Jonathan, a giant tortoise nearing his 195th birthday, may offer scientists important clues about how to extend healthy lifespan after researchers found that some parts of his body appear far younger than his extraordinary age.
Recognised as the world’s oldest known living land animal, Jonathan was born before Queen Victoria ascended to the throne. He has spent much of his long life on the remote South Atlantic island of St Helena.
Researchers have now found evidence that some of the biological systems operating inside his cells remain remarkably youthful, despite his estimated age of 194.
The discovery could give scientists a new way to study how certain animals withstand the effects of ageing. However, more research is needed before the findings can be linked to human longevity.
Jonathan is also very much alive after scammers falsely claimed earlier this year that he had died, apparently in an attempt to attract cryptocurrency donations.
Scientists sequenced Jonathan’s genome—the complete set of instructions contained in his DNA—using a cheek swab collected by his vet, Dr Joe Hollins.
The study, published in the journal Science Advances, identified genetic variants linked to DNA repair, metabolic regulation and protection against cancer.
One of the most striking findings involved his mitochondria, the tiny structures within cells responsible for producing energy.
Jonathan, the world’s oldest known living land animal, was born before Queen Victoria came to the throne and has spent much of his life on the remote South Atlantic island of St Helena
Vet Joe Hollins, pictured left with Jonathan
Prince Edward met the 194-year-old tortoise in 2024
A decline in mitochondrial performance has been associated with ageing and a range of age-related illnesses.
The researchers also analysed chemical markers attached to Jonathan’s DNA. These markers help control how genes function and were compared with those found in other giant tortoises.
Many of Jonathan’s patterns were similar to those seen in older animals. But the markers connected with mitochondrial activity more closely resembled those of much younger tortoises.
Stephen Clark, a researcher involved in the project at the non-profit Kallel Foundation, told the Guardian: “His mitochondria must be especially stable and that’s an insight into longevity in general. It’s important that the mitochondria are kept as pristine as possible.”
It remains unclear whether these molecular patterns directly explain Jonathan’s remarkable lifespan, or how significant a role they may have played.
The team also detected differences linked to DNA repair and the upkeep of telomeres—the protective caps found at the ends of chromosomes.
DNA damage builds up over time, while telomeres gradually shorten, a process believed to contribute to biological ageing.
Jonathan also shares several genes with other exceptionally long-lived species, including naked mole rats. These rodents can live for up to 40 years and rarely develop cancer.
Steve Horvath, a biologist at the University of California, Los Angeles, who studies ageing and co-authored the research, told the New York Times: “We almost never get to study an animal this old while it is still alive.”
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Obtaining Jonathan’s DNA proved a delicate operation.
Dr Hollins had to hold his head with a thick welding glove and carefully prop open his sharp beak to swab the inside of his cheek.
An initial attempt produced a sample covered in half-chewed carrot, one of the tortoise’s favourite snacks.
Researchers were not allowed to take blood because of the risk of infection, and the saliva sample had to leave the island by boat.
Jonathan lives in the grounds of Plantation House, the official residence of St Helena’s governor, around 1,200 miles off Africa’s west coast.
His exact birth date is unknown, but he was already fully grown when he arrived on the island in 1882, suggesting he was at least 50.
The tortoise welcomed the future Queen Elizabeth II, as well as George VI and the Queen Mother, to the British overseas territory of St Helena in 1947, pictured
He was brought to St Helena from the Seychelles in the 1880s and lived on the grounds of Plantation House, the official residence of the island’s Governor
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That puts his estimated birth year at 1832, before Queen Victoria took the throne and before Charles Darwin visited the Galapagos Islands.
In April, a fake account on X posing as Dr Hollins claimed Jonathan had died.
The post spread widely, but the real vet exposed the deception and said the account was asking for cryptocurrency donations.
St Helena’s governor, Nigel Phillips, also checked on Jonathan after being contacted by the Guardian and found him asleep beneath a tree.
Despite cataracts and the loss of his sense of smell, Jonathan continues to enjoy life, retaining excellent hearing and a strong libido.
When Dr Hollins took over his care in 2009, the tortoise was struggling to forage and had a soft, crumbling beak.
Regular hand-feeding helped him regain weight and develop a hard beak within six months to a year.
Scientists caution that his protected surroundings, fresh vegetables and veterinary care could also help explain his exceptional age.
But his biology offers promising avenues for further investigation.
Steve Austad, a biologist at the University of Alabama at Birmingham, told the New York Times: ‘Each of these long-lived species has some kind of special trick. And some of those may turn out to be relevant to human aging.’