This well-known, long-necked dinosaur was named in 1878. Many Diplodocus skeletons are known from the Jurassic deposits of Colorado, New Mexico, Utah, and Wyoming. Some early reconstructions wrongly portrayed Diplodocus in a sprawling posture, but this would have required a trench in the ground to accommodate its deep chest. Other researchers suggested it was amphibious and spent its life in the water to support its great weight. In reality, Diplodocus stood tall on straight, pillar-like legs and was fully terrestrial. It spent all of its time on land using its long neck to browse on tough vegetation.
The industrialist Andrew Carnegie, who funded many early dinosaur excavations and to whom the species D. carnegii refers, donated casts of his namesake to museums around the world. These replicas were taken from an original Diplodocus skeleton in the Carnegie Museum of Natural History, Pittsburgh, and ended up in Europe, Russia, Argentina and Mexico. This contributed to Diplodocus becoming recognized around the globe.
Preserved soft tissues in some specimens show that Diplodocus had scaly skin, and may have had soft triangular spines along the top of its neck, back and tail. Its extremely long, whip-like tail was probably used as a defensive weapon.