An Ultimate Guide to Tyrannosaurus: The King of Tyrants

Leave a comment / / Updated on: 18th December 2023

NameTyrannosaurus DietCarnivorous
Name Meaning“Tyrant Lizard”Height3 to 4 meters (12–13 feet)
Pronunciationtie-RAN-oh-SAWR-usLength12–15 meters (40–50 feet)
EraMesozoicLate CretaceousWeight5–8 metric tons (11,000–17,600 pounds)
ClassificationDinosauria, Saurischia & TheropodaLocationNorth America (United States and Canada)

Tyrannosaurus Pictures

Tyrannosaurus | JoeLena via iStock

The Tyrannosaurus

Gage Beasley Prehistoric's Tyrannosaurus Concept
Gage Beasley Prehistoric’s Tyrannosaurus Concept

Throughout the 19th century (starting from 1874), scientists found bits and pieces of dinosaur bones that were either completely unknown or mislabelled as a different species. 

Some of these fossils have now been confirmed to be that of the King of Tyrant Lizards. 

In 1902, famous Paleontologist Barnum Brown found the first conclusive evidence of what would soon become the most iconic dinosaur genus ever — the Tyrannosaurus

Today, the 40-foot monster is one of the most well-known dinosaurs ever

The T. rex lived in western North America during the last few million years of the Cenozoic Era and was one of the most fearsome animals in its habitat. 

With a massive body, razor-sharp teeth, and jaws that delivered the highest bite force of any known animal, the Tyrannosaurus was built to rule. 

Gage Beasley's Prehistoric Shirt Collection
Gage Beasley’s Prehistoric Shirt Collection
Gage Beasley's Prehistoric Plush Collection
Gage Beasley’s Prehistoric Plush Collection

All we have left of this massive theropod dinosaur are pieces of bones, soft tissues, and fossil tracks that tell the story of the ultimate carnivore.

Fortunately, there’s an abundance of Tyrannosaurus fossil material that has allowed significant research into the anatomy, biology, and ecology of this dinosaur. 

In this article, we’ll discuss some fascinating facts about the Tyrannosaurus, including its appearance, feeding habits, ecology, and its significance to scientific research. 

Physical Characteristics

The Tyrannosaurus is one of the largest theropod dinosaurs to have ever walked the planet.

It was an imposing figure characterized by a massive muscular body, a big head, puny forelimbs, long hind limbs, and a thick tail.

This dinosaur was as big as a school bus. 

Measured from tail to snout, the largest Tyrannosaurus would have been at least 40 feet long. 

Gage Beasley Prehistoric's Tyrannosaurus Concept
Gage Beasley Prehistoric’s Tyrannosaurus Size Comparison Chart

It was about three to four meters (12–13 feet) tall at the hips and weighed close to nine metric tons (19,841 pounds). 

The skull of the Tyrannosaurus was one of its most distinct features. It had a large, elongated skull that measured about five feet (1.5 meters) in length. 

The T. rex’s jaws were filled with 60 dagger-like teeth, each one about 20 centimeters (8 inches) long and deeply serrated. 

The supporting muscles of this dinosaur’s jaws were built to be quite strong, enabling T. rex to deliver incredibly strong bites.  

The bite force of this dinosaur is the highest of any known land animal, both living and extinct. 

Experts think the king of dinosaurs may have been capable of crushing a car with its jaws or biting through solid bone. 

T-rex in the wild
T-rex in the wild | JoeLena via iStock

The hindlimbs were long and muscular, built to support the dinosaur’s massive weight. 

Among all theropod dinosaurs, the Tyrannosaurus had the longest hindlimbs in proportion to its body size. 

Ironically, the forelimbs of this dinosaur were extremely short and almost cartoonish. Each arm had just two functional fingers.

These fingers ended in sharp, four-inch claws that may have been effective for slashing at prey at close quarters. 

Dinosaur Fossil (Tyrannosaurus Rex) Found by Archaeologists
Dinosaur Fossil (Tyrannosaurus Rex) Found by Archaeologists | Divaneth-Dias via iStock

Although very few Tyrannosaurus fossils have been found with preserved skin impressions, scientists think this dinosaur had scaly skin similar to modern-day reptiles on most of its body. 

The scales were probably similar to that of squamates, like snakes or lizards, rather than crocodilian scales. 

There are also speculations that the Tyrannosaurus had feathers on some parts of its body, possibly on the upper side of its trunk.

However, no conclusive evidence has been found for this. 

Habitat and Distribution

Tyrannosaurus rex lived during the Late Cretaceous in what is now Western North America. 

This was approximately 68 to 66 million years ago. 

Its geographic range included parts of the present-day United States and Canada. 

