Diplodocus (De-plod-i-cuss) lived in western North America during the Late Jurassic Period. It was one of the longest dinosaurs, typically reaching 87 feet in length. Specimens are known, however, that would have reached over 100 feet.
Diplodocus was a relatively lightly-built brontosaur (if that is not a contradiction in terms) with a very long neck and tail. The tail was thin and whip-like, and it has been speculated that this dinosaur may have used it for defense. Some specimens of Diplodocus have been discovered with arthritis in the tail. Recent finds suggest that Diplodocus may have had narrow spines along its back, similar to those of the modern-day Iguana lizard.
The head of Diplodocus was very small compared to its overall size. The skull was elongated with simple, peg-like teeth near the front of the mouth. The nostrils were placed on top of the head, between the eyes.
Some scientists have conjectured that Diplodocus ate vegetation that was very high off the ground, whereas its contemporary, Camarasaurus, would have focused on vegetation at a more intermediate level. Although, Diplodocus may not have been able to raise its long neck much beyond the horizontal plane, it may have been able to reach the tops of the highest trees by standing on its hind legs.
Diplodocus has probably been featured in more museum displays than any other brontosaur. This is largely because steel magnate Andrew Carnegie donated many copies of a particular skeleton, which represented a species named in his honor (Diplodocus carnegii - pronounced carn-neg-ee-eye). Cities in which these copies were displayed include London, Berlin, Paris, Vienna, Madrid, Bologna, St. Petersburg, Buenos Aires, and Mexico City.