Hydras move by looping, basically somersaulting to a new location. The green hydra harbors symbiotic algae in its tissues. Although it receives some nutrients from its photosynthetic guests, Chlorohydra eats a balanced diet, gorging on microcrustaceans when available. Budding new individuals from a few cells located on Hydra 's lower body is a natural form of cloning. The individuals produced are identical genetically to their mother or father.
Sexual exchanges shuffle the genetic deck, usually just before winter sets in.
Fertilized eggs withstand freezing, produceing a new hydra in the spring. The fertilized eggs produce a larva that settles to become the first polyp of a new colony. Two more hydrozoan jellyfish common in bays, Gonionemus and Polyorchis , are shown. Note the large stinging capsules, which are very dangerous to swimmers. Most scyphozoans originate from small attached reproductive polyps.