Hydra vulgaris, or the fresh-water polyp, is a small hydroid measuring 10 to 30 mm in length and about 1 mm in width. It has four to twelve tentacles that extend from its mouth, which it uses to catch and ingest food. Anything indigestible is egested. Hydra cling to surfaces with a disk-shaped “foot” and can move by releasing their grip or by flipping over.
This species can reproduce in three ways: sexually, by budding, and through regeneration. In sexual reproduction, testes and ovaries develop, with sperm entering the egg to produce a chitinous exoskeleton until conditions are favorable for emergence. Budding occurs when conditions are right, leading to a miniature hydra growing from the parent, which eventually separates. Hydra can also regenerate, with segments growing into new individuals if they are large enough, similar to starfish.
