Dinosaurs ruled the Mesozoic, but Earth’s early ages - like the Ordovician and Silurian - belonged to stranger things. Think sea scorpions longer than humans and jelly-like organisms that left no ...

New Theory for What Caused Earth's Second-Largest Mass Extinction. Scientists have been trying to unravel what killed nearly all of Earth’s animals 400 million years ago.

500 million years ago, the world was a very different place. During this period of time, known as the Cambrian period, basically all life was in the water. The ocean was brimming with animals that ...

They precisely determined the absolute ages of the Katian–Hirnantian boundary (442.65+0.17/−0.23 Ma) and the Ordovician–Silurian boundary (442.33+0.34/−0.33 Ma), constraining the duration ...

Why do some ancient animals become fossils while others disappear without a trace? A new study reveals that part of the answer lies in the body itself. The research shows that an animal's size and ...

Sensory features on the armored exoskeletons of ancient fish may be the reason why humans have teeth that are sensitive to cold and other extremes.

If you were to look up from Earth some 466 million years ago, you might have seen a gleaming ring stretching across the sky, some scientists say.