyrannosaurus siblings were extremely hostile towards each other. When juveniles, siblings would commonly play-fight. However, when growing from sub-adult to adult, siblings would become extremely aggressive and would often fight. It was common for siblings to kill each other. Despite this, the parents would break up those fights if they got too violent.

Prehistoric Earth: A Natural History

Series 2

Fall of a Kingdom

At the end of the episode, a single Tyrannosaurus, Sue, is briefly seen over-looking the team as they finish their mission rescuing Tylosaurus, watching them from a distance, and then lets out a loud roar.

Allen and Rebecca spot a lone male T. rex and the two follow it to a volcanic-gas area where it picks up the body of a small dead dinosaur. They try to follow it again as it leaves the volcanic area, but it disappears into the woods.

Pending...more later.

Journal Entry

The most feared, most terrifying, and most infamous dinosaur in the world, Tyrannosaurus rex, "Tyrant Lizard King" (or T. rex for short), roamed North America during the Late Cretaceous period as the King of the Dinosaurs, ruling at the top of the primeval food chain. Tyrannosaurus rex is probably the most familiar dinosaur in history and, too many, it represents the ultimate evolution in predator physiology. Weighing more than 18,000 kilograms, growing up to stand 20 feet tall, and reaching a measurement of 50 feet long, Tyrannosaurus was the largest theropod dinosaur and terrestrial carnivore that has ever walked the Earth.

Known for its massive head with what is among the strongest bites ever to have existed, Tyrannosaurus was equipped with extraordinarily powerful and massive jaws, bearing around 50 serrated teeth (some of which were 13 inches long) and a bite force strong enough to crush bone. Arguably the most powerful terrestrial carnivore of all time, Tyrannosaurus possesses tremendous physical strength that allowed them to lift creatures heavier than 5 tons with only their mouth. In addition to their bone-crushing bite, tremendous strength, and powerful jaws, Tyrannosaurus has a bacterial bite, not unlike that of a modern-day Komodo Dragon, which can end the life of anything these predatory dinosaurs bite.

Despite their two-fingered arms being small for their overall body size, it has been discovered that T. rex's arms were actually quite functional. For example, if a T. rex had fallen over, they were able to use their arms to get back up. Additionally, they were able to use their arms to even pick up anything that weighed around 500 pounds. Surprisingly, these carnivorous dinosaurs were relatively fast and agile for creatures of their size, reaching speeds in excess of 35 miles per hour. Armed with great muscular prowess, Tyrannosaurus also had powerful senses of sight, smell, and touch. For instance, when hunting a large animal alone and anytime the animal made a footstep, Tyrannosaurus would feel the tremor through the pads of its feet, using that to zero in on its target. Their sight and intelligence was comparable to that of a bird of prey.

While they are incredibly large, massively powerful, and utterly terrifying, these carnivores also happen to exist, hunt, and travel in packs of up to several individuals, including juveniles, who often fought over scraps of food. Additionally, female Tyrannosaurus also cared for their young. Like modern birds do for their babies, female Tyrannosaurus would leave the nesting area and go out for a kill. Whenever they finished eating, they would bring food back to their territory and feed their young. When hunting in a pack, the Tyrannosaurus would chase their prey, running through the herds, find the weakest and oldest members of the herd, and bring that member to the other pack members.

With a mouth large enough to swallow a grown man whole, jaws powerful enough to crush bone, and feet large enough to crush anything underfoot, this is seven tons of 50 feet, ground-shaking hell on Earth. There are few dinosaurs that can overcome Tyrannosaurus rex in combat. When it comes to Prehistoric Earth, it's good to be the king. This magnificent animal has long been at the heart of prehistoric attractions.

— Allen, in his Journal, about Tyrannosaurus rex



  • Tyrannosaurus rex is the last, largest and strongest theropod dinosaur, as well as terrestrial carnivore, ever brought to the park.
    • Tyrannosaurus rex was the last and largest tyrannosaur brought to the park.
    • Tyrannosaurus rex is the most famous dinosaur of all time.
    • Tyrannosaurus rex was the last dinosaur brought to the park. Additionally, it was also the last creature of the Mesozoic Era brought to the park.
  • Measuring 15 m (50 ft) long, the Tyrannosaurus rex featured in the series is larger than Scotty, the largest known Tyrannosaurus specimen whom measures at 13 m (43 ft) long.
  • Despite their minuscule arms, Tyrannosaurus were excellent swimmers.
  • Additionally, despite their small arms, T. rex could lift 400 pounds in real life.
  • They are depicted as featherless. In reality, adults may have had feathers and chicks almost certainly possessed them.
  • The sound effects of Tyrannosaurus rex are that of crocodile, elephant, lion, and tiger sound effects. They also produce the dinosaur roars used in The Last Dinosaur as well as some of the sound effects used for Godzilla.
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