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 |
Trinomial name | |
Aldabrachelys gigantea hololissa (Günther, 1877) | |
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 Seychelles islands, but was hunted in vast numbers by European sailors. By around 1840 it was presumed to be extinct, along with the Arnold's giant tortoise, a subspecies which shared the same islands.
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]
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]
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]
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. Adwaita was reputedly one of four brought by British seamen from the Seychelles Islands as gifts to Robert Clive of the British East India Company in the 18th century, and came to Calcutta Zoo in 1875. At his death in March 2006 at the Kolkata (formerly Calcutta) Zoo in India, Adwaita is reputed to have reached the longest ever measured life span of 255 years (birth year 1750). [5] As of 2024, Jonathan, a 192-year-old, Saint Helena-dwelling Seychelles giant tortoise, is thought to be the oldest living terrestrial animal on Earth since the 2006 death of Harriet; a 176 year old Galapagos giant tortoise who lived at Australia Zoo. Coming in second to Jonathan is Esmeralda, at 180 years old. Esmeralda is an Aldabra giant tortoise living in the Galapagos Islands. [6] There is a report that a tortoise was kept in the garrison by French explorer Chevalier Marc-Joseph Marion du Fresne. The creature lived in the fort for 118 years. It died in 1918 when it became blind and accidentally fell to its death from atop a gun turret.
This is a controversial subspecies possibly distinct from the Aldabra giant tortoise. The species is a morphologically distinctive morphotype, but is considered by many researchers to be either synonymous with or only subspecifically distinct from that taxon. This identification is based primarily on morphological characters. Published molecular identifications are unclear with several different indications provided by different data sources. [7]
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]
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 over-exploitation in the Seychelles, it is occasionally, most recently in 1995, suggested that some Seychelles granitic island tortoises survived 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 subspecies by Dr. Justin Gerlach and Laura Canning confirmed that some living tortoises exhibited characteristics of the supposedly extinct subspecies. [11] Some recently[ when? ] published scientific papers on the genetics of the Seychelles and Indian Ocean tortoises provide conflicting results.[ citation needed ] Some studies suggest only one species (with multiple variants) was ever present in the islands, whilst others suggest three distinct, but closely related species. These different views derive from studies of different genes.[ citation needed ]
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]
Tortoises are reptiles of the family Testudinidae of the order Testudines. Like other turtles, tortoises have a shell to protect from predation and other threats. The shell in tortoises is generally hard, and like other members of the suborder Cryptodira, they retract their necks and heads directly backward into the shell to protect them.
Aldabra, the world's second-largest coral atoll, is located southeast of the continent of Africa. It is part of 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 (700 mi) southwest of the capital, Victoria on Mahé Island. Initially named by Arab seafarers for its harsh environment, Aldabra became a French colony dependency in the 18th century, leading to the exploitation of its natural resources, particularly giant tortoises. After passing through British hands, Aldabra faced potential military use in the 1960s, but international protests resulted in its protection. The atoll boasts unique geography, featuring the world's largest raised coral reef and a large shallow lagoon. Aldabra's history involves human impact, including failed agricultural ventures.
Giant tortoises are any of several species of various large land tortoises, which include a number of extinct species, as well as two extant species with multiple subspecies formerly common on the islands of the western Indian Ocean and on the Galápagos Islands.
The Pinta Island tortoise, also known as the Pinta giant tortoise, Abingdon Island tortoise, or Abingdon Island giant tortoise, is a recently extinct subspecies of Galápagos tortoise native to Ecuador's Pinta Island.
The Aldabra giant tortoise is a species of tortoise in the family Testudinidae and genus Aldabrachelys. The species is endemic to the Seychelles, with the nominate subspecies, A. g. gigantea native to Aldabra atoll. It is one of the largest tortoises in the world. Historically, giant tortoises were found on many of the western Indian Ocean islands, as well as Madagascar, and the fossil record indicates giant tortoises once occurred on every continent and many islands with the exception of Australia and Antarctica.
Adwaita, also spelled Addwaita, was a male Aldabra giant tortoise that lived in the Alipore Zoological Gardens of Kolkata, India. At the time of his death in 2006, Adwaita was believed to be amongst the longest-living animals in the world.
Cousine Island is a small granitic island 30 ha in the Seychelles 6 km (4 mi) west of Praslin Island. It is a combination luxury resort and since 1992 a nature preserve.
Aldabrachelys is genus of giant tortoises, including the Aldabra giant tortoise native to the Seychelles, as well as two extinct species, Aldabrachelys abrupta and Aldabrachelys grandidieri known from Madagascar. The genus name derives from Aldabra, a coral atoll in the Seychelles, plus chelys, from the Greek, χέλυς, for "tortoise" or "lyre", since Hermes was the first to invent the lyre from a hollowed out tortoise shell.
The Galápagos tortoise or Galápagos giant tortoise is a very large species of tortoise in the genus Chelonoidis. The species comprises 15 subspecies. It is the largest living species of tortoise, and can weigh up to 417 kg (919 lb). They are also the largest extant terrestrial cold-blooded animals (ectotherms).
The Reunion giant tortoise is an extinct species of giant tortoise in the family Testudinidae. It was endemic to Réunion Island in the Indian Ocean.
Cylindraspis is a genus of recently extinct giant tortoises. All of its species lived in the Mascarene Islands in the Indian Ocean and all are now extinct due to hunting and introduction of non-native predators.
The saddle-backed Rodrigues giant tortoise is an extinct species of giant tortoise in the family Testudinidae. The species was endemic to Rodrigues. Human exploitation caused the extinction of this species around 1800.
The Granitic Seychelles are the islands in Seychelles which lie in central position on the Seychelles Bank and are composed of granite rock. They make up the majority of the Inner Islands, which in addition include the coral islands along of the rim of the Seychelles Bank, namely Bird Island and Denis Island. The Granitic Seychelles contrast with the Coralline Seychelles or the Outer Islands, several island groups made up of low coral islands with dry, infertile soils.
The wildlife of Seychelles comprises the flora and fauna of the Seychelles islands off the eastern coast of Africa in the western Indian Ocean.
Aldabrachampsus is an extinct genus of small horned crocodile known from fragmentary remains. It lived during the Pleistocene on Aldabra Atoll, Seychelles in the western Indian Ocean. The name Aldabrachampsus dilophus means "Two-crested crocodile from Aldabra". It was a small animal, reaching a length of 2–2.5 m, comparable in size to the smallest extant crocodilians.
Jonathan is a Seychelles giant tortoise, a subspecies of the Aldabra giant tortoise. His approximate age is estimated to be 191 as of 2024, making him the oldest known living land animal. Jonathan resides on the island of Saint Helena, a British Overseas Territory in the South Atlantic Ocean.
Aldabrachelys grandidieri, or Grandidier's giant tortoise, is an extinct species of tortoise that was endemic to Madagascar. Mitochondrial DNA extracted from subfossil bone confirm that it is a distinct species.
Arnold's giant tortoise, also known as the Seychelles saddle-backed giant tortoise, is a tortoise subspecies in the genus Aldabrachelys.
Giant tortoises are any of various large land tortoises
Chelonoidis niger chathamensis, commonly known as the Chatham Island giant tortoise or the San Cristóbal giant tortoise, is a subspecies of Galápagos tortoise endemic to San Cristóbal Island in the Galápagos.