What the heck is an immortal jellyfish?

Immortal Jellyfish—YES it’s real and it’s sensational

Ever thought about immortality? I think we all have at one time or another, inspired by moments of pure joy or perhaps a sci-fi book or film that got the imagination going. There would be so much to consider if our natural lives could go on forever, I wouldn’t even know where to begin.

For the Turritopsis dohrnii, known informally as the “immortal jellyfish”, this eerie dream is a reality. It is a small jellyfish species from the Mediterranean that was discovered in the 1880’s. It’s a tiny little beauty, only about 4.5mm across when fully grown, with between 8 and 90 tentacles and almost fully transparent, revealing most notably a red stomach.

To achieve biological immortality, this genius of a jellyfish really pulls a fast one on mother nature. It begins its life like all jellyfish, as larva (which is what comes after a fertilized jellyfish egg) known as a planula. This little planula swims the sea floor and then grows into a colony of polyps, each of which spawns genetically identical jellyfish.

And now for the cool part. These little guys can, in the face of injury or even starvation, revert back to the polyp phase of their development and start the whole process over, releasing genetically identical jellyfish to the injured adult. Essentially, the same jellyfish can use its cells to grow up and regress back, going on forever.

The process of regressing back to the polyp phase also involves cells of the jellyfish transforming into other cells necessary for the process. This aging backwards phenomenon could be very interesting for medical science, and its applications could be incredible if ever unlocked in humans. Think about not just being immortal, but the ability to age-back to a time prior to illness or aging, now that would be something.

These jellyfish can still, of course, die as a result of serious injury so they are not immortal in the magical sense of the word. Maybe that species still hasn’t been discovered.

Scientists estimate that 91% of ocean species have not yet been classified, and 80% of the ocean is unmapped and unobserved. If a biologically immortal species has been found in that slim 9% of classified species, I wonder, what other amazing and wonderful creatures are lurking below the surface?


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