Seychelles giant tortoise
Seychelles giant tortoise | |
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A living specimen | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Order: | Testudines |
Suborder: | Cryptodira |
Superfamily: | Testudinoidea |
Family: | Testudinidae |
Genus: | Aldabrachelys |
Species: | |
Subspecies: | A. g. hololissa
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Trinomial name | |
Aldabrachelys gigantea hololissa (Günther, 1877)
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Synonyms[1] | |
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The Seychelles giant tortoise (Aldabrachelys gigantea hololissa), also known as the Seychelles domed giant tortoise, is a tortoise subspecies in the genus Aldabrachelys.
It inhabited the large central granitic
It was recently[when?] rediscovered. Currently,[when?] a little over a hundred individuals exist.[citation needed] Many had been reestablished in the wild on forested islands such as Silhouette, but were evicted in 2011 by the Seychelles Islands Development Company.[2]
Description
The three Aldabra-Seychelles giant tortoise subspecies can be distinguished based on carapace shape, however, many captive animals may have distorted carapaces and so may be difficult to identify.
The Seychelles giant tortoise (A. g. hololissa) is broad, flattened on the back and with raised scutes; it is usually a brownish-grey color. In comparison, the true Aldabra giant tortoise (A. g. gigantea) is a roundly-domed, black-colored subspecies.[3]
Diet
Like other species of tortoise, the Seychelles giant tortoise is not strictly herbivorous. There have been anecdotal reports of tortoises consuming birds, crabs, and bones. In 2021, a female tortoise on Frégate Island was recorded deliberately hunting, killing, and eating a noddy tern chick.[4]
Lifespan
Giant tortoises are among the longest-lived animals on the planet. Some individual Aldabra giant tortoises are thought to be over 200 years of age, but this is difficult to verify because they tend to outlive their human observers.
Morphotype
This is a controversial subspecies possibly distinct from the Aldabra giant tortoise. The species is a morphologically distinctive
It is a domed grazing subspecies, differing from the Aldabra tortoise in its broader shape and reduced ossification of the skeleton; it differs also from the other controversial giant tortoise in the Seychelles, the saddle-backed morphotype (Arnold's giant tortoise).
It was apparently extirpated from the wild but is now known only from 37 adults, including 28 captive, and 8 on Cousine Island, 6 of which were released in 2011 along with 40 captive-bred juveniles. Captive-reared juveniles show that there is a presumed genetic basis to the morphotype and further genetic work is needed to elucidate this.[8][9][10]
Extinction and rediscovery
Originally, several different subspecies of giant tortoise inhabited the Seychelles. Large and slow, the tortoises were reportedly friendly, with little fear of man. Sailors and settlers slaughtered thousands and swiftly drove most populations to extinction.[citation needed]
Though generally assumed that the Aldabra giant tortoise was the only one to have survived
Conservation
With DNA testing, tortoises of the "extinct" subspecies were identified and acquired by the Nature Protection Trust of Seychelles for conservation. They were brought to Silhouette Island and the captive-breeding program was initiated in 1997. For several years the female tortoises produced infertile eggs. In November 2002 eggs laid by a young female started to hatch.[12] By the time the Nature Protection Trust of Seychelles was evicted, they had produced 40 juveniles of the Seychelles giant tortoise.[8][9][13]
The decision of the Islands Development Company to evict the Nature Protection Trust of Seychelles from Silhouette island by March 2011, and their refusal to permit wild tortoises to live on the island forced them to remove and find new homes for the tortoises.
The privately managed island of Cousine agreed to provide a new home for the Seychelles tortoises.[2] In April 2011, the Seychelles giant tortoises went to Cousine.[2] If they had been able to release them on Silhouette island, they would have established a separate wild population, now they will be mixed with the Aldabra tortoises that are already on Cousine island.[2] The Nature Protection Trust of Seychelles takes consolation from producing a new generation of many young tortoises which will live for at least 100 years. In that time there may be an opportunity to establish pure populations of these tortoises. These animals live longer than short-term management and development perspectives.[10]
References
- ^ Aldabrachelys gigantea at the Reptarium.cz Reptile Database. Accessed 05 June 2015.
- ^ a b c d "Moving giant tortoises". Retrieved 5 June 2015.
- ^ "The identification of Seychelles giant tortoises". Retrieved 5 June 2015.
- PMID 34428417.
- ^ BBC News - South Asia (2006-03-23). "'Clive of India's' tortoise dies". BBC News. BBC Online. Retrieved 2014-01-23.
- ^ Kettle, Sally (13 March 2014). "Meet Jonathan, St Helena's 182-year-old giant tortoise". BBC News. Archived from the original on 2014-04-09.
- ^ "Release of Arnold's giant tortoises Dipsochelys arnoldi on Silhouette island, Seychelles; By Justin Gerlach" (PDF). Retrieved 7 June 2015.
- ^ a b "Tortoises". Retrieved 6 June 2015.
- ^ a b "Tortoise reintroduction". Retrieved 5 June 2015.
- ^ a b "Aldabrachelys hololissa, 061". Retrieved 7 June 2015.
- ^ "Giant tortoises". Retrieved 5 June 2015.
- ^ "Hatchings". Retrieved 7 June 2015.
- ^ "Tortoise news". Retrieved 7 June 2015.