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 ...

Lucas Atwell CC BY-SA 3.0 Everyone knows about the mass extinction that ended the Age of Dinosaurs. About 66 million years ago, a seven-mile-wide asteroid slammed into our planet and began a mass ...

We're in the midst of the Earth’s sixth mass extinction crisis. Harvard biologist E. O. Wilson estimated that 30,000 species per year (or three species per hour) are being driven to extinction.