Brontosaurus Vs. Brachiosaurus – Everything You Wanted to Know

Most of us have learned about dinosaurs, the previous inhabitants of our planet, from school or from watching documentaries on YouTube. Some of you may have intimate knowledge about all the different species of dinosaurs that reigned over our planet in the late Jurassic Period. 

Despite all that knowledge, there are two species of dinosaurs that almost no one is able to differentiate between. Yes, we’re talking about the Brontosaurus and the Brachiosaurus. In fact, you might not have even heard their names before reading this article (something that’s highly unlikely but possible)! 

So, to give you a complete overview of their distinct features, behaviors, characteristics, and more, we’ve come up with this article that comprehensively displays their differences in a list-style format. Without further ado, let’s get straight into the details of these two behemoths who dominated our world. 

Brontosaurus – Characteristics, Behavior, Discovery

A dinosaur’s existence can only be verified through fossils, and that’s exactly what Othniel Charles Marsh managed to do in 1879. He discovered the remains of the brontosaurus spread out over the regions of Utah, Wyoming and Mexico. And a few more spread out across the western part of the northern hemisphere. 

However, it was later determined that the remains found were of another family of dinosaurs quite similar to the brontosaurus, known as Apatosaurus. This didn’t derail the investigation into the brontosaurus, who were thought to have occupied our planet millions of years ago. 

The name Brontosaurus means “thunder lizard” in Greek. This name was assigned to them once researchers discovered they could produce sounds greater than 200 decibels, louder than a cannon. These enormous creatures could create that sound by whipping their tail and slamming it on the ground.  

They’re a genus of large, herbivorous dinosaurs with long necks and tails, belonging to the larger family Diplodocidae. To date, they’re still considered one of the largest land animals that ever existed, measuring up to 72 feet (22 meters) in length and weighing up to 15 tons. 

As a herbivore, their diet mainly consisted of plants and the leaves of trees, particularly ferns and conifers. 

When it comes to their appearance, their most distinctive feature was their incredibly long necks, which were longer than those of giraffes, measuring anywhere from 30 to 50 feet in length. This feature enabled them to reach vegetation high off the ground. Other notable physical features include a large and weighty tail that they used for balancing over their small, stubby legs. 

Here’s an interesting BBC documentary to help you learn more about these majestic giants – Brontosaurus!

Brachiosaurus – Characteristics, Behavior, Discovery

Brachiosaurus is another herbivorous dinosaur species discovered in 1900 by Elmar S. Riggs in Western Colorado. This specimen was named the brachiosaurus and was later discovered to belong to the family of Brachiosauridae. A group of sauropod dinosaurs were known for their long forelimbs and necks. Several other species since then have been discovered in the United States and Mexico, none as abundant as this one. 

Brachiosaurus, like the Brontosaurus, is still known to be one of the largest land animals that ever lived, measuring up to 85 feet (26 meters) in length and weighing up to 80 tons. On top of that, brachiosaurus was also a herbivorous dinosaur, with its diet mainly consisting of high-growing vegetation like leaves and branches. 

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The brachiosaurus was a quadrupedal dinosaur, meaning it walked on four legs. These majestic giant creatures were also known to hang around together in a herd, deterring any predators that wished to cause them harm. Besides its four legs, the brachiosaurus was known for its distinctive long neck and large nostrils at the top of its head. This feature enabled them to breathe with ease while partially submerged in water. 

Another distinct feature is their spoon-shaped teeth, adapted to strip vegetation from branches. Overall, the brachiosaurus was an impressive dinosaur that roamed the earth millions of years ago. 

Its massive size and unique body shape make it an essential part of the Late Jurassic ecosystem.

Want to learn more about Brachiosaurus? This BBC documentary has detailed information that would interest you!

5 Key Differences Between Brontosaurus and Brachiosaurus

Size and Weight

While they’re both the biggest animals, and creatures in general, to exist in the world, the brachiosaurus has an edge in size and weight over the Brontosaurus. In fact, that edge is quite significant when you compare their respective weights. The brachiosaurus was known to weigh up to 80 tons. In comparison, the brontosaurus was known to weigh up to 15 tons. 

