In 1971 a lone tortoise was found on the Galapagos island of Pinta. He is thought to be the last such Pinta tortoise, and in Lonesome George Henry Nicholls tells his story. How did it happen that a significant population of tortoises was reduced to just a single individual, and is there anything we can do to rectify this. The book examines these questions in an accessible and entertaining way.

The Galapagos tortoises were noticed when the archipelago was discovered in 1535, but the Pinta tortoises weren't discovered until 1798. The most famous visitor to the islands was undoubtably Charles Darwin on the Beagle voyage, for whom the variation of species on the different island played an important part in his formulation of the theory of evolution. Darwin was interested in how species might travel from island to island, and several people investigated this question in the case of the Galapagos tortoises. Initial research indicated that it would be unlikely that a tortoise could swim from one island to another, and other explanations were put forward, such as land bridges or transference by human explorers. However, recent geological and DNA studies indicate that the abilities of the tortoises had been grossly underestimated. The species must have travelled, not only between the islands, but also the thousand kilometres from the mainland. It is not known yet whether it was giant tortoises which made this trip, or whether the species increased in size after becoming established on the islands.

Unfortunately contact with humans often resulted in tortoises being killed - at first for use as food, and as they became rarer by collectors who wanted to have examples of the different species. Hence the Pinta tortoise was thought to have become extinct early in the 20^th century - until George was found that is.

There seems to be only one Pinta tortoise left, and so naturally there are attempts to try to get him to reproduce, but unfortunately George doesn't seem interested. Nicholls describes the work which has been done to try to get him to change his mind, and in particular that of a female research student who became known as "Lonesome George's Girlfriend". Of course it seems unlikely that a mate for George will be found on Pinta - that hasn't stopped people from looking though. At the moment the best bet seems to be to find genetically similar females from the other islands, although the world's zoos are being searched in case any of the Galapagos tortoises in captivity happen to originate from Pinta.

What if these attempts are unsuccessful? Nicholls describes how artificial insemination might be a possibility, although he makes it clear that this would be much more problematical than with farm animals. At the end of the book is a chapter looking at more speculative options such as cloning.

Persuading George to reproduce isn't just something to try for it's own sake - there is always the hope that a population of tortoises might be returned to the island, and thus reverse in some way the problems which have been caused by humans. Consideration of such conservation possibilities forms a central theme to this book. Being the only one of his kind is something that people are able to relate to, and so George is very much a flagship for conservation issues. This leads on to the question of ecotourism. An animal such as George will get a lot of visitors, which helps to fund conservation projects but may also cause problems in its own right - the number of tourists visiting the Galapagos is way above the notional maximum which was recommended in the first management plan for the national park. Also trying to conserve species in an area where there is much poverty can pose problems. One chapter in the book describes how George's status as a conservation icon lead to him receiving death threats in a dispute over the fishing of sea cucumbers around the islands.

The book is not just about George - a substantial part of it looks at how conservation issues relate to other species and other parts of the world. There are examples of how species have gone extinct and of the problems caused by deliberate introduction of alien species to an area such as rabbits (for hunting) or cane toads (for pest control) in Australia. On a more happier note, Nicholls also describes conservation projects with a positive outcome, such as the reintroduction of a species from animals bred in captivity and the ways which have been found to allow wild animals to live in proximity to local populations without threatening the people or their crops.

I felt that the book tended to steer away from questions which reflect current controversies, such as how much the powers-that-be are really doing to get George to reproduce - maybe he's more useful as a lone icon. But all in all it was highly readable and looked at some thought-provoking issues. It might also be a useful source of information for those interested in species conservation. In fact I would put such an entertaining read as my top tip for winning the General prize of the 2007 Royal Society Prizes for Science Books