KidZone Animals: Dinosaurs
A long-necked dinosaur skeleton.
Photographed by Stanley Zimny;
used with permission under CC BY-NC 2.0
All long-necked dinosaurs belong to the sauropoda group. Since their necks are so long making it harder to support a large skull at the end, their heads have to be relatively small compared to their large bodies. All of the long-necked dinosaurs also have a thumb with a big claw. The sauropods were the first dinosaurs to reach gigantic sizes! They are so big in fact that current scientists can't quite understand how these dinosaurs managed to breath, beat their hearts, and basically live. The sauropods must have had several adaptations that we can't even imagine nowadays, which allowed them to run such a large body.
The lengths of these dinosaurs' necks ranged in size from very long, to slightly shorter. They all had at least 10 neck vertebraes but some of these dinosaurs changed some of their back vertebrae to become extra neck vertebrae. Others just increased the number of their neck vertebrae over time. Some of the sauropods stretched their neck vertebrae so they would be much longer (like a giraffe neck). These are all different techniques for evolving a longer neck and all of these techniques can also be used together.
Some of the most well-known sauropods (like diplodocus and brachiosaurus) were also MASSIVE, up to the size of 15 African Elephants! Some believe that being so large was a defense mechanism, since most predators would not risk taking down such a large prey. Another theory for their gigantic size, is that sauropods needed lots of space in their stomachs to digest food. Sauropods were very bad chewers but they were still herbivore. Plants are difficult to digest and chewing is useful because it pre-digests the food. Since sauropods were bad chewers, they would have needed more internal structures (like large intestines) to digest their food properly.
Being SO big also meant that the long-necked dinosaurs were SUPER heavy. In order to lighten their skeleton, the sauropods had pneumatic bones, which means that their bones were not solid but instead filled with air sacs. Importantly, it was the neck and upper skeleton that had these air-filled bones, but the limb bones were completely solid in order to support the body weight.