Diplodocus was one of the giants of the Jurassic, being one of the biggest and longest animals ever known. It was a herbivore that moved around slowly on four large legs, using its long neck to browse vegetation inaccessible to other sauropods.
Diplodocus' fore legs were slightly shorter than the rear ones and, unusually for a dinosaur, it gave diplodocus a slightly horizontal posture. No skull belonging to diplodocus has ever been found, but skulls from close relatives of diplodocus are relatively small for the size of the body; they have a small braincase and have peg like teeth at front of the mouth. The teeth were used to strip foilage off branches and were replaced continually throughout the life of the animal.