The females were particularly devestated because they come to lower elevations to nest, where as males tend to remain in the moister highlands. As many as 200,000 tortoises may have been taken in the nineteenth century. Several races became extinct and the numbers of other races vastly reduced. There are now only about 15,000 surviving in the Galapagos. Of these, about 3000 live on Volcan Alcedo.
Tortoises are herbivores, feeding on grasses and the leaves of shrubs and cacti.
Today, their greatest threat comes from competition with feral cattle, burros, and particularly goats. Wild dogs, cats, rats, and pigs also attack the eggs and young.