Upon learning of the death of Lonesome George, the last Pinta Island tortoise, we invited comment from Craig Stanford, Professor of Biological Sciences and Anthropology at USC and author of The Last Tortoise. His post is below.
George passed away peacefully on June 24, 2012, at the age of approximately 100. He was born on Pinta Island around 1912 and lived there until 1971, when he moved to the Charles Darwin Research Station on Santa Cruz Island, Ecuador. He served his country for decades as the greatest tourist attraction in the Galapagos Islands, and was visited by tens of thousands of tourists each year. He dies leaving no surviving descendants.
That last sentence is the one that matters. Jorge Solitario, or Lonesome George, was the last surviving member of his race, the subspecies of giant Galapagos tortoise known as Chelonoidis nigra abingdoni, the Pinta Island tortoise. The main islands of the Galapagos archipelago each have or had their own distinctive giant tortoise, molded by natural selection to be adapted to the terrain and the foods of its island. George’s subspecies inhabited a small northerly island that is fairly barren, rocky, and forbidding, but which once had a large tortoise population. The whaling ships of the 18th century made short work of the islands, collecting hundreds of thousands of the animals to be stored alive in the cargo hold and butchered as needed for fresh meat during their long voyages. We estimate the pre-whaling tortoise population of the entire Galapagos chain to have been 250,000-300,000 tortoises. Perhaps 15,000 live on the islands today; at least three islands have now lost their tortoises altogether.
In 1971, seventy years after the last tortoise on Pinta was thought to have died, a biologist visiting the island spotted Lonesome George ambling across the dry landscape. Not realizing the significance of the sighting, a year passed before another biologist learned that the Pinta race was not quite extinct. Expeditions were mounted to Pinta to search for George. A large tortoise on a small island might not seem a difficult target, but only through much luck was George found. He was transported to the Darwin Station by boat, and remained there for more than forty years. All subsequent attempts to find more Pinta Island tortoises failed. For years he shared his pen with two females from the slopes of Wolf Volcano in the northernmost part of Isabela Island. But George showed no interest in having sex with them. Later, he was paired with females of other, similar subspecies from the islands, and in recent years three clutches of eggs were produced that he had fathered. But none of the clutches hatched. George was likely infertile, either through age, or just very bad luck.
The story of the Pinta Island tortoise does not quite end there. Recent genotyping of tortoises from around the Galapagos has turned up at least one tortoise, from Wolf Volcano on Isabela Island, that is fifty percent Pinta. It is likely the progeny of a Wolf tortoise and a Pinta tortoise that ended up on Isabela. Perhaps ocean currents carried it there, or more likely, he or his mother was dropped overboard by an inept crew of whalers. Only a tiny fraction of the tortoises of the islands have been genotyped, and there lies some faint hope that another male and female of the Pinta Island tortoises live still.
It is always sad and disturbing when humans drive a species into extinction. But extinction is rarely so clear-cut as with the tortoises of Pinta. One last surviving member lived on and on, reminding us of our past sins to his race and beckoning us to try one more time to save them. In the case of Lonesome George, it was too little, too late.