Extinct in the wild

[1][2] Classification requires exhaustive surveys conducted within the species' known habitat with consideration given to seasonality, time of day, and life cycle.

Reintroduction efforts, also referred to as translocation, are complex and a common source of complication is how animals behave upon release.

[34] Though many efforts translocate populations to historic ranges, climate change may be causing those previously inhabited areas to no longer be suitable for the species.

[35] Of the 2500 living, about 1360 are in the wild, and all 2500 are descended from 12 wild-caught ancestors, causing an inbreeding depression that contributes to factors, such as shorter lifespans and high mortality, that impede conservation.

[39] The IUCN developed a system of classifying species recovery efforts in 2012 entitled the Green Status.

The long-term measure is Recovery Potential, which is how much of the range is estimated to be able to house ecologically functional populations.

[41] The Pinta Island tortoise (Geochelone nigra abingdoni) had only one living individual, named Lonesome George, until his death in June 2012.

[42] The tortoise was believed to be extinct in the mid-20th century, until Hungarian malacologist József Vágvölgyi spotted Lonesome George on the Galapagos island of Pinta on 1 December 1971.

[44] With the discovery of 17 hybrid Pinta tortoises located at nearby Wolf Volcano, a plan has been made to attempt to breed the subspecies back into a pure state.