This is a list of the longest-living biological organisms: the individual(s) (or in some instances, clones) of a species with the longest natural maximum life spans. For a given species, such a designation may include:
The oldest known individual(s) that are currently alive, with verified ages.
Verified individual record holders, such as the longest-lived human, Jeanne Calment, or the longest-lived domestic cat, Creme Puff.
The definition of "longest-living" used in this article considers only the observed or estimated length of an individual organism's natural lifespan – that is, the duration of time between its birth or conception, or the earliest emergence of its identity as an individual organism, and its death – and does not consider other conceivable interpretations of "longest-living", such as the length of time between the earliest appearance of a species in the fossil record and the present (the historical "age" of the species as a whole), the time between a species' first speciation and its extinction (the phylogenetic "lifespan" of the species), or the range of possible lifespans of a species' individuals. This list includes long-lived organisms that are currently still alive as well as those that are dead.
Determining the length of an organism's natural lifespan is complicated by many problems of definition and interpretation, as well as by practical difficulties in reliably measuring age, particularly for extremely old organisms and for those that reproduce by asexual cloning. In many cases the ages listed below are estimates based on observed present-day growth rates, which may differ significantly from the growth rates experienced thousands of years ago. Identifying the longest-living organisms also depends on defining what constitutes an "individual" organism, which can be problematic, since many asexual organisms and clonal colonies defy one or both of the traditional colloquial definitions of individuality (having a distinct genotype and having an independent, physically separate body). Additionally, some organisms maintain the capability to reproduce through very long periods of metabolic dormancy, during which they may not be considered "alive" by certain definitions but nonetheless can resume normal metabolism afterward; it is unclear whether the dormant periods should be counted as part of the organism's lifespan.
If the mortality rate of a species does not increase after maturity, the species does not age and is said to be biologically immortal. There are numerous plants and animals for which the mortality rate has been observed to actually decrease with age, for all or part of the life cycle.Hydra were observed for four years without any increase in mortality rate. If the mortality rate remains constant, the rate determines the mean lifespan. The lifespan may be long or short, though the species technically does not "age".
Individuals of other species have been observed to regress to a larval state and regrow into adults multiple times. The hydrozoan species Turritopsis dohrnii (formerly Turritopsis nutricula) is capable of cycling from a mature adult stage to an immature polyp stage and back again. This means no natural limit to its lifespan is known. No single specimen has been observed for any extended period, however, and estimating the age of a specimen is not possible by any known means. At least one other hydrozoan (Laodicea undulata) and one scyphozoan (Aurelia sp.1) can also revert from a medusa stage into a polyp stage.
Similarly, the larvae of skin beetles undergo a degree of "reversed development" when starved, and later grow back to the previously attained level of maturity. This cycle can be repeated many times. However, repeated cycles result in physiological deterioration, suggesting that these beetle larvae still age.
Revived into activity after stasis
If the definition of lifespan does not exclude time spent in metabolically inactive states, many organisms may be said to have lifespans that are millions of years in length. Various claims have been made about reviving bacterial spores to active metabolism after millions of years of dormancy. Spores preserved in amber have been revived after 40 million years, and spores from salt deposits in New Mexico have been revived after 250 million years, making these bacteria by far the longest-living organisms ever recorded. Similarly, in May 2022 prokaryotic and eukaryotic microorganisms were found in crystals of halite; these could be over 800 million years old but it remains uncertain if they are alive or if they could be revived. In a related find, a scientist was able to coax 34,000-year-old salt-captured bacteria to reproduce. These results were subsequently duplicated independently.
In July 2018, scientists from four Russian institutions collaborating with Princeton University reported that they had analyzed about 300 prehistoric nematode worms recovered from permafrost above the Arctic Circle in Sakha Republic, and that after being thawed, two of the nematodes revived and began moving and eating. One found in a Pleistocene squirrel burrow in the Duvanny Yar outcrop on the Kolyma River was believed to be about 32,000 years old, while the other, recovered in 2015 near the Alazeya River, was dated at approximately 30,000-40,000 years old. These nematodes were believed to be the oldest living multicellular organisms on Earth. In 2023, it was reported that nematodes of the previously undescribed Panagrolaimus kolymaensis were revived after 46,000 years in cryptobiosis.
