Back

CNIDARIA
Lesson 2 - Page 1

Next 

Hydra - Lab

Hydras may be found on submerged weeds, sticks, dead leaves and tones.  You sometimes can see them gliding or somersaulting on the water surface when you disturb the area they are living.              

The body of the hydra is small, and “see through.”  It has arms or tentacles and is attached to the surface.  The tentacles have stinging cells at their ends and as prey move closer the hydra is able to sting it and bring it in with it’s arms.

Hydras have sexual and asexual phases.  A "baby" hydra is formed as an asexual bud  on each adult hydra every 2-4 days through spring and summer.  In "bad" conditions fertilized eggs can hatch at more favorable time (sexual phase).

The food of hydra includes small arthropods like water fleas.  They are captured by stinging cells with nematocysts of the tentacles and are subsequently carried to the mouth and ingested.