There is a species of jellyfish that is essentially immortal — Turritopsis dohrnii, which can revert from its adult form back to its juvenile polyp stage when stressed or injured, and then mature again, potentially repeating the cycle indefinitely, in the

There is a species of jellyfish that is essentially immortal — Turritopsis dohrnii, which can revert from its adult form back to its juvenile polyp stage when stressed or injured, and then mature again, potentially repeating the cycle indefinitely, in the

In the warm coastal waters of the Mediterranean, and now globally distributed via ship ballast water, lives a translucent jellyfish about the size of a pinky-nail clipping, with a bright red stomach visible through its bell. Turritopsis dohrnii looks unremarkable. It feeds on plankton, swims at the mercy of currents, and gets eaten in large numbers by fish, sea turtles, and other predators that consume jellyfish without much discrimination. What…