In 2006, Adwaitya the Aldabra giant tortoise (Geochelone gigantes), personal pet of Clive of India (1725-74), died in Kolkata Zoo, aged 255. He was, as far as we know, the planet’s oldest animal and it is astonishing to imagine a life that began before Mozart and the French Revolution ended with an announcement on CNN.
Tortoise longevity is partly due to their slow reproductivity. Giant tortoises are big, cold-blooded herbivores, with a sluggish metabolism. It takes them at least 30 years to reach sexual maturity. Today they only live in isolated island environments with no natural predators as adults, so while any tortoises which reach adulthood are relatively safe, their young are not so lucky. They hatch in batches of ten, of which of only one is likely to reach adolescence, let alone adulthood. So, a long life means a much better chance of passing on the genes.
Today, there are only 12 species, all but one of which are endangered. The speed with which humans dispatched the island tortoise species is astonishing. Early reports from the Galápagos tell of seeing 3,000 together, so that one could walk on their shells for some distance without touching the ground. Within a few decades, most species had been eaten to extinction. They had no way of defending themselves: even their heads are too big to be withdrawn into their shells. This is because they went for so many millennia without being attacked that the ability to protect themselves in this way faded out. In fact, they compete in neck-stretching competitions to establish rank; the one who can stick his neck out furthest gets to be dominant.
If there is a glimmer of hope it concerns Adwaitya’s descendents. In 1875, the government of Mauritius declared Geochelone gigantes the world’s first protected species. There are now 152,000 Aldabra giant tortoises – 90% of the world’s total population – which are happily isolated from their only serious threat: us.
Whaler crews called their tortoise-harvesting expeditions ‘turpining’, from a mispronunciation of 'terrapin'. One ship’s log records turpining parties taking 14 tons of live tortoises on board one ship in four days. They were very difficult to carry, but smaller ones could be worn on a man’s back like a rucksack.
The giant tortoises unwittingly helped the dodo to go extinct. Dutch visitors to Mauritius named dodos ‘Disgusting Birds', because they tasted so horrible that even starving men could hardly stomach them. But they found they could force dodo meat down when it was dressed with tortoise oil, which was held to be 'superior in taste to that of the olive.'
Giant tortoises helped to inspire Darwin’s theories of natural selection. Sadly, even he brought back no specimens, alive or dead, except for one juvenile pet. His crew had indeed taken dozens of tortoises on board - but they’d scoffed the lot, and chucked the remains overboard.
Giant tortoises are probably descended from normal tortoises - they grew bigger on remote islands with no predators.
The reason that the giant tortoise wasn’t properly classified by scientists for so long appears to be quite simple: they were so delicious that no specimens ever made it back to Europe without being eaten on the voyage.
According to scores of accounts over several centuries, the giant tortoise is by far the most edible creature man has ever encountered. 16th-century explorers compared them to chicken, beef, mutton and butter – but only to say how much better the tortoise was. One tortoise would feed several men, and both its meat and its fat were perfectly digestible, no matter how much you ate.
Oil made from tortoise fat was medically useful – efficacious against colds, cramps, indigestion and all manner of ‘distempers’ – and tasted wonderful. Even better were the delicious liver, and the gorgeous bone marrow. The eggs, inevitably, were the best anyone had ever eaten. Some sailors were reluctant to try tortoise meat because the animal was so ugly - but after one taste they were converted.
Giant tortoises were invaluable to sailors, as they could be kept alive for at least six months without food or water. Stacked helplessly on their backs, they could be killed and eaten as and when necessary. Better still, they sucked up gallons of water at a and kept it in a special bladder, meaning that a carefully butchered tortoise was also a fountain of cool, perfectly drinkable water. Large-scale commercial whaling in the 19th century was only made possible because the giant tortoises enabled ships to stay at sea for weeks at a .
One was eating a piece of cactus, and when I approached, it looked at me, and then quietly walked away: the other gave a deep hiss and drew in its head.
Giant tortoises compete in neck-stretching competitions to establish rank.
It took 300 years after its first discovery for the giant tortoise to receive a scientific name.
Giant tortoises can drink enough at one session to last them for several months.
Spanish sailors who discovered Galápagos 1535 named it after the tortoises; the Spanish for tortoise is galápago.
Female giant tortoises return year after year to the same place to lay their eggs.