A Hydra is a tiny, tube-shaped freshwater animal belonging to the phylum Cnidaria. It reproduces both asexually (by growing a mini-clone on its body that breaks off) and sexually (by releasing eggs and sperm into the water when living conditions turn bad).
Asexual Reproduction (Budding)
When it happens: Best food supply and warm, safe weather.
How it works: Cells on the parent's body wall divide and push outward.
The result: A small bump grows tentacles and a mouth, looks like the parent, and falls off after a few days to live on its own.
Sexual Reproduction
When it happens: Cold weather, low food, or dirty water.
How it works: Temporary bumps called gonads (ovaries or testes) form on the body wall.
Fertilization: Testes release sperm into the water. The sperm swim to find and fertilize an egg inside an ovary.
Survival: The fertilized egg grows a hard outer shell. It drops to the bottom of the pond to wait out the winter before hatching into a new hydra.
Habitat
Hydras are often found in freshwater bodies, but some Hydras are found in open water. They live attached to submerged rocks using a sticky secretion from their base. The genus Hydra occurs on all continents except for Antarctica and the Oceanic islands, though Hydras occur mainly in mesotrophic to eutrophic habitats.
