'Giganotosaurus' vs 'T-Rex': What's the Difference?

By Katie Moore, updated on September 25, 2023

‘Giganotosaurus’ vs ‘T-Rex’: What’s the difference? Whether you’re into natural history or are a huge fan of Jurassic Park, this article is for you. Let’s get prehistoric and learn to distinguish between two of Earth's largest and most dangerous dinos. 

In a hurry? Here’s a quick preview of what’s to come:

  • ‘Giganotosaurus’ was a type of carnivorous dinosaur that measured up to 48 feet long
  • ‘T-Rex’ was also a carnivorous dinosaur, most famous for its size, teeth, and powerful jaws 

What’s the Difference Between ‘Giganotosaurus’ vs ‘T-Rex’?

The most obvious difference between these two terms is that they describe two different species of dinosaurs. 

Both animals are Therapods, meaning they are carnivorous dinosaurs with hollow bones and three toes with claws. 

  • ‘Giganotosaurus’ belongs to the species G. Carolinii 
  • ‘T-Rex’ belongs to the species Tyrannosaurus

This means that while these dinosaurs may have looked similar, they had their own distinct features. Another major distinction is when and where these dinosaurs walked the earth. 

  • ‘Giganotosaurus’ lived during the Cenomian age of the Late Cretaceous period (around 99 to 95 million years ago) in modern-day Argentina. 
  • ‘T-Rex’ lived during the Maastrichtian age of the Upper Cretaceous period (around 68 to 66 million years ago) in western North America.

So, these dinosaurs never crossed paths both territorially and in terms of timeline. Additionally, scientists know much more about the ‘T-Rex’ because more of its fossils have been discovered. 

Since we have a more basic understanding of the differences between these two beasts, let’s learn more about them individually. Read below for a deep dive into the lives of ‘Giganotosaurus’ vs ‘T-Rex’.

Definition of ‘Giganotosaurus’: What is it?

According to Oxford Languages, ‘Giganotosaurus’ is a noun that means:

  • An enormous carnivorous dinosaur of the late Cretaceous period, resembling the tyrannosaurs

The origin of the word ‘Giganotosaurus’ comes from the Latin ‘gigas’ meaning “giant,” ‘nōton’ meaning “back,” and ‘sauros’ meaning “lizard.” However, the direct English translation is “giant southern lizard” because in Greek, the word ‘notos’ also meant south, indicating where the species was discovered. 

‘Giganotosaurus’ Facts

The ‘Giganotosaurus’ was discovered in modern-day Argentina in 1993 by the paleontologist Ruben Carolini. Since its discovery, about 70 percent of a full skeleton has been recovered. The recovered fossils suggest that the ‘Giganotosaurus’ may have been the largest carnivorous dinosaur. 

Here are some other facts about the ‘Giganotosaurus’: 

  • ‘Giganotosauruses’ could have been up to 43.3 to 48.5 feet in length and weighed almost 11 tons
  • It was discovered in the Candeleros Formation of Patagonia
  • It is a member of the Therapod family, meaning it has hollow bones and three toes per foot
  • It could run almost 20 miles per hour in pursuit of prey
  • Its scientific name is ‘Giganotosaurus Carolinii’ after its discoverer, and it is the only species of ‘Giganotosaurus’ that has been discovered.
  • It was close cousins with other therapods such as the Carcharodontosaurus (“great white shark lizard”) and the Tyrannotitan (“giant tyrant”).

Definition of ‘T-Rex’: What is it?

According to Merriam-Webster, ‘T-Rex’ is a noun that means:

  • A massive North American bipedal tyrannosaurid dinosaur of the late Cretaceous with a large skull, heavy tail, and reduced forelimbs having two clawed digits.

‘T-Rex’ is just a nickname for this giant beast. Its full name, ‘Tyrannosaurus Rex,’ comes from the Greek origin ‘turannos’ which means “tyrant,” ‘sauros’ which means “lizard,” and ‘Rex’ which means “king.” It is named for its size and also for the belief that it is one of the largest carnivores at the top of the food chain. 

‘T-Rex’ Facts 

While fossil fragments were discovered as early as 1874, the first fully credited discovery was in 1900 by Barnum Brown who was the assistant curator of the American Museum of Natural History. The skeleton was discovered in eastern Wyoming, which 66 million years ago would have been the island continent of Laramidia. 