Fossil remains of Tyrannosaurus rex have been found in various locations, primarily in Montana, South Dakota, Wyoming, and Alberta, Canada. 

Due to the abundance of fossil remains of this dinosaur, scientists have estimated that as many as 20,000 Tyrannosaurus individuals lived in Western North America during the Late Cretaceous. 

Tyrannosaurus Rex in the jungle, living in the warm climate during the late Cretaceous Period
Tyrannosaurus Rex in the jungle, living in the warm climate during the late Cretaceous Period | Byrdyak via iStock

During the Late Cretaceous Period, the planet was characterized by a relatively warm climate. 

The continents were situated closer to the Earth’s poles compared to their present-day positions.

The landmass of North America was split into two by a shallow sea known as the Western Interior Seaway. 

Tyrannosaurus lived on the western landmass known as Laramidia, completely isolated from Appalachia on the East. 

Unlike today’s dry and grassy landscape, Western North America was a warm and humid forest ecosystem during the Late Cretaceous.

Tyrannosaurus rex lived in lush forests, coastal floodplains, and open plains that supported a healthy prey population. 

Behavior and Diet

Tyrannosaurus rex fight in the valley
Tyrannosaurus rex fight in the valley | ALLVISIONN via iStock

Like other tyrannosaurid dinosaurs, Tyrannosaurus was bipedal, meaning it walked on two legs. 

The dinosaur’s hind limbs were long and muscular, built to support agile motion despite the dinosaur’s massive weight. 

Because it was so bulky, scientists thought Tyrannosaurus was incapable of running. 

Instead, it walked quickly, reaching speeds of up to 15 miles per hour, fast enough to catch up with other large dinosaurs. 

In some movies, the Tyrannosaurus is often described as a lumbering, almost-dumb giant with poor eyesight. 

This is inconsistent with scientific facts. 

Dinosaur Tyrannosaurus Rex On Top Of Mountain Rock
Dinosaur Tyrannosaurus Rex On Top Of Mountain Rock | chaiyapruek2520 via iStock

The Tyrannosaurus was not a dumb meat-eater. 

The dinosaur had a large brain, almost twice that of other dinosaurs, which suggests that it was quite intelligent, with a good sense of vision and smell. 

The brainy beast had forward-facing eyes, which means it may have had great depth perception, which is useful for predatory dinosaurs that hunt by chasing prey. 

The T. rex’s olfactory bulbs were also quite large, which suggests that the dinosaur had a great sense of smell. 

Gage Beasley's Tyrannosaurus Stuffed Plush Toy
Gage Beasley’s Tyrannosaurus Stuffed Plush Toy

Despite being built like a typical carnivore, the feeding habit of the Tyrannosaurus is still a subject of active debate. 

Some scientists think the well-developed sense of smell of the T. rex is an indication that it was a scavenger. 

If this is right, it most likely leveraged its size to scare off other dinosaurs and steal their kill. 

But the Tyrannosaurus was an efficient killing machine itself, and it probably didn’t need to steal food from other dinosaurs or scavenge carcasses. 

According to estimates, the Tyrannosaurus can produce up to six tons of pressure in just one bite.

With powerful jaws equipped with 60 dagger-like teeth and a bite force more than three times that of a lion, Tyrannosaurus was capable of biting through bones and killing large prey with just one bite. 

Some scientists have also suggested the possibility that the Tyrannosaurus could deliver a venomous bite with its teeth like a Komodo dragon. 

The serrations on the dinosaur’s teeth had little chambers that may have housed toxic bacteria that produced venom. 

Tyrannosaurus teeth fossil
Tyrannosaurus teeth fossil | Grafissimo via iStock

These points suggest an active predatory lifestyle for this dinosaur but do not rule out a scavenger lifestyle. 

Most paleontologists agree that this dinosaur could have been both. 

It hunted prey actively and, like most large carnivores, also scavenged occasionally. 

It probably chased down prey, killing them by biting down with its massive jaws. The dinosaur’s teeth were also effective for slicing through meat. 

The T. rex didn’t have specialized teeth for grinding or chopping food. Instead, it fed by swallowing chunks of its prey using its sharp serrated teeth. 

Life Cycle

Gage Beasley Prehistoric's Tyrannosaurus Concept
Gage Beasley Prehistoric’s Tyrannosaurus Concept

Several specimens of the Tyrannosaurus have been identified across various age categories. This has helped our understanding of the reproductive pattern and life cycle of this dinosaur. 

Like other dinosaurs, Tyrannosaurus reproduced sexually. 

Specific details of the mating behavior of this dinosaur are not well known. 

However, scientists have speculated that the short forearms of this dinosaur were probably useful for holding the female during mating. 

