Each of Isabela’s five volcanoes hosts its own unique species of Galápagos Tortoise. The rough aa lava between the volcanoes forms a sufficient barrier to isolate each species from the others. The Alcedo tortoise is the largest single population of tortoise species in the archipelago, numbering around 5,000 individuals. Feral goats released by early settlers are a serious threat to the tortoise because the goats eat the same vegetation, grazing from ground level to well above the reach of the tortoise. In addition, they move much faster and have a much higher breeding rate. At the beginning of 2004 there were an estimated 100,000-150,000 goats on Isabela. February 6 of 2004 marked the beginning of a six-year eradication program during which time park naturalists hope to extirpate all of Isabela’s goats. Our guide told us that the island was to be closed for the first week while the goats were systematically hunted from the air and the ground. Without this effort, the five species of tortoise on Isabela would be doomed to extinction.

This is a rather young individual, judging by the unworn carapace with clearly delineated growth rings. The carapaces on older individuals become worn almost smooth.