Here are some other facts about the ‘T-Rex’:

  • It is the second largest carnivorous dinosaur to have existed, falling close behind ‘Giganotosaurus’
  • The dinosaur named Sue is the largest T-Rex skeleton in existence. It measures 40 feet in length and weighs an estimated 8 tons.
  • ‘T-Rex’ has very tiny front arms
  • ‘T-Rex’ could have up to 60 banana-sized teeth in their skull
  • They could run at speeds of up to 10 miles per hour, slower than a ‘Giganotosaurus’
  • The ‘T-Rex’ was among the last non-avian dinosaurs to exist before the comet extinction event

Pronunciations: How to Pronounce ‘Giganotosaurus’ vs ‘T-Rex’

While learning facts about these creatures is important, they don’t get you very far if you can’t say the names of those they belong to. Follow the guides below to learn how to correctly pronounce ‘Giganotosaurus’ vs ‘T-Rex’, then practice saying them aloud

Use this phonetic spelling of ‘Giganotosaurus’ as a guide:

  • ‘Gi-guh-no-to-sor-us’ (note that the ‘a’ in ‘giga’ is a flat sound like in “bus” and that the ‘au’ in ‘saurus’ is more of an ‘o’ sound like in “for”)

Use this phonetic spelling of ‘Tyrannosaurus Rex’ as a guide: 

  • ‘Ti-ra-no-sor-us Reh-ks’ (note that the ‘y’ sounds more like “fin” and the ‘x’ is a combination of the ‘k’ and ‘s’ sounds)

If you simply want to say ‘T-Rex’, use this pronunciation:

  • ‘Tee Re-ks’ (the ‘Rex’ stays the same)

How to Use ‘Giganotosaurus’ vs ‘T-Rex’ in a Sentence 

Now that you’ve learned so much about these dinosaurs let’s make sure you can discuss them on your own terms. Reference the sample sentences below to get an idea of how to use the words in various contexts. 

‘Giganotosaurus’ Example Sentences

  • The Giganotosaurus was actually discovered by accident when amateur paleontologist Ruben Carolini ran over the fossil with a dune buggy.
  • Although the Giganotosaurus was discovered in Argentina, its dinosaur relatives were discovered in parts of Africa, suggesting a connection of those continents. 
  • In the most recent installment of the Jurassic World movies, the Giganotosaurus was the featured predator that hunted the cast. 

‘T-Rex’ Example Sentences

  • Due to its status as “king of the dinosaurs,” the T-Rex has become one of the most popular and best-known carnivorous dinosaurs. 
  • Despite its fearsome size, many people make fun of the T-Rex for its disproportionately tiny arms. 
  • The T-Rex had an unusually large brain in proportion to its size, making it a very intelligent hunter with keen senses.

‘Giganotosaurus’ vs ‘T-Rex’ Example Sentences

  • Since there is no complete Giganotosaurus skeleton, there is still uncertainty, but scientists are confident it was larger than the T-Rex
  • The Giganotosaurus was much older than the T-Rex, having lived almost 30 million years before the age of the “king of the dinosaurs.”

Final Advice on ‘Giganotosaurus’ vs ‘T-Rex’

Given the popularity of the ‘T-Rex,’ many people already know basic facts about it — but now you can use your knowledge to debunk any assumptions about the ‘T-Rex’ being the largest carnivore. Remember to be slow and purposeful in your pronunciation of these new words, and keep the key differences between these species in mind. 

Need a quick review? Here’s a recap of what was covered:

  • ‘Giganotosaurus’ is the term for the largest carnivorous dinosaur discovered in Argentina.
  • The famous ‘T-Rex’ is the term for another carnivore discovered in Wyoming that reigned in the final age of non-avian dinosaurs. 

If you want to learn more about other beasts, both fictional and historical, be sure to check out other confusing word articles. They will help you distinguish creatures, and give you a foundational understanding of what they did and how you can discuss them.

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Written By:
Katie Moore
Katie is a recent graduate of Occidental College where she worked as a writer and editor for the school paper while studying linguistics and journalism. She loves helping others find their voice in writing and making their work the strongest it can be. Katie also loves learning and speaking other languages and wants to help make writing accessible for everyone.

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