The Immortal Jellyfish That Rewinds Its Life

When it’s injured or aging, it doesn’t die—it starts life over again. Could this be the key to immortality?

Turritopsis dohrnii, a tiny, transparent jellyfish found in oceans around the world, has an unbelievable ability: when it’s threatened, injured, or dying of old age, it doesn’t perish—it transforms back into its earliest life stage, essentially becoming young again. This cycle can repeat indefinitely, making it the only known animal capable of biological immortality. Instead of succumbing to time, this jellyfish flips it backwards.

“It’s as if a butterfly could turn back into a caterpillar—not once, but forever.”

~ Dr. Stefano Piraino, marine biologist, University of Salento

“This creature doesn’t just escape death—it reverses it. It’s almost supernatural.”

~ Nathaniel Rich, The New York Times Magazine

“The jellyfish’s cells perform transdifferentiation—something we can barely mimic in labs.”

~ Dr. Shin Kubota, jellyfish researcher, Kyoto University

“We’ve found the only animal known to cheat death. It’s not science fiction—it’s biology.”

~ Dr. Maria Pia Miglietta, marine ecologist

“This species forces us to rethink aging itself. Is it inevitable—or just a cellular choice?”

~ Dr. Daniel Martínez, aging researcher

Knock-on effect: Inspired by this jellyfish, scientists are now studying how its cellular reprogramming could inform regenerative medicine, anti-aging therapies, and cancer research. Its biology could someday help us reprogram human cells to heal damaged tissues—or possibly, slow aging itself. What began as a curiosity of the sea may one day redefine what it means to grow old.