Tyrannosaurus

Tyrannosaurus Dinosaur

Tyrannosaurus is believed to be the most ferocious and dangerous animal that lived on earth. Around 68 million years back the dangerous carnivorous species were found in western North America in the forested river valleys of the place. The species were known to have a huge body and very sharp teeth with jaws that were capable of crushing the car as well. 

As the name Tyrannosaurus rex implies “king of the tyrant lizards”, the species were dominant enough to rule. With a size of 40 feet and a weight of around eight tons, the animal has a massive and powerful body. The t-rex size made it convenient for the animal to stroll the entire territory in just two steps headfirst.


Tyrannosaurus Rex Facts


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Most commonly known as T-Rex or T rex, this large species represented the huge theropods and belonged to the genus of tyrannosaurid. Theropods were found on the island Laramidia, current western North America. The brief and scientific classification about T rex is mentioned below:

Kingdom – Animalia

Phylum – Chordata

Clade – Theropoda, Saurischia, Dinosauria

Family – Tyrannosauridae

Sub Family - Tyrannosaurinae

Height – 3.7 to 6.1 m

Weight – 4500 to 8000 kg

Speed – almost 27 Km per hour

Life span – around 30 years

Found – 83.6 million years to 66 million years ago

Food – Carnivorous


Physical Form and Functions of Tyrannosaur

The Tyrannosaurus dinosaur has been the massive and complete specimen carnivores on the land of all ages and time. The description of its various forms and functions is mentioned below:

1. Dentition and Skull 

The huge tyrannosaur normally has some centimetres thicker skull bones and they are braced to one another. This implies that the tyrannosaur had been resisting the biting forces from others and also the self-inflicted one. If researchers are to be believed then the longest skull of the tyrannosaur that is known to mankind is been almost more than 4 feet long which is 1.3 meters. 

The 6 inches protruding 60 teeth are observed in the large mouth. Also, on the basis of the microscopic line seen, it is believed that every 250 days the crown of the teeth are shed and they then regrow. It is also seen that the serrations have pocketlike recesses which are deep to provide a place for bacteria to flourish inside. This, in turn, results in infectious bites.

The front teeth of the tyrannosaur are U-shaped and small in size while the side teeth are larger in size. In adult tyrannosaur, the side teeth are in cross-section and D shaped, unlike other flesh-eating theropods. However, the mature skulls of tyrannosaur show the classification of teeth as lower jaw teeth, upper side teeth, and upper front teeth. The traces of bites that are preserved reveal that the voracious predators have been the proof of cannibalism and had the capability to bite through limbs, pelvis, and skull of other dinosaurs. It is believed that the tyrannosaur had a strong bite force of up to 12000 pounds that had been capable of crushing even the bones of the prey. 


2. Body

Till the year 2018, the tyrannosaurus rex size had been thought of as sleek. Then research was conducted in Chicago on SUE. SUE is the only complete Tyrannosaur found to date.  the placement of series of bones was revealed. Also, it was seen that these bones go beyond the ribs up to the belly and also aid the animal in breathing. The presence of this gastralia bone had given rise to a wide rib cage and bulging belly to the creature. 


3. Tiny Arms

The 40 feet terrifying Tyrannosaur has perplexing arms with length that of human arms. Unlike other theropods who have long arms, tyrannosaur has stubby and short arms. Though a quick look gave an impression that these arms were vestigial and useless, but that was not the case. When looked closely the anatomy of the fossil revealed that the entire body plan had specialized functions assigned to every part of the body. In the year 2008, Cerpenter and Lipkin discovered that the animal’s arms were actually magnificently muscular and powerful. The remaining two-finger digits had large menacing claws.


On further research, it was investigated that the Tyrannosaur had stress fractures. Stress fractures occur due to repeated activities and high impact which can also be termed as overuse or extensive use. So it was speculated that maybe the tyrannosaur used its tiny arms to steadily hold the struggling prey, to stand up from a sitting position, or some kind of mating posture. But most prominently it should have been used for predator-prey interactions.


4. Tail and Legs 

It was always believed that based on the t rex information available that the animal was cumbersome and slow and the size made the animal difficult to have the speed. But the anatomy revealed some other facts that the species had. The T rex musculoskeletal model proved that the animal had a respectable 18 mph speed which was much faster than an elephant or a sprinting human. The tyrannosaur had a unique tail structure which was actually an extension to the leg muscles and provided support to the legs. It gave tremendous power to the legs of the theropod to be an excellent athleticism with regards to turning agility, balance and running. This also proved that the animal species was agile and highly mobile and had the capacity to chase the prey easily. So with all the research in hand, it was concluded that the tyrannosaur had a faster gait and longer stride, and the tail and the leg structure made them an expert in terms of speed and agility. 


5. Predator or Scavenger

If the research is to be believed then the tyrannosaurs were neither a predator nor a scavenger but an opportunist carnivore. The study of the anatomy of the animal, the ecological condition it prevailed in, and the healed hadrosaur vertebra all pointed towards the fact that the tyrannosaur was a predator. However, there were also traces that showed that the animal had both scavenging and predatory behaviours. It was evident though that the species had been on the top in the food chain that prevailed in that age. 


