The Gobi Desert - page 2
When at the end of the Cretaceous area, some 65 million years ago, the reptiles, and the dinosaurs in particular, lost dominance, they left a whole world to the mammals.
As a matter of fact, mammals exist as long as dinosaurs: both appeared about 220 million years ago. But for tens of millions of years, the small mammals were overshadowed by the big dinosaurs. But the death of the dinosaurs left them many diverse habitats, where they could evolve into an extraordinarily diverse range of species. This process is called radiation.
Link to the geological timescale in image format.
Link to the geological timescale in text format.
Two important epochs of the Cenozoic were the Paleocene (65 to 55 million years ago) and the Eocene (55 to 34 million years ago). A first radiation occurred during the Paleocene, the epoch after the Cretaceous, resulting in weird archaic species that soon became extinct. But we can already notice the ancestors of the hedgehogs and other insectivores!
At the dawn of the Eocene appear the first really known mammal groups, including the Perissodactyla (such as primitive little horses), the Artiodactyla (such as primitive bovines), the whales, the rodents, the bats, and the first primates (such as Teilhardina belgica.
The suddenness of the rise and flourishing of these groups is remarkable and is often cited as one of the major features of the Paleocene-Eocene transition. Nevertheless, these events are still rather unknown. When, where, and from what group did these animals originate? These are only a few of the questions to be tackled by our expedition team.
