The Diplodocus was a dinosaur that lived during the Late Jurassic period. It was an herbivore, meaning that it ate plants. It was a sauropod, or “lizard-hipped” quadruped dinosaur that walked on all four feet. Its name means “double beam”, and this comes from a special feature of the backbone of the Diplodocus which probably served as extra support for its long neck and tail.

Its backbone was hollow but very strong. There was a group of nerves concentrated in the base of the spine that specifically helped to control the hind legs and tail of the Diplodocus. Paleontologists speculate that the ribs of the Diplodocus were not attached to the backbone, but instead were attached to the skin in the belly area.

These ribs, called gastralia, were thin and fragile but still helped to support and protect the lungs and other internal organs. Although there isn’t a lot known about the skin of the Diplodocus or what color it might have been, a fossilized skin impression of a Diplodocus was found that shows it had a row of spines running down its back.

The eyes of the Diplodocus were located far back on either side of its head, and its nostrils were situated in an unusual place, on top of its head almost between the eyes instead of on the muzzle. It’s not certain why the nostrils were located in this spot. The Diplodocus was one of the bigger species of dinosaurs, often growing to be as long as 90 feet and as tall as 16 feet at the hips.

Its neck alone was as much as 26 feet long, and its tail was up to 45 feet long. In spite of its huge size, it was fairly light in weight compared to other giant sauropods. It probably only weighed 10-20 tons. Its head, however, was small in comparison to the rest of its body, and was only about 2 feet long. Therefore the brain of the Diplodocus was small as well, about the size of a fist, and that means it wasn’t very smart.

In fact it probably was among the least intelligent species of dinosaur. The front legs of the Diplodocus were slightly shorter than the hind legs, and its feet each had five elephant-like toes, one of which had a claw that could have been used for defensive purposes. It probably walked much the same as the elephants of today, with a slow, even gait.


The plant-eating Diplodocus probably ate a lot of conifer-like plants, because that was the kind of plant that was most abundant at that time. It also may have eaten a lot of different kinds of ferns, as well as softer plants such as club mosses or other kinds of moss, and perhaps even seed pods from these plants.

Scientists speculate that the neck of the Diplodocus was so long because it could use it when trying to poke its head into forests to get to the foliage or plants there. It couldn’t reach these plants otherwise because its body was too big to get into these forests. Also the long neck might have allowed the Diplodocus to reach ferns that grew in wet, swampy areas that it could not get into because of their size and weight.

However it may have been able to stand on drier, safer ground and reach these plants with its long, sinewy neck. The teeth of the Diplodocus were blunt, simple and pencil-like or peg-like, and only located in the front of the mouth, clustered closely together. This probably meant that the teeth were used to strip the leaves off of plants. Then the leaves or plant materials were swallowed whole, without any chewing.

The plant materials were digested with the aid of stones called gastroliths, which the Diplodocus would swallow. Paleontologists think that, because of its huge size, the Diplodocus would have had to eat a huge amount of leaves and other plant material every day just to stay alive. Some even speculate that this giant sauropod would have had to eat constantly during the time it was awake in order to keep its body going.


The Diplodocus probably lived mostly in the western half of the United States. Most of the fossils from this dinosaur have been discovered in the Rocky Mountains, Montana, Utah, Wyoming, and Colorado.


Although the Diplodocus might have been prey to carnivores such as Tyrannosaurus Rex or Allosaurus, its huge size probably helped to protect it somewhat from its enemies. Also it is thought that the long tail of the Diplodocus was used for protection, by swinging its tail forcefully in a whip-like fashion. If used in this way it could have been very effective and even deadly.

Social Structure

The Diplodocus may have lived in and traveled in herds, which migrated from place to place when the local supply of plants was all eaten. Living in groups may have also provided the Diplodocus extra protection from any predators that were a threat.

Birth & Offspring

The Diplodocus laid eggs like other sauropods. From what fossilized evidence tells us, the Diplodocus did not lay its eggs in a nest, but probably were laid while the dinosaur was walking. It is thought that sauropods such as the Diplodocus did not take care of their eggs or their young as some other species of dinosaurs might have, but there is really no way to tell for sure if this is so.


The eyes of the Diplodocus were located on either side of its head, and rather far back on its skull. This would allow the dinosaur to see its enemies approaching from most directions more easily. Smell was important in not only detecting predators or others in its herd, but also in locating food. Like other dinosaurs, the Diplodocus probably communicated by making some kind of sounds to signal danger or distress, to attract a mate, or keep in touch with others in the herd.

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