Walking With Wikis
Yet in the last 2,000,000 years, the Dinosaurs most infamous predator has appeared- Tyrannosaurus, a 5 ton, 13 meter long carnivore, specifically evolved to kill other giant dinosaurs.

Kenneth Branagh (Narrator)
Death of a Dynasty


Tyrannosaurus was a large theropod dinosaur, and was one of the last dinosaurs before the KT extinction event.

Creature attributes

Physical appearance and biology

Tyrannosaurus rex was among the largest terrestrial carnivores of all time, with a weight of 5–10 tons, a height of 4.5–6 meters (15–20 feet) and a length of about 12–15 meters (40–50 feet).[1] [2] This barely reached the length of the earlier Giganotosaurus from South America. However, it was very much as heavy, if not more so, due to its robust and muscular build, therefore making it stronger. [3][1] Additionally, T. rex had another advantage over Giganotosaurus: its bite. With a bite force of 4–6.5 tons, T. rex had among the strongest bite force in the animal kingdom.

Its jaws alone were 1.2 meters long and 1 meter wide filled with teeth larger than a human hand. It could bite down with a force of 35,000 newtons at the front of it’s jaw, and 57,000 at the back. The teeth were used to grip prey, breaking bones, puncturing arteries, and rupturing many organs. Tyrannosaurus was unable to chew its food, so it had to swallow food whole, gulping 70kg (154 lb) of meat at a time. This could be very dangerous, though, as it could potentially choke to death.[1]

Also, Tyrannosaurus females could lay a maximum of 12 eggs.[2]

Behavior and traits

Tyrannosaurus was the apex predator of North America during the last days of the Late Cretaceous. It preyed on many of the herbivores in the area including Anatotitan, Triceratops, and Torosaurus. 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. The only dinosaurs T. rex feared were the armored Ankylosaurus and other individuals that belonged to its own genus who were willing to commit cannibalism. Tyrannosaurus was also very aggressive and territorial with the females being the most aggressive.[2][1][4]

Females would attract males by emitting loud calls, even calling for weeks for a male. The male respond to these calls by giving the female an animal carcass as a gift to appease her.[2][4] Sometimes the male would have to call to the female on certain occasions when he had a kill for her.[4] If she liked the gift, the two would 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.[2][4]

During the incubation period, the Tyrannosaurus mother would guard their nests to prevent any nest raiders from eating their eggs, even to the point of denying themselves food just to make sure their nest was protected. But 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. After about 3 months of care, she would either detour them from her care or consume them.[2]

Classification and ancestry

Tyrannosaurus rex was closely related to the similar looking Tarbosaurus that roamed Mongolia.[5] These similarities were so prevalent that it is still debated as to whether Tarbosaurus is really a species of Tyrannosaurus.

In Walking with Dinosaurs

A Tyrannosaurus is seen roaring at the end of the show's introduction.

New Blood

During the introduction to the series when a glimpse of the cretaceous is shown, the mother Tyrannosaurus can be seen scaring off the male as the narrator describes the dinosaur.

Death of a Dynasty

A female Tyrannosaurus, (The episode's focus) defends her nest one last time from a Didelphodon, before abandoning it because the embryos within the eggs have succumbed to the volcanic atmosphere. She then begins to make mating calls to attract any males in the area so she can start a new clutch of eggs, leaving her old nest to scavengers.

Elsewhere, a male Tyrannosaurus scavenges the carcasses of dead animals that were killed by carbon monoxide released into the atmosphere by volcanic vents in the area. He nearly falls victim to the poisonous gasses being released into the atmosphere, but he manages to snatch a theropod carcass because his height keeps him above the layer of the carbon monoxide. Another male, possibly the same male who was scavenging, responds to the female Tyrannosaurus' calls by killing a Triceratops for her. She likes her gift and the two initiate the mating period.

After mating, the female Tyrannosaurus scares off the male before she lays her eggs. While guarding her nest, she successfully detours a Dromaeosaurus who could have potentially eaten her eggs. Only 3 eggs hatched in the mother Tyrannosaurus clutch of 12. When her chicks were a month old the female T. rex killed an Anatotitan at a river. She gave her young a leftover piece of her kill as food for them.


