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24 October 2026

What if an adult animal could return to an earlier stage of its life instead of simply continuing towards old age?

A tiny marine creature called Turritopsis dohrnii has a remarkable ability that makes this question more than science fiction. Under certain stressful conditions, including physical damage, the jellyfish can reverse its development. Instead of remaining in its adult, free-swimming form, it can transform into an earlier stage known as a polyp.

The change is not a simple rewind. Its body reorganises, passing through an intermediate stage before developing into the polyp form. That polyp can then produce new jellyfish through the species’ normal life cycle.

This unusual ability has earned the creature the popular nickname “the immortal jellyfish”. But the name needs a qualification. The animal is not invulnerable, and it can still be killed by predators, disease or environmental hazards. Its remarkable life-cycle reversal does not guarantee endless life in the ocean.

Researchers study this process because it may reveal more about how cells change their roles and how living organisms develop. The tiny jellyfish is not a shortcut to human immortality, but it raises fascinating questions about ageing and regeneration.

It is only a few millimetres across, easy to overlook among the countless organisms drifting through the sea. Yet its life cycle challenges one of our most familiar assumptions: that an adult animal can only move in one direction through life.

Nature has not abolished the end. It has given this small creature an extraordinary alternative route.

Rajat Chandra Sarmah, Guwahati, Assam, India, Instagram @rajatchandrasarmah, YouTube: conversewithasmile, email rajatchandrasarmah@gmail.com