Scientists have discovered evidence of a sensory system in the Tyrannosaurus’ face. 

Some areas of the dinosaur’s face had nerve openings that would have made them sensitive to touch. 

These areas were probably more sensitive than human fingertips, which would have been very useful during courtship. 

Scientists think tyrannosaurids rubbed their faces together during their pre-copulatory play. 

After mating, female Tyrannosaurus laid their eggs in suitable nesting locations. 

Tyrannosaurus rex embryo in its egg
Tyrannosaurus rex embryo in its egg | estt via iStock

Their sharp nose was probably helpful in finding the ideal nesting ground for their eggs. 

Although there’s no direct evidence that T. rex parents took care of their young, scientists think this was quite likely. 

One piece of evidence is the lack of Tyrannosaurus juveniles in the fossil records, which suggests that most juveniles made it to adulthood. 

This supports the assertion that T. rex’s protected their young in the early years of their lives. 

Once hatched, T. rex juveniles grew very quickly. 

Experts think their growth rate may have been faster than that of reptiles today. 

Their teenage years were characterized by a growth spurt, with the Tyrannosaurus juveniles gaining at least 1500 pounds per year until they reached maturity around 20 years. 

Similar to techniques used in determining the age of trees, scientists have been able to track the growth pattern of Tyrannosaurus using yearly growth rings. 

Tyrannosaurus rex escaping from three triceratops attack next to aristata pine by day
Tyrannosaurus rex escaping from three Triceratops attack next to aristata pine by day | Elenarts108 via iStock

Based on their growth patterns, experts believe Tyrannosaurus was capable of slowing down their growth rate in response to environmental pressures such as lack of food and other resources. 

As a result, they grew faster during periods of abundance and slowed down their growth when resources were scarce. 

The growth rings also indicate that the growth rate of this dinosaur slowed down considerably once they reached adulthood. 

T. rex adults didn’t grow very old. The oldest specimen found so far died at about 28 years of age. 

Evolution and History

The King of Tyrants
The King of Tyrants | digitalgenetics via iStock

Tyrannosaurus rex belongs to the family Tyrannosauridae, which includes several other large predatory dinosaurs as well as some very small ones. 

It is part of the subfamily Tyrannosaurinae, which means it is closely related to other carnivorous species such as the Albertosaurus and Daspletosaurus

These dinosaurs share various anatomical characteristics, including a robust body, large head, and powerful jaws.

The earliest known tyrannosaurids appeared in the Jurassic Period, about 160 million years ago. 

Gage Beasley's Green Tyrannosaurus Plush Toy
Gage Beasley’s Green Tyrannosaurus Plush Toy

These early relatives of T. rex were smaller and had different proportions, with longer arms and more slender builds. 

They evolved and diversified during the Late Cretaceous, eventually giving rise to the iconic Tyrannosaurus rex.

Several transitional species between the smaller primitive tyrannosaurs and the massive ones like the T. rex have been identified. 

Some of them, like the Suskityrannus, show a typically tyrannosaurid body plan but have a more slender build. 

Apart from the difference in size, another obvious change in younger tyrannosaurids compared to the primitive forms was the absence of feathers on their body

The ancestors of the Tyrannosaurus probably had feathers all over their bodies.

But as the dinosaurs evolved, this became restricted to only certain parts of their body or was completely absent. 

Primitive tyrannosaurids also had longer forearms compared to their Late Cretaceous successors.

Experts think the Tyrannosaurus’ forearms grew shorter as they evolved into bigger sizes with massive heads. 

The shorter hands helped to counterbalance their enormous head in order to maintain a stable posture. 

T-rex short hands
T-rex short hands | para827 via iStock

As a result, their hands became less useful for grabbing but may have served other purposes. 

Some scientists also believe Tyrannosaurus may have evolved directly from Daspletosaurus, demonstrating a phenomenon referred to as anagenesis. 

This means the entire Daspletosaurus transformed over time until they became the Tyrannosaurus

Scientists have found at least two Daspletosaurus that show features similar to that of the Tyrannosaurus. These individuals are considered transitional forms between the two species, confirming the anagenesis theory. 

Interactions With Other Species

Computer artwork of a Tyrannosaurus rex dinosaur hunting small prey
Computer artwork of a Tyrannosaurus rex dinosaur hunting small prey | Mark Garlick via GettyImages

The Tyrant Lizard King ruled in Late Cretaceous North America with an iron fist. 

The dinosaur’s range covered a vast area, and they probably interacted with several other dinosaurs across the different ecosystems they lived in. 

The herbivorous dinosaur species of the Late Cretaceous most likely formed the base of the Tyrannosaurus’ diet. 