While the juvenile Tyrannosaurus rex were eating, two of them abused their sibling severely. This chick disappears two days later, possibly having been killed by its older and more successful siblings. The remaining T. rex juveniles then began to explore the area around them while their mother rested, pestering a Dinilysia they found during their brief exploration.

While her chicks were exploring the mother noticed an Ankylosaurus in her territory. Her young took refuge under a tree as she did her best to detour the intruding the Ankylosaurus by lunging very close to the herbivore. During one of her lunges, however, the Ankylosaurus swung its tail club successfully hitting her side, cracking one of her femurs and rupturing several internal organs in the process.

The next morning she dies from her fatal injuries with her young waiting for her to wake her, not knowing her fate. Hours later the K-T Extinction occurs. The juvenile Tyrannosaurus first seen the bright light of the impact, seconds before a shock wave blows them away in a cloud of dust, killing them as well as their species.

At the end of the credits the roar of Tyrannosaurus rex is played.

In Walking with Dinosaurs: A Natural History

Death of a Dynasty

A male Tyrannosaurus eats a Didelphodon that was scavenging an abandoned T. rex nest before proceeding to eat the eggs for himself. The reason this nest was abandoned was because the embryos inside the eggs suffocated from the shell being uneven and were decaying. After eating the rotten eggs, the male hearing the mating call of a female. Wanting to mate with her, he goes hunting the next morning.

The male T. rex approaches a herd of Anatotitan, scaring many of the herd's members with the goal of pressuring the herd into giving up any individuals weakened by sickness or injuries. Several males confront him to defend their herd so tries to find another way around the large males, but the fog around him thickens so he decides to forgo attacking due to the risk involved.

However, in the fog he spots the colorful frills of a Torosaurus herd whom he makes his next target. It is mating season for the Torosaurus as well, so the male T. rex watches the fencing males closely because the loser of these mating rituals will be tired and even injured, which makes them easy prey. The Tyrannosaurus attacks a male Torosaurus that is 50 years of age who had lost a fight with a younger male that cost him one of his brow horns and was disoriented by the pain from the loss.

The T. rex bites the bull in one of his flanks, tearing off 65 pounds of flesh in the process. Unable to find the herd he belongs to, the Torosaurus attempted to charge at his attacker, only to stumble from the great pain he felt. The male Torosaurus then decides to run to find his herd, only for the Tyrannosaurus follows in pursuit and bites his flank again, shattering the herbivore's hip bone in the attack. With his prey pinned down and dying, the male calls out to the female he has been wanting to attract.

A half-hour later the female arrives in the location of the kill with the male waiting. It is revealed that the female T. rex is rather old, with gout in one of her legs and has several scars on a side of her face. She is initially uninterested in the male, but later that night she mates with him. The next day a Torosaurus approaches the two predators and proceeds to harassment. As the tyrannosaurs leave the female decides to betray the male. The male survives her pursuit of him though he does receive a bite to the back of his head.

Two months later, the female Tyrannosaurus begins to build her nest and lays her eggs in the completed nest. Only three of her eggs hatch out of the nest. Two days after her chicks hatched, the mother Tyrannosaurus hunts Anatotitan and successfully kills one of the hadrosaurs to feed her and her young. However, she and her chicks had to abandon the carcass because it attracted several pods of Deinosuchus.

In the days that follow the mother is unable to provide her young with any food due to a decrease in the hadrosaur population. Because they of the lack of food two of the chicks kill and eat the weakest sibling of the three. With her behavior becoming erratic from the food shortage, the mother rests on some warm rocks in the mid-afternoon a day before the KT Extinction. In the mother's deep slumber, she is unable to detect any threats to her juveniles.

An Ankylosaurus and her young enter the territory of the tyrannosaurs to feed on the vegetation. The two juvenile Tyrannosaurus attempt to hunt the adult Ankylosaurus, but the armored dinosaur collects their scent. The mother T. rex rushes towards the Ankylosaurus an attempt to protect her young. But this costs the tyrannosaur her life as the ankylosaur proceeds to attack the leg that has gout and continues to do so before Tyrannosaurus finally dies from the persistent clubbing.

