The diversity of animal life on earth is seemingly infinite in its richness. From human beings to the most minute of insects; giraffes and elephants to deep-sea fish; the planet’s disparity in form, behavior, and habitat is expressed through an almost unending range of biological differences. Yet there is also a shared commonality which binds this multiplicitous whole of existence together: our very mortality. That is to say, coming-into-being as any sort of animal also entails falling subject to the cycle of senescence. As cells degrade and deteriorate over time, life must lead to an inevitable death.

Recent discoveries, however, may suggest otherwise. The hydrozoa Turritopsis nutricula, a Cnidarian relative of the more commonly known jellyfish, has been observed as being potentially immortal. Rather, T. nutricula does not fall to the otherwise universal cycle of life, but instead may reverse its direction through a process by the name of transdifferentiation.


Turritopsis nutricula originated in the Caribbean, but have since come to proliferate themselves across the world’s oceans (Piraino et al., 1996).

Typically, transdifferentiation is not understood to be a means for immortality; it operates on a much smaller scale, allowing for already differentiated cells to be transformed into whatever other varieties are needed. The conventional limits of cell use, growth, and decay are thereby stripped for a wholly renewed function (Collas & Håkelien, 2003). This can occur within the components of a few organisms, such as with a salamander’s eyes, wherein “mature” cells are de-particularized so as to rebuild them in the event of damage (Hongbao Ma, 2010). A variety of hydrozoan are also reportedly capable of taking this one step further, regenerating any part of the organism, but remain limited to their current stage of maturity (Aerne 1996). Thus, it is only T. nutricula that can use transdifferentiation to an otherwise unrecorded extreme, achieving an entirely chimeric reversal of its lifecycle: crossing ontogenic boundaries, reverting from adulthood to its earliest, larval stage (Bavestrello, et al. 1992). This process can occur infinite times over, thereby rendering T. nutricula potentially immortal.

By better understanding how T. nutricula utilize this self-regenerative behavior for their own biotic needs, we may come to entirely new realizations (and better yet, generate new questions) about the otherwise inescapable order of life and death.



A fully matured T. nutricula undergoes transdifferentiation, reverting to its most larval stage (Piraino et al., 1996).