island of Mahé (extinct 1850) A. g. hololissa , Seychelles giant tortoise, from the Seychelles islands of Cerf, Cousine, Frégate, Mahé, Praslin, Round, and Silhouette The subspecific name, daudinii, is in honor of French zoologist François Marie Daudin. Genetic evidence suggests that A. gigantea is most closely related to the extinct giant tortoise Aldabrachelys abrupta from Madagascar, from which it is estimaged to have diverged from approximately 4.5 million years ago. Range and distribution The main population of the Aldabra giant tortoise resides on the islands of the Aldabra Atoll in the Seychelles. The atoll has been protected from human influence and is home to some 100,000 giant tortoises, the world's largest population of the animal. Smaller populations of A. gigantea in the Seychelles exist on Frégate Island and in the Sainte Anne Marine National Park (e.g. Moyenne Island),, where they are a popular tourist attraction. Another isolated population of the species resides on the island of Changuu, near Zanzibar, and other captive populations exist in conservation parks in Mauritius and Rodrigues. The tortoises exploit many different kinds of habitat, including grasslands, low scrub, mangrove swamps, and coastal dunes. Ecology Habitat A peculiar habitat has coevolved due to the grazing pressures of the tortoises: "tortoise turf", a comingling of 20+ species of grasses and herbs. Many of these distinct plants are naturally dwarfed and grow their seeds not from the tops of the plants, but closer to the ground to avoid the tortoises' close-cropping jaws. As the largest animal in its environment, the Aldabra tortoise performs a role similar to that of the elephant. Their vigorous search for food fells trees and creates pathways used by other animals. Feeding ecology Primarily herbivores, Aldabra giant tortoises eat grasses, leaves, woody plant stems, and fruit. They occasionally indulge in small invertebrates and carrion, even eating the bodies of other dead tortoises. In captivity, Aldabra giant tortoises are known to consume fruits such as apples and bananas, as well as compressed vegetable pellets. In 2020, a female Aldabra giant tortoise on Fregate Island was observed hunting and eating a juvenile lesser noddy, indicating that the species was in the process of learning to catch birds. Little fresh water is available for drinking in the tortoises' natural habitat, so they obtain most of their moisture from their food. The Aldabra giant tortoise has two main varieties of shells, related to their habitat. Specimens living