Immortal Jellyfish
The immortal jellyfish is the common name for *Turritopsis dohrnii*, a tiny hydrozoan cnidarian known for its ability to revert from the adult medusa stage back to the juvenile polyp stage.
The immortal jellyfish is the common name for *Turritopsis dohrnii*, a tiny hydrozoan cnidarian known for its ability to revert from the adult medusa stage back to the juvenile polyp stage. It is often described as biologically immortal, although it can still die from predation, disease, or other hazards. The species is native to the Mediterranean Sea and has been introduced to other marine regions worldwide.
Taxonomy and naming
*Turritopsis dohrnii* is a hydrozoan cnidarian commonly called the immortal jellyfish. The name refers to its unusual biology rather than true immortality, and it is not classified as a scyphozoan jellyfish.
Life cycle reversal
When stressed or damaged, the adult medusa can revert to a polyp stage and later develop back into a medusa. This process has made the species a key model in studies of regeneration and cellular change.
Distribution and habitat
The species is native to the Mediterranean Sea but has spread to other marine regions around the world. Sources attribute this broader distribution to human-mediated transport, especially ballast water from ships.
Scientific significance
Because it can repeatedly cycle between life stages, the species is widely discussed in research on aging and developmental biology. Its biology is often described as a form of biological immortality, though the term is limited by external causes of death.
Key facts
- It is not a true jellyfish in the strict taxonomic sense because it belongs to Hydrozoa, not Scyphozoa.
- Its famous ability is a life-cycle reversal that returns adult medusae to the polyp stage.
- The reversal is associated with cellular reprogramming, often described as transdifferentiation.
- Despite the nickname, it is not literally invulnerable and can still be killed by predators, disease, or environmental stress.
- It is a small, translucent marine invertebrate.
Canadian marine biology and aging researchers may study *Turritopsis dohrnii* as a model for regeneration, cellular reprogramming, and developmental biology, but it is not a species uniquely associated with Canada.
Frequently asked questions
What is the immortal jellyfish?
Is the immortal jellyfish actually immortal?
How big is it?
Where does it live?
Why is it important to science?
References
- Encyclopaedia Britannica — https://www.britannica.com/animal/immortal-jellyfishSupports: Taxonomy, scientific name, native range, and the fact that it is a hydrozoan rather than a true jellyfish.
- American Museum of Natural History — https://www.amnh.org/explore/news-blogs/immortal-jellyfishSupports: Life-cycle reversal from medusa to polyp and scientific interest in the species.
- Natural History Museum (UK) — https://www.nhm.ac.uk/discover/immortal-jellyfish-secret-to-cheating-death.htmlSupports: Size, life-cycle reversal, and common name usage.
- The New York Times — https://www.nytimes.com/2022/09/06/science/immortal-jellyfish-gene-protein.htmlSupports: Description of the reversal process and the distinction between biological immortality and vulnerability to external causes of death.