Living Habitats of Tyrannosaur

The tyrannosaur was believed to be originated in Laramidia which is currently in western North America. Being an island it was surrounded by oceans and so the species could not have migrated to even the nearest destinations such as Easter North America or South America. Way back it also was evident that Asia was connected to Laramidia through maybe Siberia and Alaska.  As per the geographical study, the pacific ocean was not that wide at those ages. And so maybe the land animal migrated to Asia. But it could not have travelled to Europe or Africa or even Australia due to the huge separation created by the water bodies.

Therefore the Tyrannosaur was found in Asia and Laramidia islands while the Jurassic Dinosaurs were found in Australia, Antarctica, Africa, and South America as well.


Types of T rex

The tyrannosaur family had a genetic in Ceolurosauria clade theropods that are associated with birds. Currently, this family is supposed to include nine genres that have attributes such as short arms, forward-facing eyes, robust and large skulls. However, a wide diversity can be seen among these nine genres based on the environment and time period they belonged to.

The distinctive characteristics of these 9 genres are mentioned below:

1. Lynthronax Argestes 

This species is believed to be the oldest one among all the tyrannosaur discovered until now. It is aged to 80 million years back. They were found in South Laramidia and were shorter as compared to other tyrannosaurs with their length being 24 feet. They had stubby arms, forward-facing eyes, robust teeth, and a wide and short skull. 

2. Daspletosaurus Torosus 

They were believed to be around 77 million years back in North Laramidia. They were approximately 30 feet in length and had a distinctive unique feature of a crest above their eyes. It is observed that this species lived alongside another carnivorous theropod, Gorgosaurus though this hypothesis is not proven with surety. It is also speculated that the two species lived in different ecological niches and survived on different prey. So they did not overlap each other.

3. Teratophoneus Curriei 

This species was found around 76 million years back in South Laramidia. They were shorter therapods with only 20 feet in length and had a shorter skull and lesser teeth. 

4. Bistahieversor Sealeyi 

This species was found 74 million years back in Kirtland in New Mexico. With 28 feet in length, this species had an extra opening above the eye socket. It is speculated that this was to lighten the skull and it also had a keel besides the lower jaw.

5. Nanotyranosaurus Lancensis

As the name suggests, this species is the smallest one among all the species that were discovered until now with only 21 feet in length. They were found in North Lamidia around 67 million years back. They had more teeth and long and slender arms. 

6. Tyrannosaurus Rex 

t rex full name is Tyrannosaurus rex and it was found in South and North Laramidia around 67 million years ago. The Tyrant Lizard King was 40 feet and the last to be found on earth. They died in the mass event of extinction at Cretaceous.

7. Nanuqsaurus Hoglundi

Also called Polar Bear Lizard these theropods were found in the polar region of Northern Alaska and were only 18 feet. The smaller size may be due to the harsh environment in the arctic region. The Pygmy polar tyrannosaur was found around 69 million years ago. 

8.Tarbosaurus Bataar

This species is the Tyrannosaur of Asia commonly called as Alarming Lizard Hero. They were found in China and the Gobi Desert region around 70 million years ago. They were around 40 feet in size and very similar to the one found in Laramidia and so were also termed as sister species. 

9. Yutyrannus Huali


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This species was the oldest one and commonly called as Feathered Tyrant. They were believed to be living around 124 million years ago in Asia. They were around 29.5 ft in size and fossils also revealed traces of feathers on upper arms, neck, pelvis, and tail. It is presumed that the presence of feathers was for the purpose of regulating temperature.


Final Thoughts

It is speculated that the Tyrannosaurs may have been originated in South America in the Jurassic era. However, in the early cretaceous era, some relatives of T- rex moved to Laramidia. The early Allosaurs were ruling Laramidia at that time and only after their extinction, the Tyrannosaurs have been taken the place of apex predators. 

FAQs on Tyrannosaurus

1. What Killed the T- Rex or the Tyrannosaur and Made them Extinct?

Ans. Around 65 million years ago, mass extinction happened at the end of the cretaceous. It is believed that this may have happened due to the collision of a catastrophic asteroid with the Earth. At this period many species and groups of plants and animals were killed and became extinct. This also included dinosaurs with the extinction of Tyrannosaur.

2. State the Population Estimates of Tyrannosaurs.

Ans. As per the studies by Charles Marshall published in the year 2021, it is estimated that the individual population of adult Tyrannosaur should have been 20 thousand individuals at any given time. However, the estimations also suggest that the numbers could have never been less than 1300 and never exceeded 328000. Some speculations suggest that there may have been around 127000 generations and around 2.5 billion animals till they were entirely extinguished. However, it should be noted that the studies did not account for juvenile animals.

3. How and When was the First Tyrannosaur Skeleton Discovered and How was it Named?

Ans. The very first skeleton of a tyrannosaur was discovered by Barnum Brown in the year 1900 in Wyoming.  Another partial skeleton formed with 34 fossilized bones was again found in the year 1902 in Montano. The second skeleton was named as T- rex by Henry Osborn in the year 1905. The tyrannosaurus t rex full name is a combination of Greek and Latin words meaning King of Tyrant Lizard.

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