''Chelonoidis niger duncanensis'', commonly known as the Pinzón Island giant tortoise, is a

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 ...

Galápagos tortoise The Galápagos tortoise or Galápagos giant tortoise (''Chelonoidis niger'') is a species of very large tortoise in the genus ''Chelonoidis'' (which also contains three smaller species from mainland South America). It comprises 15 subspecies (13 ...

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Pinzón Island Pinzón Island (Spanish: ''Isla Pinzón''), sometimes called Duncan Island (after Adam Duncan, 1st Viscount Duncan), is an island in the Galápagos Islands, Ecuador. Pinzón is home to giant Galápagos tortoises of the endemic subspecies '' Chel ...

in the Galápagos.

Population history

Although relatively undisturbed by whalers, fairly large numbers of tortoises were removed by expeditions in the latter half of the 19th century and the early 20th. After the introduction of

black rat The black rat (''Rattus rattus''), also known as the roof rat, ship rat, or house rat, is a common long-tailed rodent of the stereotypical rat genus ''Rattus'', in the subfamily Murinae. It likely originated in the Indian subcontinent, but is n ...

s (''Rattus rattus'') and brown rats (''Rattus norvegicus'')Rat eradication program begins in Galapagos Islands
''Scientific American''. (Accessed 2012-01-14.) some time before 1900, no natural breeding succeeded. Since 1965, eggs have been transported to the Charles Darwin Research Station for hatching and rearing. Over 75% of those released between 1970 and 1990 survived.Cayot 1994. ''Conservation biology of Galápagos reptiles: twenty-five years of successful research and management.'' In: J. B. Murphy, K. Adler, and J. T. Collins (eds.). Captive Management and Conservation of Amphibians and Reptiles, pp. 297–305. Ithaca, New York: Society for the Study of Amphibians and Reptiles. Contributions to Herpetology. vol. 11. . There are currently around known individuals, which live in the southwestern side of

Description

This saddle-backed species is one of the smallest of the Galápagos tortoises. Its brownish-gray, oblong carapace has only a very shallow cervical indentation, the anterior marginals little to much upturned, and the slightly serrated posterior marginals flared and upturned. The carapace is usually compressed or narrowed anteriorly.

References

* Pritchard, 1996 : ''The Galápagos Tortoises: Nomenclatural and Survival Status.'' Chelonian Research Monographs, , . Chelonoidis Subspecies Taxa named by Samuel Garman Endemic reptiles of the Galápagos Islands Reptiles described in 1917 {{turtle-stub