Hydra is a minute predatory animal found in unpolluted fresh-water water courses. The body of ths animal is usually anchored to a surface and when feeding they extend tentacles which then wait for prey contact. On contact, specialized cells on the tentacles called nematocysts fire dart-like threads into the prey which then discharge paralysing neurotoxins into the prey.
Hydra considered to be biologically immortal, that is they do not age, and Hydra stems cells have the capacity for indefinite self renewal. Hydra also have enormous regeneration capacity and if an intact Hydra is broken down to just single cells, in a few days it will reconstitute itself into a once more perfect animal. Here are a few videos of this remarkable animal.