'Extinct' Giant Tortoises Rediscovered

The survival of 'extinct' giant tortoises from the granitic islands of Seychelles was confirmed by the Nature Protection Trust of Seychelles in 1997. Giant tortoises were common on all islands in the western Indian Ocean until Mauritius was colonised in the 1600s when increasing numbers of explorers and settlers visited the Seychelles islands and removed or killed the tortoises in vast numbers. By 1840 the only surviving giant tortoises in the wild were those on the inhospitable Aldabra atoll some 700 miles away and the unrelated Galapagos giant tortoises in the Pacific. Even on these islands extinction was only narrowly avoided. In the Indian Ocean the Aldabran tortoises were saved by appeals for the conservation of Aldabra by eminent scientists of the time, including Charles Darwin, and the leasing of the island by Lord Walter Rothschild who maintained a passionate interest in the biology and conservation of these animals.

It has generally been assumed that only the Aldabran species survived this over-exploitation. Occasionally, most recently in 1995, it has been suggested that some Seychelles granitic island tortoises survive in captivity. The report of oddly-shaped captive tortoises prompted the Nature Protection Trust of Seychelles to examine the identity of the living tortoises. Examination of museum specimens of the 'extinct' Seychelles species by Dr. Justin Gerlach and Laura Canning confirmed that some living tortoises do show characteristics of the supposedly extinct species. A discussion of the identification of these tortoises and controversies surrounding their origins are discussed on other pages.

These species, thought to have been driven to extinction 120 years ago, are now the subject of a conservation programme being carried out by the Nature Protection Trust of Seychelles.  This includes searches for further living individuals in captive collections around the world.  NPTS is bringing the Seychelles giant tortoises together into a captive breeding programme.   NPTS would be pleased to hear from anyone  who has information on captive giant tortoises or is interested in supporting the efforts to save these critically endangered species. Other pages provide the latest news of the captive breeding programme and profiles of the captive tortoises.  The biology and conservation of Indian Ocean giant tortoises is described in detail in 'Giant Tortoises of the Indian Ocean' by Justin Gerlach.

Living Indian Ocean giant tortoises:

Aldabra giant tortoise - Dipsochelys dussumieri

This species is often known as Geochelone gigantea or Dipsochelys elephantina but should, more correctly, be called Dipsochelys dussumieri.  It is naturally restricted to Aldabra atoll, and possibly the nearby atolls, although it has been introduced to several of the granitic Seychelles islands.  Some 100,000 wild tortoises live on Aldabra.

It is a domed species adapted to grazing on the low grass and herbs of the atoll.

Seychelles giant tortoise - Dipsochelys hololissa

This species inhabited the granitic islands of the Seychelles group where it grazed the vegetation on the edges of marshes and streams.  By 1840 it had disappeared from the wild and was assumed to be extinct.  In 1997 8 captive survivors were recognised in Seychelles.  These are now included in the NPTS Seychelles Giant Tortoise Conservation Project.  Since then other survivors have been found in zoos elsewhere in the world.  Only 12 individuals are known.

As a grazing species, it superficially resembles the Aldabran tortoise in its domed shape but is distinct on close examination.

Arnold's giant tortoise - Dipsochelys arnoldi

Also known as the Seychelles saddle-backed tortoise.  This species also inhabited the granitic Seychelles islands until 1840.  Captive tortoises were recognised in 1997 and are part of the NPTS Seychelles Giant Tortoise Conservation Project. Only 18 individuals are known.

This species is adapted to browsing, it has a flattened 'saddle-backed' shell and unique jaw and leg modifications to enable it to  browse efficiently.  The 'saddle-backed' shape is most developed in some Galapagos tortoises where it is involved in browsing and in ritual combats.  Such combats are not known in Seychelles tortoises and the 'saddle-backed' shell is less extreme.