One of the 11 (or 12) species of Galapagos giant tortoise still living, Chelonoidis porteri is endemic to the island of Santa Cruz and has a current population of around 3300 individuals. Like most Galapagos tortoise species, their population was severely depleted after the archipelago was discovered by man. Thousands were taken to provide fresh meat for passing sailing ships while in later years thousands more were killed to produce oil. Now days, the tortoise’s biggest threat is from their nest sites being raided by introduced mammalian species such as rats, dogs and pigs. Until these pest species can be eradicated, the long-term survival of Galapagos giant tortoises is heavily reliant on breeding programmes run by the Galapagos National Park.