The lumbering giant tortoise known as Lonesome George lifts up his head during a walk in his protected home in Puerto Ayora, in central Galapagos, Ecuador, in 2001. He was notoriously disinterested in the opposite sex and failed to produce any offspring. Provided to china daily

Lonesome George, the last remaining tortoise of his kind and a conservation icon, died on Sunday of unknown causes, the Galapagos National Park said. He was thought to be about 100 years old.

Lonesome George was found in 1972 and had become a symbol of Ecuador's Galapagos Islands, which attracted some 180,000 visitors last year.

"This morning the park ranger in charge of looking after the tortoises found Lonesome George. His body was motionless," the head of the Galapagos National Park, Edwin Naula, told Reuters.

"His life cycle came to an end."

He lived at a tortoise breeding center on the archipelago's island of Santa Cruz. He was found Sunday morning in his pen by his longtime keeper, Fausto Llerena, the park said in a statement.

"The plight of Lonesome George provided a catalyst for an extraordinary effort by the government of Ecuador to restore not only tortoise populations throughout the archipelago but also improve the status of other endangered and threatened species," the park said.

In honor of Lonesome George, it said it was convening an international workshop in July on management strategies for restoring tortoise populations over the next decade.

"Lonesome George's legacy will be an increased effort in both research and management to restore all of the giant tortoise populations of Galapagos," it said.

George was the last member of a species of giant tortoise from La Pinta, one of the smallest islands in the Galapagos, the park said.

The giant Galapagos tortoises, which can live up to 200 years, were among the species that helped Charles Darwin formulate his theory of evolution in the 19th century.

The park is considering embalming George's body so that it can be displayed there, Naula said.

A spokesman said the park plans to carry out a postmortem to determine what may have killed the tortoise.

Scientists had been trying to get George to mate since 1993. He was notoriously disinterested in the opposite sex and failed to produce any offspring.

The pen where George lived was visited by thousands of tourists every year, who often had to scramble over each other to take pictures of one of the rarest creatures on Earth.

The islands often attract celebrities, including Angelina Jolie and Brad Pitt, who visited earlier this year.

Sailors and fishermen hunted tortoises for their meat, to the point of extinction.

Their habitat has been eaten away by goats introduced from the mainland.

The Galapagos' giant tortoise population was decimated after the arrival of humans, but a recovery program run by the park and the Charles Darwin Foundation has increased the overall population from 3,000 in 1974 to 20,000 today.

The archipelago has been a UNESCO World Heritage Site since 1978 for the rich plant and animal life found both on its land and in the surrounding sea.

In 2007, the organization declared the island chain's environment endangered due to the increase of tourism and the introduction of invasive species.

Agencies in Quito, Ecuador