Leave a jellyfish out in the sun for long enough, and it will evaporate. Over 95% water, jellyfish are ludicrously simple creatures. They have no brain, no lungs and no eyes. Assemble some tentacles, a stomach cavity, an umbrella head and you are nearly done. For respiration they just have skin thin enough to let oxygen slip through. Yet in this simplicity there is variety, and in one case, immortality.
Turritopsis nutricul is the immortal jellyfish and no hulking monstrosity. Adults are 5mm across, and transparent. Were you able to spot it you would see an approximate circle surrounded by anywhere between 8 and 24 tentacles protruding, wiggling and wobbling contentedly. When the jellyfish gets bored, or when things get tough it can change. It begins to grow younger.
It moves onto a surface and grips on tightly. Then it slowly becomes a blob. As a blob it performs the special process, transdifferentiation. This is the way in which some animals, like crabs, regrow their limbs. Cells become simplified, then are remade as new types of cell, giving a crab a new arm, or a starfish a new tentacle. Turritopis nutricul is unique in the animal kingdom because it does this to its entire body.
The jellyfish emerges as a perfectly formed child, ready to live all over again. As long as the jellyfish isn’t killed and doesn’t evaporate, scientists expect that the trick can be repeated infinitely. Making it the only possibly immortal creature.
Given their long lifespans, it is no surprise they want to travel; they are spreading from their Caribbean home to places as varied as Spain, Japan and Panama. As long as the water is warm, they may find their way there, bringing a dose of immortality to waters near you. Long live the jellyfish!