Prehistoric Animals


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Dinosaurs skeleton

Skull and skeleton

The wide variety of skeletons exhumed for more than 200 years reflects the immense diversity of the group of dinosaurs. The dinosaurs formed an important and very diverse group, which is well illustrated by their varied skeletons, from the largest animals on Earth to the elegant and delicate shapes of the smallest specimens. Despite this, they had a lot of common traits.

Diversity of skeletons

If dinosaurs were a flourishing group, it's partly because of their anatomical structure. Their hind limbs were just above the body, allowing them to swing back and forth, not crawling like many other reptiles. Some, including theropods, also had hollow bones which reduced their weight while providing a strong support. In sauropods, the skeleton was also adapted to be less heavy. Despite, or more accurately because of their gigantic size, this skeleton should be as light as possible while being strong enough to support their weight. The vertebrae of the neck, for example, had orifices and cavities with numerous projections reduced to flying buttresses. For example, the American paleontologist Edward Drinker Cope gave the dinosaur with this type of hollow cervical the name of Camarasaurus (chambered lizard). In other parts of the skeleton, structural strength was more important than weight gain. In sauropods, ceratopsians, stegosaurs, and ankylosaurs, the bones of the anterior and posterior limbs were massive to carry the heavy burden of the animal. The hind limbs were standing as straight as possible to improve their carrying capacity. Armours, points, plates and bony shields, which weighed down the animal, were found only in quadrupeds whose weight was better distributed. In small dinosaurs, flexibility and agility were important. The small theropods and ornithopods had a skeleton of light structure and a great flexibility of joints. They also usually had very long legs for their size, which made them famous for escaping the biggest predators.


Carnivorous skull

Bones weighing a lot more than flesh or muscles, the heads of some dinosaurs were very heavy because their size was imposing. For ceratopsians, however, this bone box was an advantage because it protected the animal against predator attacks and injuries in combat. The heavy weight of the skull rested on a very short neck, supported by huge muscles. In sauropods, on the other hand, the head was perched at the end of a long neck. It had to be big enough to allow the animal to take the amount of food it needed, and small enough not to weigh too much on the neck. In some specimens, windows in the skull contributed greatly to lighten the weight of the skull. The theropods usually had a large head that should not only be as light as possible, but also withstand the force on it when the animal gutted its prey or fought violently with another dinosaur. Their skull thus included large orifices framed by very robust bone arches.