As the mother T. rex is beaten to death the chicks decide to hunt the juvenile Ankylosaurus only to become uninterested afterward. Once the ankylosaur family leaves the chicks begin to call to their mother for food. After much waiting with no response, the juveniles decide to scavenge their mother's carcass to due to smell it begins to emit. The next day while they eat more of their mother's carcass the KT Extinction occurs and they are killed by the maelstrom that follows the impact of the asteroid. Eventually, all members of the Tyrannosaurus rex species die from the mass extinction.

In Walking with Beasts

New Dawn

Stock footage of the fight between the Tyrannosaurus and the Ankylosaurus plays at the beginning of the episode.

In Sea Monsters

Tyrannosaurus rex is one of the creatures on Nigel Marven's Time map.

To Hell... and Back?

While Nigel Marven and his crew are in the Late Cretaceous, they see a Tyrannosaurus roaring near the land surrounding the ocean.

Behind the scenes

The Generation 1 Tyrannosaurus has multiple inaccuracies. First, like all theropods of that generation, the hands were never pronated. Second, Tyrannosaurus chicks wouldn't be 1 meter tall at only 1 month of age according to fossil juveniles of related genera. Third, recent discoveries might suggest that Tyrannosaurus more than likely had some form of feathers, however it is unknown if these feathers fully covered the animal, or were only present in sparse patches. Fourth, Tyrannosaurus' head wasn't as cubed and short like in Walking with Dinosaurs. Finally, many of the behaviors of the Tyrannosaurus in Generation 1 are highly speculative.

Texture artist Daren Horley gave all of the carnivores in Walking with Dinosaurs heavy scales on their heads, including T. rex. Horley explained that since carnivores like T. rex would use their heads for attacking prey and butting heads with rival mates it would make sense for them to have heavier scales in that region of the body to provide protection.[6]

The date in which Tyrannosaurus rex first evolved in Generation 1's timeline was retconned. In Death of a Dynasty, the narrator states that it evolved 68mya, but later installments stated that it first appeared before this date.

Several Walking with... sources (such as the fact files on the Walking with Dinosaurs companion websites and the fact file sheet that was included with The Big Dinosaur Box DVD) state that Tyrannosaurus fossils have been found in Asia. These fossils are now assigned to the related genus Tarbosaurus.

Unlike what is shown in Sea Monsters and The Complete Guide to Prehistoric Life, Tyrannosaurus never lived before 68mya. Though it was thought that T. rex lived from at least 70 to 65mya, recent evidence now suggests that it lived from 68 to 66mya. Some believe that the Tyrannosaurus that appeared in Sea Monsters is actually T. rex's relative Daspletosaurus, which did indeed live in the episode's setting.

The Tyrannosaurus model and animatronic from Walking with Dinosaurs was reused in several other BBC productions outside of the Walking with... series. The animatronic head of Tyrannosaurus was used in the first episode of Dragons Alive, a documentary about modern reptiles, in a brief segment about the reign of the dinosaurs and their extinction. The 3D model of the G1 Tyrannosaurus appeared in the Horizon episode Extreme Dinosaurs, which was included as a special feature of the Chased by Dinosaurs DVD.

More recently stock footage of T. rex from its appearance in WWD was reused for CBeebies Andy's Dinosaur Adventures.

In 2005, stamps from Liberia reused images of many Walking with... animals including Tyrannosaurus.[7]

The 2007 cover of The Complete Guide to Prehistoric Life, which prominently features Tyrannosaurus, was used as the banner for Series 5 of Primeval on Amazon Instant Video. Primeval istelf was created by Impossible Pictures who created Walking with...

In the video game Primal Carnage, the free skin for Tyrannosaurus in the game called "Battle Scarred Tyrannosaurus" closely resembles the Generation 1 Tyrannosaurus from Walking with... minus the scars.

List of appearences


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Printed Media