Turritopsis Dohrnii most commonly known as the immortal jellyfish are very small simple bodied marine invertebrates. The jellyfish are referred to as simple bodied invertebrates because they have no brain, blood, or other organs. The immortal jellyfish is one of the few known species capable of reverting completely back to restart their life cycle. These jellyfish begin their life as small free swimming larvae, also known as planulae, and develop into a colony of polyps that attach to the seafloor. These polyps form into a branched form that is not commonly seen in most jellyfish. The Turritopsis Dohrnii, is bell-shaped, with diameter up to 2.7 millimeters and is about as tall as it is wide. The relatively large stomach is bright red and has a cruciform shape in cross section. Young specimens only have eight tentacles evenly spaced out around the edge, in comparison to adult specimens having 80-90 tentacles.These small jellyfish are most often found worldwide in temperate to tropical waters.


Adult immortal jellyfish are approximately two and a half millimeters tall.

After reaching sexual maturity, if these jellyfish sense danger, experience physical assault, becoming sick or old, these jellyfish can return back to the polyp stage and start their life cycle over. This is completed through the process of transdifferentiation, which alters the state of the cells and transforms the cells of the jellyfish into new cells. Transdifferentiation is the process of cells turning into new and different kinds of cells. This process mimics the idea of immortality, the newly generated polyps bud and eventually release medusa that are genetically identical to the injured adult. Despite their name these jellyfish can and do die, if the jellyfish have not fully matured, and experience starvation or get sick as polyps the transdifferentiation process can not occur and the jellyfish can not regenerate and will die. The main diet for the immortal jellyfish consists of fish eggs, plankton and small mollusks. 

With increased numbers of Turritopsis dohrnii found around the world, scientists are once again visiting the cell makeup of these seemingly immortal jellyfish. In the past two decades stem cell research has improved and expanded, allowing scientists to continue researching the importance of jellyfish behavior and characteristics, and how it could improve the human experience. Many scientists are still immersed in researching the stages of life of the immortal jellyfish and trying to understand how these characteristics could translate into human life advances in immortality. There are also studies that explore the possible benefits of the immortal jellyfish in relation to combating cancer. The characteristics of immortal jellyfish being able to leave cells behind on revert back to a previously healthy state, and understanding how these jellyfish complete this action could aid scientists in finding clues that could aid in cancer research. 

Although my name suggests the ability to defy death, I can and many of us do die. 
I am a staple meal for many other animals, and can only successfully stay immortal after I progress into the adult stage of my life. After reaching full maturity we are able to go back to a polyp stage to restart our journey. So essentially we are able to revert back to a sexually undeveloped stage in life, over and over again giving us the immortal name. If we are harmed, become sick, or are eaten of course, we are unable to complete the restart of the life cycle and will most likely die from these causes. 

Animation of the life cycle of the Immortal Jellyfish.


AMNH, The Immortal Jellyfish, 2015

Fofonoff PW, Ruiz GM, Steves B, Simkanin C, & Carlton JT National Exotic Marine and Estuarine Species Information System. 2018

Than, Ker, “Immortal” Jellyfish, 2009