During the Mesozoic Era millions of dinosaurs belonging to thousands of species roamed our planet. They were the largest and most important animals on land. Today there are no living dinosaurs anywhere, they have all become extinct. Dinosaurs became extinct at the end of the Cretaceous Period, and then vanished from all the continents at the same time. As fossils cannot be dated exactly it is impossible to say if the extinction happened suddenly or was spread out over thousands of years. Once an animal has become extinct it cannot come back naturally.

Blood sucking insects, such as mosquitoes, used to feed on the blood of dinosaurs, much as they feed on animals today. Sometimes these insects have been trapped inside the resin from trees and become fossilized and form amber, thus preserving the insect. This could enable scientists to recreate dinosaurs from information contained in the DNA extracted from the blood of these insects.

Several other groups of animals vanished at the same time that dinosaurs became extinct. The flying reptiles, the pterosaurs and sea reptiles. Several types of shellfish, reptiles and other animals also died out about the same time.

Scientists studying the rocks from the time dinosaurs became extinct noticed that they contained large amounts of a chemical called Iridium. This chemical is rare on Earth, but is common in asteroids. This interestingly enough suggests one theory that a giant asteroid hit our planet and from the impact and explosion scattered dust all over the planet, and if it was big enough would have filled the upper atmosphere blocking the sun and plunging it into a long period of freezing darkness. Inevitably this would have killed most plants and without food, the dinosaurs would have become extinct and died out.

There are obviously no dinosaurs alive today and to date there have been no fossils found which date to after the Cretaceous Period. It would seem that all the dinosaurs died out. However a type of Theropod dinosaur had evolved into birds around one hundred and sixty million years ago. These birds survived, so the descendants of dinosaurs did survive the extinction. After the dinosaurs became extinct other types of animals took over the world, and even though mammals were small in numbers when the dinosaur was about, they have now increased in number and have rapidly evolved into many different types of animal, and now it is the mammals that rule the planet as the dinosaurs once did.

There are other theories that can explain the extinction of dinosaurs this is just one of them, and if scientists could recreate dinosaurs from the DNA of prehistoric insects, how would they contain such large and ferocious animals amongst our populated world, scary stuff.


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