Turritopsis Dohrnii

Turritopsis dohrnii is known as the eternal jellyfish because it has the ability to live indefinitely—it is also on the list of the longest living animals in the world. Jellyfish begin life as larvae before settling on the seabed and developing into polyps. These polyps eventually give rise to free-swimming medusas, sometimes known as jellyfish. According to the American Museum of Natural History, mature Turritopsis dohrnii can convert back into polyps if they are physically wounded or starved, and then return to their jellyfish condition.

According to the Natural History Museum in London, jellyfish, which are endemic to the Mediterranean Sea, may repeat this feat of reversing their life cycle numerous times and hence may never die of old age given the appropriate conditions. Turritopsis dohrnii are small (less than 0.2 inch (4.5 millimeters) wide) and are eaten by other species like fish or may die of other causes, preventing them from obtaining immortality.

Age: potentially immortal