Do organisms exist that are able to live indefinitely if they are not killed by external factors?

Under external factors I would consider things like predators and natural disaster but not illness by bacteria for example.

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    $\begingroup$ See biology.stackexchange.com/questions/6884/… $\endgroup$
    – kmm
    Commented May 2, 2013 at 12:21
  • $\begingroup$ the biggest issues for immortality are internal factors - senescence (aging) is a planned death on a cellular and organismal level. the above referenced question is a pretty good review of answers. Aubrey de Grey is another good google term to understand proposals which may reverse aging. $\endgroup$
    – shigeta
    Commented May 2, 2013 at 13:18
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    $\begingroup$ If you're referring to the elves of Middle Earth, I'm sorry no they do not exist. $\endgroup$ Commented May 2, 2013 at 13:20
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    $\begingroup$ @StevenRoose see this book (books.google.co.uk/…) page 108. It defines extrinsic and intrinsic causes of death - as someone studying aging and lifespan I can tell you these are standard definitions and bacterial/viral infections are considered extrinsic. $\endgroup$
    – rg255
    Commented Jul 8, 2013 at 21:36
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    $\begingroup$ The immortal jellyfish, Turritopsis dohrnii en.wikipedia.org/wiki/Turritopsis_dohrnii $\endgroup$
    – Kevin
    Commented May 16, 2014 at 20:25

4 Answers 4


I now found this Wikipedia article on biological immortality. It's pretty much what I was looking for.

Wikipedia describes the phenomenon as follows:

Biological immortality refers to a stable or decreasing rate of mortality from cellular senescence as a function of chronological age. Various unicellular and multicellular species may achieve this state either throughout their existence or after living long enough. A biologically immortal living thing can still die from means other than senescence, such as through injury or disease.

It has a list of such organisms as well, consisting of

Addendum: This blog post takes a good look into the myth of lobster immortality. It seems to be as much a myth as the result of any substantial observation.

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    $\begingroup$ It would be helpful to summarise the content of your links for future readers $\endgroup$
    – Rory M
    Commented May 2, 2013 at 16:57

Yes. The Bristlecone Pine, Pinus longaeva, is one example. This species boasts the oldest individual living organisms, and also has been convincingly argued by Lanner and Connor (2001) to show no evidence of senescence.

While the Wikipedia page on Biological Immortality (as of June 2013) unfortunately ignores plants, the pages on Negligible Senescence and Longest-lived Organisms list many plant seeds, clonal groups, and individuals.

  • $\begingroup$ This is indeed a correct answer, as many organisms listed on other answers show some aging. The entire list of (presently 7) organisms, including P. longaeva, which do not show signs of senescence is given in a subsection of the reference AnAge database, which collects information on aging of every species: genomics.senescence.info/species/nonaging.php $\endgroup$
    – tsttst
    Commented Feb 21, 2019 at 0:33

The immortal jellyfish (Turritopsis dohrnii) is capable of biological immortality.

enter image description here

It's one of few known species capable of reverting completely to a sexually immature, colonial polyp stage after having reached sexual maturity as a solitary (free-floating) individual (called a medusa).

Theoretically, this process can go on indefinitely, effectively rendering the jellyfish biologically immortal

enter image description here

Image source: Piraino et. al. 1996


Piraino, Stefano, et al. 1996. "Reversing the life cycle: medusae transforming into polyps and cell transdifferentiation in Turritopsis nutricula (Cnidaria, Hydrozoa)." The Biological Bulletin 190(3): 302-312.


Examples found in plant world also- especially those with high vegetative reproduction and regeneration property.


Great banyan tree in Indian botanic garden Great banyan tree in Indian botanic garden


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