Category Zoology

                    The Pachycephalosaurus had a reinforced skull, which was probably used   when rival males fought each other.

                     Pachycephalosaurus was a medium-sized dinosaur, up to about 8 m long, although many of its relatives were much smaller. They all had an enormously thickened domed skull, and their spine was strengthened. Scientists think that adult males could ram each other with force when competing for a mate.

                    Despite its fierce appearance, Pachycephalosaurus was a plant-eater. In many forms, the skull was decorated with spikes and knobs of bone.

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                 The hip bones of many dinosaurs evolved in such a way that walking upright on two legs became an efficient way to travel. Dinosaurs that walked in this way developed long legs, which allowed them to walk and run very efficiently. Scientists used to think that they walked in an upright position with their tail dragging on the ground, but we now know that the tail stuck out horizontally to balance the forward-leaning body. These dinosaurs were able to stand upright while grazing.

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                       There were thousands of different species of dinosaur, and we have discovered only a small proportion of these. It is important to realize how rare fossils are. A few dinosaur species must have been very common, for example Iguanodon, which left many fossils. Others were probably scarce when they were alive or lived in regions where fossilization was unlikely, and so there are few remains of these dinosaurs.

                      Herbivores often lived in groups or herds, but carnivores were usually more solitary and their fossils are therefore more rare. Many of the most interesting dinosaurs are known from a single fossil, or sometimes from just one or two bones. Palaeontologists must deduce the shape and size of the animal from these few remains.

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                    We can reconstruct the shape and habits of dinosaurs from their remains. Dinosaurs also left behind other evidence, in the form of their footprints.

                     These were imprints in mud that were later covered by flood waters and became fossilized. Some of the dinosaur footprints give us a good idea about how these animals lived and moved. By measuring the distance between each footprint we can measure the stride of the animal, and from this we can calculate how fast the dinosaur moved. Footprints also show that dinosaurs sometimes moved in herds or small family groups, and they show evidence of dinosaurs being hunted by predators.

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                     How do you measure the intelligence of an extinct animal? What we can say is that the intelligence of dinosaurs must have been sufficient for their way of life — otherwise they would not have survived for millions of years. Some plant-eating dinosaurs certainly had very small brains in proportion to their size. However, a large brain is not important in an animal which is too enormous to be attacked and has little to think about apart from grazing. On the other hand, some of the predatory dinosaurs had quite large brains, presumably because they needed to think quickly as they pursued their prey.

                   In comparison with their size, the brains of the smallest dinosaur predators were the biggest, because they needed to be agile and fast moving.

                The main thing that distinguishes dinosaurs from other reptiles is the way their body is supported by their legs. The legs of ancient and existing reptiles stick out sideways, so the body drags on the ground for most of the time. It is raised briefly when the animal runs. This is very obvious with crocodiles, which can run very fast for short distances. The skeletons of dinosaurs developed so the legs were beneath the body, raising the whole body off the ground. This allowed them to stand erect, and to walk and run with long strides. Predators developed that could run faster than more primitive reptiles, which soon became extinct.

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