A 194-year-old tortoise, world's oldest land animal, may hold clues to longer life

In 1882, a giant Aldabra tortoise named Jonathan arrived on the remote South Atlantic island of St Helena, likely from the Aldabra Atoll or the Granitic Seychelles. He is now believed to be 194 years old, making him the world's oldest known terrestrial animal. Scientists are studying Jonathan to uncover the secrets behind his remarkable longevity.

By analyzing his genome and epigenome, researchers found changes in pathways related to longevity, such as DNA repair, mitochondrial function, insulin regulation, and telomere function. Jonathan's methylation entropy, a measure of disorder in biochemical processes, was lower in certain regions compared to other tortoises, suggesting his genes are better controlled.

He also has extra copies of a gene associated with tumour suppression and DNA repair, and is unusually efficient at mitochondrial function. Despite his advanced age, Jonathan remains a "gentle giant," with a voracious appetite and an affectionate nature, according to his longtime veterinarian.