194 years old and still going! Jonathan, the 194-year-old giant tortoise, has the supergenes of a five-year-old to stop his cell batteries from running down, scientists have found… Jonathan hatched in 1832 and is still on the lawn at Plantation House in St Helena (2000 miles from land in the Atlantic). A DNA reading by researchers at the University of Cambridge finds that large parts of his gene regulation still match a five-year-old of his species. The work, published in Science Advances, compared the Aldabra giant tortoise with four others aged between five and 91. Jonathan carries 287 gene variants the comparison animals do not. The variants sit in pathways that repair DNA damage, reduce inflammation, regulate insulin, and suppress cancer. Of his genes, 272 look, in their on-and-off state, like the genes of the five-year-old. The chemical marks that usually accumulate on a genome and change how genes behave are sparse in him. The original function of many of those genes has barely shifted across nearly two centuries. Dr Justin Gerlach, the Cambridge ecologist on the study, said Jonathan is slightly better able to cope with the symptoms of ageing and that he is ageing more slowly. The longevity, Gerlach said, comes from the combination of those variants and stable gene regulation. The switches that govern DNA repair and metabolism have stayed close to the setting seen in the younger tortoises. In ordinary ageing those switches drift, and genes begin to be expressed in the wrong amount. The genes that still look young cluster on the mitochondria, the structures that supply the cell with energy. Dr Stephen Clark, founder of the longevity group Kallel, who worked with Cambridge on the analysis, said Jonathan has kept his mitochondria in a more youthful state than the 91-year-olds in the set. Mammalian work has shown for decades that mitochondrial efficiency falls with age. The tortoise profile is evidence that the fall can be delayed in this lineage, not proof of a method for doing the same thing in a person. The sample was a cheek scrape. A blood draw was not permitted, so telomere length was not measured and no estimate of remaining life was made from it. Jonathan’s eyesight is failing. A report of his death earlier in 2026 was a hoax. The team does not know how long he has left. He was brought from the Seychelles in 1882 and has lived on St Helena since. Aldabra tortoises often pass 150 years. A specimen at Kolkata Zoo is said to have reached 255; that figure has not been fixed to the same standard as Jonathan’s record. Kallel intends to read more long-lived animals in the hope of finding a drug or a treatment that slows human ageing. No such compound has come out of this genome. A single extraordinary tortoise is not a trial, and a reptile regulator is not yet a human one. What the scrape supports is narrower. Extreme age in this animal lines up with repair and energy genes whose regulators have not drifted, and with mitochondria that still resemble those of a juvenile. The stability is measured. The transfer to human cells is not. Source: University of Cambridge, “Genetic analysis of the world’s oldest land animal reveals secret of living 194 years,” 7 October 2026, on the Science Advances paper.