Aldabra Atoll

Aldabra Atoll

Aldabra Atoll is the world’s second-largest coral atoll, spanning a total area of 60 square miles. It consists of four large coral islands, each enclosing a shallow lagoon, and the entire group is surrounded by a coral reef. Due to its remote geographic location and inaccessibility to most people, Aldabra has remained largely untouched by human activity. It serves as a sanctuary for around 2,000 giant tortoises, making it the largest population of these creatures in the world. Approximately 150,000 Aldabra giant tortoises (Dipsochelys dussumieri)—one of the most abundant giant tortoise species—call this ring-shaped coral island home.

The entire atoll is encircled by coral, with its outer rim divided by three passages: two deep channels that separate the atoll into four major islands, surrounding a large, shallow lagoon fringed with mangroves. This lagoon covers an area of 150 square kilometers and contains several small islets. The largest of the four islands is South Island, which, together with West Island, Middle Island, and Île Polymnie, makes up the atoll’s total land area of 186 square kilometers.

This isolated coral atoll in the Indian Ocean, forgotten by modern civilization, is now a particularly rich nature reserve. It is home to the world’s largest land crab—the coconut crab (Birgus latro). Owing to its isolation, many seabirds favor Aldabra as a breeding site, and it serves as a major nesting ground for both greater and lesser frigatebirds in the western Indian Ocean. The atoll also supports a large population of red-tailed and white-tailed tropical birds.