Hydra, genus of invertebrate freshwater animals of the class Hydrozoa (phylum Cnidaria). The body of such an organism consists of a thin, usually translucent tube that measures up to about 30 millimetres (1.2 inches) long but is capable of great contraction.

Hydra are a group of invertebrates that look like tiny tubes with tentacles protruding off one end. They grow only about 0.4 inches (10 millimeters) long and eat even tinier aquatic animals. Hydra, by contrast, constantly renew their bodies with fresh cells.

Hydra has a tubular, radially symmetric body up to 10 mm (0.39 in) long when extended, secured by a simple adhesive foot known as the basal disc.

This hydra grows heads out of its other heads, and to kill it, you need to cut off the shortest head branches, lest it regrow that entire section twice (which it does any time you cut off a head anywhere).

This Tiny Animal Can Live an Estimated 1,400 Years. Some of us age more gracefully than others, but perhaps no animal group does it better than the tiny freshwater polyps known as hydras.

Fact: There’s a jellyfish which can survive being put in a blender. This impressive skill is held by a freshwater cousin of the jellyfish called a hydra. If you blend a hydra until it’s a pile of sludge and leave it floating at the bottom of a glass, you’ll see something you won’t believe.

The hydra of the real world can do the same, only way, way more impressively. “You can poke a hole in them and they seal it up,” Steele said. “You can cut them in half and they regenerate the missing halves.

Hydra can be found in large variety of freshwater habitats. They mostly occur in ponds, lakes, and slow flowing parts of streams and rivers. Hydra are sessile and live attached to aquatic vegetation, submerged wood, or stones.

Hydra, a powerful dragon with multiple heads. The Hydra(Draco hydra.), uniquely amongst the dragons, reproduces by splitting heads off from its body. This only happens after the Hydra is several hundred years old.

Hercules (who is called “Heracles” in Greek mythology) kills the Hydra as one of his labors. As soon as Hercules cut off one head, Iolaus would cauterise the wound with a flaming torch so that nothing could grow to replace it. After removing the Hydra immortal head, Hercules buried it under a large rock.

The Lernaean Hydra was a Greek Monster that had many heads, and each time a head was cut off, two would grow in its place….

Hydra vulgaris