Tortoises are serene creatures, who never rage, so Harriet, a 23-stone giant from the Galapagos, would have gone ‘gently into that good night.’ She lived through interesting times. Her career in public life began when Charles Darwin arrived at the Galapagos on September 15, 1835. He left on October 20, taking Harriet and a host of other creatures, dead and alive, with him back to England. In 1841, Harriet became one of the most travelled reptiles in the world when she was taken to Australia. She took up residence at the Brisbane Botanic Gardens but was moved to Queensland Zoo in 1980. Harriet was about the size of a dinner plate when captured and she would have been are least five years old then, suggesting that she had reached the age 175 ‘at close of day.’
But Harriet was not the world’s oldest animal. According to The Guinness Book of Records, a Madagascar radiated tortoise was presented to the Tonga royal family by Captain Cook in either 1773 or 1777. That tortoise died in 1965 when it was at least 188-years-old. But there is a third claimant. Robert Clive, ‘Clive of India’, was a soldier who rose through the ranks of the East India Company to become the first Governor of Bengal.
An opium addict, who committed suicide in 1774, he had a pet tortoise, which had been presented to him by traders from the Seychelles. The tortoise was reputed to be 255 years old when it died. Unfortunately, the details of its life are not sufficiently documented and the record has not been accepted. There is something suspicious about all of these claims. In each case, a celebrity is involved. If you are exhibiting a giant tortoise in your menagerie, a claim that it once belonged to the likes of Darwin, Cook or Clive would help to draw the crowds. One suspects that there is ‘creative’ element in these tortoise histories. Whatever the truth of the matter, there is no doubt that giant tortoises live very long lives.
Our own group, the mammals, can’t compete with the reptiles but there are controversies about mammal records also. Bowhead whales, for example, live in the coldest waters and seldom venture south of the Arctic Circle. Bowheads have been traditionally hunted by the Inuit. Their carcasses are often preserved in ice. Dead bowheads have scars, some of which result from wounds inflicted by Inuit harpoons. Biologists thought that the whales had a life span of about 80 years until archaeologists suggested otherwise. Stone-tipped harpoon heads, which had not been used by hunters for over a hundred years, were being been found in recently dead whales. The bowheads, the archaeologists thought, had to be much older than the biologists thought they were. Work on the amino acids in the tissues of dead whales seems to confirm the archaeologists’ findings. The oldest bowhead, and the oldest mammal, was estimated to have died at 211 years.
Whether the bowhead results are valid or not, mammals do less well in longevity contests than cold brooded reptiles. Tortoises, not having to generate their own body heat, need only a fraction of the food which a mammal of comparable size consumes. They can, therefore, lead quieter, slower lives than the warm blooded highly-active mammals and it is hardly surprising that they live longer. Strife and stress tend to shorten lives.
People alive today lead far less stressful lives than their ancestors did and they manage to live longer. When I was born in 1944, the life expectancy of an Irish male was 59 years. A male born today can expect to reach 75.
‘And all the days of Methuselah were 969 years and he died’ declares the Holy Book and, if you happen to believe that the Bible story is literally true, Methuselah was the oldest member of the animal kingdom ever to have lived. Among authenticated records, however, the prize goes to a French woman who died in Arles in 1997. Jeanne Louise Calment was born in 1875 and lived to be 122.
If adversity and stress shorten the lives of animals, it has the opposite effect on plants. The oldest trees in Britain and Ireland have all been coppiced or pollarded. In coppicing, the tree has it trunk severed at ground level. In pollarding, it is cut at the height of a person. The trees then grow, mushroom-shaped from the stump and, paradoxically, live much longer than they would if allowed to grow normally. The oldest known tree was a bristle-cone pine of the southern United States. It too faced adversity, living in windswept rocky terrain, 3,000 metres above sea level and relying on snow to obtain moisture. A specimen, known as Prometheus, was cut down on Mount Wheeler in Nevada in 1963. It had 4,867 rings but old trees become hollow and some rings are lost. Prometheus is estimated to have lived for 5,200 years. It is regarded as the world’s oldest living thing although some micro-biologists would not agree. They claim that a bacterium found in the north of England is 260 million years old.