Tyrannosaurus Rex – A Formidable Predator of the Cretaceous

Quick Biography

The Tyrannosaurus Rex is one of the most well-known dinosaurs that have ever existed, if not the most popular. This is in part due to its popularity in the Jurassic Park franchise, but also because there have been more than 50 individual near-complete fossils found, and many more less-complete ones, as well.

Quick Facts

  • Scientific Name: Tyrannosaurus
  • Period: Upper Cretaceous
  • Size (m): 12.4
  • Weight (tons): 8.8
  • Diet: Carnivore
Tyrannosaurus rex skeleton
© Wikimedia Commons

Discovery & Location

The Tyrannosaurus Rex, also known as “T. Rex,” is a Theropod. Its name ‘rex’ means “King” in Latin. It lived throughout what is now known as western North America, on an island then known as Laramidia. It had one of the largest ranges of hunting grounds of most other tyrannosaurids. They lived around 66 Million Years ago.

Tyrannosaurus rex size comparison
© Wikimedia Commons

How Big Did It Grow?

It was the last known member of the tyrannosaurid family. Like other tyrannosaurids and theropods alike, they were bipedal in nature, with a massive skull. The most complete specimen was 40 feet (12.3 meters) in length and was about 12 feet (3.66m) tall. It is thought to have between 8.4 and 14 metric tons in weight. There have been many discussions about whether they had feathers or not, as well.

What Did It Eat?

It was by far the largest carnivore in its environment, so it was most likely an Apex Predator and preyed upon hadrosaurs, armored herbivores (including Ankylosaurus), and quite possibly Sauropods like the Apatosaurus. The Tyrannosaurus Rex was estimated to have the strongest bite force of all terrestrial animals of its time. Feeding habits though have been a matter of a few subjects of debate. Some say it was more of a scavenger than an active predator, while others say that it was more of an active predator. Both of these were likely true, it likely ate both already dead animals (as in a scavenger), and actively hunted for food.

Body Design & Health

As for the debate on whether the Tyrannosaurus Rex was feathered or not, filamentous structures, which commonly are recognized as precursors to feathers, have been found in other tyrannosaurids like the Dilong Paradoxus found in China. They may have had feathers when they were younger and lost them when they grew, or they may have had them during their entire lifespan. Studies have found that they may have even only had feathers on the upper side of the trunk area.

Their lifespan was likely around 30 years old if they survived that long. The fossil, Sue, was estimated to be 28 years old when it died, and they’ve found bones from an estimated 14-year-old T. Rex, as well as a 2-year-old T. Rex. The sudden change in growth rates at the end of growth spurts may have indicated physical maturity; a hypothesis that is supported by the discovery of medullary tissue in the femur of a 16 to 20-year-old fossil from Montana. Medullary tissue is found only in female birds during the time of mating. This indicates that they may have been able to reproduce around that age.

The Tyrannosaurus Rex was historically described as a “living tripod,” with the body at a 45-degree angle, and dragging its tail along the ground, like a kangaroo. But in 1970, they realized that this was incorrect. It would have resulted in a dislocation or weakening of several joints, including their hips and the articulation of their head and spinal column. Thankfully, films like Jurassic Park used a more accurate posture to show to the general public! Modern representations of the T. Rex in museums, art, and film show that it was approximately parallel to the ground, with the tail extended to balance the head.

Tyrannosaurus rex - colored
© Wikimedia Commons

Speed & Survival

It is unknown how fast it could run exactly, but scientists have estimated that it could have been around 25 MPH (or 40 KM/h) on average, as low as 11 MPH (18 KM/h), and as high as 45 MPH (72 KM/h). There are many tracks of large theropods walking, but rarely (if any) have the pattern of running. Scientists who think the T. Rex was able to run have pointed out that hollow bones and other features that would’ve lightened its body may have kept an adult to a max weight of a mere 4.5 metric tons; like ostriches and horses which have long and flexible legs are able to reach high speeds through slower and longer strides.

The estimated top speeds of the Tyrannosaurus Rex were around 25 MPH, but were deemed impossible because it would require exceptional leg muscle mass of around 40 to 85% of its total weight! Even moderately fast speeds would require large leg muscles. If their leg mass was less, their max speeds would have been around 11 MPH.

The Tyrannosaurus Rex may have hunted in packs at times, according to fossil evidence. This was because a fossil that has been found in South Dakota found 3 T-Rex skeletons in close proximity to each other. Some of their prey, like Triceratops & Ankylosaurus, had significant defenses, so it would have been more effective for them to hunt in groups. Although this behavior has been criticized, due to not having been peer-reviewed, like normal, but was discussed on a TV interview. The Tarbosaurus and Albertosaurus, on the other hand, likely did hunt in packs (the basis for this hypothesis).

The T. Rex may have been severely affected by parasites and other traumatic injuries by other carnivores. Infections in a Tyrannosaurus Rex were rare, according to Scientific American’s website. There has been evidence that the fossil Sue was infected by a parasite, which caused injuries to her lower jaw, which was a somewhat common occurrence amongst the Tyrannosaurus Rex species. The juvenile fossil, Jane, might have been bitten by another juvenile Rex, suggesting that the mighty Tyrannosaurus Rex may have fought each other for food, as well.

T. Rex In Media

The Tyrannosaurus Rex is one of the most popular dinosaurs in all media. If there’s a movie or video game with dinosaurs, you can almost bet that a T. Rex will show up in the movie, they’re that popular. Sometimes, it feels that they’re overrepresented, to the point that they should let other dinosaurs have time in the spotlight as main characters in a game or movie/tv show.

Want To See This Creature LIVE?
Join in Kenson’s Streams if he’s playing a game with this dinosaur, he can switch to it upon request so you can see it in action!

Concluding Thoughts

As one of our favorite species of dinosaurs, the T-Rex will sit firmly in our Top 10 Carnivores list. Thank you for your time, have a rawrsome day, and we’ll see you next time in the Mesozoic Haven! Don’t forget to pop into Kenson or Cupara’s streams!

Leave a Comment

Skip to content