Cretaceous

During the Cretaceous period, the world was a lot warmer and more humid than it is today. This provided ideal living conditions for many animals and plants. The heyday of the dinosaurs continued into the Jurassic, despite the fact that some species had died out by the end of the Jurassic. During the Cretaceous period, new species appeared. For example, during the Cretaceous, many dinosaurs arose with a horns around their mouth, and even dinosaurs with something similar to a beak. The most famous dinosaur species also developed in the Cretaceous: the Tyrannosaurus Rex. The T-Rex ruled everywhere and this put this animal at the top of the food chain.

The Cretaceous was not only a good era for dinosaurs, but also for mammals. Despite the fact that most mammals during the Cretaceous period were smaller than 15 centimetres, many new species did emerge. You can think of animals that looked like hamsters or guinea pigs. Most mammals that lived in the Cretaceous were nocturnal, so they were relatively safe from many of the carnivorous dinosaurs. Not only did new animal species emerge during the Cretaceous, but also new plants. One of the greatest developments during this era was the evolution of flower-bearing plants and trees. Before the Cretaceous, there were no flowers, but plants used other ways to spread themselves. With the emergence of more and more mammals, as well as plants and trees which bore flowers, nature during the Cretaceous became more and more recognisable as it is today.

The Cretaceous period ended about 66 million years ago with another wave of mass extinction, but this one was perhaps the biggest of all. This mass extinction was probably caused by a meteorite impact. In Mexico, a crater from this time was found, and it showed that the meteorite that hit the earth had a diameter of 30 kilometres! Due to the enormous impact and the fires that started in the area, many animals must have died, but the effects were worldwide. The meteorite impact created so much dust in the air, that the sun could hardly break through to the ground all over the world. Without sunlight, no plants would grow, so the large herbivores soon starved to death. As a result, the large predatory dinosaurs hardly had any food left either, so they also became extinct. The only dinosaurs that survived were a few small species of flying dinosaurs. Scientists think that these dinosaurs are the ancestors of all the birds we have on Earth today. Have you ever noticed that some dinosaurs look very much like birds?

It is a pity that dinosaurs became extinct, because they must have been such beautiful, impressive animals. But maybe we should be glad about it. With the disappearance of the dinosaurs, small, vulnerable mammals could become the dominant group of animals in the post-Cretaceous era. After the dust clouds had settled, and with no large predators left, there was enough food again. These small mammals could easily develop and ultimately, humans also evolved from this!