Like bacterial spores, plant seeds are often capable of germinating after very long periods of metabolic inactivity. A seed from the previously extinct Judean date palm was revived and managed to sprout after nearly 2,000 years. Named "Methuselah", it is currently growing at Kibbutz Ketura, Israel. Similarly, the flowering plant Silene stenophylla was grown from fruit found in an ancient squirrel's cache. The germinated plants bore viable seeds. The fruit was dated at 31,800 ± 300 years old. In 1994, a seed from a sacred lotus (Nelumbo nucifera), dated at roughly 1,300 ± 270 years old, was successfully germinated.
Some endoliths have extremely long lives. In August 2013, researchers reported evidence of endoliths in the ocean floor, perhaps millions of years old, with a generation time of 10,000 years. These are slowly metabolizing and not in a dormant state. Some Actinomycetota found in Siberia are estimated to be half a million years old.
As with all long-lived plant and fungal species, no individual part of a clonal colony is alive (in the sense of active metabolism) for more than a very small fraction of the life of the entire colony. Some clonal colonies may be fully connected via their root systems, while most are not interconnected but are nonetheless genetically identical clones that populated an area through vegetative reproduction. Ages for clonal colonies are estimates, often based on current growth rates.
A huge colony of the sea grass Posidonia oceanica in the Mediterranean Sea near Ibiza, Spain, is estimated to be between 12,000 and 200,000 years old. The maximum age is theoretical, as the region it now occupies was above water at some point between 10,000 and 80,000 years ago.
King Clone is an individual creosote bush (Larrea tridentata) in the Mojave Desert of southern California, United States, estimated at 11,700 years old. Another creosote bush has been said to be 12,150 years old, but this is as yet unconfirmed.
A Huon pine colony on Mount Read, Tasmania, is estimated at 10,000 years old, with individual specimens living over 3,000 years.
Pando is a clonal colony of Populus tremuloides (quaking aspen) trees in south-central Utah, United States, that is estimated to be several thousand years old, possibly as much as 14,000 years. Unlike many other clonal "colonies", the above-ground trunks of these trees remain connected to each other by a single massive subterranean root system.
A Panke baobab (Adansonia digitata) in Zimbabwe was some 2,450 years old when it died in 2011, making it the oldest angiosperm ever documented, and two other trees of the same species – Dorslandboom in Namibia and Glencoe in South Africa – were estimated to be approximately 2,000 years old.
The Fortingall Yew, an ancient yew (Taxus baccata) in the churchyard of the village of Fortingall in Perthshire, Scotland, is one of the oldest known individual trees in Europe. Various estimates have put its age between 2,000 and 5,000 years, although it is now believed to be at the lower end of this range.
A specimen, "Ming" of the Icelandic cyprine Arctica islandica (also known as an ocean quahog), a mollusk, was found to have lived 507 years. Another specimen had a recorded lifespan of 374 years.
The tubeworm Escarpia laminata that lives in deep sea cold seeps regularly reaches the age of between 100 and 200 years, with some individuals determined to be more than 300 years old. Some may live for over 1000 years.
The Greenland shark had been estimated to live to about 200 years, but a study published in 2016 found that a 5.02 m (16.5 ft) specimen was between 272 and 512 years old. That makes the Greenland shark the longest-lived vertebrate.
The great white shark is estimated to live for 70+ years, making it one of the longest lived cartilaginous fishes currently known. 
A killer whale of the "Southern Resident Community" identified as J2 or Granny was estimated by some researchers to have been approximately 105 years old at her death in 2017; however, other dating methods estimated her age as 65–80.
A goldfish named Tish lived for 43 years after being won at a fairground in 1956.
The oldest known bird in the world was an Australian sulphur-crested cockatoo called Cocky Bennett, who lived to 120. He could recall phrases such as "one feather more and I'll fly" and "one at a time, gentlemen, please". He lived from 1796 to 1916 and traveled the world with various owners.
