In the popular imagination there are several animal species that are considered particularly long-lived, such as the giant tortoises of the Galapagos or elephants. Some of these species reach an advanced age if we compare them with other animals that are more common in our lives, such as dogs (which live up to 20 years) or cats (which can live up to 30 years if they are well cared for). Some species, like the Galapagos tortoise, can outlive any human. But there are species that grow even older under natural conditions. In this article we will review some of the oldest animal species and the oldest known animal.
The oldest animal among insects
The group of animals with a more limited life span are insects . For this reason, mayflies are known, whose adult individuals live from a few hours to just a day. But not all insects have short lives. The larvae of some cicadas can remain buried in the ground for between two and seventeen years before emerging as adults. The queens of eusocial insects (those that present social organization) are also quite long-lived. A queen bee can live up to four years, a queen ant up to 20, and the queen termite, the oldest insect, up to 50 years .
The longest-lived amphibian
Amphibians tend to have short lifetimes, with a few exceptions. Axolotls, Mexican salamanders that in many cases do not complete their metamorphosis and remain all their lives as larvae, can live up to 15 years. The three largest salamander species in the world, all native to Asia, in addition to being large, reach a very advanced age. Thus, the Japanese giant salamander ( Andrias japonicus ) can live up to 80 years , while the two species of Chinese giant salamanders ( A. davidianus  and  A. sligoi ) reach 60 years.
How long do reptiles live?
Among the reptiles there are some that can reach greater ages. The Nile crocodile lives for an average of 70 years, and can reach 100. Turtles are widely recognized as the longest-lived reptiles, the slowness of their metabolism being the key to their advanced age. Within the freshwater species, the Florida tortoise ( Trachemys scripta ) reaches 40 years. Those of salt water are more long-lived, the leatherback turtle lives up to 50 years and the loggerhead turtle until 60.
The oldest animal
Land tortoises are even longer-lived, the box turtle ( Terrapene california ) is over 100 years old, and the giant Galapagos tortoises (a total of ten species grouped in the Chelonoidis nigra Complex  ) are over 200 years old. The oldest tortoise on record was Adwaita, a specimen of the Aldabra giant tortoise ( Aldabrachelys gigantea ) that died in a Calcutta zoo at the estimated age of 255 years. The oldest tortoise today is called Jonathan, it is also an Aldabra giant tortoise (of the Seychelles subspecies) and has an age of 189 years. Giant tortoises are older in captivity than in the wild, due to the different dangers they face. The reason for its longevity is its slow metabolism.
The longest living bird
As for land birds and mammals , they do not reach as old an age as turtles. The Andes condor ( Vultur gryphus ) reaches 79 years in captivity, and the golden eagle ( Aquila chrysaetos ) 46. A case of a Laysan albatross ( Phoebastria immutabilis ) with a minimum age of 65 years in the wild was recorded , as it was ringed in 1956 while hatching an egg (these birds are fertile from 5 years of age) and found again in 2016. Parrots are also quite long-lived in captivity, the gray parrot ( Psittacus erithacus ) can live up to 60 years , being therefore the longest of the usual pets.
Which land mammal lives the longest?
As already mentioned, some varieties of dogs and cats can live up to 20 years if they are well cared for. Pigs or cows also reach this age. Horses can live to be 35 years old, although the oldest on record died at 62 years of age. Elephants live to be 80 years old, the longest being 86. Human beings have an average life expectancy of 79 years (it is higher in women). The oldest man with exact data (which excludes Methuselah) was the Japanese Jiroemon Kimura, who died at 116 years old, while the oldest woman was the French Jeanne Calment, who died at 122 and a half years . Therefore, the terrestrial mammal that reaches the longest age is the human being.
The life span of marine animals
While the longest-lived land animal is the giant tortoise, there are marine animals with an even longer life expectancy. Deep-sea fish such as coelacanths ( Latimeria  sp.) Live up to 100 years. Sea lobsters, which do not suffer from the effects of old age in their adulthood, also reach 100 years of age. The red sea urchin ( Strongylocentrotus franciscanus ), native to the Pacific Ocean, lives for more than 30 years, and living specimens of more than 200 years have been found. Boreal whale or Greenland whale,  Balaena mysticetus, it can live up to 200 years. Notably, in 2007 an individual was caught with the remains of an explosive harpoon under his skin, which had ceased to be manufactured in 1885. Therefore, this individual was over 120 years old when he was caught. This species of whale is the oldest mammal in the world .
As for the oldest vertebrate, it is the Greenland shark ( Somniosus microcephalus ), which lives for more than 300 years . These fish live in the icy waters of the North Atlantic, at a depth of up to 2,000 meters, and in the final stage of their life they move slowly and are almost blind. As in the case of turtles, it is the slow metabolism of these animals that allows them to live to very advanced ages. There is no reliable way to date the age of these animals, so it is accepted that they can live more than 300 years, but some researchers believe that this figure could increase to 500. However, although it may seem so, this is not the animal longer lived.
The oldest animal
The oldest animal found to date is the Icelandic clam ,  Arctica islandica . Individuals of this species can exceed 400 years of age. The longest-lived individual on record is known as Ming (by the Chinese dynasty that reigned when this individual was born in the 15th century), he died in 2006 at the age of 507 years , making it the oldest animal longevity of which there is evidence. Despite its surprising age, its size was modest, reaching 8cm in length.
There are, however, animals that in theory can live indefinitely . These are several species of jellyfish ( Turritopsis dohrnii ,  Laodicea undulata  or  Aurelia  sp.) That, once they have reached the adult stage of their lives, retain the ability to return to the larval phase and give rise, through clonal reproduction, to new genetically identical individuals . Although this allows the individual’s genes to survive unlimitedly due to biological factors, this does not mean that a specific individual will live for hundreds of years.
