How Far the Light Reaches: A Life in Ten Sea Creatures

by Sabrina Imbler

But when the immortal jellyfish’s body begins to fail, it ages backwards. Its ailing body sinks to the seafloor or some hard surface and rearranges itself into a silky lump, looking like an egg, or a cell, primordial, all potential. It seals itself in an envelope of chitin and shuffles around the meaning of its cells. And then it sprouts into a polyp and grows, into not one individual jellyfish but many clones. So the single damaged jellyfish becomes a host of younger, possible selves, each with the same power to regenerate. As far as we know, the jellyfish can do this over and over and over, as many times as they are damaged, into something like eternity. The scientists who originally described the peculiar regeneration did not choose to call the creature, also known as Turritopsis dohrnii, “immortal.” One scientist went so far as to write that he would never have used that word; he originally said the jellyfish was capable of “ontogeny reversal,” meaning reversing the direction of the ordinary life cycle. But “ontogeny reversal jellyfish” does not make headlines or earn grant funding, and so the creature became immortal.