Oldest land animal (living)

The oldest-known living terrestrial animal is Jonathan, a Seychelles giant tortoise (Aldabrachelys gigantea hololissa), originally from the Seychelles but now a long-time resident of the remote South Atlantic island of St Helena, where he is affectionately known as "Jono". He is believed to have been born c. 1832, thus making him at least 194 years old in 2026. His age has been reliably estimated from the fact that he was said to be "fully mature" (and hence at least 50 years old) when he was brought to the island in 1882. As his age on arrival is a conservative estimate, in all likelihood he is even older. Although cataracts have dimmed his sight, and his sense of smell is diminished, his hearing remains excellent.

Direct evidence supporting his estimated age came to light when an old photograph taken between 1882 and 1886 was uncovered that showed a fully grown Jonathan munching on grass with several local "St Helenians" in the garden of Plantation – the residence of the island's governor and where Jonathan resides to this day.

Jonathan's health had deteriorated markedly by around 2009; he was thin and his beak had become soft and crumbly. But Joe Hollins, a vet who was then Jonathan's primary carer, helped him recover. He told GWR: "I began to feed him once weekly with fruit and vegetables to boost his calory intake... Much to my surprise, this once weekly feeding rejuvenated him and gave him back a sharp grazing beak, whereupon I realized, of course, that through lack of nutrition he was deficient in minerals, vitamins and trace elements."

Having studied Jonathan's shell, some experts have suggested that he may belong to a separate species, or subspecies, of Seychelles tortoise though this debate has yet to be settled conclusively.

Jonathan has lived through many major events in modern-day history. When he was born in 1832, William IV was Britain's king. Queen Victoria, who was 13, would not accede to the throne until Jonathan was five. When Jonathan was two, Britain abolished slavery. When he was nine, missionary and explorer David Livingstone sailed for Africa, discovering a spectacular waterfall that he named Victoria Falls when the giant tortoise was 23. Lewis Carroll's beloved children's novel Alice's Adventures in Wonderland was first published in 1865 when Jonathan was 33. It wasn’t until Jonathan was 35 that antiseptics were first used during surgery, and it wasn’t until he was 71 that the women’s suffrage movement was formed, three years after the turn of the 20th century.

Joe Hollins explained to GWR that in 2021, he took a swab so that Jonathan's DNA could be analysed by the Vanderbilt Medical Research Center in Nashville, Tennessee, USA. "Because giant tortoises have better monitoring and surveillance systems to repair degraded and oxidated genes, they are more resistant to developing cancers," he told GWR. "The researchers are looking into this for the benefit of humanity and a scientific paper is in the offing."