Giant tortoises are probably the most famous animals in the Galapagos Islands, and the Galapagos were named after the Spanish word for tortoises. The tortoises are huge, reaching 400 pounds (880 kg) and 5.9 feet (1.8 m.). They live in the wild on only a few of the islands.
During the last 500 years, the number of Galapagos tortoises declined from an estimated 250,000 to just 3,000 in the 1970's. Conservation efforts have increased the population to about 20,000 today. Several of the species have become extinct, including "Lonesome George," that last of his species, who died within the past two years.
We went up into the highlands and stopped at a field where there were dozens of giant tortoises walking around, eating, and quite comfortable with people taking their photos, as shown by my husband's photo of me taking pictures of the tortoises.
It seemed like the tortoises were eating almost all of the time, as they must consume lots of grass to provide nutrition for a body of their large size and weight. Most of the decline in their population was due to the use of tortoises for food for sailors on whaling ships. They would typically capture more than a hundred tortoises per ship, as they could be kept on the ships easily and eaten when needed.
Darwin failed to study the tortoises in a scientific way. He collected specimens and made detailed studies of differentiation in mockingbirds and other species to arrive at the theory of evolution. He did not do so for the tortoises, even though he noted in his journal that people who lived on the islands could tell what island a tortoise came from just by looking at the shape of the shell in an adult. He failed until years later to recognize the support for the theory of evolution that can be deduced from the differences that have evolved in tortoises that have lived in separate colonies on the different islands, or even among tortoises living on the same island but separated by lava fields that they cannot cross.