Aldabra tortoise only occurs naturally on the Atoll of Aldabra a part of the Seychelles Islands group situated
426 kilometres (265miles)northwest of Madagascar. It really should be called the ‘Seychelles’ tortoise as it once occurred on 31 out of the 110 Islands that make up the Seychelles, these other populations were wiped out by man and the domestic animals he usually brings with him, rats, cats, pigs and goats. These introduced invasive alien species are the biggest killer of island endemic species. Aldabra atoll is the second largest coral Atoll in the world, around 151sq kilometres (58sq miles) in size, it is made up of four separate islands which surround a large lagoon, which empties out though narrow channels twice a day.
The Atoll has been totally submerged or partially submerged several times in the last few million years, and may have been much bigger or smaller in the past. The Tortoises there probably arrived from Madagascar each time the atoll re-emerged from the sea. Aldabras have the ability to float in sea water and are able to go a long time with out food or water. Sea levels were lower in the past and they may have used other islands as stepping stones to Aldabra and islands further north. Recent DNA work has also shown that one of the extinct giant tortoises from Madagascar. Dipsochelys abrupta was also likely the same species as the Aldabra tortoise.
There is still debate about the correct scientific name for the Aldabra tortoise; It has been known commonly as Gechelone gigantean by most people, but has been known as Testudo gigantea; Aldabachelys gigantea; Testudo dussumieri Dipsochelys elephantine.
Two other species of Seychelles giant tortoise were also described recently, thought to be survivors from the past, but this has not been widely accepted and the differences in the animals is thought to be due to being kept for a long time in captivity.
The population of tortoise on Aldabra has fluctuated a great deal in the last century. In the early part of the 20thcentury the numbers were down to a few thousand tortoises. After protection, they numbers rose to 150.000 in the 1970s. That has since gone done to around80.000 tortoises today. This is due to various factors, including interference by man, along with lack of rainfall, food supply and enough shade. There are now also several other introduced populations living on some on the other islands in the Seychelles. The Aldabra tortoise seems to have no immediate threats to its survival at the moment.
Aldabras in Captivity.
Before you think of buying an Aldabra tortoise, you should be aware that they can grow to a very large size and weigh up to 400kilos, (900lbs) they are also very long lived animals, passing 100 year life span if properly looked after. And can eat a great amount of food.
If you do not have the time and space to house a very large tortoise perhaps they are not the pet for you. Please research Aldabra tortoises before purchasing one, there are several good book available on the captive keeping of Aldabras and plenty of information on the Internet. Or contact other Aldabra keepers before you decide.
If you do decide you do want to keep an Aldabra, you will find them a rewarding pet, they can become very personable and soon come to recognise their keepers. They are very hardy animals; they do best in large outdoor enclosures with access to direct sunshine for at least a part of the year. In temperate climates they will need to keep inside in a heated barn or greenhouse during the cold winter months, but may be let out on sunny days when temperatures are over15ºc.(59ºf) Ideal climates include anywhere in the tropics, southern states oft he USA, tropical and southern Africa, Asia, Australia, and South America. They are also very sociable animals and do better if kept in groups.
La Tortue géante des Seychellesune survivante (Giant tortoise of the Seychelles, a survivor by Bernard Devaux)
(text in French and English) Cheonii Volume5
Giant Tortoises of the Indian Oceanby J.Gerlach (Chimaira)
Aldabra Tortoise experts guide by Richard Cary Paull (Green Nature Books)