I'm So Lonely -- Discovered in 1971 by a National Parks expedition out hunting feral goats, Lonesome George is believed to be the sole survivor of the Isla Pinta tortoise subspecies. Previously, the last recorded sighting of an Isla Pinta tortoise had been in 1906. Lonesome George was brought to the Charles Darwin Research Station for a variety of reasons. Scientists, for example, are frantically trying to find a mate for him so that the species doesn't become extinct. They've even offered a $10,000 reward to anyone who finds another Isla Pinta tortoise. They have also tried to breed Lonesome George -- estimated to be between 70 and 80 years old -- with closely related female species, but so far these attempts have been unsuccessful. Hopes were high in 2008, when eggs were discovered in the nest of one of the closely related females who shares her pen with George. However, none of 13 incubated eggs successfully hatched.

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