Since it is capable of cycling from a mature adult stage to an immature polyp stage and back again, there may be no natural limit to its life span. Scientists say the hydrozoan jellyfish is the only known animal that can repeatedly turn back the hands of time and revert to its polyp state (its first stage of life).Jelllyfish might be taking over the world. . .
Because they are able to bypass death, the number of individuals is spiking. They're now found in oceans around the globe rather than just in their native Caribbean waters. "We are looking at a worldwide silent invasion," says Dr. Maria Miglietta of the Smithsonian Tropical Marine Institute.