The tuatara, a lizard-like reptile native to New Zealand, can live well over 100 years. Henry, a tuatara at the Southland Museum in New Zealand, mated for the first time at the estimated age of 111 years in 2009 with an 80-year-old female and fathered 11 baby tuatara.
Dakshayani, a female Asian elephant, initially owned by the Travancore royal family and later by the Travancore Devaswom Board, was 88 or 89 years old when she died on February 5, 2019. She is believed to be the oldest elephant in captivity in Asia and was nicknamed ‘Gaja Muthassi’ (grandmother of elephants).
Lin Wang, an Asian elephant, was the oldest elephant in the Taipei Zoo. He was born on January 18, 1917, and died on February 26, 2003, at 86 years, surpassing the previous record of 84. Normally, elephants live up to 50 years, while their maximum lifespan is generally estimated at 70.
The oldest living horse on record, Ol' Billy, was allegedly born in the year 1760 in London, England. Bill died in 1822 at the age of 62. Henry Harrison, a resident of London during the time, had also allegedly known Ol' Billy for 59 years until Bill's death.
Rod, an Egyptian vulture who lived at the Jurong Bird Park from 1971 to his death in 2022. Estimated to be 60 prior to his euthanasia, he may have been the oldest known individual of his species.
A bearded dragon owned by Nik Vernon, was 16 years 129 days old when he died on December 2, 2013.
The oldest gerbil was a Mongolian gerbil named Sahara, she was born in May 1973 and died on 4 October 1981 aged 8 years and 4 months.
A mouse named Patrick Stewart (in tribute to the iconic actor), has been verified by Guinness World Records as the oldest living mouse in human care as well as the oldest mouse ever, aged 9 years 210 days as of 9 February 2023.
^De Vito; et al. (2006). "Evidence of reverse development in Leptomedusae (Cnidaria, Hydrozoa): the case of Laodicea undulata (Forbes and Goodsir 1851)". Marine Biology. 149 (2): 339–346. doi:10.1007/s00227-005-0182-3. S2CID84325535.
^Shatilovich, A. V.; Tchesunov, A. V.; Neretina, T. V.; Grabarnik, I. P.; Gubin, S. V.; Vishnivetskaya, T. A.; Onstott, T. C.; Rivkina, E. M. (2018-05-01). "Viable Nematodes from Late Pleistocene Permafrost of the Kolyma River Lowland". Doklady Biological Sciences. 480 (1): 100–102. doi:10.1134/S0012496618030079. ISSN1608-3105. PMID30009350. S2CID49743808.
^Riley, FR (2002). "Olive Oil Production on Bronze Age Crete: Nutritional properties, Processing methods, and Storage life of Minoan olive oil". Oxford Journal of Archaeology. 21 (1): 63–75. doi:10.1111/1468-0092.00149.
^McMurray, SE; Blum, JE; Pawlik, JR (2008). "Redwood of the reef : growth and age of the giant barrel sponge Xestospongia muta in the Florida Keys". Marine Biology. 155 (2): 159–171. doi:10.1007/s00227-008-1014-z. S2CID55834932.
^Butler, Paul; AD Wanamaker; JD Scourse; CA Richardson; DJ Reynolds (2012). "Variability of marine climate on the North Icelandic Shelf in a 1357-year proxy archive based on growth increments in the bivalve Arctica islandica". Palaeogeography, Palaeoclimatology, Palaeoecology. 373: 141–151. Bibcode:2013PPP...373..141B. doi:10.1016/j.palaeo.2012.01.016.
^Ziuganov, V., San Miguel, E., Neves, R.J., Longa, A., Fernandez, C., Amaro, R., Beletsky, V., Popkovitch, E., Kaliuzhin, S., Johnson, T. (2000). "Life span variation of the freshwater pearlshell: a model species for testing longevity mechanisms in animals". Ambio. XXIX (2): 102–105. doi:10.1579/0044-7447-29.2.102. S2CID86366534.((cite journal)): CS1 maint: multiple names: authors list (link)
^Зюганов В.В. (2004). "Арктические долгоживущие и южные короткоживущие моллюски жемчужницы как модель для изучения основ долголетия". Успехи геронтол. 14: 21–31.