Diplodocus was a genus of several four-legged, plant-eating dinosaurs with very long necks, whiplike tails and a specialized claw on one toe of each foot. Its tail and claw may have been defensive weapons, but paleontologists haven’t confirmed this theory. These dinosaurs were among the longest land animals ever to walk the Earth. But while they were very long, they weren’t bulky. Diplodocus weighed less than half as much as similarly shaped dinosaurs like Apatosaurus.
Old Diplodocus illustrations often show it using its long neck to reach food in the tops of trees. Newer research suggests that the dinosaur wasn’t built to move this way — it probably couldn’t lift its head far above its shoulders. It could, however, move its head in great arcs from side to side. Instead of grazing from the tops of trees, it probably stripped vegetation from a wide swath of plants. As it grazed, Diplodocus didn’t do a lot of chomping. All of Diplodocus’ teeth were in the front of its mouth, so it couldn’t chew its food. Instead, it nipped at vegetation and swallowed it whole. These large chunks of vegetation would have been hard to digest, so Diplodocus got some help from rocks. It swallowed stones, known as gastroliths, which helped grind the leaves inside the dinosaur’s digestive system. Many depictions of Diplodocus show its nostrils on top of its head, near its eyes. In 2001, researcher Lawrence Witmer published a paper in the journal Science that refuted this idea. Witmer claims that the dinosaur’s nostrils didn’t line up with the nasal cavity in its skull. Instead, the nostrils were much closer to the mouth, allowing the nasal passageway to act as a heat exchanger and move excess heat away from the dinosaur’s brain. There’s evidence to suggest that some dinosaurs warmed their nests with their bodies and cared for their young. Diplodocus wasn’t one of them. Paleontologists have found lines of fossilized Diplodocus eggs, suggesting that these animals lay eggs while on the move and left them behind.