The fascinating group of animals called dinosaurs became extinct around 65 million years ago, except for their feathered descendants, the birds.
A wide variety of land creatures then developed, especially mammals, which in their own way were just as impressive as their predecessors.
The age of mammals, the Cenozoic era, was an incredible period in the history of the earth, populated by a wonderful diversity of fascinating animals.
The terrestrial vegetation has also undergone significant changes. After the greenhouse conditions of the Mesozoic gave way to consequent variations, the earth warming up dramatically around 55 million years ago, then cooling rapidly so that by 33 million years ago, the glacial ice has returned.
The rapid evolution of thousands of species of mammals has given rise to many incredible creatures, including our own ancestors.