island

Aldabra

4 species

Aldabra is the world's second-largest coral atoll. It is situated in the Aldabra Group of islands in the Indian Ocean that are part of the Outer Islands of the Seychelles, with a distance of 1,120 km southwest of the capital, Victoria, on Mahé Island.

The atoll has distinctive fauna including the largest population of giant tortoises in the world, Tortoise size varies substantially across the atoll, but adult tortoises typically have a carapace length of about 105 centimetres and can weigh up to 350 kilograms, They are herbivores and feed on a variety of plants, trees and even algae that grows in the freshwater pools. The tortoises mate between February and May, the females then lay their eggs from June to September in areas with suitable soil layers. They lay eggs in a clutch of three to five eggs every few years in high-density areas and 14-16 eggs in low-density areas. The females can lay several clutches in a year and the incubation period is 73–160 days. The small vulnerable juveniles have to survive the predation by coconut crabs, land crabs, rats and birds. In the past giant tortoises have been relocated to many other islands in Seychelles and also to Victoria Botanical Gardens in Mahé. One of the longest-lived Aldabra giant tortoises was Adwaita, a male who died at the age of about 250 years at Kolkata's Alipore Zoological Gardens on March 24, 2006.

Aldabra is a breeding ground for the hawksbill sea turtle and green sea turtle, Aldabra has one of the largest populations of nesting green turtles in the Western Indian Ocean. Aldabra has a large population of the world's largest terrestrial arthropod, the coconut crab and hosts the white-throated rail, the only surviving flightless rail species in the Indian Ocean. Sharks, manta rays, barracuda can be found in the seas surrounding the island. During the Pleistocene the dominant land predator was the crocodilian Aldabrachampsus which is now extinct. Three extant species of lizards occur, the skink Cryptoblepharus boutonii and the geckos Phelsuma abbotti and Hemidactylus mercatorius. Pleistocene fossils also indicate the former presence of an Oplurus iguana and other skink and gecko species. There are three endemic species of bat from Aldabra: Paratriaenops pauliani, Chaerephon pusilla and the Aldabra flying fox, as well as the more widely distributed Mauritian tomb bat, There are 1,000 species of insects, many of them endemic. Many species of butterflies also flutter around Aldabra.

Endemic birds include the Aldabra drongo, the Aldabran subspecies of the white-throated rail, the last surviving flightless bird of the Indian Ocean region, and the endemic Aldabra fody, The islands are important breeding grounds for thousands of seabirds, including several species of tern, red-tailed tropicbirds, white-tailed tropicbirds, red-footed boobies, and the world's second largest breeding populations of great and lesser frigate birds. The bird fauna is most similar to Madagascar or Comoros and other birds found here include greater flamingos, the Malagasy pond heron, Comoros blue pigeon, Malagasy kestrel, Malagasy coucal, Madagascar nightjar, Malagasy bulbul and souimanga sunbird.

At least 13 species of cetaceans, including dolphins, orcas, and especially humpback whales, have been known in the waters. Dugongs, once thought to be regionally extinct in the 18th century, have been confirmed multiple times in very recent years.

Aldabra is the world's second-largest coral atoll. It is situated in the Aldabra Group of islands in the Indian Ocean that are part of the Outer Islands of the Seychelles, with a distance of 1,120 km southwest of the capital, Victoria, on Mahé Island.

The atoll has distinctive fauna including the largest population of giant tortoises in the world, Tortoise size varies substantially across the atoll, but adult tortoises typically have a carapace length of about 105 centimetres and can weigh up to 350 kilograms, They are herbivores and feed on a variety of plants, trees and even algae that grows in the freshwater pools. The tortoises mate between February and May, the females then lay their eggs from June to September in areas with suitable soil layers. They lay eggs in a clutch of three to five eggs every few years in high-density areas and 14-16 eggs in low-density areas. The females can lay several clutches in a year and the incubation period is 73–160 days. The small vulnerable juveniles have to survive the predation by coconut crabs, land crabs, rats and birds. In the past giant tortoises have been relocated to many other islands in Seychelles and also to Victoria Botanical Gardens in Mahé. One of the longest-lived Aldabra giant tortoises was Adwaita, a male who died at the age of about 250 years at Kolkata's Alipore Zoological Gardens on March 24, 2006.

Aldabra is a breeding ground for the hawksbill sea turtle and green sea turtle, Aldabra has one of the largest populations of nesting green turtles in the Western Indian Ocean. Aldabra has a large population of the world's largest terrestrial arthropod, the coconut crab and hosts the white-throated rail, the only surviving flightless rail species in the Indian Ocean. Sharks, manta rays, barracuda can be found in the seas surrounding the island. During the Pleistocene the dominant land predator was the crocodilian Aldabrachampsus which is now extinct. Three extant species of lizards occur, the skink Cryptoblepharus boutonii and the geckos Phelsuma abbotti and Hemidactylus mercatorius. Pleistocene fossils also indicate the former presence of an Oplurus iguana and other skink and gecko species. There are three endemic species of bat from Aldabra: Paratriaenops pauliani, Chaerephon pusilla and the Aldabra flying fox, as well as the more widely distributed Mauritian tomb bat, There are 1,000 species of insects, many of them endemic. Many species of butterflies also flutter around Aldabra.

Endemic birds include the Aldabra drongo, the Aldabran subspecies of the white-throated rail, the last surviving flightless bird of the Indian Ocean region, and the endemic Aldabra fody, The islands are important breeding grounds for thousands of seabirds, including several species of tern, red-tailed tropicbirds, white-tailed tropicbirds, red-footed boobies, and the world's second largest breeding populations of great and lesser frigate birds. The bird fauna is most similar to Madagascar or Comoros and other birds found here include greater flamingos, the Malagasy pond heron, Comoros blue pigeon, Malagasy kestrel, Malagasy coucal, Madagascar nightjar, Malagasy bulbul and souimanga sunbird.

At least 13 species of cetaceans, including dolphins, orcas, and especially humpback whales, have been known in the waters. Dugongs, once thought to be regionally extinct in the 18th century, have been confirmed multiple times in very recent years.