Triceratops were the most common herbivores in the T. rex’s northern range. Although it was large and armored, this dinosaur probably fell prey to the T. rex quite often. 

Tyrannosaurus confronting a Triceratops from the Cretaceous era
Tyrannosaurus confronting a Triceratops from the Cretaceous era | Warpaintcobra via iStock

There’s a record of at least one such encounter between these two species in the fossil record. 

In this case, the battle was fatal for both dinosaurs as they both likely died in combat and were entombed together. 

Some other possible prey for this dinosaur includes Edmontosaurus, Thescelosaurus, Ankylosaurus, and Pachycephalosaurus

Alamosaurus, a type of titanosaurian sauropod, was also quite common in the T. rex’s southern range. 

Because the T. rex was an apex predator and was by far the biggest dinosaur in Late Cretaceous Laramidia, it probably didn’t have a lot of natural enemies. 

However, competition between this dinosaur and other carnivores in the region, such as Dakotaraptor, may have happened quite often. 

Tyrannosaurus individuals may have also competed against each other. 

There’s evidence that the T. rex was cannibalistic, and bigger individuals may have killed off smaller ones.

Cultural Significance

The fearsome Tyrannosaurus
The fearsome Tyrannosaurus | Roger Haris via GettyImages

Tyrannosaurus rex is arguably the most referenced dinosaur in pop culture, so much so that it has become the iconic symbol not just for dinosaurs but also for prehistoric times in general. 

The imposing size, fearsome appearance, and reputation as a formidable predator are some of the reasons why the T. rex has been so popular with the general public. 

This dinosaur has been featured in books, documentaries, TV shows, and video games. 

Perhaps the most popular appearance of the T. rex on the big screens is in the Jurassic Park movies, where it commonly features as the antagonist. 

The Tyrannosaurus’ appearance in these movies has made it one of the most recognizable dinosaurs to the general public. 

T-Rex Ambush Scene - Jurassic Park (1993)
T-Rex Ambush Scene – Jurassic Park (1993) | Image Clip via BestClips

Of course, being a Hollywood star often means this dinosaur is often overly fictionalized, and many of the depictions in movies were inaccurate. 

For instance, the Tyrannosaurus was not as fast as it is often depicted in movies. It also had good vision and probably made sounds more akin to a low rumble than a loud roar. 

The Tyrannosaurus is also a star in the world of paleontology. 

Several fossils of this dinosaur have been recovered, some of them in very good condition. 

The specimen nicknamed “Sue,” for instance, had at least 85% of its bones intact and is the most complete Tyrannosaurus fossil found so far. It is also the most expensive dinosaur fossil, showing just how precious this dinosaur is. 

Tyrannosaurus Rex specimen "SUE" on display at the Field Museum of Natural History in Chicago, Illinois.
Tyrannosaurus Rex specimen “SUE” on display at the Field Museum of Natural History in Chicago, Illinois | Evolutionnumber9 via Wikipedia CC BY-SA 4.0

Studying the bones of this dinosaur has provided a wealth of information on the evolutionary history of theropod dinosaurs, their unique adaptations, and the ecological dynamics of the Late Cretaceous environment where they lived. 


The Tyrannosaurus rex (more commonly called T-Rex or T. rex) was one of the largest carnivores to have ever lived anywhere in the world. 

It was native to North America, and its range covered areas of present-day Canada and the United States. 

An apex predator built to kill, the Tyrannosaurus was most likely an active hunter that took down giant dinosaurs with its massive jaws and sharp teeth. 

There’s also a chance it scavenges on carrion occasionally. 

Yet, this dinosaur was probably an affectionate lover that courted each other with cute face rubs and tended to their young till they were old enough. 

The king lizard probably didn’t live long, too, peaking at about 28 years before dying off. 

But for the last few million years of the Cretaceous Period, this dinosaur was the top dog in Western North America and was alive till the last days of the dinosaurs on the planet. 


How did Tyrannosaurus rex become extinct?

Tyrannosaurus rex, along with all non-avian dinosaurs, went extinct around 66 million years ago, likely due to the catastrophic event known as the Cretaceous-Paleogene (K-Pg) extinction event. 

This event was caused by a combination of factors, including a massive asteroid impact and volcanic activity that triggered significant environmental changes and the decline of all dinosaurs. 

What does the “rex” in Tyrannosaurus mean? 

The term “rex” in “Tyrannosaurus rex” is the specific name for the Tyrannosaurus genus. It is a Latin word that translates as king, highlighting the perception of Tyrannosaurus as a dominant and formidable dinosaur. 

The full name translates as Tyrant Lizard King. 

Was the T. rex cold-blooded or warm-blooded?

While a few dinosaur species were cold-blooded, most of them, like the T. rex, were warm-blooded. 


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