Scientists find jellyfish enjoy an 'immortal' life
Smithsonian researchers have found jellyfish practically live forever. A particular type of jellyfish switches back to juvenile form after it mates.

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Turritopsis nutricula jellyfish
Marine biologists from the Smithsonian Tropical Marine Institute are
puzzled by this behavior of “
Turritopsis Nutricula” jellyfish found in the Caribbean.
This behavior is only found in this type of jellyfish; in other varieties they die normally after propagating. The Turritopsis nutricula on the other hand has developed a unique ability to switch back to its juvenile form, a polyp state.
Since it doesn’t die, this jellyfish is exploding in large numbers and has spread worldwide from the Caribbean according to Dr. Maria Miglietta of the
Smithsonian Tropical Marine Institute.
The scientists believe this jellyfish achieves the transformation
through the cell development process of transdifferentiation.
Now many marine biologists and geneticists are studying this jellyfish type to see how it is able to achieve the “immortality”.
Even
Darwin will be puzzled to see this in nature.
Here is more information about "Turritopsis nutricula" jellyfish.