The oldest living creature in the world will come as a surprise to you. Many of the animals in the seas, skies, and earth live long lives. Yet the oldest living creature in the world is an immortal jellyfish that has never died. Its family name is Turritopsis Dohrnii. It hails from a class of small animals that live mainly in saltwater.

The Dohrnii begin their life journey as larvae with a diameter of no more than 4 millimeters. The larvae have a tiny vase-shaped body with a mouth surrounded by tentacles. They come together and attach themselves to the ocean floor. Soon, they mature into jellyfish. Once they mature, they travel great distances and hunt other fish for food. The Dohrnii has currently spread across three continents by hitchhiking on the underside of cargo ships. Due to their tiny size, the countries they are invading are unaware that it is even happening.

Turritopsis dohrnii medusa [Source : Bachware / CC BY-SA 3.0]( ]
Turritopsis dohrnii medusa Source : Bachware / CC BY-SA 3.0 ]

When a Dohrnii jellyfish is exposed to shock, these marvelous creatures reverse their aging process and slowly turn back into larvae, to be reborn again when the danger has passed. It is the only biological example of true immortality. Turritopsis Dohrnii achieves this through a process that is quite remarkable. The cells of the larvae get assigned roles before maturing. The roles are assigned by a tiny strand of genetic material called MiRNA. MiRNA decides which jobs a mature cell receives. When the jellyfish receives a shock, MiRNA begins converting the jellyfish cells back into larvae. Scientists are studying this to see if it can be used to reverse the aging process in other species.

The biggest danger to these immortal jellyfish comes from sea plankton, which eats them for survival. Dohrnii are hard to study because of their size and are hard to keep alive in captivity. Today, only one scientist, Shin Kubota from Japan University, has managed to keep them alive. The Dohrnii jellyfish provides the only known method for a living being to cheat death and its secrets are yet to be fully uncovered.

Honorary mentions:

  • Greenland Shark: Oldest recorded - 400 years
  • Bowhead Whale: Oldest recorded - 211 years
  • Galapagos Giant Tortoise: Oldest recorded - 152 years
  • African Elephant: Oldest recorded - 86

381 words | 3 minutes
Readability: Grade 9 (14-15 year old children)
Based on Flesch–Kincaid readability scores

Filed under: 5ws and h
Tags: #jellyfishes, #larvae, #plankton

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