A fountain of youth exists, and a tiny species of jellyfish can be found swimming around in its eternal waters.
Well, not exactly. An invertebrate capable of immortality does exist, but it doesn’t achieve endless life via its swimming location but instead through its unique biological make-up.
Found in the waters of both the Mediterranean Sea and Japan, a tiny invertebrate called Turritopsis dohrnii is the only animal known to be biologically capable of reverting back to sexual immaturity after reaching adulthood. As there is no limit to the number of times it reverts back to a near-infant state, it can conceivably repeat the process forever, rendering it immortal.
Formerly known as Turritopsis nutricula, scientists first discovered the immortal jellyfish in 1883, when they found it swimming in the warm waters of the Mediterranean.
But it would take another century for scientists to discover the species’ unique abilities — and to discover that the immortal jellyfish’s long life wasn’t some otherworldly blessing, but an attempt to save itself from the dangers of the deep sea.
The Process Of Achieving Immortality
So just how does one go about living forever?
If you’re thinking of these creatures as a thousands-of-years-old entity, you’re not technically wrong, but you’re not quite right, either. Turritopsis dohrnii, like any other type of jellyfish, starts out as larva developed from a fertilized egg to create what is known as a planula.
These free-swimming planula go off on their own, eventually settling on the ocean floor to create a colony of polyps, which grow upward from the seafloor to form a cylindrical shape. From these polyps, a medusa, or jellyfish, forms, which breaks off from the branch after reaching adulthood in a matter of weeks.
Now fully grown to measure a whopping 4.5 mm — about the width of your pinky fingernail — the newly adult jellyfish is recognized by its bright red stomach, easily visible through a transparent, bell-shaped body lined with 90 tentacles around its edges.
This tiny being may not seem like much, but its singular survival skill allows it to adapt to various environmental threats, from physical harm to starvation.
For example, let’s say a Turritopsis faces a lack of food. Your average jellyfish would simply die of starvation, but not this one. Instead, it will attempt to get a “second chance” at life by reverting back to sexual immaturity.
On a cellular level, this means that the immortal jellyfish will effectively recycle its existing cells to form a new self in a process known as “transdifferentiation.” In terms of physical process, this means that the jellyfish will retract its tentacles and shrink its body, and then drop to the ocean floor. From there, the jellyfish regresses into a sexually immature larva and forms new polyps until it reaches adulthood once again.
As astounding as that process it, it doesn’t necessarily mean that the jellyfish is technically “immortal” in every sense of the word. For one, the Turritopsis can be killed — by a predator, for example.
Moreover, as James Carlton, a professor of marine sciences at Williams College, told The New York Times Magazine, “That word ‘immortal’ is distracting. If by ‘immortal’ you mean passing on your genes, then yes, it’s immortal. But those are not the same cells anymore. The cells are immortal, but not necessarily the organism itself.”
Nevertheless, the immortal jellyfish is surely an incredible creature, and one whose abilities might just have some use for humankind…