Yet, in the last 25,000,000 years, the dinosaurs most infamous predator has appeared. The meanest ans 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 rex (ty-ran-o-saw-us rex; name meaning "Tyrant Lizard King"), or commonly abbreviated to T. rex for short, is a genus of large carnivorous coelurosaurian theropod tyrannosaurid dinosaur that originated during the Middle to Late Cretaceous period up until the extinction of the non-avian dinosaurs in what is now North America. Among the last of the dinosaurs, Tyrannosaurus rex is also among the most well-known and most feared predator ever to live on Planet Earth.

Additionally, it was the largest terrestrial carnivore of all time, being 15 meters long at maximum, standing 6 meters tall, and weighing more than roughly 7.5 tons in weight. Tooth sizes ranged from 15 cm in any given individual, with the smallest 2 cm teeth performing their role, and the largest 17 cm teeth interestingly acting as a battery of sabre teeth - many pairs mind putting Sabre Toothed Cats to shame. They are serrated on the edges, and designed for crushing bone. Bone is found in fossil coprolites from Tyrannosaurus, as fragments.

It is the most famous and popular of all prehistoric creatures, known for its cultural impact, even much more so than Smilodon, Apatosaurus, and even the Woolly Mammoth. It is also called the King of the Dinosaurs. T.rex is among the largest land predator ever, larger, heavier, and even stronger than the theropod Giganotosaurus of South America as well as the carnivores Spinosaurus and Carcharadontosaurus of Northern Africa.

Tyrannosaurus rex was the apex predator of North America in the last days of the dinosaurs, preying on animals such as ornithopods, ornithomimids, pachycephalosaurs, ankylosaurs, ceratopsians, hadrosaurs, and even the large sauropod dinosaurs. Tyrannosaurus was also the largest of the tyrannosaur family of dinosaurs, a family which also included Albertosaurus, Gorgosaurus, and Tarbosaurus.


Era & DiscoveryEdit

Tyrannosaurus rex first appeared in North America during the Middle Cretaceous Period around 90 million years ago and lived up until the very end of the Late Cretaceous Period 65 million years ago, ruling planet 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 and lived alongside dinosaurs and other creatures like Albertosaurus, Ornithomimus, Dromaeosaurus, Troodon, Deinosuchus, QuetzalcoatlusPteranodon, Nyctosaurus, DidelphodonDinilysia, Edmontosaurus, Triceratops, Parasaurolophus, Torosaurus, Ankylosaurus, Pachyrhinosaurus, Pachycepholosaurus, and Parksosaurus. 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.

Physical AttributesEdit

WWD Tyrannosaurus

Tyrannosaurus rex was among the largest, if not, the largest terrestrial carnivore of all time, with a fully grown Tyrannosaurus, on average, weighing of 5–7 tons (10,000–14,000 lbs.), reaching a height of 15–18.5 feet (4.5–5.6 m) tall, and measuring approximately of 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 Carcharadontosaurus of North Africa. However, the largest Tyrannosaurus ever discovered weighed in at up to a staggering 7.5 tons (15,000 lbs.), grew up to stand 20 feet (6.1 m) tall, and reached a staggering measurement of 50 feet (15.3 m) in length, therefore making Tyrannosaurus larger than those other carnivorous dinosaurs.

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. Its body was strong and muscular with a long, heavy tail, two very large and strong legs and two tiny, two-clawed forearms.

Despite their heavy-weight, T. rex were relatively fast and agile dinosaurs, reaching speeds as fast as over 25–45 mph 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. Its brain was well developed, which gave it excellent senses including eyes like that of a hawk, great hearing, and advanced olfactories that allowed Tyrannosaurus to efficiently smell prey. 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 also been discovered that Tyrannosaurus rex possessed a biological weapon. Much like the Komodo dragon, T. rex bites could cause infections and diseases like septicemia, therefore their bites induced a vast amount of bacteria onto its victims. 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. 

Tyrannosaurus rex was a deadly predator with a massive, 1.5 meters (5ft) long skull and a strong, muscular body that was balanced by a long, heavy tail, two very large and strong legs and two tiny, two-clawed forearms. 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 that was 4 tons of pressure, 10 times more powerful than that of a lion's bite force. Its jaws alone were 1.2 meters long and 1 meter wide filled with 150mm long, sharp, serrated bone-crushing teeth that were like thick pegs, larger than a human hand, some being close to 13 inches long (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.

Behavior & TraitsEdit

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 often traveled and hunted in packs, ranging from pairs to a small group of around several individuals, including juveniles and even hatchlings. Tyrannosaurus was also a hypercarnivore. Its prey consisted of the many herbivores in the area, including ceratopsians, hadrosaurs, pachycephalosaurs, ornithopods, and even 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. Tyrannosaurus had enormous territories of hundreds of square kilometers. In a home of T. rex, there were bones of various dead animals scattered all over. Like modern birds and lions, T. rex brought food back to their territory and the juveniles often fought over scraps of food.

It had no predators, but the unborn would fall victim to air pollution from nearby volcanoes that prevented their egg shells from forming correctly and nest raiders, like Dromaeosaurus and the mammal Didelphodon. There were no known predators of Tyrannosaurus, however, the only dinosaurs T. rex feared were the armored Ankylosaurus and other, larger individuals of their own species who were willing to commit cannibalism. But like all reptiles, T. rex were at times 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, even calling 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 to call to the female on certain occasions when he had a kill for her. When the females arrived to 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 detour the male and would lay her eggs in a mound shaped nest, much like modern crocodilians.
Fighting Tyrannosaurus

Female T-Rex scaring off her mate

Tyrannosaurus females could have laid 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 are believed to have been the size of a mango and were 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 rex mothers would end their fasting period and would give the juveniles any remains left from their kills. The mother would still protect her chicks even if it killed her in the process. The young were able to to get their mother's attention by chirping. Female Tyrannosaurus were also highly protective of their offspring and would find food for them, even at the cost of her own life. 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. 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 sub-adult to adult, siblings would become extremely aggressive and would often fight. It was common for siblings to kill the other.

Prehistoric Earth: A Natural HistoryEdit

Series 2Edit

Fall of a KingdomEdit

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 letting out a loud roar.


Journal EntryEdit

The most fierce, most terrifying, and most infamous predatory dinosaur of them all that has ever walked the Earth, Tyrannosaurus rex, "Tyrant Lizard King" (or T. rex for short), stalked the landscapes of the Cretaceous Era, as the King of the Dinosaurs and ruling at the top of the food chain. These monsters were the most notorious predators ever known; weighing more than 6800 kilograms, growing to 20 ft. tall, and measuring 50 ft. long, Tyrannosaurus was the largest carnivorous dinosaur that has ever walked the planet.

It appears the Tyrannosaurus possessed extraordinarily powerful jaws with serrated teeth, some of which were 12 inches, that can crush straight through the bone of almost any other creature. Arguably the most powerful terrestrial carnivore of all time, Tyrannosaurus possess 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 also relatively fast for creatures of their size, running as fast as 35 miles per hour.

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 scrapes of food. Additionally, female Tyrannosaurus also cared for their young. Like modern birds do for their babies, female Tyrannosaurus would leave the nesting era and go out for a kill. Whenever they would finish eating, they would bring food back to their territory and feed their young.

— Allen, in his Journal, about Tyrannosaurus rex