Weird and Mysterious Animals: Immortal Jellyfish

by Shruthi Ravichandran

Hey again! This is Shruthi with a special extra edition this week! (Don’t forget to check out our awesome article on the insanely cute Axolotls!) Meet the Immortal Jellyfish! Turritopsis dohrnii, the immortal jellyfish, is the only known official biologically immortal species! What’s the secret? Adult Jellyfish, even after they have reproduced, actually revert back to their polyp stage- their bodies shrink, their tentacles retract, and they sink back to the ocean floor, almost as if they were reborn! The even cooler thing is that they can do this for eternity–they quite literally can’t die (of natural causes)!! Because of this perfected process, called transdifferentiation, there are only two ways they can die, being eaten by another fish and contracting a disease.

The question everyone asks: How old are they actually? Unfortunately, we have absolutely no idea! We are currently unable to observe them in the wild and in lab environments, they live longer than the experiments and scientists, themselves!

These jellyfish thrive in the warm waters of the Caribbean and the Mediterranean. They feed on small mollusks, plankton, and fish eggs. But don’t let this cool feature fool you! These creatures are tiny! They reach a maximum of four and a half millimeters! That’s about a third of an aspirin pill! Baby jellyfish have on average eight tentacles, while adults can have up to ninety!

Unfortunately, we can’t count on seeing one anytime soon! They are almost completely invisible and live in waters much deeper than humans can go for now! The only distinctive features are their bright red-colored stomachs!

Know of a weird creature you want to share with the world? Leave a comment below and we’ll write an article about it!!

Until next time!

Happy Sciencing!!

Shruthi 🙂

2 thoughts on “Weird and Mysterious Animals: Immortal Jellyfish

Add yours

  1. ​There’s an episode about these awesome little dudes on the children’s television show “the Octonauts”. I found the short 11-minute episode which teaches all about these jellies on YouTube here:

    “The Octonauts” teaches about the many interesting facts of marine biology. Though definitely a kids’ show my wife and I also find it entertaining and have even learnt some stuff we neverknew before. Let’s see if I can think of a good example… How about these awesome jellies! The show is available on Netflix and this particular episode is in season 3.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

Blog at

Up ↑