ABC News correspondent Jeffrey Kofman perches behind two Galapagos tortoises. When Charles Darwin came to the islands in 1835, it is estimated there were 300,000 tortoises there. Today, there are fewer than 3,000. In the 19th century, sailors took tortoises aboard ships for food. They could survive on deck for months without food or water, providing fresh meat at sea. (Wonbo Woo/ABC News)