A Sheltered Life: The Unexpected History of the Giant Tortoise

Paul Chambers

305pp, John Murray, £17.99

Despite the title, giant tortoises have had anything but a sheltered life, at least since humans became interested in them. Unlike other giant species, such as killer kangaroos or cave lions, tortoises managed to survive the ice age, taking refuge on isolated archipelagos like the Galápagos islands in the Pacific, or the Mascarene islands in the Indian Ocean. But mankind has proved a more deadly opponent than nature because, unfortunately for the giant tortoises, they tasted great.

William Dampier, a 17th-century British pirate based on the Galápagos islands, described them as "extraordinary large and fat, and so sweet, that no pullet eats more pleasantly". At the same time in the Indian Ocean, adventurer François Leguat had been stranded on the Mascarene island of Rodriguez. He had plenty of time to get to know the island's "land-turtles" and described gatherings of 3,000 of the creatures. But Leguat looked on the giant tortoises not with a scientist's thirst for knowledge but with a gourmet's hunger for exotic food: their "flesh is very wholesome, and tastes something like mutton", drooled the Frenchman. Indeed, on this point everyone agreed: giant tortoises were simply delicious and, as Paul Chambers says, until the 19th century, descriptions of them were more like restaurant reviews than natural history.

Sadly, our taste for tortoise was their downfall. Not only were they very palatable but they could live on ships which, in an age of long voyages before refrigerators, meant fresh food for sailors. The giant tortoises were "a captain's dream come true", and as a result many tortoises spent their last months wandering the decks of ships, waiting to be eaten. (One resourceful tortoise reportedly went missing on board a ship, only to be discovered two years later living in the hold among the casks.)

In the 18th century, more than 4,000 tortoises a year were taken from Rodriguez island alone. By 1770 it seemed that the giant tortoises would follow in the foot steps of that other former inhabitant of the Mascarene islands: the dodo. The giant tortoises of the Galápagos islands fared little better. By 1830 some 100,000 had been taken, mostly by British whaling ships.

In September 1835 Charles Darwin arrived on the Galápagos islands. He was distinctly unimpressed by what he saw. The volcanic islands were, he wrote, "what we might imagine the cultivated parts of the Infernal regions to be". But as Chambers argues, it was a conversation about giant tortoises with the governor of these islands, Captain Nicholas Lawson, which provided the father of evolution with a vital piece of evidence that he would recall many months later as he began formulating his paradigm-shifting theory. Lawson boasted that he could tell from which island a tortoise came simply by looking at the shape of its shell. "In time," Chambers writes, "Governor Lawson's remark would be the spark that started a fully fledged scientific revolution."

Darwin's ship, The Beagle, took more than 30 live tortoises with it as food for the voyage to Polynesia. On leaving, Darwin wrote in his diary: "I should think it would be difficult to find ... a piece of land 75 miles long, so entirely useless to man or the larger animals." It wasn't until he was back in England that Darwin realised the true significance of the islands, each with their unique species of giant tortoise. Unfortunately, en route Darwin and the crew ate "the most important specimens on board the Beagle" - the tortoises - and so vital evolutionary evidence ended up in the cooking pot.

A Sheltered Life is a wonderful exploration of the history of this gentle giant, "the longest-living vertebrate species on earth". Lovingly researched and engagingly narrated, Chambers's account of these "magnificent and inspirational creatures" shows our own species in a very bad light. Lonesome George, the last survivor of the giant tortoises that once thrived on the Galápagos island of Pintais, is "a poignant symbol of the destruction that Homo sapiens has meted out to the natural world".

· PD Smith's illustrated biography of Einstein is published by Haus.