Category Science

                            Various reptiles have developed the ability to glide, but the pterosaurs were the only ones to develop true flight. The arms of a pterosaur were quite short, and its entire wing was supported by an enormously long fourth finger, leaving the other fingers free to function as a hand. A thin, skin-like membrane was stretched from the elongated finger to the sides of the body, and sometimes to the hind legs.

                             The whole body of the pterosaur was extremely light, with hollow bones. In several forms the head was larger than the entire body. Some pterosaurs had tails, while others were tail-less. Some fossils even show signs of hair covering the body. Many pterosaurs lived a similar life to the modern seagull and the albatross.

Picture credit: google

                        Crocodiles are not dinosaurs, although they both evolved from the same type of reptilian ancestors at about the same time. Crocodiles have changed very little over millions of years, because their body is vet well suited to their lifestyle and has not needed to evolve. Fossil forms range from tiny crocodiles of less than 1 m up to 16 m long giants. This is more than twice as long as any crocodiles still living today.

Picture credit: google

                            Placodus was a very large, heavily built reptile that probably lived on shellfish. It had spade-like teeth at the front of its mouth for chipping shellfish off rocks. The broad blunt teeth at the back of its mouth were used to crush the shells before the meat was swallowed. Placodus was a stocky, clumsily built animal that would have found it awkward to move about on land. Some species developed heavy armour like that of a turtle.

                    Ichthyosaurs are an interesting example of what is known as parallel evolution (when unrelated animals sharing the same habit come to look very similar). In this case, ichthyosaurs, dolphins and sharks evolved into almost the same shape. Ichthyosaur fossils are very common, and there were many different types. They all had long beaks lined with shark teeth for feeding on fish. The largest types were 10 m long. Although some other marine reptiles probably laid their eggs on beaches, the streamlined fish-like ichthyosaurs were completely aquatic and gave birth to live young. Unborn babies have been found inside their remains. One odd feature of the ichthyosaurs is the large ring of bony plates around their eyes.

Picture credit: google

                       Mosasaurs were relatives of the modern monitor lizards, but they differed from monitors in being up to 10 m in length. Mosasaurs had a long snaky body, which was flattened to help them swim, and paddle-like limbs. These animals were so modified to suit their marine environment that they could probably not venture onto the land. They are known to have fed on ammonites, because mosasaurs teeth marks have been found on the fossil shells of these creatures. Mosasaurs died out at about the same time as the dinosaurs.

                              Many scientists believe that the largest dinosaurs, such as the sauropods, may have lived for as much as 100 years. This can be calculated because of the time it would take for an animal to reach the enormous body weight of these sauropods. This calculation takes into account their vegetable diet, which was not very nutritious.

                            The world would have been a very dangerous place for young dinosaurs. We do not know which dinosaurs cared for their young. However, young dinosaurs probably developed quickly in order to become independent and able to look after themselves. The modern crocodile is one of the few reptiles that look after its young until they are able to avoid predators.