Sandra Blakeslee in The New York Times:
The dodo is dead. The passenger pigeon has passed on. But Lonesome George, the iconic Galápagos tortoise whose death marked the end of his species, is in post-mortem luck. A scientific expedition has discovered some of his close blood relations alive and well. With careful breeding, biologists now hope to revive George’s species and reintroduce the tortoises to the island on which they evolved. It would be a signal achievement in a place that gave rise to our understanding of evolution and speciation. Originally there were at least eight species of Galápagos tortoise, scientists now believe. (One was discovered only this year.) At least three species are now extinct, including tortoises on Pinta Island. The last one, George, was discovered wandering alone in 1972 and taken into loving custody. His death, in 2012 at more than 100 years old, was a powerful reminder of the havoc visited by humans on delicate ecosystems worldwide over the last two centuries.
There are two types of Galápagos tortoises: saddlebacked and domed. The sailors much preferred the smaller saddlebacks, which were easier to lug around and said to taste better. They were also easier to find: Domed tortoises live at higher elevations and can weigh 300 pounds. Saddlebacks evolved at lower elevations and feed on drier vegetation. Saddlebacked tortoises disappeared from Santa Fe Island and Floreana Island, a favorite hangout for sailors posting letters for other ships to carry home. With George’s death, the Pintas were gone, too. But now the story of extinct Galápagos tortoises has taken a strange, and hopeful, twist. More than a century ago, it turns out, sailors dumped saddlebacked tortoises they did not need into Banks Bay, near Wolf Volcano on Isabela Island. Luckily, tortoises can extend their necks above water and float on their backs. Many of them made it to shore, lumbered across the lava fields and interbred with Isabela’s native domed tortoises. In 2008, scientists tagged and collected blood samples from more than 1,600 tortoises living on the flanks of the volcano. Back in the laboratory, there was a genetic eureka: Eighty-nine of the animals were part Floreana, whose full genetic profile DNA had been obtained from museum samples.