In ancient Greek myth, the Hydra was a multi-headed monster that grew two more heads for every one that it lost. As it turns out, the real-life animal named after this mythical beast may be even more ...

But there’s one creature that doesn’t need to get hung up on retirement or deadlines, and accordingly it could well be immortal. This is the bizarre existence of the hydra, a half-inch tube of jelly ...

An ancient marble altar showing a nude warrior battling a serpent monster has been discovered by villagers near the Akçay River in Turkey. Archaeologists said the altar likely dates to the second ...

There’s a small, tentacled freshwater animal called a hydra, whose mouth disappears every time it closes. I really mean that: it disappears. When your mouth closes, the two halves are still distinct.