Prehistoric animals once roamed — and ruled — planet Earth. Some of them, like the giant sloth or the woolly rhino, were generally gentle. Others, like the saber-toothed tiger and the dire ...

Some were the size of a dog. Others were as large as polar bears. A newly-discovered fossil of the ferocious hyaenodont is ...

Scientists still debate the purpose of this dinosaur's iconic horns and spiky head plate. Find out what we’ve learned about how Triceratops lived and why it went extinct. Triceratops’ enormous ...

Polar bears are one of the largest surviving prehistoric animals. Their existence is deeply connected to the health of polar ecosystems.