Could this be the world's oldest living creature?

The span of history a giant tortoise can live through is vividly illustrated in a remarkable picture on the British island colony of St Helena in the year 1900.

One of the men behind them (in our second picture) is believed to be an Afrikaner captured during the Boer War, which lasted from 1899-1902. The remote South Atlantic island, the final prison of Napoleon from 1815 until his death there in 1821, later housed a Boer War prison camp holding 6,000 inmates.

The scene is thought to be the grounds of Plantation House, the St Helena governor's residence in the island capital of Jamestown, where three giant tortoises were brought as ornamental pets from the Seychelles in the Indian Ocean in 1882.

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The animals may have been 50 years old then, and so would be about 70 when the photo was taken – and one of the three, named Jonathan, is still alive. At a possible age of 175-plus he would be the world's oldest living animal. The previous oldest-known tortoise was thought to be Harriet, a giant Galapagos land tortoise who died, aged 175, in 2005 in Australia.

Jonathan is treated as a celebrity, and for good reason: during his remarkable lifespan he has seen the coronation of eight British monarchs, from George IV to Elizabeth II, and a staggering 50 prime ministers.

These days he hangs out with fellow land tortoises David, Speedy, Emma, Fredricka and Myrtle, who are much younger; and according to locals, he still has the energy to mate regularly with the three females. "Jonathan feeds on the grass of the main paddock and is still very active despite his age, and adores attention," said a spokesman for the island's tourist board. "He is a real poser. He seems to be sightless in one eye, but does not let that slow him down."

One reason giant tortoises live so long is their armour, which defends them against predators, and that on the islands where they evolved they did not have any predators anyway.

The three animals brought to St Helena in 1882 were examples of Dipsochelys hololissa, the Seychelles giant tortoise, which went extinct in the wild in the middle of the 19th century. Similar giant tortoise species existed on other Indian Ocean islands but these have also gone extinct. The only species of Indian Ocean giant tortoise that has avoided this fate is the Aldabra giant tortoise, of which more than 100,000 survive in the wild.

The earlier picture came to light after a photograph album was found in a rubbish skip in Hampshire: it is a collection of rare images taken by St Helena's resident photographer, LA Innes, between 1899 and 1902. Many of the 100 prints show scenes from the period when the island was a Boer prison camp. The album fetched £4,000 when sold at auction six weeks ago.