Another term for the Hydra Viridissima is; green hydra. Hydras are tiny animals that are closely related to jellyfish. Green hydras live in freshwater such as streams, rivers, lake, and ponds. They can grow up to 30 millimeters long however, most are around 15 mm long. Green hydras are found in shallow water, where they can attach themselves to plants, stones, twig, and other objects.

 

The body of the green hydra is skinny and long. Like a jellyfish, they hunt with tentacles. One hydra can have anywhere from 4 to 12 tentacles. Each Tentacle has a tiny bump, called nematocysts. Green hydras eat water fleas and scrubs, flatworms, aquatic worms, tiny fish, and other small creatures in the water. They also use a certain type of algae, called chlorella, which makes the hydras green.

 

The way green hydra reproduces (make more hydras) is by budding. Budding starts with a small bump on the body of the hydra. The bump continues to grow until there is a stalk. Next, the stalk grows tentacles. When it is ready to live on its own, it pinches off the parent. Their body is like a hollow cylinder, with an opening for the mouth end. The mouth leads into a mouth interior of the cylinder which acts like a digestive cavity. The mouth is surrounded by tentacles. Because the digestive cavity has only one opening food goes in and out the same opening.

 

Author: Macaela S

Published: 02/2008

 

Sources:

http://www.fcps.edu/islandcreekes/ecology/green_hydra.htm

http://www.sciencemag.org/cgi/content/short/131/3394/160

 

Photo Credit:

Andrew Skolnick www.aaskolnick.com/hydra.htm