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[dih plO dah' kus] the "double beam" dinosaur


This sauropod lived during the Late Jurassic period, from 155 to 145 million years ago. Its name means "double beam," which refers to a special feature of the backbone -- it had extra bones underneath it, which had bony protrusions running both forwards and backwards, probably for support and extra mobility of its neck and tail. A group of nerves concentrated in the base of the spine is believed to have helped control the hind legs and tail of the Diplodocus. A fossilized skin impression of a Diplodocus was found that shows it had a row of spines running down its back. The front legs were slightly shorter than the hind legs, and each foot 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 way as modern-day elephants.

One of the longer species of dinosaurs, the Diplodocus grew 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. It probably weighed between 10 and 20 tons.

Diplodocus skeleton in relation to humans
Diplodocus skeleton in relation to humans

The eyes of the Diplodocus were located far back on either side of its head, and its nostrils were situated on top of its head almost between the eyes.

Diplodocus skull
Diplodocus skull


Most Diplodocus fossils have been discovered in the Rocky Mountain region of North America, particularly in Montana, Utah, Wyoming, and Colorado.


The Diplodocus probably fed on conifer-like plants, ferns, and mosses, since these were the plants that were most abundant at that time. Its teeth were blunt and only located in the front of the mouth, which probably meant that they were used to strip the leaves off of plants.

diagram of a Diplodocus tooth
diagram of a Diplodocus tooth


Like other Sauropods, the Diplodocus probably laid its eggs while walking, as opposed to in a nest.


Diplodocus probably traveled in herds, migrating when the local food supply was depleted.

Fossil History

The first Diplodocus fossil was found by Earl Douglass and Samuel W. Williston in 1877, and was named Diplodocus longus by paleontologist Othniel C. Marsh in 1878.

Scientific Classification

phylum Chordata
subphylum Vertebrata
class Archosauria
order Saurischia
suborder Sauropoda
family Diplodocidae
genus Diplodocus


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The Robinson Library >> Paleontology

This page was last updated on 09/28/2018.