The individual members of a very small number of species are functionally immortal. These are all lower animals that exhibit a profound capacity for regeneration and lack sophisticated nervous systems, such as hydra or jellyfish. A hydra is essentially a hunger-motivated bundle of stem cells, at least from the perspective of the mammalian world of limited and regimented tissue regeneration. Absent predation or accident these animals do not exhibit any increase in mortality rate over time. Proving that to be the case is actually quite challenging. For hydra, for example, researchers conducted a long-running experiment to assess mortality that <a href="https://www.fightaging.org/archives/2015/12/confirming-d…
The Freshwater Fish Species of Bigmouth Buffalo Exhibits Negligible Senescence
The individual members of a very small number of species are functionally immortal. These are all lower animals that exhibit a profound capacity for regeneration and lack sophisticated nervous systems, such as hydra or jellyfish. A hydra is essentially a hunger-motivated bundle of stem cells, at least from the perspective of the mammalian world of limited and regimented tissue regeneration. Absent predation or accident these animals do not exhibit any increase in mortality rate over time. Proving that to be the case is actually quite challenging. For hydra, for example, researchers conducted a long-running experiment to assess mortality that <a href="https://www.fightaging.org/archives/2015/12/confirming-d…