Lonesome George, the giant tortoise who became the face of the Galapagos Islands conservation effort, was found dead in his corral Sunday morning, according to a statement by the Galapagos National Park Service. He was believed to be more than 100 years old and weighed 200 pounds.

He is the last known Pinta Island giant tortoise, and his death likely marks the complete extinction of his subspecies.

Fausto Llerena, Lonesome George’s longtime caretaker, discovered the tortoise stretched out, leaning toward his watering hole. The cause of death remains undetermined and the tortoise’s body is being held in a cold chamber to avoid decomposition before officials conduct a necropsy, the park said.

For years, Lonesome George’s minders tried to encourage him to procreate, even offering $10,000 for a pure Pinta Island tortoise. The reward went unclaimed, and park conservationists brought in four female tortoises of similar species, but their eggs proved infertile.

Sveva Grigioni, a 26-year-old Swiss zoology graduate student, nobly contributed to the effort by attempting to manually stimulate George, according to “Lonesome George: The Life and Loves of a Conservation Icon,” a book by Henry Nicholls about the famous tortoise.

Grigioni’s work wasn’t completely for naught, as George started showing interest in the females in his corral.

“He started to try copulation but it was like he didn’t really know how,” Grigioni told Nicholls, according to a book review in the Guardian of London.

The giant tortoise is native to several of the Galapagos Islands, a volcanic archipelago west of the Ecuadoran mainland. Lonesome George was the last known individual of the Pinta Island tortoise subspecies (Chelonoidis nigra abingdoni).

A scientist studying snails spotted the tortoise later known as Lonesome on Pinta Island in 1971. The tortoise was brought to the Darwin research station the following year.

He was named Lonesome George (or Solitario Jorge) for George Gobel, the television star who played, according to a 2007 in The New York Times, the role of a “hapless, hen-pecked husband."

Some 20,000 giant tortoises of different subspecies still live on the Galapagos, according to Reuters.

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