Dinosaur Facts: Brachiosaurus

One of the tallest and biggest dinosaurs found in history is the Brachiosaurus, which had a lengthy neck, small head, and relatively thick tail. In this article, you will learn about the body features, diet, and habits of the dinosaur nicknamed the “Arm Lizard.”

The Brachiosaurus lived during the middle to late Jurassic time period, which was 156 to 145 million years ago. They lived close to the middle of the Mesozoic Era , referred to as the Age of Reptiles. Other dates estimate the Brachiosaurus as surviving until 140 million years ago, which is the dawn of the Cretaceous period.

The Body

Walking on four legs, the Brachiosaurus traveled about with front legs that were longer than its hind legs. This was a common characteristic of Brachiosaurids that most other dinosaurs do not possess. Because of their unique front legs coupled with their long necks, the Brachiosaurus resembled a giraffe with its height and body posture. The creatures could reach heights up to 40 to 50 feet tall and lengths around 85 feet long. They could weigh anywhere from 33 to 88 tons.

On the feet of the Brachiosaurus, a claw was found on the first toe of each front foot and claws on the first three toes of each back foot.

Other features of the dinosaurs include:

Chisel-like teeth
Nostrils found on the top of the head
Large nasal openings that indicate an efficient sense of smell


The Brachiosaurus lived on land and were herbivores, which means that the dinosaurs’ diet consisted of plants. Scientists believe that the dinosaurs consume the tops of tall trees using their large teeth. The food is swallowed whole and is digested in the gut without it even being chewed.


Researchers suspect that the Brachiosaurus traveled in herds and may have migrated whenever they had depleted their local food supply. Like other sauropods, this species of dinosaur was though to hatch from eggs. Found in a linear pattern (instead of gathered in a nest), sauropods eggs have been found, which makes some researchers think that the eggs were laid while the creature was walking. The eggs are believed to have been left behind with no one to take care of the hatchlings.


When the Brachiosaurus reached the age of an adult and was in good health, the creature most likely did not have any predators. During the late Jurassic period, the Brachiosaurus had to contend with the Allosaurus, Ceratosaurus, and a few other theropods. Although they were the largest meat-eaters of the time period, the therapods were less than half the size of the Brachiosaurus. To them, smaller sauropods and dinosaurs, such as the stegosaurus, were much easier to hunt than the larger Brachiosaurus.

Brachiosaurus Fossils

The first Brachiosaurus fossils were discovered in the Grand River Valley in 1900, which is located in the western part of Colorado. It was an incomplete specimen that paleontologist Elmer S. Riggs named in 1903. A collection of Brachiosaurus fossils were uncovered in Tanzania, Africa by Werner Janensch in 1909. The bulk of fossils belonging to this dinosaur species have been found in North America and Africa.