Life on Earth is anything but predictable. For evidence, look no further than the five mass extinctions that have occurred over the past 500 million years: Even in the midst of widespread ...

After the extinction of the dinosaurs during the Cretaceous mass extinction (the fifth mass extinction) about 66 million years ago, a new era of “megafauna” emerged. These were large animals ...

At the beginning of the Cretaceous Period (145 million to 66 million years ago) sharks were once again widely common and varied in the ancient seas, before experiencing their fifth mass extinction ...

The mass extinction that wiped out the dinosaurs was triggered by a massive asteroid that slammed into Earth 66 million years ago. But what triggered the asteroid? Harvard physicist Lisa Randall ...