Meaning there’s a 65-ton difference between their respective weights! That’s not all, as the brachiosaurus was also larger in size than the brontosaurus. The former majestic giants measured up to 85 feet (26 meters) in length, while the latter measured up to 72 feet (22 meters). 

Not unlike giraffes, both creatures were also quite docile, and only used their huge size and weight to forage for high-growing vegetation like the leaves and branches of trees. 

Neck and Forelimbs

As we’ve already established in the sections above, the Brontosaurus and Brachiosaurus were known for their huge necks stretching over trees and four shorter, stubby legs. 

Unlike giraffes, who are also known for their incredibly long necks, the necks of both the Brontosaurus and Brachiosaurus were almost completely bone. This is because their spines stretched across nearly the entire length of their necks. 

However, you might not have known that the brachiosaurus had a longer neck and forelimbs relative to its body size than the Brontosaurus. There were some differences recorded in the forelimbs of the two giant beings as well. The forelimbs of brachiosaurus were discovered to be much more robust and vertical. In comparison, those of Brontosaurus were found to be more slender and angled downwards. 

Lastly, a unique trait found in brachiosaurus that further differentiates them from Brontosaurus was that Brachiosaurs’ forelimbs were bigger than their hind limbs. 

Placement of Nostrils

We’ve previously discussed how the nostrils of the brachiosaurus were placed on the top of their head, allowing them to breathe while partially underwater. In fact, as we’ve continued to discover more about dinosaurs, we’ve realized that almost all of these creatures had their nostrils placed in different places, and the Brontosaurus is no exception to that rule. 

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The Brontosaurus, unlike the brachiosaurus, had its nostrils placed at the side of its head. This little physical feature hugely helped these massive creatures. 

Firstly, having nostrils at the sides of their heads allowed the brontosaurus to detect the scent of predators much faster, detecting them from all around rather than just the front of its face. Thereby extending the radius of detection. 

Like the Brachiosaurs, the Brontosaurs used these nostrils to breathe partially underwater as they foraged for food. 


Teeth are important classifiers when it comes to identifying different species of dinosaurs that occupied the earth all that time ago. That’s because almost every dinosaur species had different types of teeth used for various purposes while they walked the earth. 

This rule also applies to Brachiosaurs and Brontosaurs. They both possessed a set of teeth vastly different in appearance and size. According to research, a Brachiosaurus has longer spoon-shaped teeth used to strip off branches from trees. 

While, Brontosaurus were known to have shorter, more peg-like teeth that they used to strip off branches and eat the vegetation of trees. 


Our last difference on this list is not physical in nature. But we’d argue it’s just as important if you want to differentiate between these two behemoths completely. This difference relates to the different habitats both Brachiosaurs and Brontosaurs chose to live in. 

While they’re are considered to be living relatively close together in terms of the actual timelines of their existence, brachiosaurs were slightly superior to Brontosaurs, primarily because of their larger size and weights. 

So, it shouldn’t be a shock to anyone that Brachiosaurs preferred living in higher elevations than Brontosaurs. This brings us to the conclusion that many have spent most of their lives in forests. 

Brontosaurs, on the other hand, evident from their remains being found in low-lying areas of Utah, Wyoming and Mexico, preferred to live in lowland, desert-style regions.

Final Words

And there you have it folks, that was our list of the key differences between a Brontosaurus and a Brachiosaurus. We hope you enjoyed and absorbed all the information we dished out. No matter how much we progress, dinosaurs have and will always fascinate us and keep our imaginations active. There’s obviously a lot of information that’s based on reality, but a lot is also debatable because the Jurrasic Period existed millions of years ago.

However, we tried to stick to the facts as much as possible to help you learn more about your favorite dinosaur species and the features that keep them distinctive.

Most of all, we hope we have answered all your questions regarding the similarities and differences between the two distinctive dinosaur species. Especially their physical features, which are quite different once you take a closer look at them. You know, if it ever comes up in a discussion or argument. 

Lastly, we hope that we’ve also managed to clue you in on some of the history relating to these two gigantic creatures that used to live way before our time. 

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Nadine Oraby

My name is Nadine; I am a passionate writer and a pet lover. People usually call me by the nickname “Joy” because they think that I am a positive and joyful person who is a child at heart. My love for animals triggered me to create this blog. Articles are written by vets, pet experts, and me. Thanks for visiting. Your friend, Nadine!

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