Scientists study Jonathan, the tortoise estimated to be 194, for clues to longevity
A new genetic study examines how the world’s oldest known living land animal has endured. The findings offer research leads, with important limits on what they can tell us about human aging.
Jonathan, a giant tortoise estimated to be 194 years old, has become the subject of a new investigation into extreme longevity. Research published in Science Advances on October 7, 2026, examines both his DNA and the chemical controls that help regulate how his genes work. 1
A remarkable age, with an important qualification
Jonathan lives in the grounds of Plantation House, the governor’s residence on St Helena in the South Atlantic. He arrived on the island in 1882 already fully grown. That observation underlies an estimated hatch year of about 1832, rather than a documented birthday. Guinness World Records identifies him as the oldest known living land animal. 2
The number 194 should therefore be read as an estimate for 2026. Guinness notes that the assumptions used to calculate it are conservative, and Jonathan could be older. His exact age remains uncertain even as his extraordinary longevity is clear. 2
The study began with a cheek sample
According to Vanderbilt Health’s account, the project began with a request for a blood sample in 2017. Concerns about Jonathan’s health ruled that out, but veterinarian Joe Hollins was allowed to collect a small amount of tissue from inside his cheek. Researchers used that material to investigate his genome and epigenome. 3
The genome contains the DNA sequence. The epigenome includes chemical features that influence gene activity without changing that sequence. Vanderbilt’s release describes work by scientists associated with the Kallel Foundation, Igenbio and Vanderbilt’s genomics team, among other collaborators. 3
Two kinds of clues to a long life
Cambridge’s research summary reports 287 distinctive gene variants in pathways associated with aging, including DNA repair, inflammation, insulin regulation and tumor suppression. These are leads for understanding Jonathan’s biology; the number alone cannot explain how long an animal will live. 1
The team also compared Jonathan’s epigenetic patterns with those of younger giant tortoises of the same species. Cambridge reports that controls associated with DNA repair and metabolism were strikingly similar. Its researchers interpret that resemblance as evidence of unusual stability in systems that can change with age. 1
What remains to be tested
Further validation is still needed. Vanderbilt reports that additional work using blood samples could provide a more complete DNA sequence, and that the researchers plan to examine other long-lived species. 3
The distinction between a biological clue and a proven intervention matters here. Studying an exceptionally long-lived tortoise can help researchers choose what to investigate next. It does not demonstrate that changing the same pathways will safely extend human life. The institutional accounts describe human applications as a future research ambition, not an established result of this study. 13
Story context and image credits
Research published October 7, 2026. Jonathan’s age of 194 is an estimate for 2026 based on an approximate 1832 hatch year. Both photographs were taken March 10, 2020, and do not show the research being conducted.
View the full photo-credit recordView the original Instagram publicationSources & notes
- Return 1 Return 2 Return 3 Return 4
- Guinness World Records: Jonathan’s age estimate, record and life on St Helena, June 25, 2026guinnessworldrecords.comReturn 1 Return 2
- Vanderbilt Health: sampling, sequencing, collaborators and further-research plans, October 7, 2026news.vumc.orgReturn 1 Return 2 Return 3 Return 4
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