The Floreana giant tortoise (''Chelonoidis niger niger''), also known as the Charles Island giant tortoise, is an extinct

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

of the Galápagos tortoise endemic to the Galápagos archipelago in the

equator The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can als ...

ial eastern Pacific Ocean. The

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''niger'' (‘black’) probably refers to the colouration of the holotype specimen. The species name has often been misspelled as ''nigra'', an error introduced in the 1980s when ''Chelonoidis'' was elevated to genus and mistakenly treated as feminine, an error recognized and fixed in 2017. Although considered extinct as a pure population, hybrids still exist from an introduced population on

Isabella Island The Isabella Island, part of the Big Green Group within the Furneaux Group, is a unpopulated granite island, located in the Bass Strait, west of the Flinders Island and south of Chalky Island, in Tasmania, in south-eastern Australia.Brother ...

, which have been used to breed genetically-similar tortoise hatchlings that will be reintroduced to Floreana.

Taxonomy

This tortoise is a member of ''Chelonoidis niger'', comprising all Galápagos tortoise subspecies, of which it is the nominate form.

Description

Male tortoises grew to about 138 cm and females to 88 cm in length, with strongly saddlebacked

carapace A carapace is a Dorsum (biology), dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tor ...

Behaviour

The tortoises used to descend to the lower slopes of their volcanic island to graze on new vegetation after wet season rains. They fed on grass, bitterbush and

cacti A cactus (, or less commonly, cactus) is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1750 known species of the order Caryophyllales. The word ''cactus'' derives, through Latin, from the Ancient Greek ...

, obtaining water from springs and from cracks in the lava rocks.

Distribution and habitat

The tortoise's natural range was limited to 173 km²

Floreana Island Floreana Island (Spanish: ''Isla Floreana'') is an island of the Galápagos Islands. It was named after Juan José Flores, the first president of Ecuador, during whose administration the government of Ecuador took possession of the archipelago. ...

(formerly Charles Island) where it inhabited deciduous and evergreen forests.

Conservation

The tortoise population of Floreana is estimated to have originally comprised some 8,000 individuals. Extinction occurred during the 1840s or 1850s following overexploitation for food by sailors and settlers, as well as predation and habitat degradation from introduced species, including goats, pigs, dogs, cats,

donkey The domestic donkey is a hoofed mammal in the family Equidae, the same family as the horse. It derives from the African wild ass, ''Equus africanus'', and may be classified either as a subspecies thereof, ''Equus africanus asinus'', or as a ...

s, and rodents. Also blamed for the extinction was a massive wildfire on Floreana in 1820, initially started as a prank by Thomas Chappel, a crewman on the whaling ship '' Essex'' (best known for being sunk by a

sperm whale The sperm whale or cachalot (''Physeter macrocephalus'') is the largest of the toothed whales and the largest toothed predator. It is the only living member of the genus ''Physeter'' and one of three extant species in the sperm whale famil ...

shortly afterwards, inspiring the novel '' Moby-Dick''). By the time Charles Darwin arrived in 1835, decades of exploitation had driven the population to critically low levels, with Darwin recording that about 20 years worth of harvestable tortoises were left. The tortoises finally disappeared around 1850. In 2012, several

hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two dif ...

s between this species and '' Chelonoidis becki'' were discovered around Wolf Volcano on Isabela Island, apparently from some of the Floreana tortoises being transported there in the early 19th century. In 2017, a breeding program began to

resurrect Resurrection or anastasis is the concept of coming back to life after death. In a number of religions, a dying-and-rising god is a deity which dies and is resurrected. Reincarnation is a similar process hypothesized by other religions, which ...

the Floreana subspecies. By 2023, about 400 Floreana tortoise offspring had been produced from the breeding program, and there are plans to

reintroduce Species reintroduction is the deliberate release of a species into the wild, from captivity or other areas where the organism is capable of survival. The goal of species reintroduction is to establish a healthy, genetically diverse, self-sustainin ...

some of these to Floreana in 2024, as part of a rewilding program following the successful removal of invasive species from the island in December 2023.

References

{{Taxonbar, from1=Q486672, from2=Q107481890 niger Subspecies Turtles of South America Endemic reptiles of the Galápagos Islands Reptiles of Ecuador Taxa named by Jean René Constant Quoy Taxa named by Joseph Paul Gaimard Reptiles described in 1824 Extinct turtles Extinct animals of South America Reptile extinctions since 1500