Tyrant Lizard King: Everything There is to Know About T. Rex


Tyrant Lizard King

On a strange planet much more humid than ours, there lived a carnivorous, giant and fiercely intimidating creature. With 50 to 60 teeth, the Tyrannosaurus Rex could rip off five hundred pounds of meat in one tear. Luckily, the closest living relative of this behemoth alive today is the chicken, according to Jeanna Bryner of Live Science. With the plethora of fossil record information on T.Rex currently available to paleontologists, we can become better acquainted with this colossal predator.

According to an Encyclopedia Britannica article written by Kevin Padian, Tyrannosaurus Rex means “tyrant lizard king” in Greek. The name was coined by paleontologist Henry Fairfield Osborn in 1905. The first T.Rex was found by Barnum Brown in 1902 in Hell Creek, Montana. Fossils have been found in the USA in Montana, Texas, Utah, and Wyoming, Canada, including Alberta and Saskatchewan, and Mongolia in east Asia , only about 30 skeletons have been found, all are incomplete.

This region of North America where T.Rex has been found was an island then that we call Laramedia. Laramedia existed late into the Cretaceous period from 85 million years ago to 66 million years ago.(Saurian) North America was split in half by a large body of water called the Western Interior Seaway. Fig.1. The Tyrannosaurus Rex scale to the height to an average human.(Padian)

Anatomy of the T Rextyrannosaurus-447801_1920

The T.Rex was one of the biggest land carnivores of all time. According to Padian, the mass of one of these full grown beasts is estimated to be somewhere between 7.2 metric tons to 4.3 metric tons. The monster had been 40 feet long(12.4m), and about 15 to 20 feet(4.6 to 6m) tall.(see fig.1) The skull gives evidence to believe that the head alone could have weighed around a ton. The bite force of a Tyrannosaurus Rex has been rounded to an approximate figure by professor Mason B. Meers of the University of Tampa to be  around one hundred eighty three thousand to two hundred thirty thousand newtons or 18.3 to 23.5 metric tons.(Padian) According to researcher Dave Smith, this meat eating machine had teeth that could measure up to a foot, including the root of the tooth when the creature was alive. The teeth were shaped like “lethal bananas”, being D shaped in a cross section.

Although it is widely accepted that the Tyrannosaurus Rex had been a vicious hunter of smaller dinosaurs, some paleontologists doubt that the T.Rex could be an effective hunter because of its unfortunate anatomy including small eyes and tiny arms. Paleontologist Jack Horner argues that there is more evidence that the Tyrannosaur had been a hunter due to a tooth mark found of a healed wound on a hadrosaur given by a T.Rex tooth.(Zimmerman) Either its primary source of meat was hunting or scavenging, there’s evidence of both, therefore, most paleontologists believe it was an opportunist.

Paleontologists have discovered that most of the bones of T.Rex were hollow, like the bones of their cousins the birds. The advantage of hollow bones is that they kept from adding additional weight to its already massive body without loss of strength.(Smith) Also like birds, there are scientists who now believe that T.Rex(and other dinosaurs) had most likely had feathers covering the body partially. The Dilong, a species of Tyrannosaur, was found in China with fossilized imprints of feathers covering where the body had been. Researchers debate whether Tyannosaurus Rex had feathers or scales, one hypothesis is that juvenile T.Rexs had protofeathers at birth then shed them at a mature age to give way to scales.

Tyrannosaurus had been a bipedal dinosaur, meaning T.Rex walked on two limbs.(Padian) The back legs of the tyrannosaur could carry the mass to speeds of up to 20 miles per hour. These two back legs were very powerful while the two front limbs were virtually useless because of their tiny size. For decades, paleontologist and biologists have debated how T.Rex used its arms due to their relatively small size. In science magazine Smithsonian, author Helen Fields gives some uses that have been concluded by biologists; the T.Rex male could have used them during mating, the predator could have used them to lift themselves off of the ground during a fight and/or T.Rex used the forearms to clutch tightly to prey while eating.

Because the head of the T.Rex weighed about a ton, the tail was long and heavy to keep the body balanced. The tail was about 20 feet long and weighed close to a ton. This limb also helped the Tyrannosaurus turn it’s body when running. The position of the tyrannosaurus tail was straight behind the body because the muscles surrounding the sometimes forty vertebrae was thick to create the immense weight to balance the body. The tail is also believed to act as a third leg while the T.Rex walked or stood in a vertical position close to the posture of a kangaroo.

dino-648712_1920Inside Their Minds

According to Josh Newman’s writing in Science 2.0 an online scientific journal, T.Rex was a relatively smart dinosaur. Although the ratio of brain size to body mass was very small for T.Rex, it was larger than most other dinosaurs. T.Rex’s brain was larger than the human brain, but the cerebrum (the part of the brain that animals use to think) was tiny. T.Rex’s brain was long and almost cylindrical in shape. T.Rex also had depth perception (since both eyes faced forwards on the front of its skull, and not placed on the sides), but it was not the only dinosaur that had depth perception. In general, predators often have depth perception to help them hunt their prey. Animals that are hunted, omnivores or herbivores, usually have eyes located on the sides of their head (having no depth perception); this lets them see predators approaching from both sides. The senses of Tyrannosaurus were highly developed and surpassed those of most dinosaurs. T.Rex had large visual lobes in its brain that processed visual information. Their visual acuity(the accuracy of the processing of images in the brain) was 13 times that of a human, an eagle has the visual acuity 3.5 times human sight. (Newman) T.Rex could easily process about 4 miles in distance while humans can only process objects one mile ahead. T.Rex had a very acute sense of smell as well, it is found that the olfactory bulbs(the part of the brain that processes sent) were larger than any species of dinosaur found at this time. These estimates are taken from examinations of the skull and size of the brain cavity of the fossil, along with studies and prior knowledge of similar species such as birds and alligators. With this sensing ability, the Tyrannosaurus Rex would be able to smell the blood of any large animal within a 21 mile radius. (Newman)

Ongoing Discoveries

In May of 2005, scientist Mary Schweitzer found soft tissue of T.Rex within a fossilized femur bone, and the specimen is believed to contain cells of T.Rex.

When an animal dies, soft tissues such as blood vessels, muscle and skin decay and disappear over time, while bones may gradually be replaced by minerals from the environment and become fossils.

The soft tissue was found when Schweitzer probed the bone of a Tyrannosaurus:

‘The reason it hasn’t been discovered before is no right-thinking paleontologist would do what Mary did with her specimens. We don’t go to all this effort to dig this stuff out of the ground to then destroy it in acid,’ says dinosaur paleontologist Thomas Holtz Jr., of the University of Maryland. ‘It’s great science.’(Fields)

The soft tissue observations could shed new light on how dinosaurs evolved and how their muscles and blood vessels worked. And the new findings will help settle many debates about dinosaurs. More interestingly though, these remains could contain DNA. As molecular biology improves, these specimens could hold the key to Jurassic Park.


Tyrannosaurus Rex was a huge meat eating creature that, if alive today, would be unstoppable if it weren’t for our weapons. More advanced than us in many ways, these dinosaurs lived in a time where they were king of the world. With bodies built for killing, and a brain programmed for hunting, this brute’s only enemy were members of its own species. Naturally, the only thing that could kill off this species was the mysterious Extinction Event 66 million years ago that killed off all the dinosaurs If not for this catastrophic happenstance, we might still have these terrific creatures roaming our world.


Check out my long Works Cited page for any additional fact resources you may need if you are also doing this essay:





Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.