Seychelles giant tortoises

I identified survivors of the 'extinct' giant tortoises of the Seychelles islands 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 me to examine the identity of the living tortoises. Examination of museum specimens of the 'extinct' Seychelles species confirmed that some living tortoises do show characteristics of the supposedly extinct species. This proved highly controvertial and there are conflicting interpretations of the morphology and genetic data, this is duscussed on other pages. Current they are regarded as subspecies of the Aldabra giant tortoise (Aldabrachelys gigantea hololissa and A. g. arnoldi).

These species, thought to have been driven to extinction 120 years ago, were the subject of a highly successful conservation programme by Nature Protection Trust of Seychelles.

Other pages provide more information on the captive breeding programme and reintroductions.

Restoring wild tortoise popualtions on the islands has led to the appearance of new behaviours, including the remarkable observation of a tortoise hunting and eating a bird. The biology and conservation of Indian Ocean giant tortoises is described in detail in 'Giant Tortoises of the Indian Ocean' by Justin Gerlach.

Sir David Attenborough was the patron of this conservation project

Sir David Attenborough with Justin Gerlach

Seychelles biodiversity

Phelsuma journal


Justin Gerlach by e-mail