Wednesday, August 8, 2007

Hopes rise of a mate for rarest living creature on earth

Ian Sample, science correspondent
Tuesday May 1, 2007
The Guardian

Lonesome George, conservation icon of the Galápagos islands, celibate pensioner and officially the rarest living creature on Earth, may soon have a playmate, raising hopes he may father young and so save his species from imminent extinction. The 80-year-old giant tortoise was discovered in 1972 among the foliage of Pinta island in the archipelago. He has since been cared for as the sole survivor of his species, Geochelone abingdoni, and become a stark symbol of Earth's rapidly declining biodiversity.
Despite heroic efforts from his carers, from engineered trysts with females of similar species to attempts at "digital manipulation" to gather his sperm, George has so far failed to produce any off spring, leading scientists to fear his death will spell the end for his unique lineage.

But researchers say there is renewed hope for George and his kind. A genetic survey of giant tortoises on Isabela island, the largest of the Galapágos, has revealed proof that another of George's species was, and may still be, breeding on the island.

A team led by Jeffrey Powell, an evolutionary biologist at Yale University, took blood samples from 27 giant tortoises living on the western side of a volcano on Isabela's northern tip. Among them, they found one male, aged around 30, who is a cross between a native species and a Pinta island male just like George. The discovery means that in the recent past, a Pinta male was breeding on the island. "If that's the case, it is possible there are other Pinta individuals out there, maybe even a female," said Professor Powell, whose study was published yesterday in Current Biology.

The researchers intend to return to the island and take blood samples from more than 2,000 giant tortoises . If they find a Pinta female, they hope to take her to George's enclosure at the Charles Darwin research station on Santa Cruz island and attempt to breed the pair. The researchers concede the chances of fi nding a pure Pinta female are slim, but even if they are unable to, they could start a selective breeding programme using a female sibling of the 30-year-old male already discovered. By mating subsequent off spring with George, the scientists would slowly be able to make them more and more like the Pinta species.

Henry Nicholls, an evolutionary biologist and author of Lonesome George, a book about the animal, said: "I can't think of a better conservation achievement than managing to resurrect a population when you thought you only had one left."

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